Dissertations / Theses on the topic 'Solar thermal HVAC technologies'

The present thesis investigates innovative energy technologies and control algorithms for enhancing demand-side management in buildings. The work focuses on an innovative low-temperature solar thermal system for supplying space heating demand of buildings. This technology is used as a case study to explore possible solutions to fulfil the mismatch between energy production and its exploitation in building. This shortcoming represents the primary issue of renewable energy sources. Technologies enhancing the energy storage capacity and active demand-side management or demand-response strategies must be implemented in buildings. For these purposes, it is possible to employ hardware or software solutions. The hardware solutions for thermal demand response of buildings are those technologies that allow the energy loads to be permanently shifted or mitigated. The software solutions for demand response are those that integrate an intelligent supervisory layer in the building automation (or management) systems. The present thesis approaches the problem from both the hardware technologies side and the software solutions side. This approach enables the mutual relationships and interactions between the strategies to be appropriately measured. The thesis can be roughly divided in two parts. The first part of the thesis focuses on an innovative solar thermal system exploiting a novel heat transfer fluid and storage media based on micro-encapsulated Phase Change Material slurry. This material leads the system to enhance latent heat exchange processes and increasing the overall performance. The features of Phase Change Material slurry are investigated experimentally and theoretically. A full-scale prototype of this innovative solar system enhancing latent heat exchange is conceived, designed and realised. An experimental campaign on the prototype is used to calibrate and validate a numerical model of the solar thermal system. This model is developed in this thesis to define the thermo-energetic behaviour of the technology. It consists of two mathematical sub-models able to describe the power/energy balances of the flat-plate solar thermal collector and the thermal energy storage unit respectively. In closed-loop configuration, all the Key Performance Indicators used to assess the reliability of the model indicate an excellent comparison between the system monitored outputs and simulation results. Simulation are performed both varying parametrically the boundary condition and investigating the long-term system performance in different climatic locations. Compared to a traditional water-based system used as a reference baseline, the simulation results show that the innovative system could improve the production of useful heat up to 7 % throughout the year and 19 % during the heating season. Once the hardware technology has been defined, the implementation of an innovative control method is necessary to enhance the operational efficiency of the system. This is the primary focus of the second part of the thesis. A specific solution is considered particularly promising for this purpose: the adoption of Model Predictive Control (MPC) formulations for improving the system thermal and energy management. Firstly, this thesis provides a robust and complete framework of the steps required to define an MPC problem for building processes regulation correctly. This goal is reached employing an extended review of the scientific literature and practical application concerning MPC application for building management. Secondly, an MPC algorithm is formulated to regulate the full-scale solar thermal prototype. A testbed virtual environment is developed to perform closed-loop simulations. The existing rule-based control logic is employed as the reference baseline. Compared to the baseline, the MPC algorithm produces energy savings up to 19.2 % with lower unmet energy demand.

Advances in Information and Communication Technology (ICT) paved the way for decentralized Heating, Ventilation, and Air-Conditioning (HVAC) HVAC operations. It has been envisioned that development of personal thermal comfort profiles leads to accurate predictions of each occupant's thermal comfort state and such information is employed in context-aware HVAC operations for energy efficiency. This dissertation has three key contributions in realizing this envisioned HVAC operation. First, it presents a systematic review of research trends and developments in context-aware HVAC operations. Second, it contributes to expanding the feasibility of the envisioned HVAC operation by introducing novel sensing technologies. Third, it contributes to shedding light on viability and potentials of comfort-aware operations (i.e., integrating personal thermal comfort models into HVAC control logic) through a comprehensive assessment of energy efficiency implications. In the first contribution, by developing a taxonomy, two major modalities – occupancy-driven and comfort-aware operations – in Human-In-The-Loop (HITL) HVAC operations were identified and reviewed quantitatively and qualitatively. The synthesis of previous studies has indicated that field evaluations of occupancy-driven operations showed lower potentials in energy saving, compared to the ones with comfort-aware operations. However, the results in comfort-aware operations could be biased given the small number of explorations. Moreover, required data representation schema have been presented to foster constructive performance assessments across different research efforts. In the end, the current state of research and future directions of HITL HVAC operations were discussed to shed light on future research need. As the second contribution, moving toward expanding the feasibility of comfort-aware operations, novel and smart sensing solutions have been introduced. It has been noted that, in order to have high accuracy in predicting individual's thermal comfort state (≥90%), user physiological response data play a key part. However, the limited number of applicable sensing technologies (e.g., infrared cameras) has impeded the potentials of implementation. After defining required characteristics in physiological sensing solutions in context of comfort-aware operations (applicability, sensitivity, ubiquity, and non-intrusiveness), the potentials of RGB cameras, Doppler radar sensors, and heat flux sensors were evaluated. RGB cameras, available in many smart computing devices, could be a ubiquitous solution in quantifying thermoregulation states. Leveraging the mechanism of skin blood perfusion, two thermoregulation state quantification methods have been developed. Then, applicability and sensitivity were checked with two experimental studies. In the first experimental study aiming to see applicability (distinguishing between 20 and 30C with fully acclimated human bodies), for 16 out of 18 human subjects, an increase in their blood perfusion was observed. In the second experimental study aiming to evaluate sensitivity (distinguishing responses to a continuous variation of air temperature from 20 to 30C), 10 out of 15 subjects showed a positive correlation between blood perfusion and thermal sensations. Also, the superiority of heat flux data, compared to skin temperature data, has been demonstrated in predicting personal thermal comfort states through the developments of machine-learning-based prediction models with feature engineering. Specifically, with random forest classifier, the median value of prediction accuracy was improved by 3.8%. Lastly, Doppler radar sensors were evaluated for their capability of quantifying user thermoregulation states leveraging the periodic movement of the chest/abdomen area induced by respiration. In an experimental study, the results showed that, with sufficient acclimation time, the DRS-based approach could show distinction between respiration states for two distinct air temperatures (20 and 30C). On the other hand, in a transient temperature without acclimation time, it was shown that, some of the human subjects (38.9%) used respiration as an active means of heat exchange for thermoregulation. Lastly, a comprehensive evaluation of comfort-aware operations' performance was carried out with a diverse set of contextual and operational factors. First, a novel comfort-aware operation strategy was introduced to leverage personal sensitivity to thermal comfort (i.e., different responses to temperature changes; e.g., sensitive to being cold) in optimization. By developing an agent-based simulation framework and thorough diverse scenarios with different numbers and combinations of occupants (i.e., human agents in the simulation), it was shown that this approach is superior in generating collectively satisfying environments against other approaches focusing on individual preferred temperatures in selection of optimized setpoints. The energy implications of comfort-aware operations were also evaluated to understand the impact from a wide range of factors (e.g., human and building factors) and their combinatorial effect given the uncertainty of multioccupancy scenarios. The results demonstrated that characteristics of occupants' thermal comfort profiles are dominant in impacting the energy use patterns, followed by the number of occupants, and the operational strategies. In addition, when it comes to energy efficiency, more occupants in a thermal zone/building result in reducing the efficacy of comfort-driven operation (i.e., the integration of personal thermal comfort profiles). Hence, this study provided a better understanding of true viability of comfort-driven HVAC operations and provided the probabilistic bounds of energy saving potentials. These series of studies have been presented as seven journal articles and they are included in this dissertation.
Doctor of Philosophy
With vision of a smart built environment, capable of understanding the contextual dynamics of built environment and adaptively adjusting its operation, this dissertation contributes to context-aware/decentralized HVAC operations. Three key contributions in realization of this goal include: (1) a systematic review of research trends and developments in the last decade, (2) enhancing the feasibility of quantifying personal thermal comfort by presenting novel sensing solutions, and (3) a comprehensive assessment of energy efficiency implications from comfort-aware HVAC operations with the use of personal comfort models. Starting from identifying two major modalities of context-aware HVAC operations, occupancy-driven and comfort-aware, the first part of this dissertation presents a quantitative and qualitative review and synthesis of the developments, trends, and remaining research questions in each modality. Field evaluation studies using occupancy-driven operations have shown median energy savings between 6% and 15% depending on the control approach. On the other hand, the comfort-aware HVAC operations have shown 20% energy savings, which were mainly derived from small-scale test beds in similar climate regions. From a qualitative technology development standpoint, the maturity of occupancy-driven technologies for field deployment could be interpreted to be higher than comfort-aware technologies while the latter has shown higher potentials. Moreover, by learning from the need for comparing different methods of operations, required data schemas have been proposed to foster better benchmarking and effective performance assessment across studies. The second part of this dissertation contributes to the cornerstone of comfort-aware operations by introducing novel physiological sensing solutions. Previous studies demonstrated that, in predicting individual's thermal comfort states, using physiological data in model development plays a key role in increasing accuracy (>90%). However, available sensing technologies in this context have been limited. Hence, after identifying essential characteristics for sensing solutions (applicability, sensitivity, ubiquity, and non-intrusiveness), the potentials of RGB cameras, heat flux sensors, and Doppler radar sensors were evaluated. RGB cameras, available in many smart devices, could be programmed to measure the level of blood flow to skin, regulated by the human thermoregulation mechanism. Accordingly, two thermoregulation states' quantification methods by using RGB video images have been developed and assessed under two experimental studies: (i) capturing subjects' facial videos in two opposite temperatures with sufficient acclimation time (20 and 30C), and (ii) capturing facial videos when subjects changed their thermal sensations in a continuous variation of air temperature from 20 to 30C. Promising results were observed in both situations. The first study had subjects and 16 of them showed an increasing trend in blood flow to skin. In the second study, posing more challenges due to insufficient acclimation time, 10 subjects had a positive correlation between the level of blood flow to skin with thermal sensation. With the assumption that heat flux sensing will be a better reflection of thermoregulation sates, a machine learning framework was developed and tested. The use of heat flux sensing showed an accuracy of 97% with an almost 4% improvement compared to skin temperature. Lastly, Doppler radar sensors were evaluated for their capability of quantifying thermoregulation states by detecting changes in breathing patterns. In an experimental study, the results showed that, with sufficient acclimation time, the DRS-based approach could show distinction between respiration states for two distinct air temperatures (20 and 30C). However, using a transient temperature was proven to be more challenging. It was noted that for some of the human subjects (38.9%), respiration was detected as an active means of heat exchange. It was concluded that specialized artifact removal algorithms might help improve the detection rate. The third component of the dissertation contributed by studying the performance of comfort-driven operations (i.e., using personal comfort preferences for HVAC operations) under a diverse set of contextual and operational factors. Diverse scenarios for interaction between occupants and building systems were evaluated by using different numbers and combinations of occupants, and it was demonstrated that an approach of addressing individual's thermal comfort sensitivity (personal thermal-comfort-related responses to temperature changes) outperforms other approaches solely focusing on individual preferred temperatures. The energy efficiency implications of comfort-driven operations were then evaluated by accounting for the impact of human and building factors (e.g., number of thermal zones) and their combinations. The results showed that characteristics of occupants' thermal comfort profiles are dominant in driving the energy use patterns, followed by the number of occupants, and operational strategies. As one of the main outcomes of this study, the energy saving and efficiency (energy use for comfort improvement) potentials and probabilistic bounds of comfort-driven operations were identified. It was shown that keeping the number of occupants low (under 6) in a thermal zone/building, boosts the energy saving potentials of comfort-driven operations. These series of studies have been presented as seven journal articles, included in this dissertation.

During the last 10 years solar cooling systems attracted more and more interest not only in the research area but also on a private and commercial level. Several demonstration plants have been installed in different European countries and first companies started to commercialise also small scale absorption cooling machines. However, not all of the installed systems operate efficiently and some are, from the primary energy point of view, even worse than conventional systems with a compression chiller. The main reason for this is a poor system design combined with suboptimal control. Often several non optimised components, each separately controlled, are put together to form a ‘cooling system’. To overcome these drawbacks several attempts are made within IEA task 38 (International Energy Agency Solar Heating and Cooling Programme) to improve the system design through optimised design guidelines which are supported by simulation based design tools. Furthermore, guidelines for an optimised control of different systems are developed. In parallel several companies like the SolarNext AG in Rimsting, Germany started the development of solar cooling kits with optimised components and optimised system controllers. To support this process the following contributions are made within the present work: - For the design and dimensioning of solar driven absorption cooling systems a detailed and structured simulation based analysis highlights the main influencing factors on the required solar system size to reach a defined solar fraction on the overall heating energy demand of the chiller. These results offer useful guidelines for an energy and cost efficient system design. - Detailed system simulations of an installed solar cooling system focus on the influence of the system configuration, control strategy and system component control on the overall primary energy efficiency. From the results found a detailed set of clear recommendations for highly energy efficient system configurations and control of solar driven absorption cooling systems is provided. - For optimised control of open desiccant evaporative cooling systems (DEC) an innovative model based system controller is developed and presented. This controller consists of an electricity optimised sequence controller which is assisted by a primary energy optimisation tool. The optimisation tool is based on simplified simulation models and is intended to be operated as an online tool which evaluates continuously the optimum operation mode of the DEC system to ensure high primary energy efficiency of the system. Tests of the controller in the simulation environment showed that compared to a system with energy optimised standard control the innovative model based system controller can further improve the primary energy efficiency by 19 %.

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2009.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 144-150).
To build an electric car plus renewable energy system for Singapore, solar thermal technologies were investigated in this report in the hope to find a suitable "green" energy source for this small island country. Among all existing solar thermal technologies, parabolic trough power plants represent a well established technology with more than twenty years of operation experiences. This report reviewed recent progress of research in this field. It was found that significant progresses have been made in solar collector, heat transfer fluid and thermal storage. An economic assessment of the parabolic trough power plant technology was also carried out. By comparing a parabolic trough power plant and a concentrating photovoltaic solar farm, both advantages and limitations of these plants were indentified. Based on these findings, the niche market for parabolic trough power plants was analyzed. It was found that in the next few years, the deployment of parabolic trough plants would mainly occur in south-western U.S. and Mediterranean countries. However, it was found that concentrating solar thermal technologies were not suitable for Singapore, due to this country's limited land and high fraction of diffuse solar radiation. Therefore, PV technology was selected as a "clean" energy source. Based on PV electricity, a few electric vehicle (XEV) models were developed and evaluated.
by Xiaogang Liu.
M.Eng.

This thesis deals with the potential contribution that state-of-the-art solar thermal (ST) systems enhanced by thermal energy storage (TES) technologies might have in reducing the energy use in Welsh dwellings. The focus of this work lies with the share of the overall amount of conventional energy currently consumed for thermal comfort and hot water preparation that could be replaced by solar energy harvested by active, water-based, solar systems. Twelve typical Welsh dwellings drawn from a recent survey and considered as representative of the Welsh housing stock are modelled and the solar collectors' yield for different orientations and tilts is predicted. The subject is investigated with computer simulations using the TRNSYS simulation engine. The methodology dictates at first prediction and analysis of the thermal energy demand profiles of 12x4 case studies using average (smoothed) and actual (warmer) weather conditions, continuous and intermittent comfort maintenance. Next the ST potential is estimated considering solely a maximum (0.7) and an average (0.4) overall system efficiency and no other technical part for the ST system (modelling approach), in order to investigate the mismatch of energy demand and availability and the TES contribution. The performance characteristics of some representative European ST systems (short-term TES only), as derived from the IEA SHC Task 26 FSC method, are then applied to the simulations to reveal the potential with realistic losses and parasitic energy consumption included (applied only to 5 compatible models). It is revealed that all these house types are possible candidates for effective ST applications, assuming that economies of scale would allow for large absorber areas in the near future. The modelling approach shows that ST systems could contribute to thermal savings between 9%-34% solely with direct utilisation of the collected energy. Furthermore, for most cases, if reasonable sized stores would be used (up to 300kWh TES capacity) then the solar contribution to the overall thermal energy consumption, in the most favourable conditions, would be around 42-58%. Only a couple of models appear to have a lower potential, mainly due to lack of sufficient absorber areas. However for reaching the highest end of expectations for certain house types---up to 54% with average and up to 100% with warmer weather conditions---inter-seasonal storage would be required. In this case, the justifiable storage capacities predicted correspond to very large store volumes, revealing that these are currently not feasible options, as sensible heat storage is still the state-of-the-art for TES. Use of innovative storage types identified by the literature survey, that would only be available in the future, are required in order to achieve high solar contributions, considering space limitations in Welsh dwellings. The FSC results show that for the 5 models the use of solar energy would bring thermal energy savings of around 41-47% if the best system is employed compared to a conventional system, while if parasitic (electric) energy consumption is considered the expected energy savings could be as low as 10%. The actual ST potential is analysed and is found to be in between the two approaches, as both methods have advantages and limitations and complement each other.

Buildings contribute a significant part to the electricity demand profile and peak demand for the electrical utilities. The addition of renewable energy generation adds additional variability and uncertainty to the power system. Demand side management in the buildings can help improve the demand profile for the utilities by shifting some of the demand from peak to off-peak times. Heating, ventilation and air-conditioning contribute around 45% to the overall demand of a building. This research studies two strategies for reducing the peak as well as shifting some demand from peak to off-peak periods in commercial buildings: 1. Use of gas heat pumps in place of electric heat pumps, and 2. Shifting demand for air conditioning from peak to off-peak by thermal energy storage in chilled water and ice. The first part of this study evaluates the field performance of gas engine-driven heat pumps (GEHP) tested in a commercial building in Florida. Four GEHP units of 8 Tons of Refrigeration (TR) capacity each providing air-conditioning to seven thermal zones in a commercial building, were instrumented for measuring their performance. The operation of these GEHPs was recorded for ten months, analyzed and compared with prior results reported in the literature. The instantaneous COPunit of these systems varied from 0.1 to 1.4 during typical summer week operation. The COP was low because the gas engines for the heat pumps were being used for loads that were much lower than design capacity which resulted in much lower efficiencies than expected. The performance of equivalent electric heat pump was simulated from a building energy model developed to mimic the measured building loads. An economic comparison of GEHPs and conventional electrical heat pumps was done based on the measured and simulated results. The average performance of the GEHP units was estimated to lie between those of EER-9.2 and EER-11.8 systems. The performance of GEHP systems suffers due to lower efficiency at part load operation. The study highlighted the need for optimum system sizing for GEHP/HVAC systems to meet the building load to obtain better performance in buildings. The second part of this study focusses on using chilled water or ice as thermal energy storage for shifting the air conditioning load from peak to off-peak in a commercial building. Thermal energy storage can play a very important role in providing demand-side management for diversifying the utility demand from buildings. Model of a large commercial office building is developed with thermal storage for cooling for peak power shifting. Three variations of the model were developed and analyzed for their performance with 1) ice storage, 2) chilled water storage with mixed storage tank and 3) chilled water storage with stratified tank, using EnergyPlus 8.5 software developed by the US Department of Energy. Operation strategy with tactical control to incorporate peak power schedule was developed using energy management system (EMS). The modeled HVAC system was optimized for minimum cost with the optimal storage capacity and chiller size using JEPlus. Based on the simulation, an optimal storage capacity of 40-45 GJ was estimated for the large office building model along with 40% smaller chiller capacity resulting in higher chiller part-load performance. Additionally, the auxiliary system like pump and condenser were also optimized to smaller capacities and thus resulting in less power demand during operation. The overall annual saving potential was found in the range of 7-10% for cooling electricity use resulting in 10-17% reduction in costs to the consumer. A possible annual peak shifting of 25-78% was found from the simulation results after comparing with the reference models. Adopting TES in commercial buildings and achieving 25% peak shifting could result in a reduction in peak summer demand of 1398 MW in Tampa.

Traditionally, energy capture by non-concentrating solar collectors is calculated using the Hottel-Whillier Equation (HW): Q(u)=A(c)*F(r)*S-A(c)*F(r)*U(l)*(T(fi)-Tₐ), or its derivative: Q(u)=A(c)*F(r)*S-A(c)*F(r)*U(l)*((T(fi)-T(fo))/2-Tₐ). In these models, the rate of energy capture is based on the collector's aperture area (A(c)), collector heat removal factor (F(r)), absorbed solar radiation (S), collector overall heat loss coefficient (U(l)), inlet fluid temperature (T(fi)) and ambient air temperature (Tₐ). However real-world testing showed that these equations could potentially show significant errors during non-ideal solar and environmental conditions. It also predicts that when T(fi)-Tₐ equals zero, the energy lost convectively is zero. An improved model was tested: Q(u)=A(c)F(r)S-A(c)U(l)((T(fo)-T(fi))/(ln(T(fo)/T(fi)))-Tₐ) where T(fo) is the exit fluid temperature. Individual variables and coefficients were analyzed for all versions of the equation using linear analysis methods, statistical stepwise linear regression, F-Test, and Variance analysis, to determine their importance in the equation, as well as identify alternate methods of calculated collector coefficient modeling.

Thesis (MEng)--Stellenbosch University, 2013.
ENGLISH ABSTRACT: Solar Assisted Power Generation (SAPG) can be seen as a synergy of solar and fossil plants – combining the environmental benefits of the former and the scale, efficiency and reliability of the latter. SAPG offers great potential for cost effective utilization of solar energy on utility scale and could accelerate the adoption of solar thermal energy technologies in the short and medium term, especially in countries with a significant coal base and a good solar resource such as Australia, China, United States, India and South Africa. SAPG is the replacement of bled-off steam in a Regenerative Rankine power cycle. Power plant simulations were performed using weather data for Lephalale, South Africa (Matimba power station). With an increase in the solar field outlet temperature, an increase in overall solar to electric efficiency was observed, superior to a stand-alone Solar Thermal Power Plant(s) (STPP) at similar temperatures. The performance of four solar collector technologies was compared: flat plate, evacuated tube, Linear Fresnel (LF) and Parabolic Trough (PT). This comparison was limited to the normal incidence angles of irradiation. For this application, nonconcentrating technologies are not competitive. For non-normal incidence angles, annual simulations were limited to PT and LF at final feedwater heater temperatures. The actual aperture area of around 80 000 m2 was used (50 MW thermal based on LF). On an equal aperture area basis, PT outperforms LF significantly. For the conventional North-South arrangement, LF needs to be around 53% of the specific installation cost (in $/m2 aperture area) of PT to be cost competitive. A SAPG plant at Lephalale was compared to a stand-alone Solar Thermal Power Plant STPP in a good solar resource area, namely Upington, South Africa – Parabolic Trough solar collector fields of equal size were considered for both configurations. It was found that the annual electricity generated with a SAPG plant is more than 25% greater than a stand-alone STPP. If the cost of SAPG is taken as 72% of the cost of a stand-alone STPP, this translates into SAPG being 1.8 times more cost effective than stand-alone STPP. Furthermore, SAPG performs better in high electricity demand months (South African winter – May to August). Stand-alone STPP have been adopted in South Africa and are currently being built. This was achieved by the government creating an attractive environment for Independent Power Producers (IPP). Eskom, the national power supplier, is currently investigating solar boosting at existing Eskom sites. This report argues that on a national level, SAPG, specifically solar preheating of feedwater, is a more viable solution for South Africa, with both its significant coal base and good solar resource.
AFRIKAANSE OPSOMMING: Son ondersteunde krag generasie (SOKG) kan gesien word as sinergie van sonkrag en fossiele brandstof aanlegte – dit voeg die omgewings voordele van die eersgenoemde en die grote, effektiwiteit en betroubaarheid van die laasgenoemde by mekaar. SOKG opper groot potensiaal vir koste effektiewe gebruik van son energie op nutsmaatskappyskaal en kan die aanvaarding van sontermiese energietegnologieë in die kort en medium termyn versnel, veral in lande met beduidende kool reserwes en goeie sonkrag voorkoms soos Australië, China, Verenigde State van Amerika, Indië en Suid-Afrika. SOKG impliseer die vervanging van aftap stoom in die regeneratiewe Rankine krag kringloop. Kragstasie simulasies was gedoen met die gebruik van weer data van Lephalale, Suid-Afrika (Matimba kragstasie). Met die toename van die sonveld uitlaat temperatuur kon oorhoofse son-na-elektrisiteit effektiwiteit vasgestel word, wat hoër is as die van alleenstaande sontermiese krag stasie (STKS) by soortgelyke temperature. Die effektiwiteit van vier son kollekteerder tegnologieë was vergelyk: plat plaat, vakuum buis, lineêre Fresnel (LF) en paraboliese trog (PT). Die vergelyking was beperk tot normale inval van bestraling. Vir hierdie toepassing is nie-konsentreerende tegnologie nie mededingend nie. Vir nie-normale inval hoeke was jaarlange simulasies beperk tot PT en LF by finale voedingswater temperatuur. Die werklike opening area van omtrent 80 000 m2 was gebruik (50 MW termies gebaseer op LF). By gelyke opening area, uitpresteer PT LF beduidend. Vir die gebruiklike Noord-Suid rankskikking benodig LF omtrent 53% van die spesifieke installasie kostes (in $/m2 opening area) van PT om kostes mededingend te kan wees. ‘n SOKG aanleg by Lephalale was vergelyk met alleenstaande STKS in die goeie son voorkoms gebied van Upington, Suid-Afrika – Paraboliese trog kollekteerder velde van gelyke grote was oorweeg vir al twee konfigurasies. Dit was gevind dat die jaarlikse elektrisiteit gegenereer vanaf SOKG meer as 25% is as die van alleenstaande STKS. Indien SOKG oorweeg word met 72% van die kostes van alleenstaande STKS, dan beteken dit dat SOKG 1.8 keer meer koste effektief is as alleenstade STKS. Verder, SOKG presteer beter in die hoer elektrisiteitsnavraag maande (Suid- Afrikaanse winter – May tot Augustus). Alleenstaande STKS is gekies vir Suid-Afrika en word tans gebou. Dit is bereik deur dat die regering ‘n aantreklike omgewing geskep het vir onafhanglike krag produsente. Eskom ondersoek tans SOKG by bestaande Eskom persele. Hierdie verslag beweer dat op nasionale/Eskom vlak, SOKG, besonders son voorverhitting van voedingswater, meer haalbare oplossing is vir Suid-Afrika met sy beduidende koolreserwes en goeie son voorkoms.

Solar thermal technology is a rapidly evolving technology that still has a smaller market share than other green technologies. Therefore, this study aims to recognize barriers and drivers for the use of solar thermal technologies in the industrial sector. A literature review summarized the existing literature problems concerning drivers and barriers for the use of solar thermal technology in the industrial sector. To establish drivers and barriers to the use of solar thermal technology in the industrial sector and to supplement the literature review, a cross-sectional analysis was carried out in this study. Case studies have been performed in India, where two companies have undergone pilot testing of solar thermal systems in their manufacturing processes, and one has an option to incorporate solar thermal systems. Purposeful sampling was used to select the companies for the interviews, while convenience sampling and the snowball sampling were used to pick interview participants, further in this research six interviews was conducted from 4 different companies in the industrial sector. The findings were presented with thematic analysis. Drivers and Barriers have been divided into themes. Namely, Drivers include futuristic technology and Barriers include high costs, infrastructure requirements, more efficient and cheaper alternatives and lack of institutional support. Futuristic technology theme explains why this technology is beneficial for industrial adoption in the Indian market. High-cost theme explains why this technology is expensive over other renewable sources. Infrastructure requirements theme explains installation barriers influencing the adoption of solar thermal systems in the industrial process. Efficient and cheaper alternatives theme explains competitors influencing the adoption of solar thermal energy in the industrial sector. Lack of institutional support theme explains government and multinational companies that are influencing the adoption of solar thermal energy in the industrial sector. Aspects covered by the theme, high costs were most frequently mentioned among the respondents, suggesting that barriers play a significant role in implementing solar thermal systems. In contrast, aspects covered by the themes lack institutional support, infrastructure requirements, and more efficient and cheaper alternatives have not been addressed in the literature. Finally, the study concluded that the adoption of solar thermal energy in the Industrial Sector faces various barriers and drivers that must be investigated before the implementation.

The rising concerns of climate change and global warming have made the current practices of industrial energy generation and consumption highly unsustainable. There is a growing awareness of the importance of renewable energy use in addressing climate change and establishing sustainable development. One of the renewable sources which have gained popularity over time is solar energy. Among the various solar technologies, one potential segment is solar thermal technology which involves solar thermal collectors. This technology mainly concentrates on providing industrial process heat across a wide range of temperature, and it's classified within the industry of Solar Heat for Industrial Process (SHIP). Though the SHIP technologies show strong technical feasibility, only few industries employ solar heat and there is a decreasing trend of adoption.  Hence, this research aims to understand the reasons for decreasing adoption by studying what and how are the factors affecting the adoption of solar thermal technology. This is done by performing a qualitative study across two industrial sectors food and chemical in the region of Middle East and North Africa (MENA). The obtained data by conducting semi-structured interviews are analysed using the Technological-Organization-Environment (TOE) theoretical framework.  The results from the study show that there are 9 important factors affecting the adoption of solar thermal technology that are categorized into technological factors (reliability, flexibility, financial attractiveness, and competitive alternatives), organizational factors (management support and resources) and environmental factors (regulatory environment, technology support provider and competitive pressure). Apart from the technological factors of lack of reliability and financial attractiveness, the organizational factors of lack of resources and the environmental factor of low incentives in MENA region, the aspect of cheap competitive alternatives especially in the MENA region, is causing the decrease in adoption within the food and chemical industry.

In recent years there has been an increasing trend in the provision of central heating and split vapour compression air conditioning systems to domestic dwellings in Cyprus. To minimise their economic and environmental impact, this study examines the feasibility and economic viability of energy conservation measures and the feasibility of the application of solar driven LiBr-water absorption system for space conditioning. Initially, the study compares through simulation, the heating and cooling requirements of domestic dwellings constructed in Cyprus during the last century. The simulations required values for the thermal conductivity of local building materials, like the hollow brick and mud and straw block. These were not available, and measurements were performed on a machine specifically purchased for the project to establish these values for the first time. These material properties will be of value to building services engineers in Cyprus and the Middle East for the more precise determination of building heating and cooling loads. Evaluation of the internal conditions resulting from the various types of constructions indicated that the traditional and insulated modem houses, could maintain indoor temperature in winter between 16°C and 20°C, but in the summer temperatures exceeded 36°C. The use of natural and mechanical ventilation could reduce slightly the maximum indoor summertime temperatures, but not to a level that could provide thermal comfort. Window gains are an important factor in domestic building energy requirements, and significant savings can result when extra measures are taken. The savings in cooling energy demand for a well-insulated house may be as high as 24% when low-emissivity double glazed windows are used compared to clear double glazed windows giving a pay-back period of 3.8 years. Other factors investigated are the effect of overhangs, shape and orientation of buildings and thermal mass. The results show that the roof is the most important structural element of domestic dwellings in the Cypriot environment. For good thermal performance, the roof must offer a discharge time of 6 hours or more and have a thermal conductivity of less than 0.48 W/m-K. Life cycle cost analysis has shown that measures that increase the roof insulation pay back in a short period of time, between 3.5 to 5 years. However, measures taken to increase wall insulation pay back in a longer period of time, approximately 10 years. The only natural energy resource abundantly available in Cyprus is solar energy, which could be used to power a low energy active cooling system based on the absorption cycle. To facilitate investigation of the feasibility of the application of solar driven absorption systems for domestic cooling, a 1 kW LiBr-water absorption-cooling unit was designed and constructed. The unit was used to determine experimentally the heat and mass transfer coefficients in the heat exchangers of absorption systems. In certain cases these were found to differ considerably from values obtained from heat and mass transfer correlations published by other investigators. The experimentally determined heat and mass transfer coefficients were employed in the design and costing of an 11 kW cooling capacity solar driven absorption cooling machine which, from simulations, was found to have sufficient capacity to satisfy the cooling needs of a well insulated domestic dwelling. Economic analysis has shown that for such a system to be economically competitive compared to conventional cooling systems its capital cost should be below C£ 2000. This drawback can be balanced by a lower total equivalent warming impact being 2.7 times smaller compared to conventional cooling systems.

With the increasing awareness of global warming and the need for limiting greenhouse gas emissions, several sectors are witnessing comprehensive transformations towards sustainable generation and consumption. The European Union can be considered the home for most of these transformations given the union’s efforts to enable decarbonization through regulatory frameworks and initiatives. However, one overlooked source of carbon emissions is the industrial heating sector which is heavily dependent on fossil fuel. Emerging technologies such as solar thermal could provide a solution for limiting the greenhouse gases emitted by this sector. This study examines the factors influencing the diffusion of solar thermal technology and its potential for substituting natural gas in the industrial heating sector. Specifically, the study examines the thermal energy supply side as being a potential facilitator for the diffusion of solar thermal technology. Certain elements from Everett Rogers’ (1995) work on the diffusion of innovations are applied to solar thermal technology along with the concept of lead users by Hippel (1986). The study follows a qualitative approach in collecting and analyzing data through interviews and document analysis. Experts from the energy sector were interviewed along with examining public documents of two major utility companies. The findings suggest that utility companies examined, despite their evident decarbonization efforts, do not represent a suitable vehicle for the diffusion of solar thermal technology. Instead, a business model based on energy efficiency could be the possible breakthrough for this technology. Finally, the study concludes with suggestions for possible actions to expedite the diffusion of solar thermal in the industrial sector.

Energy is the core component for all industries. Most of the energy demand is met by fossil fuels, which is one of the main reasons for the high level of carbon emissions from industries. To decrease emissions or even become carbon neutral by 2050, many companies have made sustainability goals to implement renewablesin their production processes. Industries consume 74% of the energy in the form of heat, of which 30% of energy is consumed in low-temperature applications. Substituting fossil fuels in low-temperature applications with renewable energy sources such as solar-thermal technology (STT) can significantly reduce emissions. This study explores how can focus on sustainability by companies facilitate the diffusion of STT in low-temperature applications in brewery and mining industries. The study comprises a comprehensive literature review on sustainable development, drivers, and barriers of STT. The theoretical framework of the studyis based on diffusion of innovation by Rogers (2003). Empirical data is collected using semi-structured interviews to gain insights from multi-national companies about their focus on sustainability, transition towards renewable energy sources in meeting heat demand and aspects considered by companies. The study results show that companies focusing on sustainability goals are incorporating new renewable energy technologies such as STT in their processes. Companies are also making heat purchase agreements and are collaborating with neighbouring companies to incorporate STT. This form of integration of new solutions can increase the adoption rate of STT. Further, it is found that brewery companies have a better scope of implementing STT compared to mining companies.

A tendência em ampliar o uso das tecnologias com aproveitamento da energia solar no setor residencial traz para os profissionais da área de projeto novos desafios que é o de reestruturar seus modelos de concepção e desenvolvimento de projetos a fim de garantir o comportamento em uso e a eficiência dos sistemas construtivos seguros. O Modelo conceitual de identificação e qualificação de risco proposto foi elaborado a partir da pesquisa de investigação e de desenvolvimento experimental. Foram considerados aspectos relativos às demandas de segurança em uso, construção do conhecimento a partir da sistemografia e a forma de integração desses saberes em um único sistema. O desenvolvimento experimental ocorreu durante o processo de projeto, produção, montagem, uso e operação de um protótipo denominado Ekó House. A metodologia aplicada envolveu quatro fases: Fase 1 - Exploratória - com pesquisas bibliográficas (as tecnologias, normas e práticas de projeto; Fase 2 - Definições - com a escolha da base teórica de apoio ao modelo; Fase 3 - Desenvolvimento - proposições e experimentos e Fase 4 - Teste e consolidação. Para validar o modelo aplicou-se a validação por generalização analítica, ou seja, expandir e generalizar a teoria. O modelo proposto, inovador no âmbito da sistemografia, apoiou-se na Teoria do Sistema Geral: teoria da modelização proposta por LE MOIGNE. Essa teoria trabalha com sistemas complexos e se apoia em processadores, são eles: de operação, informação e decisão que condicionam a integração sistêmica do projeto. Verificou-se durante a aplicação do modelo que ele estimula o aprofundamento das análises das soluções de projeto, quando: a)Identifica e formaliza conceitos que suportam o desenvolvimento das soluções nos diversos sistemas; xv b)Facilita a compreensão e síntese das múltiplas informações que precisam ser compatibilizadas no projeto; c)Formaliza um único principio \"segurança do usuário\" para a lógica de concepção e desenvolvimento de projeto; d)Organiza e permite que se priorizem as informações técnicas [fabricantes e normas];e)Facilita o entendimento por meio de informações as ações de organização e coordenação dos sistemas no espaço e de sua relação com as funcionalidades, uso e estética; e f)Fomenta a busca de soluções mais adequadas a segurança do usuário. Sendo assim, o teste do modelo validou a hipótese. Ele contribui como ferramenta guia de aprimoramento do processo de projeto.
The increasing use of solar energy technologies in the residential sector brings new challenges to professionals who work in the field of design, such as the need to restructure their mindset regarding to the conception and to the development of design, in order to ensure the performance and the efficiency of safe building systems. In this context, this thesis main goal is to propose a conceptual model for the identification and qualification of risk within residential architecture that uses solar energy technologies based on systemography. It\'s an investigative and experimental research, considering aspects related to: meet the demands of safety in use, the knowledge construction and how those could be managed. The experimental development was carried out during the process of design, production, assembly, use and operation of a prototype named Ekó House. The applied method has encompassed four stages: 1) Exploratory - bibliographic research about technologies, codes, rules and design practices; 2) Definitions - the choice of the theoretical basis to ground the model; 3) Development - propositions and experiments and 4) Proofing and consolidation. In order to verify the model it was carried out a test wherewith is possible to perform a validation by analytical generalization, that is, expand and generalize the theory. The proposed model, which represents an innovation in sistemography field, was based on LE MOIGNES\'s Systemic Theory. This Theory enabled the implementation in complex systems, using information, decision and operating processors which condition the design systemic integration. The results obtained by the research show that the model: a) incorporates knowledge, thus, being helpful along the decision-making process; b) eases the understanding and the overview of the diverse information needed by the design; c) formalizes a logic of design conception and development; d) xvii organizes and prioritizes the design technical recommendations [rules and manufacturers]; e) is able to promote an interference in the system\'s organization and coordination in space and also in its relation to functionality and aesthetics; it also f) guides the use of more suitable configurations to the design development. The model presents itself as a tool that is capable of reducing misuse of standards, conflicts between building systems, Technologies and architecture, as well as design failures that compromise safety in use.

Buildings account for up to 40% of the total energy use in the world. Directives from the European Union have pointed out the significance of increasing the energy efficiency in buildings. New regulation in countries like Sweden has established that new buildings should fulfil regulations of Nearly Zero Energy Buildings (NZEB), providing the opportunity for renewable energy technologies to achieve these goals. In this paper, the retrofitting potential of renewable energy technologies for a single-family home in Sweden was investigated.The present work studied the characteristics of several renewable energy technologies and their applications for a single-family home in Sweden, including biomass, solar photovoltaics, solar thermal, heat pump, and small-scale wind turbine. Three renewable energy technologies (solar thermal, heat pump and small-scale wind turbine) and one renovation method (window) were selected to investigate. The analysis was made of the current energy use and the potential energy (and cost) savings from each retrofitting of these facilities by means of simulation models using IDA ICE software. The study results show that the proposed renewable energy technologies are technically feasible and economically viable as a source of alternative renewable energy in order to produce clean energy and reduce electricity bills for an electric-heated single-family home located in Sweden. Moreover, the combined retrofitting scheme consist of solar thermal system and window renovation was also proposed and explored. As a result the energy performance of the single-family home would satisfy the nearly-zero energy building requirements and thermal comfort could be maintained at an acceptable level.

Because of the harsh climate of Saudi Arabia, residential buildings on average, consume more than half of the total consumed energy. A substantial share of energy goes to the air-conditioning of buildings. Cooling buildings during summer is a major environmental problem in many Middle Eastern countries, especially since the electricity is highly dependent on fossil fuels. The aim of this study is to obtain a clearer picture of how various measures on the building envelope affects the buildings energy consumption, which can be used as a tool to save energy for buildings in the Middle East. In this study, different energy efficiency measures are evaluated using energy simulations in IDA ICE 4.7 to investigate how much energy can be saved by modifying the building envelope. A two-storey residential building with 247 m2 floor area is used for the simulations. The measures considered are; modifications of the external walls, modification of the roof, window type, window area/distribution, modification of the foundation, shading, exterior surface colour, infiltration rate and thermal bridges. All measures are compared against a base case where the building envelope is set to resemble a typical Saudi Arabian residential. First, all measures are investigated one by one. Thereafter, combinations of the measures are investigated, based on the results from single measure simulations. All simulations are carried out for two cities in Saudi Arabia, both with arid desert climate. Riyadh (midlands) with moderately cold winters and Jeddah (west coast) with mild winter. The results from simulations of single measures show the highest energy savings when changing the window type from single clear glass to double glass with reflective surface saving 27 % energy (heating & cooling) in Riyadh and 21 % in Jeddah. Adding insulation to an uninsulated roof saved up to 23 % and 21 % energy for Riyadh respectively Jeddah. Improvements of the thermal resistance of the exterior walls show 21 % energy savings in Riyadh and only 11 % in Jeddah. Lowering the window to wall ratio from 28 % to 10 % and changing the window distribution results in 19 % (Riyadh) and 17 % (Jeddah) energy savings. Adding fixed shades saves up to 8 % (Riyadh) and 13 % energy (Jeddah) when dimensioned for the peak cooling load. Using bright/reflective surface colour on the roof saves up to 9% (Riyadh) and 17 % (Jeddah) when the roof is uninsulated. For the exterior walls, bright/reflective surface saves up to 5 % (Riyadh) and 10 % (Jeddah) when the walls are uninsulated. The other single measures investigated show less than 7 % energy savings. The results for combined measures show the highest energy savings for two combined measures when improving the thermal resistance of the exterior walls and changing window area/distribution saving up to 52 % (Riyadh) and 39 % (Jeddah). When performing three measures the addition of improved thermal resistance and reflectance of the windows resulted in the highest energy savings, saving up to 62 % (Riyadh) and 48 % (Jeddah). When adding a fourth measure, improving the thermal resistance of the slab shows the highest energy savings, 71 % (Riyadh) and 54 % (Jeddah). Applying all measures on the building envelope results in 78 % (Riyadh) and 62 % (Jeddah) energy savings. Significant energy savings can be achieved with measures on the building envelope. Major savings can be made by adding only 50-100 mm of insulation to the exterior walls and roof. Decreased window area and improvements on the thermal resistance and reflectance on the windows result in significant energy savings. Energy savings achieved with shadings and reflective surface colours decrease significantly when the thermal resistance of the roof and external walls are improved. All measures concerning thermal resistance have a higher impact in Riyadh than in Jeddah due to that a large part of the total heating and cooling is air handling unit (AHU) cooling in Jeddah. AHU cooling is not affected significantly by measures on the building envelope. To optimise energy savings, measures on the building envelope should be considered in combination with measures concerning the AHU.
På grund av det hårda klimatet i Saudiarabien, konsumerar bostadshus mer än hälften av den totala energi som förbrukas. En stor del av den förbrukade energin går till luftkonditionering. Kylningen av byggnader är ett stort miljöproblem i många länder i Mellanöstern, särskilt eftersom elektriciteten till stor del är helt beroende av förbränning av fossila bränslen. Syftet med denna studie är att få en tydligare bild av hur olika åtgärder på klimatskalet påverkar byggnaders energiförbrukning. Tanken är att resultaten ska kunna användas som ett hjälpmedel vid design av mer energieffektiva byggnader i Mellanöstern. I denna studie är olika energieffektivitetsåtgärder utvärderade med hjälp av energisimuleringar i IDA ICE 4.7 för att undersöka hur mycket energi som kan sparas genom att modifiera klimatskalet. Ett bostadshus med 247 m2 golvyta i två våningar används för simuleringarna. De åtgärder som övervägs är; modifieringar av ytterväggar, modifiering av tak, fönstertyp, fönster area/ distribution, modifiering av fundamentet, skuggning, ytskikt, infiltration och köldbryggor. Alla åtgärder jämförs mot ett Base Case där klimatskalet är inställt för att likna en typisk bostad i Saudiarabiens. Först undersöks alla åtgärder en åt gången. Därefter undersöks kombinationer av de studerade åtgärderna, baserat på resultat från simuleringar av enskilda åtgärder. Alla simuleringar utförs för två städer i Saudiarabien, både med torrt ökenklimat. Riyadh (inlandet) med måttligt kalla vintrar och Jeddah (västkusten) med mild vinter. Resultatet från simuleringar av enskilda åtgärder visar högst energibesparing när fönstertypen byts ut från enkelt klarglas till dubbelt reflekterande glas. Med byte av fönstertyp sparas upp till 27 % energi (uppvärmning och kylning) i Riyadh och 21 % i Jeddah. Att isolera taket sparar upp till 23 % och 21 % för Riyadh respektive Jeddah. Förbättrat värmemotstånd i ytterväggarna resulterar i upp till 21 % energibesparing i Riyadh och endast 11 % i Jeddah. Minskning av fönsterarean från 28 % av väggytan till 10 % och omplacering av fönsterna ger19 % (Riyadh) och 17 % (Jeddah) energibesparingar. Solavskärmning med hjälp av fasta skärmtak och fenor sparar 8 % (Riyadh) och 13 % energi (Jeddah) när de är dimensionerad för maximalt kylbehovet. Använda ljus/reflekterande yta på taket sparar upp till 9 % (Riyadh) och 17 % (Jeddah) när taket är oisolerad. För ytterväggar, sparar ljust/reflekterande ytskikt upp till 5 % (Riyadh) och 10 % (Jeddah) när väggarna är oisolerad. De övriga enskilda åtgärderna som undersökts visar mindre än 7 % energibesparing. Resultaten för kombinerade åtgärder visar högst energibesparingar för två kombinerade åtgärder när ytterväggens värmemotstånd förbättras tillsammans med mindre fönsterarea och ändrad fönsterplacering. De två åtgärderna sparar upp till 52 % energi i Riyadh och 39 % i Jeddah. När tre åtgärder utförs, fås den högsta energibesparingen med de två åtgärderna ovan med tillägg av förbättrade fönster med lägre u-värde och högre reflektants. Tillsammans resulterar de tre åtgärderna i en energibesparing upp till 62 % för Riyadh och 48 % för Jeddah. När man lägger till en fjärde åtgärd, fås den högsta besparingen med tillägg av förbättrat u-värde på grunden till de tre tidigare åtgärderna. De fyra åtgärderna sparar upp till 71 % energi i Riyadh och 54 % i Jeddah. Tillämpning av alla åtgärder på klimatskalet resulterar i 78 % (Riyadh) och 62 % (Jeddah) energibesparing. Betydlig reducering av energianvändningen kan uppnås med åtgärder på byggnadens klimatskal. Stora besparingar fås med endast 50 – 100 mm isolering i ytterväggar och tak. Att minska fönsterarean och förbättra fönsternas u-värde och reflektivitet bidrar till stora energibesparingar.  Besparingarna som fås vid solavskärmning och reflektiva ytor på tak och väggar minskar signifikant när taket och ytterväggarna isoleras. Alla åtgärder som förbättrar u-värdet på klimatskalet har en större inverkan i Riyadh än i Jeddah på grund av att en större andel av total uppvärmning och kylning upptas av kylning av inkommande luft i ventilationen. Energin som behövs för att kyla inkommande luft påverkas inte nämnvärt av åtgärderna på klimatskalet. För att optimera energibesparingarna ytterligare, bör åtgärder på klimatskalets övervägas tillsammans med energieffektivitetsåtgärder av ventilationen.

Thermal comfort in an indoor environment is largely dependent on the four environmental and two personal parameters which is most commonly measured by the Predicted Mean Vote (PMV) model developed by Fanger. It has been studied that variations in these parameters beyond a range could lead to discomfort complaints. However, little research has been done on the effect of mean radiant temperature variations and its influence on predicted mean vote and thermal comfort specially in an actual building environment. This study aims to investigate the relationship between mean radiant temperature and predicted mean vote in indoor environment. Using the methods of on-site measurement of indoor environmental parameters and subjective votes on thermal sensation in an educational building; it was found that rise in mean radiant temperature lead to rise in PMV value and discomfort vote amongst occupants seated near glazed façade. A very strong positive correlation was found between mean radiant temperature and PMV near the window side of the room under warm and sunny weather conditions. Analysis of indoor environmental data from the several measurement sessions concluded that rise in mean radiant temperature and PMV was not noticed until there was a direct solar transmission through the window. It is advisable to use solar shading on windows, but special consideration should be given to the trade-offs between energy consumption (heating or cooling) and lighting energy consumption. No conclusions could be made in terms of ankle draft discomfort due to experimental limitations and more research would be required to investigate this phenomenon.
Termisk komfort inomhusmiljö är till stor del beroende av de fyra miljö och två personlig parametrar som oftast mäts av Predicted Mean Vote (PMV) modell som utvecklats av Fanger. Det har studerats att variationer i dessa parametrar utanför en limit kan leda till missnöjeklagomål. Däremot har lite forskning gjorts på effekten av mean radiant tempratur och dess inverkan på predicted mean vote och termisk komfort speciellt i en verklig byggnadsmiljö. Syftet med denna studie är att undersöka sambandet mellan mean radiant tempratur och predicted mean vote i inomhusmiljö. Användning mätmetoderna av inomhusmiljöparametrar och subjektiva röster av termisk komfort uppfattning i en byggnad för utbildning; det konstaterades att stiga i medel leda mean radiant tempratur att stiga i predicted mean vote värde och missnöje rösta bland byggnad brukarna sitter nära glasfasaden. En väldigt positiv korrelation mellan men radiant tempratur och predicted mean vote nära en fönstersida under varma och soliga väder var noterat. Genom att analysera data av inomhusmiljön från de multipla mätningssessionerna konkluderat att ökningen i mean radiant tempratur och predicted mean vote inte märktes tills det fanns en direkt soltransmission genom fönstret. Det är rekommenderar att använda solskydd på fönster, men med tanke på kompromisser mellan energiförbrukning (värme eller kyla) och ljussättning konsumtion.   Inga slutsatser kan göras om luftdrag på fotled grund av experimentella begränsningar och mer forskning skulle krävas för att undersöka detta fenomen.

The United Nations (UN) project "Sustainable energy for all" sets three ambitious objectives to favor a sustainable development and to limit climate change: - Universal access to modern energy services. Electricity is currently not available for 1.3 billion people and the global energy demand is expected to grow of about 35% within 2040, due to the increasing world population and the expanding economies - Double the global rate of improvement in energy efficiency - Double the share of renewable energy sources (RESs) in the global energy mix In addition, according to the climate scenario assessed in the fifth assessment report (AR5) of the International Panel on Climate Change (IPCC), the prevention of undesirable climate effects requires a 40-70% reduction of greenhouse gas (GHG) emissions, compared with 2010 levels, by mid-century, and to near-zero by the end of this century (IPCC, 2014). The achievement of such objectives requires and encourages the spread of RESs in the global energy mix, gradually replacing depleting and polluting energy sources based on fossil fuels, which still have the main incidence on the energy sector. RESs already play a major role in several countries, due to the technological development and the increasing market competitiveness, and the world renewable power capacity reached 22.1% in 2013, showing an increasing trend in 2014 (REN, 2014). However, supporting policies, robust investments from the private sector and efforts from the scientific community are still crucial to demonstrate the technical and economic sustainability and effectiveness of RESs, helping their large-scale diffusion. Starting from such a background, this Ph.D dissertation focuses on the study, design and development of methods and tools for the optimization and enhancement of renewable energy technologies and their effective integration with energy storage solutions and traditional energy sources powered by fossil fuels (hybrid energy systems). The analysis of the major literature and the different scenarios and perspectives of RESs in the national and international contexts have shown that their economic sustainability, and then their diffusion, is closely connected to a number of technical, economic/financial and geographical parameters. Such parameters are the input of the analytic models developed for the techno-economic design of photovoltaic (PV) plants and small wind turbines (SWTs) and applied to the economic feasibility study, through multi-scenario analysis, of such systems in some of the main European Union (EU) Countries. Among the obtained results, the self-consumption of the produced energy plays a crucial role in the economic viability of SWTs and PV plants and, particularly, after the partial or total cut of incentives and uncertainties related to supporting policies within the EU context. The study of the energy demand profile of a specific user and the adoption of battery energy storage (BES) systems have been identified as effective strategies to increase the energy self-consumption contribution. Such aspects have led to the development of an analytic model for the techno-economic design of a grid connected hybrid energy system (HES), integrating a PV plant and a BES system (grid connected PV-BES HES). The economic profitability of the grid connected PV-BES HES, evaluated for a real case study, is comparable with PV plants without storage in case of a significant gap between the cost of energy purchased from the grid and the price of energy sold to the grid, but high BES system costs due to the initial investment and the maintenance activities and the eventual presence of incentives for the energy sold to the grid can make the investment not particularly attractive. Thus, the focus has shifted to the techno-economic analysis of off-grid HES to meet the energy demand of users in remote areas. In this context, BES systems have a significant role in the operation and management of the system, in addition to the storage of exceeding energy produced by the intermittent and variable RESs. The analysis has also been strengthened by an industrial application with the aim to configure, test and install two off-grid HESs to meet the energy demand of a remote village and a telecommunication system. In parallel, two experimental activities in the context of solar concentrating technology, a promising and not fully developed technology, have been carried out. The former activity deals with the design, development and field test of a Fresnel lens pilot-scale solar concentrating prototype for the PV energy distributed generation, through multi-junction solar cells, and the parallel low temperature heat recovery (micro-cogeneration CPV/T system). The latter activity deals with the development of a low cost thermal energy (TES) storage prototype for concentrating solar power (CSP) plants. TES systems show a great potential in the CSP plants profitability since they can overcome the intermittent nature of sunlight and increase the capacity factor of the solar thermal power plant. Concluding, the present Ph.D dissertation describes effective methods and tools for the optimization and enhancement of RESs. The obtained results, showing their critical issues and potential, aim to contribute to their diffusion and favor a sustainable development
Il progetto delle Nazioni Unite "Sustainable energy for all" ha fissato tre obiettivi ambiziosi per favorire uno sviluppo sostenibile e limitare l'impatto del cambiamento climatico: - Accesso universale a moderni servizi elettrici. Tali servizi sono attualmente indisponibili per circa 1.3 miliardi di persone ed è previsto un aumento del 40% della domanda globale di energia elettrica entro il 2040, a causa dell'incremento della popolazione mondiale e delle economie in crescita nei paesi in via di sviluppo - Raddoppio del tasso globale di miglioramento dell'efficienza energetica - Raddoppio del contributo di fonti di tipo rinnovabile nel mix energetico globale Inoltre, lo scenario climatico proposto nel "fifth assessment report (AR5)" redatto da "International Panel on Climate Change (IPCC)" stabilisce la necessità di ridurre l'emissione di gas ad effetto serra del 40-70%, rispetto ai valori registrati nel 2010, entro il 2050 ed eliminarli in modo quasi definitivo entro la fine del secolo con lo scopo di evitare effetti climatici indesiderati. Il raggiungimento di tali obiettivi richiede e incoraggia la diffusione di fonti energetiche rinnovabili (FER) all'interno del mix energetico globale, rimpiazzando gradualmente le fonti di energia convenzionali basate su combustibili fossili, inquinanti e in via di esaurimento, che hanno ancora l'incidenza principale nel settore energetico. A seguito nel loro sviluppo tecnologico e la crescente competitività nel mercato, le FER rivestono già un ruolo fondamentale nel mix energetico di numerose Nazioni ricoprendo il 22.1% del fabbisogno globale di energia nel 2013 e mostrando un andamento in rialzo nel 2014 (REN, 2014). Tuttavia, sono ancora cruciali politiche di supporto, ingenti investimenti privati e contributi della comunità scientifica per dimostrare l'efficacia e la sostenibilità tecnica ed economica delle FER e favorire, quindi, una loro diffusione in larga scala. In questo contesto, la seguente tesi di dottorato è rivolta allo studio, progettazione e sviluppo di metodi e strumenti per l'ottimizzazione e la valorizzazione di tecnologie energetiche rinnovabili e la loro integrazione efficace con fonti di produzione di energia convenzionali alimentate da combustibili fossili e sistemi di accumulo di energia (Sistemi energetici di tipo ibrido). I contributi scientifici disponibili in letteratura e l'analisi dei diversi scenari e delle prospettive delle FER nei vari contesti nazionali ed internazionali hanno dimostrato che la loro sostenibilità economica, e quindi la loro diffusione, è strettamente legata ad una serie di parametri tecnici, economico / finanziari e geografici. Tali parametri sono stati impiegati come input in due modelli analitici sviluppati per la progettazione tecnico-economica di impianti fotovoltaici (FV) e micro turbine eoliche e applicati per lo studio della loro fattibilità economica, attraverso analisi multi-scenario, in alcuni dei maggiori Paesi Europei. I risultati ottenuti hanno mostrato come l'autoconsumo dell'energia prodotta rivesta un ruolo fondamentale nella redditività economica dei citati impianti ed, in particolare, a seguito del taglio parziale o totale dei sistemi di incentivazione e l'incertezza attorno alle politiche di supporto all'interno del panorama Europeo. Lo studio specifico del profilo di domanda elettrica delle utenze e l'impiego di sistemi di accumulo di energia sono stati identificati come strategie efficaci al fine di incrementare la quota di autoconsumo. Tali considerazioni hanno portato allo sviluppo di un modello analitico utile alla progettazione tecnico-economica un sistema energetico ibrido connesso alla rete Nazionale integrante un impianto FV e un sistema di accumulo a batterie. La redditività del sistema, valutata su un caso reale, risulta comparabile a un impianto fotovoltaico privo di batterie in caso di un gap significativo tra il costo dell'energia elettrica acquistata dalla rete e il prezzo di vendita dell'energia elettrica ceduta in rete. Tuttavia, gli elevati costi dovuti all'acquisto iniziale e alle attività di manutenzione, e l'eventuale incentivazione sulla vendita dell'energia in rete, non rendono l'investimento particolarmente attrattivo per impianti connessi alla rete. L'attenzione si è quindi rivolta all'analisi tecnico-economica di sistemi energetici ibridi non connessi alla rete, comunemente definiti in isola o off-grid, per soddisfare il fabbisogno energetico di utenti in area remote e quindi prive di allaccio a una rete elettrica. In tali sistemi, i sistemi di accumulo a batterie, oltre alla capacità di accumulo dell'energia prodotta in eccesso variabili e intermittenti FER, hanno funzioni fondamentali nella gestione del sistema stesso. L'attività è stata anche rafforzata da un'applicazione industriale per la configurazione, test e installazione di due sistemi energetici ibridi in isola impiegati per soddisfare il fabbisogno energetico di un villaggio e di un sistema di telecomunicazione situati in aree remote. In parallelo, sono state svolte due attività sperimentali applicate alla promettente, ma non ancora completamente sviluppata a livello industriale, tecnologia solare a concentrazione. La prima attività riguarda la progettazione, sviluppo e test sperimentali di un prototipo in scala ridotta di concentratore solare a lenti di Fresnel per la produzione distribuita di energia elettrica, mediante l'uso di celle fotovoltaiche multi giunzione, ed energia termica a bassa temperatura, tramite un sistema di recupero termico. La seconda attività concerne lo sviluppo e test sperimentali di un prototipo di sistema di accumulo termico per impianti termodinamici alimentati da sistemi a concentrazione solare. Il sistema di accumulo consente di compensare la natura intermittente e variabile della fonte solare incrementando le ore di funzionamento dell'impianto termodinamico con i conseguenti benefici economici. Concludendo, la presente tesi di dottorato include la descrizione di metodi e strumenti per l'ottimizzazione e valorizzazione delle FER. I risultati evidenziano le criticità e potenzialità dei sistemi studiati con lo scopo di contribuire a una loro diffusione e favorire uno sviluppo sostenibile

När byggnader projekteras används klimatfiler från 1981-2010 för att dimensionera konstruktionen och energisystemet. Detta leder till att byggnader dimensioneras för ett klimat som varit och inte ett framtida klimat. SMHI har tagit fram olika klimatscenarier för framtiden som beskriver möjliga utvecklingar klimatet kan ta beroende på fortsatt utsläpp av växthusgaser. Dessa scenarier kallas för RCP (Representative Concentration Pathways). I denna studie används två olika klimatscenarier, RCP4,5 och RCP8,5. Siffran i namnet står för den strålningsdriving som förväntas uppnås år 2100. I RCP4,5 kommer medelårstemperaturen öka med 3 °C fram till år 2100 jämfört med referensperioden 1961-1990.  För samma tidsperiod sker en ökning på 5 °C enligt RCP8,5.  Ett flerbostadshus certifierad enligt Miljöbyggnad 2.2 nivå silver placerat i Vallentuna i Stockholms län används i denna studie som referensbyggnad. Byggnaden simuleras i programmet IDA ICE där den utsätts för RCP4,5 och RCP8,5. Resultatet visar att byggnaden inte skulle klara av kraven för Miljöbyggnad 2.2 gällande termiskt klimat sommar i något av de två klimatscenarierna. De operativa temperaturerna blir för höga i byggnaden utan att tillsätta komfortkyla.  Byggnaden ändras för att se vilka faktorer som kan förbättra resultatet gällande det termiska klimatet. Resultatet visar att värmelagringsförmåga hos byggmaterial och solavskärmning har störst påverkan på det termiska klimatet.  I studien gjordes flertal olika kombinationer av byggnadsutformningar. Enbart kombinationen av en tung stomme av betong tillsammans med fönster med lägre g-värde klarar kraven för Miljöbyggnad 2.2 i RCP4,5 och RCP8,5 utan komfortkyla. Kombinationen får lägst energianvändning i RCP8,5 av de olika kombinationerna som testats i studien.  En kombination av tung stomme av KL-trä med lågt U-värde, fönster med lägre g-värde och komfortkyla får lägst energianvändning i grundklimatet och RCP4,5 av de olika kombinationerna som testats i studien trots användningen av komfortkyla.  Frågan om vilket alternativ som är bäst ur ett hållbarhetsperspektiv är svårt att svara på. Det finns många aspekter som behöver tas i hänsyn till som byggnadens totala klimatavtryck både i tillverkning och användning. Oavsett val av konstruktion är det viktigt att projektera för att komfortkyla och solavskärmning skall kunna appliceras när ett varmare klimat råder.
When buildings are designed climate files from 1981 to 2010 are used to construct the building and its energy system. This leads to building being designed to a climate that has been and not to a future warmer climate that will come. SMHI has developed different climate scenarios for the future that describe different paths the climate can take depending on continued emissions of greenhouse gas. This climate scenarios are called RCP (Representative Concentration Pathways) In this study two of the climate scenarios, RCP4,5 and RCP8,5 are used. The number in the name stands for the radiation forcing that is expected in the year 2100.  In RCP4,5 the mean average air temperature will increase with 3 °C until year 2100 compared to the reference period 1961-1990. In the same time period RCP8,5 will increase with 5 °C.  An apartment building certified according to Miljöbyggnad 2.2 level silver placed in Vallentuna, Stockholms län is used as a reference building. The building is simulated through the simulation software program IDA ICE where it´s exposed to RCP4,5 and RCP8,5. The results demonstrate that the reference building would not meet Miljöbyggnad 2.2 requirement in the indicator about thermal comfort during summer. The operative temperature in the building is too high unless comfort cooling is used.  The design of the building changes to see what factors can improve the results regarding the thermal comfort. The results demonstrate that thermal conductivity and solar shading has the greatest impact on thermal comfort.  In this study several combinations of different building designs were made. Only the combination of a concrete frame with windows with low g-value met the requirement of Miljöbyggnad 2.2 regarding the thermal comfort during summer without using comfort cooling in RCP4,5 and RCP8,5. The combination had the lowest energy demand in RCP8,5 of all the combinations tested in the study.  A combination of cross laminated wood frame with low U-value, windows with low g-value and comfort cooling had the lowest energy demand in the original climate file and RCP4,5 despite the use of comfort cooling.  The questing about which building construction is the best from a sustainable perspective is difficult to answer. To answer that question the building´s total climate footprint in both production and use must be calculated. Regardless of the choice of building construction it is important to have in mind when designing a building that comfort cooling and solar shading should be easily applied when a warmer climate will prevail.

Recently, there has been an uptake of integrating solar thermal into district heating (DH) systems. It has been recognized as one of the paths towards a more sustainable future. However, there are some countries where the adoption is very slow, regardless of its market readiness. Adoption and diffusion literature points to the need to investigate slow adoption examples to contribute to the already existing knowledge. Consequently, this thesis investigates influencing factors, barriers, and drivers for the slow adoption of solar thermal into DH systems.   A case study was carried out to identify influencing factors for the slow adoption of solar thermal within DH systems. The case was chosen based on purposive and extreme sampling as it referred to the adoption of the first large-scale solar thermal into DH systems in France. Stratified purposive sampling, in combination with snowball sampling, was used to acquire eleven interviews. Thematic analysis was utilized to analyse the findings.   Results identified four themes, Technology, Environmental Regulations, Management of DH systems, and Financials, where each theme contained several subthemes. Barriers and drivers were developed from the subthemes. Among the most prominent barriers were the combination of lack of experience and a rigid legal framework, resulting in the barrier of ex-post integration, which implies considering the whole DH system when integrating new technologies. Another identified prominent barrier was cheap fuels which include biomass, as well. Environmental policies were found to both help and hamper the adoption. A driver, called a champion, mainly pushed the adoption of solar thermal within the studied case.    In conclusion, several barriers and drivers can influence the adoption of solar thermal into DH systems, and taking them into account should facilitate its adoption. Next, investigating a slow adoption case proved to be a valuable venue for acquiring new knowledge. Lastly, based on the empirical results of the studied case, solar thermal could not be labelled as an environmental innovation, which has alarming implications for achieving sustainable development goals in the future.

Impediments to investment in renewable energy resources arise in five areas, namely, infrastructure access, technological and resource uncertainty, competition from established fossil fuel alternatives, asset financing and public policy. Together these can lead to large capital cost penalties and poor resource productivity that reduce the viability of projects. Presented here are system-wide analyses of two novel pathways to generate new investment in concentrated solar thermal and in geothermal energy resources. The pathways are designed to reduce the minimum capital outlay required for the development of renewable energy resources, by identifying synergies with established energy and non-energy infrastructure and technologies. The endothermic, thermochemical processing of fossil, waste and biomass using concentrated solar energy has been demonstrated, at experimental scales between 3-500 kWth, to upgrade the calorific value of syngas relative to the feedstock by ~30%, depending on the reactor technology employed and the fuel that is processed. However, no process modeling analysis has previously been presented of the impacts of diurnal, seasonal and cloud-induced solar resource availability on the operational limits of commercially available Fischer-Tropsch (FT) liquids syngas processing infrastructure. Presented here, are process modeling analyses of the relative performance of two solar gasification reactor systems and the operational impacts of their integration with a coal-to-liquids polygeneration facility. The reactor designs assessed were the batch process, indirectly irradiated solar packed bed gasifier that operates with solar input alone and a hybridised configuration of the solar vortex reactor that is assumed to integrate combustion to account for solar resource transience and thus enable a continuous non-zero syngas throughput. To address the impacts of solar resource transience, the process modeling analyses showed that the packed bed solar reactor requires syngas storage equivalent to >30 days of gas flow to maintain feasible operation of unit operations downstream of the gasifier. In comparison, the hybrid solar vortex reactor was shown to require only ~8 hours of syngas storage. A dynamic process modeling study of integrating a hybrid solar vortex coal gasifier with a FT liquids polygeneration system was shown to improve the overall energetic productivity by 24% and to reduce mine-to-tank CO2 emissions by 28%. This is the first comprehensive system analysis of a solar hybridised coal-to-liquids process that has assessed all the impacts of solar resource transience on the unit operations that comprise a FT liquids polygeneration system. Geothermal resources can face barriers to investment arising from their remoteness—in particular, distance from established electricity transmission lines—uncertainty in the cost of establishing well infrastructure and uncertainty in the scale of the recoverable resource. To address these challenges, presented here is a comprehensive system evaluation of the potential of high-value energy load data-centres to reduce the cost of developing geothermal resources. This potential arises from the data-centres’ modularity, their stable load for both electricity and refrigeration, and because their energy demand can be scaled commensurate to geothermal resource availability. Moreover, they can be connected to market by fibre optic network infrastructure, which is at least two orders of magnitude less expensive than electricity transmission. System analyses of this concept showed that a hybrid energy system that integrates low-temperature geothermal resources to meet data-centres’ refrigeration load, and natural gas to meet the electrical load, could generate expected returns of 25% and reduce the cost of developing geothermal resources by >30 times. The systems modelled in this thesis have shown that, compared with stand-alone development, the hybridised development of renewable energy resources with fossil fuel energy technologies offers a lower cost pathway.
Thesis (Ph.D.) (Research by Publication) -- University of Adelaide, School of Mechanical Engineering, 2016

Studies undertaken by Eskom in 2001 identified three sites near the Northern Cape town of Upington which are suitable for a 100 MW Concentrating Solar Power (CSP) generating plant. Of the CSP technologies investigated, the central receiver option was identified as best for the Northern Cape, however almost none of Eskom’s analysis was made public. The basis of the central receiver’s suitability versus other CSP options is not publicly known. Given recent advances in concentrating systems, an argument exists for reassessing the suitability of various solar thermal technologies for bulk power generation. This study first characterises the incident solar radiation (insolation) levels at Upington from six data sources and assesses their quality. The data are then used to model performance of the parabolic trough, compact linear Fresnel reflector, central receiver, and dish-engine technologies. A software modelling tool of the United States National Renewable Energy Laboratory (System Advisor Model) is used to facilitate the comparison. Simulation results are compared with data from similar studies to ensure consistency of the CSP model inputs and performance outputs. Constraining the results to the environmental conditions of Upington, it is found that while central receiver technology produces less electricity per square kilometre of collector area, it uses less water than parabolic trough technology to obtain a higher annual electric output. Dish-engine technology has the most favourable annual electricity production to water-usage ratio, however, its modest annual electricity output and lack of energy storage capability weaken the case for it to match South Africa’s national load profile substantively. Examining the modelled month-to-month electricity output characteristic, the central receiver technology delivers significantly more electricity during the lower insolation winter period of the year than the competing technologies. This results in the central receiver technology achieving the highest annual electric output of the four technologies compared under the same insolation levels, strengthening the case for its implementation. As a whole, this work characterises the insolation levels at Upington, provides an analysis of the technical performance of competing CSP technologies for the proposed Northern Cape site, and argues quantitatively in favour of the central receiver option.
Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2012.

This work aims to conduct a comparative economic analysis on different domestic hot water production systems: a conventional electric water heater, a ST (solar thermal) system, and a PV (photovoltaic) system. The systems were analysed for two different locations in Portugal, different daily hot water demands and under various economic conditions. A TRNSYS simulation model was built for all systems and validated with experimental or simulated data from the literature. A parametric study was made in order to assess the impact of increasing the number of panels and hot water storage capacity on the performance standpoint. Those results were utilized in an economic analysis to determine their economic viability considering different economic indicators. A sensitivity analysis was also conducted to study the impact of the price of electricity, the discount rate and inflation of prices of electricity on the viability of SWHS (solar water heating systems). The results showed that a photovoltaic solar water heating system is better than a solar thermal system from the economic standpoint mainly due to a lower investment cost and low maintenance. A solar thermal system still has better performance due to a higher efficiency at converting solar energy to heat. The economic conditions and DHW (domestic hot water) profile have a big effect on the viability of these investments, as the research showed that for low electricity prices and low hot water necessities, a ST can have a negative NPV (net present value) and high payback periods which are usually not acceptable.
Este trabalho tem como objetivo efetuar uma análise económica comparativa entre diferentes sistemas de produção de água quente sanitária: aquecedor elétrico convencional, sistema solar térmico e um sistema fotovoltaico. Os sistemas foram analisados para duas localizações em Portugal, diferentes necessidades diárias de água quente e sob diferentes condições económicas. Foi desenvolvido um modelo de simulação TRNSYS para cada sistema e validado com dados experimentais ou simulados da literatura. Foi efetuada uma análise paramétrica de modo a avaliar o impacto do aumento do número de painéis e capacidade de armazenamento de água no desempenho e esses resultados foram usados numa análise económica a fim de determinar a sua viabilidade económica considerando diferentes indicadores económicos, em conjunto com uma análise de sensibilidade para estudar o impacto do preço da eletricidade, taxa de desconto e inflação do preço da eletricidade na viabilidade dos sistemas solares de produção de água quente. Os resultados mostraram que um sistema de produção de água quente fotovoltaico é melhor que o sistema solar térmico do ponto de vista económico devido a um menor custo de investimento e menor manutenção. Um sistema solar térmico tem melhor desempenho devido à maior eficiência na conversão de energia solar para calor. As condições económicas e perfil de consumo de água quente sanitária têm um grande impacto na viabilidade económica destes investimentos visto que, para preços baixos e pouca necessidade de água quente, um sistema solar térmico pode ter um valor atual líquido negativo e períodos de retorno de investimento muito elevados que normalmente são inaceitáveis.
Mestrado em Engenharia Mecânica

abstract: This dissertation presents my work on development of deformable electronics using microelectromechanical systems (MEMS) based fabrication technologies. In recent years, deformable electronics are coming to revolutionize the functionality of microelectronics seamlessly with their application environment, ranging from various consumer electronics to bio-medical applications. Many researchers have studied this area, and a wide variety of devices have been fabricated. One traditional way is to directly fabricate electronic devices on flexible substrate through low-temperature processes. These devices suffered from constrained functionality due to the temperature limit. Another transfer printing approach has been developed recently. The general idea is to fabricate functional devices on hard and planar substrates using standard processes then transferred by elastomeric stamps and printed on desired flexible and stretchable substrates. The main disadvantages are that the transfer printing step may limit the yield. The third method is "flexible skins" which silicon substrates are thinned down and structured into islands and sandwiched by two layers of polymer. The main advantage of this method is post CMOS compatible. Based on this technology, we successfully fabricated a 3-D flexible thermal sensor for intravascular flow monitoring. The final product of the 3-D sensor has three independent sensing elements equally distributed around the wall of catheter (1.2 mm in diameter) with 120° spacing. This structure introduces three independent information channels, and cross-comparisons among all readings were utilized to eliminate experimental error and provide better measurement results. The novel fabrication and assembly technology can also be applied to other catheter based biomedical devices. A step forward inspired by the ancient art of folding, origami, which creating three-dimensional (3-D) structures from two-dimensional (2-D) sheets through a high degree of folding along the creases. Based on this idea, we developed a novel method to enable better deformability. One example is origami-enabled silicon solar cells. The solar panel can reach up to 644% areal compactness while maintain reasonable good performance (less than 30% output power density drop) upon 40 times cyclic folding/unfolding. This approach can be readily applied to other functional devices, ranging from sensors, displays, antenna, to energy storage devices.
Dissertation/Thesis
Doctoral Dissertation Electrical Engineering 2014

abstract: Limited access to clean water due to natural or municipal disasters, drought, or contaminated wells is driving demand for point-of-use and humanitarian drinking water technologies. Atmospheric water capture (AWC) can provide water off the centralized grid by capturing water vapor in ambient air and condensing it to a liquid. The overarching goal of this dissertation was to define geographic and thermodynamic design boundary conditions for AWC and develop nanotechnology-enabled AWC technologies to produce clean drinking water. Widespread application of AWC is currently limited because water production, energy requirement, best technology, and water quality are not parameterized. I developed a geospatial climatic model for classical passive solar desiccant-driven AWC, where water vapor is adsorbed onto a desiccant bed at night, desorbed by solar heat during the day, and condensed. I concluded passive systems can capture 0.25–8 L/m2/day as a function of material properties and climate, and are limited because they only operate one adsorption-desorption-condensation cycle per day. I developed a thermodynamic model for large-scale AWC systems and concluded that the thermodynamic limit for energy to saturate and condense water vapor can vary up to 2-fold as a function of climate and mode of saturation. Thermodynamic and geospatial models indicate opportunity space to develop AWC technologies for arid regions where solar radiation is abundant. I synthesized photothermal desiccants by optimizing surface loading of carbon black nanoparticles on micron-sized silica gel desiccants (CB-SiO2). Surface temperature of CB-SiO2 increased to 60oC under solar radiation and water vapor desorption rate was 4-fold faster than bare silica. CB-SiO2 could operate >10 AWC cycles per day to produce 2.5 L/m2/day at 40% relative humidity, 3-fold more water than a conventional passive system. Models and bench-scale experiments were paired with pilot-scale experiments operating electrical desiccant and compressor dehumidifiers outdoors in a semi-arid climate to benchmark temporal water production, water quality and energy efficiency. Water quality varied temporally, e.g, dissolved organic carbon concentration was 3 – 12 mg/L in the summer and <1 mg/L in the winter. Collected water from desiccant systems met all Environmental Protection Agency standards, while compressor systems may require further purification for metals and turbidity.
Dissertation/Thesis
Doctoral Dissertation Civil, Environmental and Sustainable Engineering 2020

Three different green technologies are compared in terms of net energy and carbon savings for a theoretical Toronto rooftop. Embodied energy values are calculated through Life Cycle Analysis and compared to the estimated energies produced and/or saved by each technology. Results show that solar photovoltaics displace the most carbon per m2 of roof space and solar thermal (for hot water) displaces the most energy. An in-depth analysis of an intensive green roof for growing food indicates that the high embodied energy of the materials is not quickly repaid by the sum of six energy savings that were examined (direct and indirect cooling, run-off treatment, transport of food, on-farm energy use, and activities that would otherwise be carried out). However, the energy and carbon benefits are not insignificant, but depend strongly on various assumptions. The methodology used is replicable and therefore useful for other locations.

O objetivo do presente documento é apresentar o meu trabalho como engenheiro mecânico, demonstrando as competências e aptidões adquiridas ao longo destes anos. O documento apresenta inicialmente a empresa onde tenho trabalhado até agosto do ano 2016, a Active Space Technologies S.A.. Posteriormente serão apresentados os projetos desenvolvidos e também explicadas outras tarefas desempenhadas.

Energy expenditure is one of the significant overheads in the lifespan of multistoreyed buildings. Reliable and proficient functions of Heating, Ventilation and Air Conditioning (HVAC) systems are further imperative as a result of the climbing price of electricity. This research recommends that the compounded energy utilisation to meet the demand from high humidity and temperature could be minimised by adopting the alternative high-performance building envelope and low emission cooling method along with the optimised control of additional operational parameters. The core purpose of this research is to computationally evaluate the performance of various alternative building envelopes and low energy cooling methods to determine the best performing envelop and cooling method to enhance the energy efficacy and human comfort in buildings in a subtropical climate in Australia. Firstly, a detailed energy assessment of the current building systems is undertaken on a selected case study building in Rockhampton, Central Queensland. Then, a comprehensive energy simulation model is developed, employing a building energy simulation algorithm. The modelled energy and comfort data of the building systems are validated by means of on-site recorded data. The substantiated model is then expanded to evaluate the efficacy of several alternative building envelopes such as bio-phase change material (BioPCM), cavity wall, Trombe wall, building integrated photovoltaic (BIPV) and low emission cooling methods such as, cooled Beam, ground source heat pump, variable air volume, variable refrigerant flow system to secure better comfort and energy savings in both summer and winter months. Furthermore, an extensive multicriteria based optimisation is undertaken to determine combined alternative envelope and cooling method for retrofitting of the existing systems that will meet the requisite of the present and the future depending on the potential climate change scenario. This study found that both cooled beam and ground source heat pump as low energy high-performance cooling alternatives, and BioPCM as high-performance building envelope have the higher potential for energy conservation and better thermal comfort based on the present and future weather conditions. Through multi-criteria optimisation, the study found that BioPCM and Cooled Beam as an integrated mechanism can be successfully incorporated into buildings in subtropical climate to improve the energy efficiency by 30% and human comfort which have not been evaluated in any other studies in the past. Furthermore, the use of the combined optimised approach, i.e. integration of BioPCM and Cooled Beam, produces significantly less emission (21%) per year at the same time ensures the comfortability of the occupants which is the utmost consideration in the study. Finally, the study offered a net positive energy operating method to ensure that carbon footprint is minimised considering the present and future weather conditions. Overall, a practical thermal simulation orientated optimisation framework is developed and executed that unites the objective of minimising energy consumption of building systems as well as maintaining superior comfort of the people based on the present and future weather conditions.

The systemic relationship between the human entity and its environment, under the constraint of its function, were used as the perfect example to design and create the systemic relationship of an urban regenerative building with its economical, environmental and social context in the Inner City of Pretoria.
Dissertation (MArch (Prof))--University of Pretoria, 2005.
Architecture
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