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Tesi sul tema "Heating and ventilation control"
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1
Dong, Bing. "Integrated Building Heating, Cooling and Ventilation Control". Research Showcase @ CMU, 2010. http://repository.cmu.edu/dissertations/4.
Testo completoAbstract (sommario):
Current research studies show that building heating, cooling and ventilation energy consumption account for nearly 40% of the total building energy use in the U.S. The potential for saving energy through building control systems varies from 5% to 20% based on recent market surveys. In addition, building control affects environmental performances such as thermal, visual, air quality, etc., and occupancy such as working productivity and comfort. Building control has been proven to be important both in design and operation stages.
Building control design and operation need consistent and reliable static and dynamic information from multiple resources. Static information includes building geometry, construction and HVAC equipment. Dynamic information includes zone environmental performance, occupancy and outside weather information during operation.. At the same time, model-based predicted control can help to optimize energy use while maintaining indoor set-point temperature when occupied. Unfortunately, several issues in the current approach of building control design and operation impede achieving this goal. These issues include: a) dynamic information data such as real-time on-site weather (e.g., temperature, wind speed and solar radiation) and occupancy (number of occupants and occupancy duration in the space) are not readily available; b) a comprehensive building energy model is not fully integrated into advanced control for accuracy and robustness; c) real-time implementation of indoor air temperature control are rare. This dissertation aims to investigate and solve these issues based on an integrated building control approach.
This dissertation introduces and illustrates a method for integrated building heating, cooling and ventilation control to reduce energy consumption and maintain indoor temperature set-point, based on the prediction of occupant behavior patterns and weather conditions. Advanced machine learning methods including Adaptive Gaussian Process, Hidden Markov Model, Episode Discovery and Semi-Markov Model are modified and implemented into this dissertation. A nonlinear Model Predictive Control (NMPC) is designed and implemented in real-time based on Dynamic Programming. The experiment test-bed is setup in the Solar Decathlon House (2005), with over 100 sensor points measuring indoor environmental parameters such as temperature, relative humidity, CO2, lighting, motion and acoustics, and power consumption for electrical plugs, HVAC and lighting. The outdoor environmental parameters, such as temperature, relative humidity, CO2, global horizontal solar radiation and wind speed, are measured by the on-site weather station. The designed controller is implemented through LabVIEW.
The experiments are carried out for two continuous months in the heating season and for a week in cooling season. The results show that there is a 26% measured energy reduction in the heating season compared with the scheduled temperature set-points, and 17.8% energy reduction in the cooling season. Further simulation-based results show that with tighter building façade, the cooling energy reduction could reach 20%. Overall, the heating, cooling and ventilation energy reduction could reach nearly 50% based on this integrated control approach for the entire heating/cooling testing periods compared to the conventional scheduled temperature set-point.
2
Graham, W. J. "Adaptive control of wet heating systems". Thesis, University of Oxford, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370317.
Testo completo
3
Kranz, Jürgen. "Intelligent automotive thermal comfort control". Thesis, Nelson Mandela Metropolitan University, 2011. http://hdl.handle.net/10948/1435.
Testo completoAbstract (sommario):
Mobility has become a substantial part in our society. Since we spend a lot of our available time on the road, we expect the automotive environment to provide similar comfort levels than residential buildings. Within this context, this research thesis especially focuses on automotive thermal comfort control. The automotive cabin is a very special environment, which is characterized by extreme inhomogeneity and overall transient behavior. Thermal comfort is a very vague and a very subjective term, which depends on physiological and psychological variables. Theories for thermal comfort in transient environments have not been fully established yet and researchers are still busy with its investigation. At present, automotive industry relies on extensive thermal comfort models, manikins and powerful simulation tools to assess and control thermal comfort. This thesis studies the application of artificial intelligence and proposes a blackbox approach which aims for extracting thermal comfort knowledge directly from human's interaction with the HVAC controls. This methodology avoids the use of human physiological and psychological thermal comfort models and does not require any a-priori knowledge. A novel comfort acquisition tool has been developed and has been integrated into a research vehicle in order to gather the required data for system learning. Data has been collected during spring, autumn and summer conditions in Southern Africa. Methods of data mining have been applied and an intelligent implementation using artificial neural networks has been proposed. The achieved results are promising and allow for about 87 perecent correct classification. It is concluded that methods of artificial intelligence perform well and are far superior compared to conventional approaches. These methods can be used as a powerful tool for the development process of vehicle air-conditioning controls and have great potential for time and cost reduction.
4
Rashid, Dewan Md Harunur Mechanical & Manufacturing Engineering Faculty of Engineering UNSW. "Wake survey behind a rotating ventilator". Awarded by:University of New South Wales. School of Mechanical and Manufacturing Engineering, 2002. http://handle.unsw.edu.au/1959.4/19076.
Testo completoAbstract (sommario):
With environmental concern growing in both affluent and developing countries, roof top ventilators, a form of natural ventilation requiring only wind energy to ensure quality air circulation and comfort is becoming a considered choice of many households and industries. Unfortunately, however, many of these ventilators have evolved through trial and error and the flow physics associated with these ventilators is barely understood. The present experimental project was, therefore, undertaken as part of UNSW- Industry collaboration program funded under an Australian Research Council Grant to explore whether the aerodynamics forces acting on these ventilators during their operation could be obtained. A commercial roof top ventilator supplied by industry was, therefore, tested in an open jet wind tunnel of the University of New South Wales and the results are presented in this thesis. A novel feature of this project is the examination of the suitability of ???the three dimensional wake traverse??? technique to the wake of rotating ventilator. This technique has so far been applied with limited success to the wake of lifting bodies of fixed wing configuration only. In the absence of adequate data in the literature on rotating ventilator, the aerodynamics force components obtained by this technique have been compared against force balance measurements. The results show that the wake traverse technique is capable of determining lift and total drag forces associated with the ventilator flow during its operation from the pressure and velocity information gathered downstream of a ventilator in its wake. Generally, from these data, the technique also allows isolation of the profile and induced components of the drag force. However, from the induced drag value, while it is possible to determine the lift force, it is however, found that a more accurate value of lift force can be evaluated using axial vorticity formulation. The availability of the above technique which does not require measurements on the test specimen itself, will aid in providing a cost efficient investigation of the aerodynamic forces and consequently the performance of a roof top ventilator.
5
Hayat, Tariq. "Modelling, simulation and control of mine ventilation systems". Thesis, University of Sheffield, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.387494.
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6
Tank, Prabhulal M. "Single and multiple boiler control for efficiency". Thesis, London South Bank University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.259992.
Testo completo
7
Asmar, Basel Nashat. "Control of a two-stage refrigeration system". Thesis, University of Nottingham, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287167.
Testo completo
8
Trinder, M. C. J. "Active noise control in finite length ducts". Thesis, University of Essex, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.371924.
Testo completo
9
Florenz-Esnal, Julian. "Temperature prediction models and their application to the control of heating systems". Thesis, University of Manchester, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335130.
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10
Hawkins, M. E. "Fuzzy rule-based control of ducted air flows". Thesis, University of Oxford, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334222.
Testo completo
11
Unruh, Cassie, Austin Johnson e Lisa Nordman. "Residential Telemetry Applications for HVAC Control". International Foundation for Telemetering, 2011. http://hdl.handle.net/10150/595643.
Testo completoAbstract (sommario):
ITC/USA 2011 Conference Proceedings / The Forty-Seventh Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2011 / Bally's Las Vegas, Las Vegas, NevadaMuch of the energy consumed in developed countries is for residential heating and cooling. Substantial savings are possible if one can monitor the indoor environment at many locations, and then actively control the heating, ventilation and air conditioning (HVAC) system. This project uses a wireless sensor array and dedicated microcontroller system to control a residential HVAC system. A low data rate, ad-hoc network of sensors is deployed throughout a residence, with the data sent to a central controller. A graphical user interface allows the resident to monitor the system status, and to set parameters.
12
Al-Nizari, Hamdan Omar A. "Dynamic performance and refrigerant flow control in refrigeration systems". Thesis, Brunel University, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315452.
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13
Basharhagh, M. Zia. "Recess vane passive stall control for axial flow fans". Thesis, Cranfield University, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.305269.
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Datta, Debarati. "Frosting and demand defrost control of retail food refrigeration systems". Thesis, Brunel University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.285094.
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15
Harson, Andrew. "A blade angle control system for large variable pitch fans". Thesis, Queen's University Belfast, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334529.
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16
Peel, D. "Self-tuning process control with application to an industrial dryer". Thesis, University of Newcastle Upon Tyne, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375162.
Testo completo
17
Ho, Wai Fuk. "Air-conditioning system design for optimum control performance in Hong Kong". Thesis, Loughborough University, 2000. https://dspace.lboro.ac.uk/2134/7242.
Testo completoAbstract (sommario):
Studies on design for control optimization of air-conditioning (a/c) system for better performance in Hong Kong are reported in this thesis. Typical plant configuration data was collected from an in-depth survey of a/c systems and control used in Hong Kong. Control performance has been used for the first time as an objective for optimizing a/c system designs. The study investigates and illustrates that optimization of a/c systems for application in the Hong Kong by simulation is promising and flexible. The accuracy of simulation is enhanced by using the survey data. The survey shows that some a/c control systems and their control strategies are not well considered in the design stage and their operation and set-up are not properly addressed. Hence, there exists optimization opportunities in the a/c system design and control strategies for a/c systems used in Hong Kong. Parameters affecting the control performance of a/c systems were investigated by carrying out experiments. Identified parameters are the objective function of optimization, controller settings, control valve and drive and, in case of direct digital control, sampling rate. The influence of these factors on the control performance is an essential consideration for the entire optimization process. Strategies in applying the findings in optimizing an a/c system for control performance by simulation were developed and suggested. This study provides platform for further simulation study of optimization in both methodologies and control strategies for a/c system design and operation.
18
Silva, Pedro Miguel Abreu. "Multiple-model structures applied to fault tolerant control in heating, ventilation and air conditioning systems". Thesis, University of Reading, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.541957.
Testo completo
19
Dzidic, Elvira, e Mbonyimana Benjamin Jansson. "Penetration Testinga Saia Unit : A Control System for Water, Ventilation, and Heating in Smart Buildings". Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-299862.
Testo completoAbstract (sommario):
The concept of Smart Buildings and automated processes is a growing trend. Due to a rapidly growing market of buildings that relies on the Internet, improper security measures allow hackers to gain control over the whole system easily and cause devastating attacks. Plenty of effort is being put into testing and securing the devices within a smart building in order to contribute to a more sustainable society. This thesis has evaluated the security of a control system for water, ventilation, and heating in smart buildings by using ethical hacking, where the testing is based on a systematic and agile pentesting process. The penetration testing was conducted using the method Black- box testing, and the testing was based on a threat model that was created to identify vulnerabilities. The results from the penetration tests did not find any exploitable vulnerabilities. However, flaws in the system, such as data being transferred in clear text and unlimited login attempts, that need to be addressed to avoid further problems, were found. The conclusion from evaluating the control system affirms that the strength of the password has a significant role, but that system can still be exposed to other hacking techniques, such as ”Pass the hash”.Begreppet smarta byggnader och automatiserade processer är en växande trend. På grund av en snabbt växande marknad av byggnader som är beroende av Internet, har bristfälliga säkerhetsåtgärder resulterat i att hackare enkelt kan få kontroll över hela systemet och orsaka förödande attacker. Ansträngningar läggs på att testa och säkra enheterna i en smart byggnad för att bidra till ett mer hållbart samhälle. Denna avhandling har utvärderat säkerheten för ett styrsystem för vatten, ventilation och uppvärmning i smarta byggnader med hjälp av etisk hacking, där testningen baseras på en systematisk och agil pentestning process. Penetrationstestningen genomfördes genom att använda sig av metoden Blackbox testning, medan testningen baserades på en hotmodell som skapades för att identifiera sårbarheter. Resultaten från penetrationstesterna hittade inga sårbarheter att dra nytta utav. Dock hittades brister i systemet, bland annat att data överförs i klartext och att användaren har oändligt många inloggningsförsök, som måste åtgärdas för att undvika framtida problem. Slutsatsen från utvärderingen av styrsystemet bekräftar att styrkan på lösenordet har en signifikant roll, men att systemet ändå kan vara utsatt av andra hackningstekniker så som ”Pass the hash”.
20
Deng, Shi-Ming. "Modelling and control of an air conditioning system with emphasis on cooling coil behaviour". Thesis, London South Bank University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303912.
Testo completo
21
Sklavounos, Dimitris C. "Detection of abnormal situations and energy efficiency control in Heating Ventilation and Air Conditioning (HVAC) systems". Thesis, Brunel University, 2015. http://bura.brunel.ac.uk/handle/2438/12843.
Testo completoAbstract (sommario):
This research is related to the control of energy consumption and efficiency in building Heating Ventilation and Air Conditioning (HVAC) systems and is primarily concerned with controlling the function of heating. The main goal of this thesis is to develop a control system that can achieve the following two main control functions: a) detection of unexpected indoor conditions that may result in unnecessary power consumption and b) energy efficiency control regarding optimal balancing of two parameters: the required energy consumption for heating, versus thermal comfort of the occupants. Methods of both orientations were developed in a multi-zone space composed of nine zones where each zone is equipped with a wireless node consisting of temperature and occupancy sensors while all the scattered nodes together form a wireless sensor network (WSN). The main methods of both control functions utilize the potential of the deterministic subspace identification (SID) predictive model which provides the predicted temperature of the zones. In the main method for detecting unexpected situations that can directly affect the thermal condition of the indoor space and cause energy consumption (abnormal situations), the predictive temperature from the SID model is compared with the real temperature and thus possible temperature deviations that indicate unexpected situations are detected. The method successfully detects two situations: the high infiltration gain due to unexpected cold air intake from the external surroundings through potential unforeseen openings (windows, exterior doors, opened ceilings etc) as well as the high heat gain due to onset of fire. With the support of the statistical algorithm for abrupt change detection, Cumulative Sum (CUSUM), the detection of temperature deviations is accomplished with accuracy in a very short time. The CUSUM algorithm is first evaluated at an initial approach to detect power diversions due to the above situations caused by the aforementioned exogenous factors. The predicted temperature of the zone from the SID model utilized appropriately also by the main method of the second control function for energy efficiency control. The time needed for the temperature of a zone to reach the thermal comfort zone threshold from a low initial value is measured by the predicted temperature evolution, and this measurement bases the logic of a control criterion for applying proactive heating to the unoccupied zones or not. Additional key points for the control criterion of the method is the occupation time of the zones as well as the remaining time of the occupants in the occupied zones. Two scenarios are examined: the first scenario with two adjacent zones where the one is occupied and the other is not, and the second scenario with a multi-zone space where the occupants are moving through the zones in a cascade mode. Gama and Pareto probability distributions modeled the occupation times of the two-zone scenario while exponential distribution modeled the cascade scenario as the least favorable case. The mobility of the occupants modeled with a semi-Markov process and the method provides satisfactory and reasonable results. At an initial approach the proactive heating of the zones is evaluated with specific algorithms that handle appropriately the occupation time into the zones.
22
Li, Y. "Thermal performance analysis of a PCM combined solar chimney system for natural ventilation and heating/cooling". Thesis, Coventry University, 2013. http://curve.coventry.ac.uk/open/items/0bca9412-8b49-4d3c-84e5-453e315d4c6b/1.
Testo completoAbstract (sommario):
Solar chimney is an important passive design strategy to maximize solar gain to enhance buoyancy effect for achieving adequate air flow rate and a desired level of thermal comfort inside a building. Therefore, solar chimney has the potential advantages over mechanical ventilation systems in terms of energy requirement, economic and environmental benefits. The main aim of this project is to study the technical feasibility of a solar chimney incorporating latent heat storage (LHS) system for domestic heating and cooling applications. The research work carried out and reported in this thesis includes: the development of a detailed theoretical model to calculate the phase change material (PCM) mass for solar chimney under specific climatic condition, the development of a CFD model to optimise the channel depth and the inlet and outlet sizes for the solar chimney geometry, experimental and numerical investigations of the thermal performance of the proposed system using a prototype set-up, a parametric study on the proposed system to identify significant parameters that affect the system performance was carried out by using the verified numerical model. The numerical and experimental study showed that the numerical model has the ability to calculate the PCM mass for the proposed system for the given weather conditions. The optimum PCM should be selected on the basis of its melting temperature, rather than its other properties such as latent heat. The experimental work on the thermal performance of the proposed system has been carried out. The results indicated that the LHS based solar chimney is technically viable. The outlet air temperature and the air flow rate varied within a small range during phase change transition period which are important for a solar air heating system. A numerical model was developed to reproduce the experimental conditions in terms of closed mode and open mode. The model results were in a close agreement with the experimental results particularly the simulated results for the discharging process. With the verified model, a comprehensive parametric analysis intended to optimise the thermal performance of proposed the system was performed. The results analysed are quantified in terms of charging/discharging time of the PCM, temperature difference between outlet air and inlet air of the solar chimney, and mass flow rate of the chimney, which are the most important quantities of the proposed system.
23
Gross, Steven James. "A Feasibility Study of Model-Based Natural Ventilation Control in a Midrise Student Dormitory Building". PDXScholar, 2011. http://pdxscholar.library.pdx.edu/open_access_etds/449.
Testo completoAbstract (sommario):
Past research has shown that natural ventilation can be used to satisfy upwards of 98% of the yearly cooling demand when utilized in the appropriate climate zone. Yet widespread implementation of natural ventilation has been limited in practice. This delay in market adoption is mainly due to lack of effective and reliable control. Historically, control of natural ventilation was left to the occupant (i.e. they are responsible for opening and closing their windows) because occupants are more readily satisfied when given control of the indoor environment. This strategy has been shown to be effective during summer months, but can lead to both over and under ventilation, as well as the associated unnecessary energy waste during the winter months. This research presents the development and evaluation of a model-based control algorithm for natural ventilation. The proposed controller is designed to modulate the operable windows based on ambient temperature, wind speed, wind direction, solar radiation, indoor temperature and other building characteristics to ensure adequate ventilation and thermal comfort throughout the year without the use of mechanical ventilation and cooling systems. A midrise student dormitory building, located in Portland OR, has been used to demonstrate the performance of the proposed controller. Simulation results show that the model-based controller is able to reduce under-ventilated hours to 6.2% of the summer season (June - September) and 2.5% of the winter (October - May) while preventing over-heating during 99% of the year. In addition, the model-based-controller reduces the yearly energy cost by 33% when compared to a conventional heat pump system. As a proactive control, model-based control has been used in a wide range of building control applications. This research serves as proof-of-concept that it can be used to control operable windows to provide adequate ventilation year-round without significantly affecting thermal comfort. The resulting control algorithm significantly improves the reliability of natural ventilation design and could lead to a wider adoption of natural ventilation in appropriate climate zones.
24
Turner, Carolyn S. "Perceived thermal comfort and energy conservation strategies in residential heating". Diss., Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/49947.
Testo completoAbstract (sommario):
The perception of thermal comfort is an important factor influencing the acceptability of residential heating strategies. The perceived thermal comfort may affect a person's inclination to try a strategy or to use it on a long-term basis. In the study, perceived thermal comfort was assessed in relation to room temperature, humidity, clothing worn, preferred room temperatures, personal control over the temperatures, and energy consumption. The relationships among these variables were examined for five families participating in a live-in study comparing five residential heating strategies. The strategies tested included closing off bedroom vents/doors, setting the thermostat at 65°F, and the use of a solar greenhouse and a woodstove as supplemental heat sources. The families lived in a retrofitted solar test house for a period of four to six weeks. The house was equipped with a computer which monitored 37 channels of information at ten-second intervals and recorded the data hourly. The data collected included temperatures in every room, inside and outside humidity, wind velocity, and other variables that interplay in comfort levels and energy use. The ten adult respondents completed daily and weekly questionnaires containing Likert-type scales of thermal comfort and checklists of clothing worn. The results suggest the following conclusions: 1) the use of a residential setting to measure thermal comfort under varying environmental conditions can be successfully accomplished, 2) psychological variables such as personal control should be considered and tested by persons involved in standards development for the thermal environment, 3) the ability and experience of the persons to use a strategy can affect the achieved energy saving benefits of the strategy, 4) personal preference in the amount of personal effort a person is willing or able to give will impact on the decision on whether to use certain strategies, 5) heating strategies that can produce a direct source of heat or at least some warmer areas were rated higher by the project participants, and 6) weather can play an important role in the effectiveness of the solar greenhouse as a heating source.Ph. D.
incomplete_metadata
25
Zajic, I. "A Hammerstein-bilinear approach with application to heating ventilation and air conditioning systems". Thesis, Coventry University, 2013. http://curve.coventry.ac.uk/open/items/bb74b3bc-b12b-4a92-8aac-9781131cc75e/1.
Testo completoAbstract (sommario):
This thesis considers the development of a Hammerstein-bilinear approach to non-linear systems modelling, analysis and control systems design, which builds on and extends the applicability of an existing bilinear approach. The underlying idea of the Hammerstein-bilinear approach is to use the Hammerstein-bilinear system models to capture various physical phenomena of interest and subsequently use these for model based control system designs with the premise being that of achieving enhanced control performance. The advantage of the Hammerstein-bilinear approach is that the well-structured system models allow techniques that have been originally developed for linear systems to be extended and applied, while retaining moderate complexity of the corresponding system identification schemes and nonlinear model based control designs. In recognition of the need to be able to identify the Hammerstein-bilinear models a unified suite of algorithms, being the extensions to the simplified refined instrumental variable method for parameter estimation of linear transfer function models is proposed. These algorithms are able to operate in both the continuous-time and discrete-time domains to reflect the requirements of the intended purposes of the identified models with the emphasis being placed on straightforward applicability of the developed algorithms and recognising the need to be able to operate under realistic practical system identification scenarios. Moreover, the proposed algorithms are also applicable to parameter estimation of Hammerstein and bilinear models, which are special cases of the wider Hammerstein-bilinear model class. The Hammerstein-bilinear approach has been applied to an industrial heating, ventilation and air conditioning (HVAC) system, which has also been the underlying application addressed in this thesis. A unique set of dynamic control design purpose oriented air temperature and humidity Hammerstein-bilinear models of an environmentally controlled clear room manufacturing zone has been identified. The greater insights afforded by the knowledge of the system nonlinearities then allow for enhanced control tuning of the associated commercial HVAC control system leading to an improved overall control performance.
26
Sun, Jie. "Modelling and intelligent control of vehicle climatronic systems". Thesis, Nelson Mandela Metropolitan University, 2009. http://hdl.handle.net/10948/1118.
Testo completoAbstract (sommario):
The modelling and control method of a vehicle climatronic system, based on MATLAB/SIMULINK, is presented. In order to achieve high modelling accuracy, a developed simulation model library is introduced. The modelling approach is described and the developed models are validated with some of experimental data obtained. The models are nonlinear, independent of fluid type and based on thermo-dynamic principles. Analysis of the cooling circuit modelling and empirical real-time control models are created by using Fuzzy logic controller and Stateflow. Both of control input and output are implemented essentially at original vehicle CAN-Bus system. Feasible digital automatic control strategy basic to fuzzy theory, hardware and software solution are given. The simulation experiment is achieved with the Hardware-in-Loop technology. This control methodology is easily operated and worth applying for any further studies or methods.
27
Voigt, Juan-Dirk. "Optimal control of a heating ventilation and air-conditioning system with ice-storage vessel in a commercial building". Diss., University of Pretoria, 2015. http://hdl.handle.net/2263/56123.
Testo completoAbstract (sommario):
Current research indicates that optimal control methods can be used to control heating ventilation and air-conditioning (HVAC) systems with ice-storage tanks installed in commercial buildings that employ a time-of-use billing structure. An optimal control model for the cooling cycle of the HVAC system with an ice-storage tank for a commercial building is proposed. This nonlinear optimisation problem can be solved by existing software packages. The results are compared with the existing conventional control strategy employed on the HVAC system under consideration. It is shown that the optimal control of the ice storage can realise a greater energy and demand cost saving compared to the conventional control strategy for different billing periods. The research will present a comparative benchmark for other thermal energy storage systems installed in commercial buildings.Huidige navorsing wys dat optimale beheermetodes aangewend kan word vir die beheer van n verhitting-, ventilasie- en lugversorgingstelsel met ysstoor, wat geïnstalleer is in n kommersiële gebou en waar die energieverbruik gemeet word volgens n tyd-van-verbruikelektrisiteittariefstruktuur. n Optimale beheermodel vir die verkoelingslassiklus van die lugversorgingstelsel met ysstoor in n kommersiële gebou word voorgestel. Die nie-liniêre optimaliseringprobleem kan deur middel van bestaande sagteware opgelos word. Die resultate van die model word vergelyk met die huidige konvensionele beheerstrategie wat toegepas word op die geëvalueerde lugversorgingstelsel. Daar word aangetoon dat optimale beheer groter aanvraag- en energiekostebesparing sal bewerkstellig in vergelyking met die konvensionele beheerstelsel vir die verskillende faktuur periodes. Die navorsing sal n vergelykende maatstaf bied vir soortgelyke stelsels met ysstore wat geïnstalleer is in kommersiële geboue en die verwagte kostebesparings.
Dissertation (MEng)--University of Pretoria, 2015.
tm2016
Electrical, Electronic and Computer Engineering
MEng
Unrestricted
28
Vorderbruggen, Joan Marie. "Evaluating How Attributes of Operable Window Design Affect Office-workers' Perception of Personal Control". Thesis, University of Oregon, 2009. http://hdl.handle.net/1794/10326.
Testo completoAbstract (sommario):
xvi, 117 p. : ill. (some col.) A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number.Energy and environmental concerns warrant reconsideration of operable windows as a means of ventilating and cooling office environments. To design for optimal window use and performance, architects must understand human interaction with operable windows and the factors that influence occupant participation in their thermal environment. This thesis examines workers' personal control of operable windows in their office space through the lens of the following attributes: proximity, orientation, and accessibility to operable windows, office floor height, and the operational methods of windows. Three sites in the Minneapolis metro area were examined through site visits, informalinterviews, collection of physical traces, and a questionnaire. Research data reveal that proximity is the greatest determinant of window use. Other attributes have varying degrees of influence on use of windows. Surprisingly, workers valued operable windows significantly more for fresh air than for cooling.
Committee in Charge: Professor John Rowell, Chair; Professor Brook Muller; Professor G.Z. Brown
29
Chirattikalwong, Anawat. "Natural ventilation and solar control : design analysis of suburban Bangkok housing estates". Virtual Press, 2007. http://liblink.bsu.edu/uhtbin/catkey/1365783.
Testo completoAbstract (sommario):
The housing estates boom was and is a result of the Southeast Asia economic growth after the economic crisis between 1997 and 1998. Housing estates, especially in the suburbs of Bangkok, are designed by considering only aesthetics and costs without considering the negative effects that might occur to the occupants and nature. These negative effects lead to the insufficiency energy crisis.Determining how to reduce the energy used and increase the living quality in the building type is the critical question for architects to answer. Redesigning the housing estate using sustainable design concepts, especially with a focus on the natural ventilation and shading device strategies, can lift up the occupants' living quality because such design can provide cross ventilation through the house and solar shading to reduce the heat gain in the house. Not only would such design improvements make houses more comfortable for inhabitants, they also would reduce the energy use.The methodologies of research start with spatial analyses to define the general character of this type of house, then the redesigning of a selected existing house is used to focus on natural ventilation and shading devices design in order to improve the occupants living quality and to reduce the energy used in the house. It is hoped that this project can be the first step for other architects to understand the logic of natural ventilation and shading control design strategies within the realm of sustainability.Department of Architecture
30
Ménard, Odette. "A solar climate control system using a water film flow to conserve energy in greenhouses /". Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=60540.
Testo completoAbstract (sommario):
One of the greatest problems encountered in greenhouses and buildings with large glazing is control of the internal atmosphere. The inherent characteristic of these buildings to act as solar collectors is to be used effectively for collecting and storing the excess solar energy. A new type of glazed roof, a Solar Climate Control roof system, was designed as a means to cool the interior environment of the greenhouses during the daytime and to heat during the nighttime or on overcast days.A heat exchanger-storage system, using water as a thermal mass is included in the design of the Solar Climate Control system. A film of water flows on the inner surface of the roof and absorbs the direct solar heat radiation, acting then as a cooling agent. The energy absorbed may be reused for nighttime heating.
An efficient water dispersion pipe for the Solar Climate Control system was developed. The use of a soap solution rather than water alone for the Solar Climate Control water film system permitted a significant reduction in pumping rate and improved uniformity of the film.
A computer simulation model was run to determine the energy loads for both a conventional (double glazed roof) greenhouse and one equipped with the Solar Climate Control system. The Solar Climate Control system shows low operating cost and very good efficiency in heat removal.
31
Liew, Yu-Loong. "REMOTE CONTROL OF HEATING, VENTILATING, AND AIR CONDITIONING SYSTEM WITH LABVIEW". MSSTATE, 2003. http://sun.library.msstate.edu/ETD-db/theses/available/etd-10132003-183826/.
Testo completoAbstract (sommario):
Recent technological advances have extended the use of some old technology such as the X-10 home automation. With the use of X-10 and the Internet, a remote control home is possible. One of the major energy consumption appliances in a house is the heating, ventilating, and air conditioning system. The main objective of this study is to explore the possibility of using X-10 and the Internet to serve as an energy saving system. A simulation is used to estimate the energy consumption.
32
Sun, Jian Reddy Agami T. Dr. "Methodology for adapting rigorous simulation programs to supervisory control of building HVAC & R systems: simulation, calibration and optimization /". Philadelphia, Pa. : Drexel University, 2004. http://dspace.library.drexel.edu/handle/1860/381.
Testo completo
33
Lei, Tong Weng. ""D_PID" method for on-demand air conditioning system control in meetings, incentives, conventions and exhibition (M.I.C.E.) building". Thesis, University of Macau, 2009. http://umaclib3.umac.mo/record=b2148238.
Testo completo
34
Al-Siyamer, Akram Dahham. "Energieffektivisering av Byggnader : En kartläggning av energianvändningen på två förskolor och två skolor i Västerås med hjälp av timvärden". Thesis, Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-40813.
Testo completoAbstract (sommario):
In the development of society towards renewable energy sources, the target in Sweden is 100% energy supply from renewable energy sources by the year 2040. This requires increased energy production from renewable, but also energy optimization of existing buildings. The housing and service sector which includes households and the public services account for about 40 % of Sweden’s total energy use. It is estimated that preschools and schools have an area of 35 million m² which have an energy savings potentials of 0,7-1 TWh in the electricity consumption and 0,9 TWh in energy use for heating. With regard to energy optimization, it is not only interesting to investigate a buildings total energy use on an annual or monthly basis, but also on shorter time intervals such hourly energy use, because of the uneven energy production of some renewable energy sources such as solar and wind. The purpose of this work is to study the energy usage for some of Västerås preschools and schools, and on the basis of it propose some energy optimization actions. To achieve this a literature study has been carried out to get knowledge about how energy usage is at preschools and schools, as well as to gain insight into what actions are appropriate to perform and how they savings look like. Other than that four objects has been studied, two preschools and two schools, one of each kind were chosen amongst those with the highest energy usage among Västerås city’s preschools and schools and one of each kind amongst those with the lowest usage. The annual energy usage have been calculated and been compared to the actual usage, and the monthly and hourly energy usage for district heating have been studied as well as the electricity usage along the day for different periods. The studied periods and energy usage shows that the energy usage, both for the monthly and hourly, for the district heating moves with regards to the outdoor temperature with some exceptions. As for the electricity usage it shows that the energy usage is even with some exceptions and there is a difference between different outdoor temperature intervals. Some conclusions could be drawn among others that the objects with higher energy usage where older buildings and the objects with lower energy usage where newer ones. There are some energy optimizations actions for the objects which would lower the energy consumption, both for district heating and electricity usage.
35
Spasis, G. "Heating, ventilation and air conditioning system optimization : a study of the effect of climate, building design, system selection and control strategy on the energy consumption of a typical office building in London and Athens". Thesis, University College London (University of London), 2007. http://discovery.ucl.ac.uk/1445105/.
Testo completoAbstract (sommario):
The increasing demand for air conditioning in commercial buildings imposes a serious threat to Europe's CO2 reduction targets. Architects and engineers are therefore in a key position to help reduce the impact of buildings on the environment by taking appropriate decisions concerning the design of the building and the associated heating, ventilation and air conditioning (HVAC) system. The thesis studies the effect of a number of building and HVAC system related design factors on the energy performance of a notional air-conditioned office building employing either a variable air volume (VAV) system with terminal re-heaters, or a four-pipe fan coil unit (FCU) system with fresh air supply from a central plant, using mainly a dynamic simulation tool and the response surface methodology. The evaluation of the energy performance of the HVAC systems is for two types of climate, using typical weather data for London (UK) and Athens (Greece). It has been found that the design variables associated with the solar radiation through the transparent building elements and the internal heat gains should be the main concern of the building designer. On the other hand, the HVAC system engineer should give emphasis to the parameters associated with the plant performance and operation, as well as the temperature control set-points. It has been shown that it is possible to reduce the carbon emissions of the base case scenario by up to 88% depending on the HVAC system and the climate for which it is simulated. The carbon savings, however, are reduced by up to 22% where humidification is provided. This reduction differs depending on the HVAC system and the climatic conditions. The VAV system is more energy efficient than the FCU system, mainly due to the exploitation of the free cooling capacity of the outdoor air. The difference in carbon emissions between the two systems drops when both of them are simulated for the Athens as opposed to the London typical weather conditions. It has been found that it is possible to turn the carbon scales in favour of the FCU system when humidification to a high RH set-point is provided throughout the year, since the adjustment of the RH of the air is particularly energy wasteful for the VAV system.
36
Justin, Moll Adam. "Inneklimatet på Skoklosters slott : en studie av ett klimatexperiments första år". Thesis, Uppsala universitet, Konstvetenskapliga institutionen, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-230680.
Testo completoAbstract (sommario):
Inneklimatet på Skoklosters slott är på vissa håll problematiskt. Mögelangrepp förekommer i somliga rum, främst sådana som är belägna i norrläge och därmed lite kallare än övriga rum. För att finna en lösning på mögelproblemen inleddes våren 2013 ett treårigt experiment vars syfte var att utröna om mögelproblemen skulle kunna undvikas med aktiv klimatstyrning, vilket inte funnits innan experimentet. Tre olika klimatstyrningsanläggningar installerades i tre rum på slottet, samtidigt som mätningar gjordes i referensrum utan aktiva åtgärder. De tre klimatstyrningsanläggningarna som valdes ut var avfuktning, skyddsvärme och fuktstyrd ventilation. I mars 2014 avslutades första året av experimentet.Ur mögelrisksynpunkt har inneklimatet i nästan alla rum, både försöks- och referensrum, varit relativt godartat. Sämst inneklimat uppmättes i skyddsvärmerummet, vilket förmodligen beror på rummets egna förutsättningar snarare än skyddsvärmen. Bäst inneklimat hade rummet med den fuktstyrda ventilationen, som gav ett oväntat bra resultat och dessutom var den av klimatstyrningsanläggningarna som var mest i bruk. Det är emellertid för tidigt att med säkerhet säga vilken av anläggningarna som vore bäst för slottet.Vid en diskussion om de antikvariska konsekvenserna av en genomgripande installation av en klimatstyrninganläggning blev slutsatsen att det för slottets kulturhistoriska värde vore gynnsamt att göra en genomgripande installation ifall detta skulle innebära att slottets samlingar kunde behållas på plats. Rummens olika fysiska och kulturhistoriska förutsättningar kräver dock att individuella utformningar undersöks, vilket innebär att det kan bli aktuellt med en kombination av olika klimatstyrningsanläggningar.The indoor climate of Skokloster palace is not without problems. There have been mould growth in some rooms, mainly those who are facing north and therefore are colder than other rooms. To find a solution for the problems with mould growth, a three-year long experiment was initiated in the spring of 2013. Its purpose was to examine if mould growth could be avoided with active climate control, which had not been tested previously in the palace. Three different climate control systems were installed in three rooms, and meanwhile the indoor climate of three rooms without active climate control was logged. The three climate control systems chosen were dehumidification, conservation heating, and humidity controlled ventilation. The first year of the experiment ended in March 2014.The climate in nearly all rooms was acceptable in a mould risk perspective. The room with conservation heating had the least suitable climate, which probably is explained by the condition of the room itself rather than the effects of the conservation heating. The room with humidity controlled ventilation hade the best climate during the year, and the ventilation system had the most uptime of the climate control systems. It is however too early to tell which system might be the best after only one year.When discussing what consequences a thorough installation of a climate control system might have on the cultural heritage values of Skokloster palace, the conclusion was that it would be favourable to install active climate control – if that allowed the collections of Skokloster to remain in the building. Due to the different physical and cultural conditions of the palace’s rooms, it will be necessary to find tailored solutions for climate control systems. In order to do that, a combination of different climate control systems might be worth looking into.
Spara och bevara - Energimyndighetens forskningsprogram för energieffektivisering i kulturhistoriskt värdefulla byggnader
37
Koutník, Martin. "Návrh teplovzdušného vytápění a větrání nízkoenergetického domku". Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2008. http://www.nusl.cz/ntk/nusl-228142.
Testo completoAbstract (sommario):
The diploma thesis deals with design of warm air heating and ventilating system for low energy house. Introduction of this thesis is focused on dividing residential buildings by their heat requirement. Then problems of residential building ventilation and possibilities of warm air heating systems including heat recovery are presented. In the next chapter summary of ventilating units with heat recovery and warm air heating units for residential low energy buildings and pasive family houses is presented. Calculation of low energy house heat losses, which is solved, is based on CSN 06 0210, CSN 73 0540 and CSN EN 12831 standards. Design and calculation of warm air heating and ventilation system and ground heat exchangers is also described. Floor heating system, fireplace insert and solar heating system are designed as supplementary systems. At the end of this thesis the control system is presented. Project documentation is enclosed in appendix.
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Bouwer, Werner. "Designing a dynamic thermal and energy system simulation scheme for cross industry applications / W. Bouwer". Thesis, North-West University, 2004. http://hdl.handle.net/10394/592.
Testo completoAbstract (sommario):
The South African economy, which is largely based on heavy industry such as minerals
extraction and processing, is by nature very energy intensive. Based on the abundance of coal
resources, electricity in South Africa remains amongst the cheapest in the world. Whilst the
low electricity price has contributed towards a competitive position, it has also meant that our
existing electricity supply is often taken for granted. The economic and environmental
benefits of energy efficiency have been well documented. Worldwide, nations are beginning
to face up to the challenge of sustainable energy - in other words to alter the way that energy
is utilised so that social, environmental and economic aims of sustainable development are
supported.
South Africa as a developing nation recognises the need for energy efficiency, as it is the most
cost effective way of meeting the demands of sustainable development. South Africa, with its
unique economic, environmental and social challenges, stands to benefit the most from
implementing energy efficiency practices. The Energy Efficiency Strategy for South Africa
takes its mandate from the South African White Paper on Energy Policy. It is the first
consolidated governmental effort geared towards energy efficiency practices throughout
South Africa. The strategy allows for the immediate implementation of low-cost and no-cost
interventions, as well as those higher-cost measures with short payback periods. An initial
target has been set for an across sector energy efficiency improvement of 12% by 2014.
Thermal and energy system simulation is globally recognised as one of the most effective and
powerful tools to improve overall energy efficiency. However, because of the usual extreme
mathematical nature of most simulation algorithms, coupled with the historically academic
environment in which most simulation software is developed, valid perceptions exist that
system simulation is too time consuming and cumbersome. It is also commonly known that
system simulation is only effective in the hands of highly skilled operators, which are
specialists in their prospective fields. Through previous work done in the field, and the design
of a dynamic thermal and energy system simulation scheme for cross industry applications, it
was shown that system simulation has evolved to such an extent that these perceptions are not
valid any more.
The South African mining and commercial building industries are two of the major
consumers of electricity within South Africa. By improving energy efficiency practices within
the building and mining industry, large savings can be realised. An extensive investigation of
the literature showed that no general suitable computer simulation software for cross industry
mining and building thermal and energy system simulation could be found. Because the
heating, ventilation and air conditioning (HVAC) of buildings, closely relate to the ventilation
and cooling systems of mines, valuable knowledge from this field was used to identify the
requirements and specifications for the design of a new single cross industry dynamic
integrated thermal and energy system simulation tool.
VISUALQEC was designed and implemented to comply with the needs and requirements
identified. A new explicit system component model and explicit system simulation engine,
combined with a new improved simulation of mass flow through a system procedure,
suggested a marked improvement on overall simulation stability, efficiency and speed. The
commercial usability of the new simulation tool was verified for building applications by
doing an extensive building energy savings audit. The new simulation tool was further
verified by simulating the ventilation and cooling (VC) and underground pumping system of a
typical South African gold mine. Initial results proved satisfactory but, more case studies to
further verify the accuracy of the implemented cross industry thermal and energy system
simulation tool are needed. Because of the stable nature of the new VISUALQEC simulation
engine, the power of the simulation process can be further extended to the mathematical
optimisation of various system variables.
In conclusion, this study highlighted the need for new simulation procedures and system
designs for the successful implementation and creation of a single dynamic thermal and
energy system simulation tool for cross industry applications. South Africa should take full
advantage of the power of thermal and energy system simulation towards creating a more
energy efficient society.Thesis (Ph.D. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2005.
39
Sylvestre, Michel J. G. "Heating and ventilation study of Inco's Creighton Mine". Thesis, McGill University, 1999. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=30273.
Testo completoAbstract (sommario):
As near surface deposits are depleted, it becomes increasingly apparent that we will have to mine deeper in order to meet future world demand for metals.Along with deeper mining comes its associated challenges: increased stresses and seismicity, increased heat load and increased inefficiencies due to hoisting constraints and travel time. All of these challenges, and more, contribute to safety concerns, higher initial capital costs and higher operating costs, which combined, can make deep reserves uneconomic.
In order to meet these challenges, we must closely examine present deep mining infrastructures and operating practices with a view to learn and enhance upon "Best Practices".
This thesis will examine the challenges of providing ventilation within deep, hot mines. Specifically, we will examine Inco Limited's Creighton Mine. A current expansion at Creighton will see mining progress to the 7660 level within the next few years. A key issue, which arises, is the question as to whether Creighton will need a refrigeration system or can it continue to rely on its natural heat exchange capacity.
40
Sylvestre, Michel J. G. "Heating and ventilation study of Inco's Creighton Mine". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0033/MQ64249.pdf.
Testo completo
41
Kuegler, Kurt W. "Heating, ventilation and air conditioning engineering and design /". Online version of thesis, 1990. http://hdl.handle.net/1850/10982.
Testo completo
42
Oakley, Gareth. "A combined daylighting, passive stack ventilation and solar heating system". Thesis, University of Nottingham, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.251743.
Testo completo
43
Mert, Cuce Ayse Pinar. "Innovative heating, cooling and ventilation technologies for low-carbon buildings". Thesis, University of Nottingham, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.716485.
Testo completoAbstract (sommario):
Sectoral energy consumption analyses clearly indicate that building sector plays a key role in global energy consumption, which is almost 40% in developed countries. Among the building services; conventional heating, ventilation and air conditioning (HVAC) systems have the greatest percentage in total energy consumption of buildings. According to the latest research, HVAC is responsible for around 40% of total building energy consumption and 16% of total global energy consumption. In this respect, decisive measures need to be taken to mitigate the energy consumption due to HVAC. The research carried out within the scope of this thesis covers innovative heating, cooling and ventilation technologies for low-carbon buildings. The novel technologies developed are introduced and investigated both theoretically and experimentally. The results indicate that optimised HVAC systems with waste heat recovery have a significant potential to mitigate energy consumed in buildings, thus to halt carbon emissions. Especially plate-type roof waste heat recovery units are very attractive for the said hybrid applications with a thermal efficiency greater than 88%. The said systems are also promising in terms of overall coefficient of performance (COP). The average COP of plate-type roof waste heat recovery unit is determined to be about 4.5, which is incomparable with those of conventional ventilation systems. Preheating performance of fresh air in winter season is found to be remarkable. Comprehensive in- situ tests clearly reveal that the temperature rise in fresh air is found to be around 7 °C. Plate-type roof waste heat recovery units also provide thermal comfort conditions for occupants. Indoor CCE concentration is observed to be varying from 350 to 400 ppm which is very appropriate in term of air quality. In addition, average relative humidity is found to be 57%, which is in the desired range according to the latest building standards. Desiccant-based evaporative cooling systems are capable of providing Abstract desired indoor environments for occupants as well as having considerably high COP ranges. An average of 5.3 °C reduction is achieved in supply air temperature by utilising those systems as well as having relative humidity distribution in thermal comfort range. The dehumidification effectiveness is found to be 63.7%, which is desirable and promising. The desiccant-based evaporative cooling system has a great potential to mitigate cooling demand of buildings not only in hot arid but also in temperate humid climates.
44
Wang, Bo. "Unsteady wind effects on natural ventilation". Thesis, University of Nottingham, 2010. http://eprints.nottingham.ac.uk/11653/.
Testo completoAbstract (sommario):
Ventilation stacks are becoming increasingly common in the design of naturally ventilated buildings. The overall aim of the work described is ultimately to improve design procedures for such buildings. This thesis presents the experimental and theoretical investigation of unsteady wind effects on natural ventilation of a single envelope with multiple openings for both wind alone, and wind and buoyancy combined cases. There are two types of openings: namely the sharp-edged orifice and the long opening (stacks being treated as long openings). Two methods are adopted: 1) direct wind tunnel measurements using the hot-wire technique; 2) theoretical analysis using steady and unsteady envelope flow models. For the wind alone experiments, the influences of wind speed, wind direction and opening configuration on flow patterns are studied. For the wind and buoyancy combined tests, the transitional process between wind dominated and buoyancy dominated states are investigated. The direct velocity measurements provide the criteria for testing the validity of the theoretical models, and ways to improve them. Additionally, improvements are made to the experimental techniques: e.g. a precise unsteady calibration method of the hot-wire is developed; improvements of pressure measurements are also investigated. The experimental technique works well with multiple stacks. Even though small openings are used, some dependence of the mean pressure coefficient on opening configuration is observed. The theoretical models also work reasonably well with multiple stacks, yet it is observed that the accuracy of the theoretical models decrease with the increasing number of openings, and is sensitive to the chosen discharge coefficient which defines the characteristics of ventilation openings.
45
Croxford, Ben. "An intelligent, domestic central heating controller". Thesis, University of Westminster, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359206.
Testo completo
46
Tunzi, Michele. "Optimising the operation of hydronic heating systems in existing buildings for connection to low temperature district heating networks". Thesis, University of Nottingham, 2016. http://eprints.nottingham.ac.uk/38724/.
Testo completoAbstract (sommario):
This thesis presents a new method developed to adapt existing hydronic systems in buildings to take advantage of low temperature district heating (LTDH). The work carried out was performed by extensive use of buildings’ energy modelling, validated through recorded data. Two different case studies were investigated and the dynamic heat demand profiles, simulated for each building, were used to evaluate plate radiators connected to single and double string heating loops. The method considered an optimisation procedure, based on supply and return temperatures, to obtain the required logarithmic mean temperature difference (LMTD). The results of the analysis are presented as the average reduction of LMTD over the heating season compared to the base case design conditions. The developed strategy was applied to a Danish single family house from the 1930s. Firstly it was hypothesised a heating system based on double string loop. Two scenarios were investigated based on the assumption of a likely cost reduction in the end users energy bills of 1% per each 1◦C reduction of return and average supply and return temperatures. The results showed possible discounts of 14% and 16% respectively, due to more efficient operation of the radiators. For the case of single loop system, the investigated scenario assumed a cost reduction in the end users energy bill of 1% per each 1◦C lower reduction of average supply and return temperature. Although low return temperatures could not be achieved, the implementation of the method illustrates how to efficiently operate these systems and for the given scenario a possible discount of 5% was quantified. The method was also applied to a UK small scale district heating (DH) network. The analysis began by assessing the buildings of the Estate having double string plate radiator systems. Assuming a likely cost reduction in the end users energy bills of 1% per each 1◦C reduction of return temperature, the optimisation led to obtain a possible discount in the end users energy bills of 14% with a possible yearly average return temperature of 41◦C, compared to the present 55◦C. Moreover, few improvements in the operation of the heat network were proposed. It was assumed to operate the buildings with underfloor heating systems (UFH) with average supply and return temperatures of 40/30◦C, whereas the ones with plate radiators with the optimised temperatures of 81/41◦C. The results shown that an overall average return temperature of 35.6◦C can be achieved operating the heat network as suggested. This corresponds to a decrease in the average return temperature of 18.6◦C compared to the present condition and to a reduction of 10% in the distribution heat losses. Finally, the lower average return temperature achievable would guarantee a better condensation of the flue gases, improving the overall efficiency of the biomass boiler. This was quantified as a possible reduction of fuel consumption of 9% compared to present conditions.
47
Straw, Matthew Peter. "Computation and measurement of wind induced ventilation". Thesis, University of Nottingham, 2000. http://eprints.nottingham.ac.uk/10110/.
Testo completoAbstract (sommario):
This thesis aims to predict wind induced ventilation of a structure through the application of current analytical techniques, computational fluid dynamics simulations and novel techniques for ventilation flows induced by turbulent mechanisms. Validation of the predictions was carried out through full-scale measurements undertaken on a purpose built test structure. The structure was of cubic design with an external dimension of 6m. The construction of this full-scale research structure at Silsoe Research Institute, Bedfordshire, England, provided a unique opportunity for undertaking full-scale experimentation on a fundamental wind engineering test case which, prior to this thesis, had only been investigated using scale models in wind tunnels and computational simulations.
48
Tang, Dechao. "Modelling of heating and air-conditioning system". Thesis, University of Strathclyde, 1985. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=21451.
Testo completoAbstract (sommario):
The shortage of natural resources calls for energy conservation and the changing structure of modern science and technology makes possible the efficient dynamic energy modelling. This thesis presents a general review of existing techniques in the field of building and plant system energy modelling and concentrates on the establishment of a generalised modelling tool - the control volume conservation state space approach - to cope with the developing modern technology. The theoretical basis of this approach is discussed and verified in detail and applications demonstrated to the modelling of HVAC systems and equipment. Using this approach, any component of an HVAC system can be modelled at different levels and the qualities of the model are fully supported by the theoretical background of this approach. A computer programme for heating system simulation has been developed for the purpose of model validation and the validation efforts have been involved in the international cooperated programme of IEA Annex 10 exercises. As a part of group research, the work presented in this thesis has been involved in the development of advanced energy modelling techniques and methodology which has taken place at the ABACUS unit.
49
Gaidukov, Vladimir A. "Multiple criteria optimisaiton of building heating systems". Thesis, De Montfort University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.391425.
Testo completo
50
Karlsson, Ejwertz Viktor. "Design of user interface for heating, ventilation and air conditioning systems". Thesis, Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-34806.
Testo completoAbstract (sommario):
The project was carried out at Karlstad University during the spring of 2014 as a degree project for a Degree of Bachelor of Science in Innovation and Design Engineering and consists of 22.5 ECTS. The supervisor was lecturer Lennart Wihk from Karlstad University. The examiner was professor Leo de Vin. The project was conducted for Swegon AB and dealt with developing a user interface for systems regulating climate parameters in indoor environments, such as hotel rooms or office environments. The area of focus has been on developing the user interface with regard to end users, giving it the right functions and making it easy to understand. Suggestions about how user interfaces of this type could look was to be delivered to Swegon. The project started with creating a foundation. This was done through literature studies, benchmarking and interviews. The information gained here was used to put together a list of requirements which was later used as a guide when developing and evaluating concepts. Idea generation-methods were used to generate concepts and the concepts were developed further to later be voted on by employees at Swegon. The votes were evaluated and two concepts were developed, based on the the voting outcome. The concepts are inspired by wishes from the end users (expressed in the interviews) and are developed with regard to principles of design. The concepts were made into prototypes, in the form of 3D-printed models. The results of the project, in short: • Two image boards. One with thoughts about functions of existing climate related user interfaces written on it, and one with thoughts of different ways of illustrating air-temperature written on it. • Explanations of and reflections about functions of four different types of user interfaces for heating, ventilation and air conditioning (HVAC) systems. • Four product semantic analyses (PSA). Three of existing user interfaces for Swegon HVAC systems and one of a concept for a user interface for HVAC systems. • Interviews with six potential end users, written down to a large extent. • A compilation of the six interviews, written down in English. • An interview with an employee at Swegon service, regarding installation of user interfaces for HVAC systems, written down to a large extent. • A functional analysis, which in this project works as a requirements specification. • 10 ideas of concepts. • Two voting-systems which are developed for use when voting for several elements which can be combined to make up a holistic concept. The voting-systems are inspired by the "morphological analysis" described by Johannesson et al. (2009). • Two final concepts of user interfaces for HVAC systems with thorough descriptions in a table in this report. The concepts are developed with respect to end users and design principles. • Simplified versions of each of the two final concepts as CAD-models and as 3D-prints.