Dissertations / Theses on the topic 'Radiant Heating and Cooling'
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Poulis, P. D. A. "Radiant wall and floor heating and cooling." Thesis, Open University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384588.
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Gong, Xiangyang. "Investigation of a radiantly heated and cooled office with an integrated desiccant ventilation unit." [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-1559.
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Jarumongkonsak, Pornput. "Development and performance investigation on solar-powered thermoelectric radiant cooling in building-integrated system for a bedroom under hot and humid climate." Thesis, University of Nottingham, 2016. http://eprints.nottingham.ac.uk/33629/.
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In order to replace a conventional air-conditioner (AC) based on vapour compression technology that directly has high global warming potential and also currently consumes the most fossil fuel primary energy in building sector of tropical countries for generating thermal comfort on sleeping purpose, other alternative green space cooling technologies, as thermoelectric cooling (TEC), has to be improved to have same performance with AC. This research aims to develop and investigate a performance of Solar-powered Thermoelectric Radiant Cooling (STRC) system, as the combination of TEC and radiant cooling (RC) that is well known in its low energy consumption advantage. The studies were conducted through calculations, CFD simulations, system performance simulations and experiments. The results of optimum STRC system design was proved to provide better thermal and air quality performances, while the result in energy performance was depended on the TEC’s COP and vapour condensation prevention. After novel developing of TEC’s cooling channel with combined helical and an oblique fin to induce effective secondary flows that highly reduced the TEC’s hot side temperature in this research, the COP was able to increase up to 175%. Meanwhile, a novel bio-inspired combined superhydrophobic and hydrophobic coating on RC panel were able to competently repel most condensed water droplets, leaving just tiny droplets that was hard to be seen by naked eye. Finally, the COP of STRC system from house model experiment in 1:100 scales under hot and high humid climate was as high as 2.1 that helped STRC to consume electricity 34% less than AC system. Along with other benefits, as no working fluid, noise-free and low maintenance needs, the return of investment (ROI) was studied to be only 5-6 years when being operated with grid electricity and 17-18 years with PV panel generated electricity.
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Romaní, Picas Joaquim. "Improvement of building energy efficiency with radiant walls." Doctoral thesis, Universitat de Lleida, 2017. http://hdl.handle.net/10803/461942.
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Els edificis suposen una part molt significant del consum energètic i de les emissions de CO2 a nivell global. Resoldre aquest problema requereix de la implementació de tecnologies d'eficiència energètica i de la integració d'energies renovables. En aquest context, els mur radiants són una tecnologia capaç d'afrontar aquests reptes. La avaluació del potencial d'aquest sistema s'ha dut a terme amb la experimentació d'una caseta amb murs radiant connectada a un sistema geotèrmic. Els resultats mostren la capacitat del sistema per reduir el consum energètic i desplaçar el pics de demanda, destacant també la sensibilitat als paràmetres de control. Les dades experimentals han servit per desenvolupar un model numèric del mur radiant, el qual s'ha fet servir per un estudi paramètric dels paràmetres de disseny. Finalment, aquest s'ha integrat a un model d'una habitació per estudiar diferents conceptes de control que maximitzin l'aprofitament de la producció d'uns panells fotovoltaics.Los edificios suponen una fracción significativa del consumo energético y de emisiones de CO2 globales. Resolver este problema requiere implementar tecnologías de eficiencia energética e integrar energías renovables. En este contexto, los muros radiantes son una tecnología capaz de lidiar con estos retos. La evaluación del potencial del sistema se ha llevado a cabo con la experimentación de un cubículo con muros radiantes conectados a un sistema geotérmico. Los resultados muestran la capacidad del sistema para reducir el consumo energético y desplazar los picos de demanda, destacando también la sensibilidad a los parámetros de control. Los datos experimentales sirvieron para desarrollar un modelo numérico del muro radiante, el cual se ha usado para un estudio paramétrico de los parámetros de diseño. Finalmente, este se ha integrado a un modelo de cubículo para estudiar diferentes conceptos de control que maximicen el aprovechamiento de la producción de unos paneles fotovoltaicos.
Buildings represent a significant fraction of the global energy use and CO2 emissions. Solving this issue require the implementation of energy efficiency technologies and the integration of renewable energies. In this context, radiant walls are a technology capable of dealing with these challenges. The evaluation of this system was carried out with the experimentation of a radiant wall cubicle coupled to a geothermal system. The results showed the capability of the system for reducing the energy and shifting the peak loads, highlighting the sensitivity to control parameters. The experimental data was used for the development of a numerical model of the radiant wall, which was used in a parametric study of the design parameters. Finally, the numeric model was integrated in a cubicle model in order to study different control concepts that maximized the use of the energy produced by photovoltaic panels.
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Benzarti, Ghedas Habiba. "Modeling and thermal optimization of residential buildings using BIM and based on RTS method : application to traditional and standard house in Sousse city." Doctoral thesis, Universitat Politècnica de Catalunya, 2017. http://hdl.handle.net/10803/406007.
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The thermal quality of the contemporary building tends to be deteriorated due to aesthetic and economic considerations. Cheap materials which are thermally inappropriate are still rising in new buildings. Actually, the architectural design has been changed. Hence, the orientation is poorly investigated. The interior height of the new buildings is defectively compared to those of traditional houses. In addition, the patio is replaced by a corridor and different parts have already become communicating. Accordingly, the heating and cooling space becomes more and more important. The traditional dwelling, in fact, has a bioclimatic architecture which provides naturally minimal comfort.
In our work, we tend to exploit the REVIT software in the residential building simulation in Tunisia and to optimize the modern housing model. Following the REVIT validation of the obtained results and comparing them to TRNSYS and SPREADSHEET ASHRAE, we have already relied on them to assess both housing models (contemporary and traditional). Using REVIT, the evaluation results show that traditional housing are more efficient than contemporary ones particularly during summer period. Then, we optimize the modern models making use of the passive strategies of traditional bioclimatic architecture and the improvement measures in the previous investigations. Numerous tests have been generated applying REVIT software in order to determine various models of contemporary housing which are able to be integrated into the Mediterranean climate. In fact, these tests indicate that REVIT efficiency is based on RTS method in thermal simulation of residential buildings.La qualité thermique des bâtiments modernes a une tendance à se détériorer en raison de considérations esthétiques et économiques. L'utilisation de matériaux de construction de bon marché et thermiquement inappropriées ne cesse d'augmenter dans les nouvelles constructions. À l'heure actuelle, la conception architecturale a changé. L'orientation est peu étudiée, la hauteur intérieure des nouveaux locaux est faible comparée à celle de la maison traditionnelle et le patio est remplacé par un couloir. Les différentes parties sont devenues communicantes. Ainsi, l'espace de chauffage et de refroidissement devient plus important. L'habitation traditionnelle tunisienne présente une architecture bioclimatique qui permet de fournir un confort minimal naturellement. Notre travail vise à exploiter le REVIT dans la simulation des bâtiments résidentiels en Tunisie et d'optimiser le modèle d'habitat moderne. Après validation des résultats obtenus par REVIT, comparés à ceux de TRNSYS et SPREADSHEET ASHRAE, nous l'avons, tout d'abord, exploité pour évaluer les deux modèles d'habitats (traditionnels et contemporains). Les résultats d'évaluation, en utilisant REVIT, montrent que l'habitat traditionnel sont plus efficaces que celui moderne particulièrement en période estivale. Par la suite, nous avons optimisé le modèle de maisons contemporaines, en utilisant en premier lieu, les stratégies passives de l'architecture bioclimatique traditionnelle, et en second lieu, en utilisant les mesures d'amélioration utilisées dans des études antérieures. Afin, de déterminer une variante de modèle d'habitat contemporain thermiquement optimal et qui s'intègre dans le climat méditerranéen, plusieurs tests sont générés en utilisant REVIT. Ces tests montrent l'efficacité de ce dernier qui se base sur la méthode RTS dans la simulation thermique des bâtiments résidentiels.
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Khanna, Amit. "Development and Demonstration of a Performance Test Protocol For Radiant Floor Heating Systems." Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/30987.
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The Radiant Heating markets - especially, the hydronic segment - are growing rapidly in North America due to homeownersâ increasing demand for comfort and the steady rise in residential construction. Radiant systems are promising technologies for energy saving in commercial and residential building sectors together with improving occupant thermal comfort. Such a technology is different from the more standard all-air systems and thus can be termed Space Conditioning. However, the thermal performance of radiant systems in buildings has not been fully understood and accounted for. This is primarily due to lack of any standard testing mechanism. The central thrust of this paper is to experimentally investigate questions relating to thermal performance of radiant systems, thus also contribute towards evolving a new standard for testing mechanisms. Products from 12 different radiant floor systems were chosen from the market. Having defined each with similar control parameters such as flow rate, supply water temperature and similar design parameters like size, insulation etc., they are separately tested in a well insulated test setup. Experiments on the time variations for each test floor were performed at supply water temperatures ranging between 100F â 140F with a 10F increment at each stage. Having gathered data through the Data Acquisition System (DAS), the data is analyzed and compared between all systems. The paper concludes by providing recommendations for experimentally testing thermal energy performance, thermal uniformity and thermal stability of radiant floor heating technology.Master of Science
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Zhang, Zhi Long. "Temperature control strategies for radiant floor heating systems." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ59301.pdf.
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Kegel, Martin. "Experimental and Analytical Analysis of Perimeter Radiant Heating Panels." Thesis, University of Waterloo, 2006. http://hdl.handle.net/10012/2867.
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In recent years the U. S. and Canada have seen a steady increase in energy consumption. The U. S. in particular uses 25% more energy than it did 20 years ago. With declining natural resources and an increase in fuel costs, it has become important to find methods of reducing energy consumption, in which energy conservation in space heating and cooling has become a widely researched area. One method that has been identified to reduce the energy required for space heating is the use of radiant panels. Radiant panels are beneficial because the temperature set points in a room can be lowered without sacrificing occupant comfort. They have therefore become very popular in the market. Further research, however, is required to optimize the performance of these panels so energy savings can be realized. An analytical model has been developed to predict the panel temperature and heat output for perimeter radiant panel systems with a known inlet temperature and flow rate, based on a flat plate solar collector (RSC) model. As radiative and convective heat transfer coefficients were required to run the model, an analytical analysis of the radiative heat transfer was performed, and a numerical model was developed to predict the convective heat transfer coefficient. Using the conventional radiative heat exchange method assuming a three-surface enclosure, the radiative heat transfer could be determined. Numerically, a correlation was developed to predict the natural convective heat transfer.
To validate the analytical model, an experimental analysis was performed on radiant panels. A 4m by 4m by 3m test chamber was constructed in which the surrounding walls and floor were maintained at a constant temperature and the heat output from an installed radiant panel was measured. Two radiant panels were tested; a 0. 61m wide panel with 4 passes and a 0. 61m wide panel with 8 passes. The panels were tested at 5 different inlet water temperatures ranging from 50°C to 100°C.
The RSC model panel temperature and heat output predictions were in good agreement with the experimental results. The RSC model followed the same trends as that in the experimental results, and the panel temperature and panel heat output were within experimental uncertainty, concluding that the RSC model is a viable, simple algorithm which could be used to predict panel performance.
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Gayeski, Nicholas (Nicholas Thomas). "Predictive pre-cooling control for low lift radiant cooling using building thermal mass." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/61508.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Architecture, 2010.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (p. 143-159).
Low lift cooling systems (LLCS) hold the potential for significant energy savings relative to conventional cooling systems. An LLCS is a cooling system which leverages existing HVAC technologies to provide low energy cooling by operating a chiller at low pressure ratios more of the time. An LLCS combines variable capacity chillers, hydronic distribution, radiant cooling, thermal energy storage and predictive control to achieve lower condensing temperatures, higher evaporating temperatures, and reductions in instantaneous cooling loads by spreading the daily cooling load over time. The LLCS studied in this research is composed of a variable speed chiller and a concrete-core radiant floor, which acts as thermal energy storage. The operation of the chiller is optimized to minimize daily energy consumption while meeting thermal comfort requirements. This is achieved through predictive pre-cooling of the thermally massive concrete floor. The predictive pre-cooling control optimization uses measured data from a test chamber, forecasts of controlled climate conditions and internal loads, empirical models of chiller performance, and data-driven models of the temperature response of the zone being controlled. These data and models are used to determine a near-optimal operational strategy for the chiller over a 24-hour horizon. At each hour, this optimization is updated with measured data from the previous hour and new forecasts for the next 24 hours. The novel contributions of this research include the following: experimental validation of the sensible cooling energy savings of the LLCS relative to a high efficiency split system air conditioner - savings measured in a full size test chamber were 25 percent for a typical summer week in Atlanta subject to standard efficiency internal loads; development of a methodology for incorporating real building thermal mass, chiller performance models, and room temperature response models into a predictive pre-cooling control optimization for LLCS; and detailed experimental data on the performance of a rolling-piston compressor chiller to support this and future research.
by Nicholas Thomas Gayeski.
Ph.D.
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Soderlund, Matthew Roger. "Congeneration dedicated to heating and cooling." Thesis, Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/17672.
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Gratkowski, Mark T. "Radiant smoldering ignition of plywood." Link to electronic thesis, 2004. http://www.wpi.edu/Pubs/ETD/Available/etd-0831104-125545/.
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Hart, Neil Anthony. "Optimisation of microwave firing of ceramics by combination with electrical radiant heating." Thesis, Staffordshire University, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.413533.
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Dong, Bing. "Integrated Building Heating, Cooling and Ventilation Control." Research Showcase @ CMU, 2010. http://repository.cmu.edu/dissertations/4.
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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.
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Bol, Bullen A. D. "A pervaporation membrane absorption cooling heating system." Thesis, University of Nottingham, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.289081.
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Karlström, Petra. "Soft Heating and Cooling in Humid Climates." Thesis, KTH, Byggnadsteknik, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-35098.
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Chekh, O. "Heat pumps technology of heating and cooling." Thesis, Сумський державний університет, 2014. http://essuir.sumdu.edu.ua/handle/123456789/34922.
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Increasing concern to society ecological and environmental issues, the demand for more efficient ways of using heat and energy is growing. Heat pump industry uses year-round heating with thermal energy. This concept is done by providing localized or redirected heat, by the exchange of cold air with the heated air.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/34922
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Marin, Pablo. "Design of the installation providing with DHW and radiant floor heating using solar energy and biomass." Thesis, Högskolan i Gävle, Avdelningen för bygg- energi- och miljöteknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-9839.
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In the last decades terms like Global Warming and Sustainable development have arisen. The anthropogenic green house gases emissions have raised the concentration of CO2 in the atmosphere to levels that might lead to a high increase in the average temperature in Earth. One of the most effective ways to fight against this phenomenon is to promote clean renewable energies. Among them, solar energy has the biggest developing potential and has proved to be an efficient and cost-effective energy source for different applications; one of them being the production of Domestic Hot Water and Space Heating. The aim of this Thesis is to study the possibilities to provide a single family house with hot water and space heating in an environmental friendly way. To do so, a solar system with biomass support will be designed for a single family house in northern Spain. The building has total energy demand of 20.5 MWh a year, of which 18 MWh correspond to space heating and 2.5 MWh to domestic hot water. The chosen solution for the building includes 12 solar collectors with a total area of 23.4 m2, a biomass boiler with a nominal power of 30 kW and a 32 kW oil boiler. Additionally, a radiant floor system was used as it perfectly adapts to the low temperature of the solar system. The result is an installation working with an 85% of renewable energies. This high share of renewable energy entails savings of 2,000 liters of oil a year, avoiding the emission of 4.5 tones of CO2 to the atmosphere every year. The economic calculations show that the pay back of the investment is 10 years with a Internal Rate of Return of 13%. Therefore, it can be said that, for this particular building and due to the governmental subsidies granted, solar energy is a cost effective alternative to provide the basic energy needs of a house.
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VILAFRANCA, MANGUÁN ANA. "Convesion of industrial compression cooling to absorption cooling in an integrated district heating and cooling system." Thesis, University of Gävle, University of Gävle, Department of Technology and Built Environment, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-4145.
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Astra Zeneca plant in Gärtuna has many compression cooling machines for comfort that consume about 11.7 GWh of electricity per year. Many of the cooling machines are old; due to the increase of production of the plant, cooling capacity was limited and new machines have been built. Now, the cooling capacity is over-sized. Söderenergi is the district heating plant that supplies heating to Astra Zeneca plant. Due to the strict environmental policy in the energy plant, last year, a bio-fuelled CHP plant was built. It is awarded with the electricity certificate system.
The study investigates the possibility for converting some of the compression cooling to absorption cooling and then analyzes the effects of the district heating system through MODEST optimizations. The effects of the analysis are studied in a system composed by the district heating system in Södertälje and cooling system in Astra Zeneca. In the current system the district heating production is from boiler and compression system supplies cooling to Astra Zeneca. The future system includes a CHP plant for the heating production, and compression system is converted to absorption system in Astra Zeneca. Four effects are analyzed in the system: optimal distribution of the district heating production with the plants available, saving fuel, environmental impact and total cost. The environmental impact has been analyzed considering the marginal electricity from coal condensing plants. The total cost is divided in two parts: production cost, in which district heating cost, purchase of electricity and Emissions Trading cost are included, and investment costs. The progressive changes are introduced in the system as four different scenarios.
The introduction of the absorption machines in the system with the current district heating production increases the total cost due to the low electricity price in Sweden. The introduction of the CHP plant in the district heating production supposes a profit of the production cost with compression system due to the high income of the electricity produced that is sold to the grid; it profit increases when compression is replaced by absorption system. The fuel used in the production of the future system decreases and also the emissions. Then, the future system becomes an opportunity from an environmental and economical point of view. At higher purchase electricity prices predicted in the open electricity market for an immediately future, the future system will become more economically advantageous.
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Ma'bdeh, Shouib Nouh. "A Decision-Support Framework for the Design and Application of Radiant Cooling Systems." Diss., Virginia Tech, 2011. http://hdl.handle.net/10919/40281.
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Creating a sense of place through a comfortable indoor condition is a goal of the architectural design process. Thermal comfort is an important component of this condition. To achieve thermally comfortable environments mechanical systems such as Radiant Cooling (RC) could be used. RC systems have potential benefit of lower energy consumption when compared to other common cooling, ventilating and air-conditioning systems. Decisions related to the use of mechanical systems such as these should be considered in the early stages of design to maximize the building performance through systems integration and minimize redesign as part of the design process.
RC systems have several special demands and related variables. Architects, HVAC system engineers, and decision-makers have to understand these issues and variables and their impact on the other building performance mandates. Through this understanding, these professionals can better evaluate tradeoffs to reach the desired solution of the design problem. Unfortunately, in the United States few architects and engineers have experience with RC systems which in turn limits the application of these systems.
Through systematic literature review, a series of case studies, and interviews with experienced professionals, this research captures and structures knowledge related to how decisions are made concerning RC systems. Through this knowledge capturing procedure, the relevant design performance mandates, barriers and constraints, and potential advantages and benefits of radiant cooling systems are determined and mapped to a decision-support framework. This framework is graphically presented which may later be translated to a decision-support software package which could then be developed as a radiant cooling system design assistance tool for architects and HVAC engineers.Ph. D.
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Chan, Hoy-Yen. "Solar facades for heating and cooling in buildings." Thesis, University of Nottingham, 2011. http://eprints.nottingham.ac.uk/12319/.
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The aim of this thesis is to study the energy performance of a building integrated heating and cooling system. The research objectives are to investigate the system operating characters, to develop mathematical models for the heating and cooling systems, to demonstrate the technologies experimentally, to identify the best designs for a combined system and to investigate the cost effectiveness of the system. The main components of the systems are the aluminium plate façade and the building wall behind it, these form a plenum between them and the air is then heated or cooled as it flows through this plenum. Mathematical models were developed based on the energy balance equations and solved by matrix inversion method. These models were then validated with experimental results. The experiments were carried out in the laboratory with a facade area of 2m2. Two designs of facade were tested, i.e. flat and transpired plates. Results showed that the transpired design gave better thermal performance; the system efficiency for the flat plate was only about 30%, whereas it was about 85% for the transpired plate. On the other hand, a cooling system with double plenums was found to be better than a single plenum. Thus, a transpired plate with two plenums was identified as the best design for space heating and cooling. The cooling efficiency was nearly 2.0 even at low solar radiation intensity. A simulation study was carried out by assuming a 40m2 of façade was installed on an office building in London. The yearly energy saving was estimated as 10,877kWh, which is equivalent to 5,874kgCO2/year of emission avoidance. The system is calculated to cost about £70/m2, and for a discount rate of 5% and 30 years of lifetime, the payback period for this system would be less than a years.
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Rybář, Jakub. "Sálavé vytápění průmyslových hal." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2012. http://www.nusl.cz/ntk/nusl-225568.
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Indoor climate of industrial halls is now advantageously shaped radiant heating systems, which are more flexible and efficient than convection systems. The crucial component of indoor climate in these systems mean radiant temperature. The work focuses on theoretical and experimental research on the location and operation of radiant panels. For the theoretical part is used new computer software able to calculate the Institute TZB mean radiation temperature distribution in 2D space. The experimental part was carried out comprehensive measurements of indoor climate parameters specific industrial halls and subsequently compared. Work includes the design and comparison of three variants of heating in the indoor facility.
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Markowicz, Catarina. "Analysis of Cooling Capability in Polish District Heating Substations." Thesis, Uppsala universitet, Institutionen för teknikvetenskaper, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-173144.
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For a district heating company it is of importance to have an efficient and well performing system. A central part in the work to lower temperature levels in district heating networks is to acknowledge and improve cooling capability in substations. The aim of this thesis is to analyse substations in Polish district heating systems in order to identify reasons of poor cooling and to present suggestions of implementable measures. Furthermore, the economical saving potential from an improved cooling is evaluated. The analysis was carried out for two of the five Polish companies included in this report; Sydkraft EC Slupsk and MEC Koszalin. It was followed by two scenarios created for evaluation of improvement possibilities based on calculated financial savings from reduction of distribution heat losses and distribution pumping. The results show that there are significant improvement possibilities. From the carried out scenarios a saving potential between 15 000 to 20 000 PLN/substation is possible to achieve for selected worst substations, if their individual annual average cooling is set to 30°C. The analysis further shows that causes of poor cooling in substations are highly individual but points out that customer owned substations are represented in the majority of worst substations.
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Amara, Sofiane. "Novel and ancient technologies for heating and cooling buildings." Doctoral thesis, Luleå tekniska universitet, Arkitektur och vatten, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-16977.
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The basic issue of this thesis concerns one of the fundamental problems of the future of our society: How to meet the energy requirements for a large and growing world population while preserving our environment? This question is important for the world and the answers are complex and interwoven.Conventional energy sources, fossil and fissile, are polluting in the present and in the future: they erode the environment and their resources are limited. Renewable energy (hydro, wind, solar, geothermal) constitutes a minimum of pollution in the different energy systems. The technologies for using renewable energy are well known though further development and progress are made. This development also requires behavioural change, adaptation, and above all political will. The transition from an economy based on fossil energy to an economy based on renewable energy appears necessary for the protection of the environment. The cost of renewable energy is often represented as an obstacle but remains competitive in the long run.The development and availability of renewable energy, which varies because of its spatial and temporal distribution, require an adaptation of lifestyle, habits, habitat design (passive bioclimatic houses), urban planning and transportation.The focus of this thesis was to apply renewable energy in an area with hot summers and cold winter, a climate like that in the northwest of Algeria. In order to provide improved comfort in the buildings and also economic development in this area, the energy demand for heating and cooling was analyzed in the ancient city of Tlemcen. To supply domestic hot water and space heating, water must be simultaneously available at two different temperature levels. Cold water temperature, close to that of the atmosphere, and hot water between 50 and 60°C. An interesting feature of the preparation of hot water is the small variation of requirements during the year, unlike that to heating. The preparation of hot water is one of the preferred applications of solar energy in the building for several reasons. For this reason an experimental study of the thermal behaviour of a domestic hot water storage tank was undertaken. The phenomena that affect the thermal behaviour of tank especially the coupling between the solar collector and storage tank was studied. This study included concentrating solar collector in which optical fibers were used to transport the energy to the storage tank. Another technology was introduced and developed for the heating and cooling of buildings in the desert involving an existing ancient irrigation system called Fouggara. The novel idea is to use the Fouggara as an air conditioner by pumping ambient air through this underground system. Then air at a temperature of about 21°C would be supplied to the building for heating in the winter and cooling in the summer. This study shows the feasibility of using this ancient irrigation system of Fouggara and contributes to reducing and eliminating the energy demand for heating and cooling buildings in the Sahara desert.Godkänd; 2011; 20110920 (sofama)
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Saman, Namir Fathullah. "Analysis of building heating and cooling requirements after shutdown." Diss., The University of Arizona, 1989. http://hdl.handle.net/10150/184867.
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The heating and cooling requirements after a shutdown period of the heating ventilating and air conditioning (HVAC) systems in buildings are studied through an analytical model. The parameters affecting the preconditioning and storage loads which are of particular importance are identified. A mathematical computer model is developed to facilitate the analysis of the shutdown loads. Zones are grouped in terms of heavy, medium and light weight construction for the study. For a specified zone, the ratio of the inside surface area to the outside exposed area, A(s)/A(w), is an important parameter in predicting the additional loads resulting from system shutdown. The computer model is validated with known computer programs, namely DOE-2, BLAST, and DARE-P. A simplification to the model is proved to be adequate for the study. The zones with similar weight characteristics and the same A(s)/A(w) ratio, prove to have the same temperature profiles during the shutdown period, provided that they are at the same ambient conditions. Design guidance and procedures for predicting the preconditioning and storage loads using the models are developed. In addition, the use of DOE-2 and ASHRAE weighting factor method for shutdown load predictions is demonstrated for generic and custom applications.
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Afroz, Zakia. "Performance improvement of building heating, cooling and ventilation systems." Thesis, Afroz, Zakia (2019) Performance improvement of building heating, cooling and ventilation systems. PhD thesis, Murdoch University, 2019. https://researchrepository.murdoch.edu.au/id/eprint/54931/.
Full textAbstract:
Heating, Ventilation, and Air Conditioning (HVAC) systems are responsible for a substantial share of the energy consumed in commercial buildings. Energy used by HVAC systems has increased over the years due to its broader application in response to the growing demand for better thermal comfort within the built environment. While existing case studies demonstrate the energy saving potential of efficient HVAC operation, there is a lack of studies quantifying energy savings from optimal operation of HVAC systems when considering indoor environmental conditions. This research aims to improve the performance of HVAC systems by optimizing its energy consumption without compromising indoor environmental conditions.
The concept of maintaining indoor environmental conditions poses new challenges to the optimal operation of HVAC systems. While the primary objective of ensuring optimal operation is to minimize energy consumption, controlling the indoor environmental parameters, e.g., temperature, humidity, the level of carbon dioxide (CO2), and volatile organic compounds (VOCs) to remain within the acceptable range imposes excess energy use. These two conflicting objectives constitute a multi-variable constrained optimization problem that has been solved using a particle swarm algorithm (PSO).
A real-time predictive model has been developed for individual indoor environmental parameters and HVAC energy consumption using Nonlinear Autoregressive Exogenous (NARX) neural network (NN). During model development, efforts have been paid to optimize the performance of the model in terms of complexity, prediction results, and ease of application to a real system. The proposed predictive models are then optimized to provide an optimal control setting for HVAC systems taking into account seasonal variations. An extensive case study analysis has been performed in a real commercial building to demonstrate the effectiveness of developing predictive models and evaluating the relevance of integrating indoor air quality (IAQ) within the optimization problem.
Results show that it is possible to minimize 7.8% energy consumption from HVAC systems without compromising indoor environmental conditions. This study demonstrates that the proposed optimal control settings maintain the indoor environment within the acceptable limit of thermal comfort conditions (indoor air temperature between 19.60 to 28.20C and indoor air humidity between 30 to 65 %RH as per ASHRAE Standard 55-2017) and air quality (CO2 ≤ 800 ppm and VOC ≤ 1000ppm as per Australian Standard AS 1668.2 2016). The outcomes of this research will act as a guideline for energy management practices, not only for energy efficient building design and retrofitting but also for building energy performance analysis. This research provides insight into the aspects that affect the performance of predictive models for indoor temperature. The proposed feature selection approach establishes its efficacy to determine salient and independent input parameters without compromising prediction performance. The application of this approach will minimize the measurement and data storing cost of variables. Further, using fewer numbers of input parameters in the model will reduce the computational cost and time. Thus, the proposed model establishes its applicability in a real system for a more extended period of advanced prediction. In addition, the need to better account for building-occupant interactions as an important step to maintain a healthy indoor environment has been recognized through evaluating a real-life demand control (DCV) system. Lastly, the proposed optimization approach, where four defined environmental parameters are considered simultaneously presents a new outlook within the HVAC control system by eliminating the unseen interface between thermal comfort and IAQ.
Overall, this unexploited potential to simultaneously improve the performance of HVAC systems and indoor environmental conditions drives the discussion on reconsidering the set-point configuration standards of HVAC in commercial buildings, either as part of individual building retrofit planning or as part of building regulatory applications.
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Alharbi, Abdulrahman. "Investigation of sub-wet bulb temperature evaporative cooling system for cooling in buildings." Thesis, University of Nottingham, 2014. http://eprints.nottingham.ac.uk/27806/.
Full textAbstract:
The work presented in this thesis investigates design, computer modelling and testing a sub-wet bulb temperature evaporative cooling system for space air conditioning in buildings. The context of this evaporative cooling technology design is specifically targeted at locations with a hot and dry climate such as that prevailing in most regions of Middle East countries. The focus of this technology is to address the ever-escalating energy consumption in buildings for space cooling using mechanical vapour compression air conditioning systems. In this work, two evaporative cooling configurations both based on sub-wet bulb temperature principle have been studied. Furthermore, in these designs, it was sought to adopt porous ceramic materials as wet media for the evaporative cooler and as building element and use of heat pipes as heat transfer devices. In the first test rig, the prototype system uses porous ceramic materials as part of a functioning building wall element. Experimental and modelling results were obtained for ambient inlet air dry bulb temperature of 30 and 35oC, relative humidity ranging from 35% to 55% and intake air velocity less than 2 (m/s). It was found that the design achieved sub-wet bulb air temperature conditions and a maximum cooling capacity approaching 242 W/m2 of exposed ceramic material wet surface area. The wet bulb effectiveness of the system was higher than unity. The second design exploits the high thermal conductivity of heat pipes to be integrated as an effective heat transfer device with wet porous ceramic flat panels for evaporative cooling. The thermal performance of the prototype was presented and the computer model was validated using laboratory tests at temperatures of 30 and 35oC and relative humidity ranging from 35% to 55%. It was found that at airflow rates of 0.0031kg/s, inlet dry-bulb temperature of 35oC and relative humidity of 35%, the supply air could be cooled to below the inlet air wet bulb temperature and achieve a maximum cooling capacity of about 206 W/m2 of wet ceramic surface area. It was shown that the computer model and experimental tests are largely in good agreement. Finally, a brief case study on direct evaporative cooling thermal performance and environmental impact was conducted as part of a field trip study conducted on an existing large scale installation in Mina Valley, Saudi Arabia. It was found that the evaporative cooling systems used for space cooling in pilgrims’ accommodations and in train stations could reduce energy consumption by as much as 75% and cut carbon dioxide emission by 78% compared to traditional vapour compression systems. This demonstrates strongly that in a region with a hot and dry climate such as Mina Valley, evaporative cooling systems can be an environmentally friendly and energy-efficient cooling system compared to conventional vapour compression systems.
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Al-Hinai, Hilal Ali Zaher. "Natural Cooling Techniques For Buildings." Thesis, Cranfield University, 1992. http://hdl.handle.net/1826/3591.
Full textAbstract:
Modern development in many Third World countries in the
hot regions of the world,, have been accompanied by the
construction of highly energy-wasteful buildings. The
interiors of these buildings have to be mechanically airconditioned
in order to achieve thermal-comfort conditions.
The consequence of this, has been the rapid increase in
electricity-generating plant capacity to match demand (of
which, for example at present in Oman, more than 70%
nationally is used for air-conditioning modern, energyinefficient
buildings).
The aim of this work was to find the most suitable way
of stabilising or even reducing the electricity demand in a
country like Oman. The first step taken to achieve this aim,
was to study and draw out lessons from the vernacular
architecture of the different climatic regions in Oman. This
has been followed by a literature survey that looks at
passive and active natural cooling techniques for buildings
in hot climates. Mathematical models were then developed to
analyze and compare those passive techniques that are most
suitable for an environment like that of Oman. Different ways
of reducing the heat gain through the roof were investigated
and compared. These include the addition of insulation,
shading, air-cooling of the roof when the ambient air
temperature is lower than that of the roof, and roof ponds.
Roof ponds were found to be the most effective of those
techniques analyzed. An improved design of the roof pond (the
Water Diode roof pond) that eliminates the need for covering
the roof pond during the day and uncovering it at night, was
suggested and analyzed. The analysis showed promising
results. Mathematical models were also developed to analyze and
compare dif f erent ways of reducing the heat gain through the
walls. These included the use of closed cavities, naturally
ventilated cavities, the addition of insulation, and the
effect of using brick as compared to concrete block. The
analysis suggested that the combination of a Water Diode roof
pond and insulated brick wall construction will reduce the
heat gain through the envelope of a single room by more than
90%, when compared to a room with un-insulated roof and
single-leaf concrete block walls.
An empirical validation of the mathematical models was
conducted. The results showed a good agreement between the
actual and predicted values. An economical analysis of the
commonly used roof and wall constructions in Oman, was also
conducted. This compared the life-cycle cost of nine
different construction techniques, with eight different airconditioning
schedules. The result of this analysis showed a
clear advantage of using roof insulation, reflective double
glazing, and insulated walls with brick outer-leaf and
concrete block inner-leaf.
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Clark, Craig R. "Sympathetic heating and cooling of trapped atomic and molecular ions." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/43757.
Full textAbstract:
Laser-cooled atomic ions have led to an unprecedented amount of control over the quantum states of matter. The Coulombic interaction allows for information to be transferred between neighboring ions, and this interaction can be used to entangle qubits for logic operations in quantum information processors. The same procedure for logic operations can be used for high resolution atomic spectroscopy, and is the basis for the most accurate atomic optical clocks to date. This thesis describes how laser-cooled atomic ions can impact physical chemistry through the development of molecular ion spectroscopy techniques and the simulation of magnetic systems by ion trap quantum computers.
A new technique developed for spectroscopy, Sympathetic Heating Spectroscopy (SHS), takes advantage of the Coulombic interaction between two trapped ions: the control ion and a spectroscopy ion. SHS uses the back action of the interrogating laser to map spectroscopy ion information onto the Doppler shift of the control ion for measurement. SHS only requires Doppler cooling of the ions and fluorescence measurement and represents a simplification of quantum logic spectroscopy. This technique is demonstrated on two individual isotopes of calcium: Ca-40(+) for cooling and Ca-44(+) as the spectroscopy ion.
Having demonstrated SHS with atomic ions, the next step was to extend the technique by loading and characterizing molecular ions. The identification of an unknown molecular ion is necessary and can be achieved by monitoring the change in motion of the two ion crystal, which is dependent on the molecular ion mass. The motion of two trapped ions is described by their normal modes, which can be accurately measured by performing resolved sideband spectroscopy of the S(1/2)-D(5/2) transition of calcium. The resolved sidebands can be used to identify unknown ions (atomic and molecular) by calculating the mass based on the observed value in axial normal mode frequencies. Again, the trapped molecular ion is sympathetically cooled via the Coulombic interaction between the Ca-40(+) and the unknown molecular ion. The sensitivity of SHS could be improved by implementing sympathetic sideband cooling and determining the heating by measuring single quanta of motion.
The ultimate limit of control would be the development of an ion trap quantum computer. Many theoretical quantum computing researchers have made bold claims of the exponential improvement a quantum computer would have over a classical computer for the simulation of physical systems such as molecules. These claims are true in principle for ideal systems, but given non-ideal components it is necessary to consider the scaling due to error correction. An estimate of the resource requirements, the total number of physical qubits and computational time, required to compute the ground state energy of a 1-D quantum Transverse Ising Model (TIM) of N spin-1/2 particles, as a function of the system size and the numerical precision, is presented. This estimate is based on analyzing the impact of fault-tolerant quantum error correction in the context of the quantum logic array architecture. The results show that a significant amount of error correction is required to implement the TIM problem due to the exponential scaling of the computational time with the desired precision of the energy. Comparison of this result to the resource requirements for a fault-tolerant implementation of Shor's quantum factoring algorithm reveals that the required logical qubit reliability is similar for both the TIM problem and the factoring problem.
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Marigny, Johan. "Analysis of simultaneous cooling and heating in supermarket refrigeration systems." Thesis, KTH, Tillämpad termodynamik och kylteknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-44469.
Full textAbstract:
In this master thesis project, conventional supermarket refrigeration systems using R404A are compared with refrigeration system solutions using natural refrigerants such as carbon dioxide and ammonia. This systems analysis considers the behavior of those systems in floating condensing and heat recovery mode. System heating and cooling COP have been calculated by using computer simulation with the calculation software EES (Engineering Equation Solver). The impact of important parameters such as sub-cooling, external superheating and compressor discharge was also determined through the computer models.The estimation of the system annual energy consumptions shows that systems using natural refrigerant can compete with systems using artificial refrigerant by using heat recovery system such as heat pump cascade, heat pump cascade for sub-cooling, fixed pressure system and de-superheater. If the indirect emission of systems using natural refrigerant and artificial refrigerant is approximately similar, the direct emission for carbon dioxide systems and ammonia systems can be estimated to be 10000 times less important than R404A systems.Multi-unit refrigeration systems have also been studied in this project; it appears that in theory COP improvement of 10% is possible if the condensing temperature of each unit is controlled adequatelly.B
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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.
Full textAbstract:
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.
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Oliver, Jason Ryan. "A micro-COOLING, HEATING, AND POWER (m-CHP) INSTRUCTIONAL MODULE." MSSTATE, 2005. http://sun.library.msstate.edu/ETD-db/theses/available/etd-11092005-123751/.
Full textAbstract:
Cooling, Heating, and Power (CHP) is an emerging category of energy systems consisting of power generation equipment coupled with thermally activated components. The application of CHP systems to residential and small commercial buildings is known as micro-CHP (m-CHP). This instructional module has been developed to introduce engineering students to m-CHP. In the typical engineering curriculum, a number of courses could contain topics related to m-CHP. Thermodynamics, heat transfer, HVAC, heat and power, thermal systems design, and alternate energy systems courses are appropriate m-CHP topics. The types of material and level of analysis for this range of courses vary. In thermodynamics or heat transfer, basic problems involving a m-CHP flavor are needed, but in an alternate energy systems course much more detail and content would be required. This instructional module contains both lecture material and a compilation of problems/exercises for both m-CHP systems and components.
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Nijmeh, Salem Daud. "Solar chemical heat pumps for heating and cooling in Jordan." Thesis, University of Reading, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303147.
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Buker, Mahmut Sami. "Building integrated solar thermal collectors for heating & cooling applications." Thesis, University of Nottingham, 2015. http://eprints.nottingham.ac.uk/29009/.
Full textAbstract:
International Energy Agency Solar Heating & Cooling (IEA SHC) programme states the fact that space/water heating and cooling demand account for over 75% of the energy consumed in single and multi-family homes. Solar energy technology can meet up to 100% of this demand depending on the size of the system, storage capacity, the heat load and the region’s climate. Solar thermal collectors are particular type of heat extracting devices that convert solar radiation into thermal energy through a transport medium or flowing fluid. Although hybrid PV/T or thermal-alone systems offer some advantages to improve the solar heat utilisation, there are a few technical challenges found in these systems in practice that prevented wide-scale applications. These technical drawbacks include being expensive to make and install, inability of switching already-built photovoltaic (PV) systems into PV/T systems, architectural design etc. The aims of this project, therefore, were to investigate roof integrated solar thermal roof collectors that properly blend into surrounding thus avoiding ‘add on’ appearance and having a dual function (heat absorption and roofing). Another objective was to address the inherent technical pitfalls and practical limitations of conventional solar thermal collectors by bringing unique, inexpensive, maintenance free and easily adaptable solutions. Thus, in this innovative research, unique and simple building integrated solar thermal roof collectors have been developed for heating & cooling applications. The roof systems which mainly based on low cost and structurally unique polyethylene heat exchanger are relatively cost effective, competitive and developed by primarily exploiting components and techniques widely available on the market. The following objectives have been independently achieved via evaluating three aspects of investigations as following: • Investigation on the performance of poly heat exchanger underneath PV units • Investigation on the performance of a Building Integrated PV/T Roof ‘Invisible’ Collector combined with a liquid desiccant enhanced indirect evaporative cooling system • Investigation on the build-up and performance test of a novel ‘Sandwich’ solar thermal roof for heat pump operation These works have been assessed by means of computer simulation, laboratory and field experimental work and have been demonstrated adequately. The key findings from the study confirm the potential of the examined technology, and elucidate the specific conclusions for the practice of such systems. The analysis showed that water temperature within the poly heat exchanger loop underneath PV units could reach up to 36°C and the system would achieve up to 20.25% overall thermal efficiency. Techno-economic analysis was carried out by applying the Life Cycle Cost (LCC) method. Evaluations showed that the estimated annual energy savings of the overall system was 10.3 MWh/year and the cost of power generation was found to be £0.0622 per kWh. The heat exchanger loop was coupled with a liquid desiccant enhanced indirect evaporative cooling unit and experimental results indicated that the proposed system could supply about 3 kW of heating and 5.2 kW of cooling power. Lastly, the results from test of a novel solar thermal collector for heat pump operation presented that the difference in water temperature could reach up to 18°C while maximum thermal efficiency found to be 26%. Coefficient Performance of the heat pump (COPHP) and overall system (COPSYS) averages were attained as COPHP=3.01 and COPSYS=2.29, respectively. An economic analysis pointed a minimum payback period of about 3 years for the system.
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Uhrík, Patrik. "Implementace kogeneracni jednotky do siti "Smart Heating and Cooling Networks"." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-318635.
Full textAbstract:
The aim of the Master‘s thesis was to create a computational model for integration of the cogeneration unit into the smart thermal network. For the better use of waste heat from the selected cogeneration unit MOTORGAS MGM250 during the summer period, the absorption circuit was dimensioned and the appropriate trigeneration computational model was formed. In the theoretical part, the function, operation and heat performance of the cogeneration unit as well as the suitability of the connection of the cogeneration unit with the absorption chiller during the summer period were described. In the practical part, the operational data of the Faculty of Mechanical Engineering of the Brno University of Technology and the theoretical performance data from created cogeneration and trigeneration computational models were compared. Based on this comparison, the conclusion about the suitability of use of both computational models was made.
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Ryjkov, Vladimir Leonidovich. "Laser cooling and sympathetic cooling in a linear quadrupole rf trap." Texas A&M University, 2003. http://hdl.handle.net/1969.1/1637.
Full textAbstract:
An investigation of the sympathetic cooling
method for the studies of large ultra-cold molecular ions in a quadrupole ion trap has been conducted.Molecular dynamics simulations are performed to study the rf heating mechanisms in the ion trap. The dependence of
rf heating rates on the ion temperature, trapping parameters,
and the number of ions is obtained. New rf heating mechanism
affecting ultra-cold ion clouds exposed to laser radiation is described.The saturation spectroscopy setup of the hyperfine spectra
of the molecular iodine has been built to provide an accurate frequency reference for the laser wavelength. This reference is used to obtain the fluorescence lineshapes of
the laser cooled Mg$^+$ ions under different trapping conditions.The ion temperatures are deduced from the measurements, and
the influence of the rf heating rates on the fluorescence lineshapes
is also discussed. Cooling of the heavy ($m=720$a.u.) fullerene ions to under 10K by the means of the sympathetic cooling by the Mg$^+$ ions($m=24$a.u.) is demonstrated. The single-photon imaging system has been developed and used to obtain the images of the Mg$^+$ ion crystal structures at mK temperatures.
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Kowsary, Farshad. "Radiative characteristics of spherical cavities having partially or completely specular walls." Diss., Virginia Polytechnic Institute and State University, 1989. http://hdl.handle.net/10919/54222.
Full textAbstract:
The radiant exchange problem for an isothermal spherical cavity having diffuse-specular walls is solved and the distribution of the local heat transfer for various opening angles and surface emissivities is obtained. Subsequently, the overall emission from the cavity (i. e., the apparent emissivity of the cavity) is calculated for various opening angles and surface conditions. In addition, the overall absorption characteristics of spherical cavities having purely specular walls is investigated analytically for the case of collimated radiation entering the cavity. Various opening angles and surface conditions are considered. The Monte Carlo method is utilized to support the results obtained from the analytical calculations. Results show that in spherical cavities the apparent emissivity is not very sensitive to the degree of specularity of the cavity wall. Also, there are situations in which the diffuse cavity is a more efficient emitter than a specular cavity. Absorption characteristic results show that for cavities having purely specular walls the absorption of collimated radiation is highly dependent on the angle of incidence of radiation on the opening for small opening angles.Ph. D.
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Liu, Shuli. "A novel heat recovery/desiccant cooling system." Thesis, University of Nottingham, 2008. http://eprints.nottingham.ac.uk/11602/.
Full textAbstract:
The global air temperature has increased by 0.74± 0.18 °C since 1905 and scientists have shown that CO2 accounts for 55 percentages of the greenhouse gases. Global atmospheric CO2 has been sharply increased since 1751, however the trend has slowed down in last fifty years in the Western Europe. UK and EU countries have singed the Kyoto agreement to reduce their greenhouse gas emissions by a collective average of 12.5% below their 1990 levels by 2020. In the EU, 40% of CO2 emission comes from the residential energy consumption, in which the HVAC system accounts for 50%, lighting accounts for 15% and appliances 10%. Hence, reducing the fossil-fuel consumption in residential energy by utilizing renewable energy is an effective method to achieve the Kyoto target. However, in the UK renewable energy only accounts for 2% of the total energy consumption in 2005. A novel heat recovery/desiccant cooling system is driven by the solar collector and cooling tower to achieve low energy cooling with low CO2 emission. This system is novel in the following ways: • Uses cheap fibre materials as the air-to-air heat exchanger, dehumidifier and regenerator core • Heat/mass fibre exchanger saves both sensible and latent heat from the exhaust air • The dehumidifier core with hexagonal surface could be integrated with windcowls/catchers draught • Utilises low electrical energy and therefore low CO2 is released to the environment The cooling system consists of three main parts: heat/mass transfer exchanger, desiccant dehumidifier and regenerator. The fibre exchanger, dehumidifier and regenerator cores are the key parts of the technology. Owing to its proper pore size and porosity, fibre is selected out as the exchanger membrane to execute the heat/mass transfer process. Although the fibre is soft and difficult to keep the shape for long term running, its low price makes its frequent replacement feasible, which can counteract its disadvantages. A counter-flow air-to-air heat /mass exchanger was investigated and simulation and experimental results indicated that the fibre membranes soaked by desiccant solution showed the best heat and mass recovery effectiveness at about 89.59% and 78.09%, respectively. LiCl solution was selected as the working fluid in the dehumidifier and regenerator due to its advisable absorption capacity and low regeneration temperature. Numerical simulations and experimental testing were carried out to work out the optimal dehumidifier/regenerator structure, size and running conditions. Furthermore, the simulation results proved that the cooling tower was capable to service the required low temperature cooling water and the solar collector had the ability to offer the heating energy no lower than the regeneration temperature 60℃. The coefficient-of-performance of this novel heat recovery/desiccant cooling system is proved to be as high as 13.0, with a cooling capacity of 5.6kW when the system is powered by renewable energy. This case is under the pre-set conditions that the environment air temperature is 36℃ and relative humidity is 50% (cities such as Hong Kong, Taiwan, Spain and Thailand, etc). Hence, this system is very useful for a hot/humid climate with plenty of solar energy. The theoretical modelling consisted of four numerical models is proved by experiments to predict the performance of the system within acceptable errors. Economic analysis based on a case (200m2 working office in London) indicated that the novel heat recovery/desiccant cooling system could save 5134kWh energy as well as prevent 3123kg CO2 emission per year compared to the traditional HVAC system. Due to the flexible nature of the fibre, the capital and maintenance cost of the novel cooling system is higher than the traditional HVAC system, but its running cost are much lower than the latter. Hence, the novel heat recovery/desiccant cooling system is cost effective and environment friendly technology.
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Chen, Xiangjie. "Investigations of heat powered ejector cooling systems." Thesis, University of Nottingham, 2013. http://eprints.nottingham.ac.uk/29721/.
Full textAbstract:
In this thesis, heat powered ejector cooling systems was investigated in two ways: to store the cold energy with energy storage system and to utilize low grade energy to provide both electricity and cooling effect. A basic ejector prototype was constructed and tested in the laboratory. Water was selected as the working fluid due to its suitable physical properties, environmental friendly and economically available features. The computer simulations based on a 1-0 ejector model was carried out to investigate the effects of various working conditions on the ejector performance. The coefficients of performance from experimental results were above 0.25 for generator temperature of lI5°C-130 °C, showing good agreements with theoretical analysis. Experimental investigations on the operating characteristics of PCM cold storage system integrated with ejector cooling system were conducted. The experimental results demonstrated that the PCM cold storage combined with ejector cooling system was practically applicable. The effectiveness-NTU method was applied for characterizing the tube-in-container PCM storage system. The correlation of effectiveness as the function of mass flow rate was derived from experimental data, and was used as a design parameter for the PCM cold storage system. In order to explore the possibility of providing cooling effect and electricity simultaneously, various configurations of combined power and ejector cooling system were studied experimentally and theoretically. The thermal performance of the combined system in the range of 0.15-0.25 and the turbine output between 1200W -1400W were obtained under various heat source temperatures, turbine expansion ratios and condenser temperatures. Such combined system was further simulated with solar energy as driving force under Shanghai climates, achieving a predicted maximum thermal efficiency of 0.2. By using the methods of Life Saving Analysis, the optimized solar collector area was 30m2 and 90m2 respectively for the system without and with power generation. The environmental impacts and the carbon reductions of these two systems were discussed.
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Twort, Charles Tyler. "An exergy analysis of mine cooling systems." Thesis, University of Nottingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323333.
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Mohamed, Y. "Interactive analysis of power station cooling systems." Thesis, University of Manchester, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.380600.
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Petters, Jonathan L. Clothiaux Eugene. "The impact of radiative heating and cooling on marine stratocumulus dynamics." [University Park, Pa.] : Pennsylvania State University, 2009. http://etda.libraries.psu.edu/theses/approved/WorldWideIndex/ETD-4602/index.html.
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Grüner, Florian. "Experiments and simulation of transverse cooling and heating in ion channeling." Diss., lmu, 2003. http://nbn-resolving.de/urn:nbn:de:bvb:19-16339.
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Hardy, John David. "A Cooling, Heating, and Power for Buildings (CHP-B) Instructional Module." MSSTATE, 2003. http://sun.library.msstate.edu/ETD-db/theses/available/etd-04082003-030901/.
Full textAbstract:
An emerging category of energy systems, consisting of power generation equipment coupled with thermally-activated components, has evolved as Cooling, Heating, and Power (CHP). The application of CHP systems to buildings has developed into a new paradigm ? Cooling, Heating, and Power for Buildings (CHP-B). This instructional module has been developed to introduce undergraduate engineering students to CHP-B. In the typical ME curriculum, a number of courses could contain topics related to CHP. Thermodynamics, heat transfer, thermal systems design, heat and power, alternate energy systems, and HVAC courses are appropriate for CHP topics. However, the types of material needed for this mix of courses vary. In thermodynamics, basic problems involving a CHP flavor are needed, but in an alternate energy systems course much more CHP detail and content would be required. This series of lectures on CHP-B contains both a stand-alone CHP treatment and a compilation of problems/exercises.
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Gurjer, Yeshwant Ramesh. "Use of Heat Pumps for Heating and Night Cooling of Greenhouses." NCSU, 2001. http://www.lib.ncsu.edu/theses/available/etd-20011105-182143.
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Gurjer, Yeshwant Ramesh. Use of Heat Pumps for Heating and Night Cooling of Greenhouses. (under the direction of Daniel H. Willits). The use of heat pumps for heating and night cooling of greenhouses was investigated using a computer simulation program and weather data from Typical Meteorological Year (TMY2) datasets for Raleigh, NC, and Wilmington, NC. A greenhouse computer model taken from the literature, along with the heat pump subroutines (HPHEAT and HPCOOL) developed in this study, were used for the simulations. The use of heat pumps for heating only, and for heating plus night cooling, were examined separately using both standard and time-of-use electricity rates for two North Carolina utility providers. When heat pumps were used only for heating, standard electricity rates were predicted to provide greater savings in utility costs compared to time-of-use rates. When heat pumps were used for both heating and night cooling, the predicted savings in utility costs was greater for time-of-use electricity rates. Night cooling was predicted to decrease the average daily temperature (0.10C to 1.10C) and average nighttime temperature (0.10C to 2.00C) inside the greenhouse providing the potential for increased yield. Although a heat pump of capacity 36.5 W/m2 of floor area provided less savings in total costs compared to a capacity of 76 W/m2, the heat pump with the smaller capacity (36.5 W/m2) may be a better proposition because of the lower purchase cost.
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Kizikoglu, Atahan Riza. "Thermo-Economic Analysis of Solar Cooling/Heating Systems for Mediterranean Climates." Thesis, KTH, Kraft- och värmeteknologi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-161065.
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This study focuses on the efficient use of solar energy for a certain region in the Mediterranean basin. Solar thermal energy becomes increasingly popular and the available solar market is investigated with the aim of selecting and assessing a pilot region for a promising solar application. The work herein focuses on estimating the potential of three different 100% solar-driven integrated systems to cover the entire cooling and heating demand of a selected single family house solely by solar energy. The three different alternative systems are presented and examined in detail for the actual case study application. The sample house within the chosen region is located on the south coast of Turkey. The entire thermal demand of this house for both cooling during summer and heating during winter has first been properly calculated. Characteristic features of the house and the typical design parameters for the region have been analyzed, as well as and their daily and annual variations. Heat loss and heating/cooling load calculations have been done with respect to these specifications and to ASHRAE regulations. After finding the building`s demands for the comfort temperature, the three different solar-driven systems are simulated for a practical application to the sample house. Required mechanical equipment and parasitic load consumption has been investigated for each system and investment cost analyses have been performed respectively. Simplified payback times for each alternative system are calculated and discussed. Payback period sensitivity analysis was attempted for two different locations featuring different grid pricing regulations. As a conclusion, feasibility analysis for the three examined types of solar-driven integrated heating and cooling systems has been attempted, which gives a good representation of the potential solar energy market in the Mediterranean region. Also some suggestions are offered to the companies which develop and market solar heating/cooling systems.
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CAMPOS, SERGIO LIBANIO DE. "DEVELOPMENT OF AN AUTOMOTIVE AIR CONDITIONING SYSTEM FOR HEATING AND COOLING." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2014. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=24641@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROSistemas condicionadores de ar automotivos têm sido extensivamente estudados, buscando melhor eficiência de resfriamento e redução do consumo de combustível. O presente trabalho tem como objetivo o estudo de um sistema condicionador de ar automotivo operando nos modos de resfriamento e aquecimento, este último atendendo às necessidades de conforto em dias frios nos veículos elétricos, os quais não apresentam calor de rejeito do motor, como nos veículos convencionais. Para tal foi projetado e montado, no Laboratório de Refrigeração, Condicionamento de Ar e Criogenia da PUC-Rio, um aparato experimental composto por duas câmaras de temperatura e umidade controladas, uma simulando o compartimento de passageiros e a outra, o ambiente externo. Um típico sistema condicionador de ar automotivo, composto por componentes comercialmente disponíveis e utilizados nos veículos atuais, foi dotado de válvulas direcionais, permitindo a inversão do ciclo de compressão de vapor do modo de resfriamento para o modo de aquecimento, operando neste último como bomba de calor. Dados experimentais foram levantados sob operação em regime permanente e transiente (período de partida), com temperaturas entre – 5 graus Celcius e 45 graus Celcius. Para o modo de resfriamento, seguiu-se a norma SAE J2765 e, para o de aquecimento, na ausência de normas, foram cobertas as operações em modos de recirculação do ar da cabine e de renovação com ar externo, entre as temperaturas de -5 graus Celcius e 10 graus Celcius. Foi também realizada uma simulação numérica, validada pelos dados experimentais, utilizando as equações fundamentais da termodinâmica e transferência de calor. O sistema testado mostrou-se viável na aplicação em veículos elétricos, uma vez que nestes o calor de rejeito previsto (regeneração de frenagem e efeito Joule na eletrônica de potência) não é suficiente para o conforto térmico em dias frios. Demonstrou-se que a bomba de calor consome menos energia que resistências as elétricas atualmente utilizadas.
Automotive air conditioning systems have been extensively studied, searching for better cooling efficiency and reduced fuel consumption. The present work aims to study a system of automotive air conditioner operating in cooling and heating modes, the latter satisfies the needs of comfort on cold days in electrical vehicles, which do not include waste heat from the engine as the conventional vehicles. To this was designed and assembled in the Refrigeration, Air Conditioning and Cryogenics Laboratory, in Puc-Rio, an experimental apparatus consists of two chambers with temperature and humidity controlled, one, simulating the passenger compartment and the other, the external environment. A typical automotive air conditioning system, composed of commercially available components used in current vehicles is provided with a directional valve, allowing the inversion of vapor compression cooling mode to the heating mode cycle, the latter operating as a heat pump.
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Boufadel, George Fadlo. "Dynamic thermal response of buildings resulting from heating and cooling interruptions." Diss., Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/74757.
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Transient modelling of heat fluxes and temperatures in structures was conducted to examine the effect of various characteristics on the temperature response during unusual operating and extreme weather conditions. The analytical model was validated using published experimental data and numerical results from well-known computer codes.
The effect of including radiation heat transfer between interior surfaces, using the Mean Radiative Temperature method, on the temperature response was investigated and found to be negligible for a typical commercial building and a house during winter and summer power outages.
The effect of thermal mass in the interior and exterior walls on the inside temperature drift after an HVAC system cutoff or a power outage was presented. The inside air temperature response curve is presented for different wall (exterior or interior) constructions of buildings. The effect of insulation position in exterior walls was also shown for several R values. The effect of exterior wall emissivity, sky temperature, outside vertical convective coefficient, furnishings, and ground temperature on the interior temperature response during winter and summer power outages were examined for buildings.
The effect of infiltration on the temperature drift in buildings was investigated during winter and summer power outages. Restarting the HVAC after the power outage was examined during both seasons for typical buildings.
Outside temperature profiles exceeding the 97.5 design temperature criterion were used to study the effect of extreme weather on the interior temperature of buildings with the HVAC system operating.Ph. D.
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Chou, Lu-chien. "Drag reducing cationic surfactant solutions for district heating and cooling systems /." The Ohio State University, 1991. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487758178238587.
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Arghand, Taha. "Human subjective response to combined radiant and convective cooling by chilled ceiling combined with localized chilled beam." Thesis, Högskolan i Gävle, Avdelningen för bygg- energi- och miljöteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-20444.
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The aim of the present research is to identify human subjective response (health and comfort) to the micro-thermal environment established by integration of individually controlled localized chilled beam and chilled ceiling (LCBCC) system and to compare its performance with the performance of mixing ventilation combined with chilled ceiling (CCMV).Experiments were carried out in mock-up of an office (4.1 m × 4.0 m × 3.1 m, L× W× H) with one person under two summer temperature conditions (26 °C and 28 °C). To mimic direct solar radiation in the room, five radiative panels on the wall together with electrical sheets on the half of the floor were used. The test room was set-up with two desks, as two workstations, and one laptop on each table. The main workstation (WS1) was located close to the simulated window. The second work station (WS2) was placed in the opposite side of the room. The room was equipped with two types of ventilating and cooling systems. The first system consisted of a localized active chilled beam (LCB) unit together with chilled ceiling (CC) panels. The LCB was installed above the WS1 to create micro-environment around the occupant sitting at the desk. The supply flow rate from the LCB could be adjusted by the occupant within the range of 10 L/s to 13 L/s by means of a desk-mounted knob. The integration of mixing ventilation (MV) system and chilled ceiling panels was the second ventilating and cooling strategy. Twenty- four subjects (12 female and 12 male) were exposed to different indoor environment established by two cooling systems. Each experiment session lasted 120 min and consisted of 30 min acclimatization period and 90 min exposure period. The performance of the systems was identified and compared by physical measurements of the generated environment and the response of the human subjects. The study showed that perceived air quality (PAQ), overall thermal sensation (OTS) acceptability and local thermal sensation (LTS) acceptability clearly improved inside the micro-environment by using LCBCC system. Moreover, at the main workstation, OTS and LTS votes were close to “neutral” thermal sensation (ASHRAE seven point scale) when LCBCC system was used. However, OTS and LTS votes increased to the “slightly warm” side of the scale by applying CCMV system which implied the better cooling performance of the LCBCC system. Acceptability of work environment apparently increased under the room condition generated by LCBCC system. In agreement with human subjective study, the results from physical measurements and thermal manikin study showed that uniform thermal condition was generated all over the room. Air and operative temperature distribution was almost uniform with no difference higher than 1 °C between the measured locations in the room. Thus, both LCBCC and CCMV systems performed equally well outside of the micro-environment region. The use of the chilled ceiling had impact on the airflow interaction in the room and changed the airflow pattern. It can be concluded that the combination of convective and radiative systems can be considered as an efficient strategy to generate acceptable thermal condition in rooms.
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Jerome, David. "Building load analysis and graphical display as a design tool." Thesis, Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/16410.
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