Thesis (M.S.E.C.E.)--Baylor University, 2009. / Includes bibliographical references (p. 139).

Thesis (MTech (Mechanical Engineering))--Cape Peninsula University of Technology, 2016. / Solar energy is still not being used effectively in countries in the developing world, though it's a partial solution to the problem of shortage and expensive energy. Normally harvested through flat plate collectors, converting solar radiation into heat is the most direct application that can be effected in water heating systems. Many researchers have attempted to develop means of improving the efficiency of the flat plate solar energy collector; however there appears to be no evidence of any work regarding the effect of geometric configuration on the performance of flat plate solar collector. This study presents results obtained when comparing the performance of a solar water heating system equipped with three manufactured flat plate solar collector panels of numerically identical surface area but of different geometric configuration as they were individually attached to a typical geyser. Data was obtained inside a laboratory. The amount of heat acquired from flat plate collectors of solar energy depends primarily on their surface area that is exposed to the solar irradiance, however, the geometry of the collectors was thought that it might affect to some extent the amount of heat harvested. The circulation of the water from the panel to the geyser was due to the self-induced thermo-syphon effect. The results obtained during the test period (7 hours per day for two consecutive days) indicated that the system’s thermal efficiency was best when the square geometrical configuration collector was used. A dimensional analysis using the Π Buckingham method that was performed on the parameters affecting a flat plate solar collector yielded three dimensionless numbers that lead to a power law relationship which might be useful in enhancing solar water heating systems’ design.

Solar heating systems, by the nature of their design and inherent thermal mass, are sensitive to the changes in the prevailing climatic conditions. A computer program has been developed to predict and display the dynamic performance of solar water heating systems and their installation designs under transient climatic and restricted site conditions. A multi-node capacitance model describes the dynamic heat transfer and energy storage processes within the solar collector unit, storage tank and the connecting pipework. This simulation model predicts the dynamic system performance under intermittent solar radiation, system operation and energy usage conditions. Validation studies have been carried out on the computer simulation results against the performance of a purpose-built solar collector test facility and a commercial solar water heating system in actual operation in Aberdeen. A good correlation has been obtained in both cases. The accuracy of the prediction was found to be dependant upon the time interval of the available climatic data and the complexity of the thermal simulation network chosen. The experimental facilities and the computer simulation program have been developed to investigate the effect of integrating the solar collector installation as part of the roof fabric, as a possible technique to improve the system performance in exposed locations. The application of this computer program lies in the development of innovative solar collector system and installation designs to achieve optimum system performance under transient climatic and restricted urban site conditions.

The main purpose of this research project was to do a comparative study, by identifying a testing methodology for transient conditions, through which to allow the expression of the relative thermal performance of two DSWH collectors in comparison. The study started off by considering literature about Solar Domestic Water Heaters and National Standards-based test methods, most of which were for Steady State testing conditions. Thereafter establishing a testing methodology and setup, identifying factors to be considered. The results were analyzed and conclusions drawn. The hypothesis was to allow the reduction in the complexity of testing equipment and methods, and by doing transient condition testing and still utilizing the Hottel-Whillier-Bliss relationship as a way of expressing efficiency, the hypothesis was proven.

The study found that investing in solar water heater system (SWH) would be an economically, socially and environmentally viable option to implement within urban households; in which the hot water demand, volume of hot water consumption, water heating costs, and electricity tariffs are high. Investing in solar water heater technology should be the key focus of South African government; in order to enhance the wellbeing of the ordinary citizens. The study made use of the qualitative research approach to investigate solar water heater drivers and barriers; from the perspective of energy consumers. This will be achieved by focusing on the major drivers and barriers that consumers consider when making decisions on adoption of solar water heater system. It is believed that solar water heater drivers and barriers substantially influence the potential and urban development thereof. Solar heat is utilized in the residential sector for heating water for bathing, cleaning, washing and cooking food, but its availability is limited (Arora & Arora, 2013). Renewable energy has become a wild card internationally and regionally because of the technical, economic and environmental barriers affecting the disadvantaged individuals.

Orientador : Laszlo Halasz / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos e Agricola / Made available in DSpace on 2018-07-15T18:54:42Z (GMT). No. of bitstreams: 1 Murr_FernandaElizabethXidieh_M.pdf: 23760384 bytes, checksum: 9c96226b1d9b16ba4363c6d80ddaa85b (MD5) Previous issue date: 1981 / Resumo: Considerando a importância da provisão dos gêneros alimentícios, parece razoável que todas as novas fontes de energia em potencial sejam utilizadas. Análises e aplicação da energia solar na estocagem e no congelamento de alimentos, surgiram desta preocupação mundial. A Faculdade de Engenharia de Alimentos e Agrícola - Unicamp, proje-tou e construiu um sistema frigorífico de absorção operado por energia solar cujas características principais: aqueci-mento direto da solução e resfriamento a ar o fazem diferenciar dos demais sistemas. Uma simulação em regime permanente foi feita, cujos resultados mostraram alternativas que poderão ser testadas experimentalmente para um futuro apri-moramento do sistema / Abstract: In view of the importance of food supply, it seems rational that all potencial energy sources should be utilized. This worldwide concern led to a wide analysis and application of solar energy for cooling and freezing of foods. The Faculdade de Engenharia de Alimentos e Agrícola- - Unicamp designed and built a solar absorption refrigeration system with the unique feature of direct heating of the solution and air-cooling. The present study concerns a working out of data on intensity of solar radiation inciding on the flat-plate collector and studies of the behavior of the system under local conditions. A steady state simulation was carried out and the results pointed out alternatives that should be confirmed experimentally for future performance im-provement / Mestrado / Mestre em Engenharia de Alimentos

Exploiting solar energy technology for both heating and cooling purposes has the potential of meeting an appreciable portion of the energy demand in buildings throughout the year. By developing an integrated, multi-purpose solar energy system, that can operate all twelve months of the year, a high utilisation factor can be achieved which translates to more economical systems. However, there are still some techno-economic barriers to the general commercialisation and market penetration of such technologies. These are associated with high system and installation costs, significant system complexity, and lack of knowledge of system implementation and expected performance. A sorption heat pump module that can be integrated directly into a solar thermal collector has thus been developed in order to tackle the aforementioned market barriers. This has been designed for the development of cost-effective pre-engineered solar energy system kits that can provide both heating and cooling. This thesis summarises the characterisation studies of the operation of individual sorption modules, sorption module integrated solar collectors and a full solar heating and cooling system employing sorption module integrated collectors. Key performance indicators for the individual sorption modules showed cooling delivery for 6 hours at an average power of 40 W and a temperature lift of 21°C. Upon integration of the sorption modules into a solar collector, measured solar radiation energy to cooling energy conversion efficiencies (solar cooling COP) were between 0.10 and 0.25 with average cooling powers between 90 and 200 W/m2 collector aperture area. Further investigations of the sorption module integrated collectors implementation in a full solar heating and cooling system yielded electrical cooling COP ranging from 1.7 to 12.6 with an average of 10.6 for the test period. Additionally, simulations were performed to determine system energy and cost saving potential for various system sizes over a full year of operation for a 140 m2 single-family dwelling located in Madrid, Spain. Simulations yielded an annual solar fraction of 42% and potential cost savings of €386 per annum for a solar heating and cooling installation employing 20m2 of sorption integrated collectors.

A novel design of hybrid thermal energy storage (HTES) using Phase Change Material (PCM) was evaluated using a mathematical model. Both single and multi-tank (cascaded) storage were explored to span small to large-scale applications (200-1600 litres). The storage element was based on the concept of a fully-mixed modular tank which is charged and discharged indirectly using two immersed coil heat exchangers situated at the bottom and top of the tank. A three-node model was developed to simulate different thermal behaviors during the operation of the storage element. Experiments were conducted on full-scale 200-l single-tank sensible heat storage (SHS) and hybrid thermal energy storage (HTES) to provide validation for the mathematical model. The HTES incorporated rectangular PCM modules submerged in the water tank. Satisfactory agreement was found between the numerical results and the experimental results obtained by Mather (2000) on single and multi-tank SHS. In addition, good agreement was noticed with the experiments performed by the author on single-tank SHS and HTES at McMaster University. The developed model was found to provide high levels of accuracy in simulating different operation conditions of the proposed design of storage element as well as computational efficiency. A parametric study was undertaken to investigate the potential benefits of the HTES over the SHS, operating under idealistic conditions. The HTES can perform at least two times better than the SHS with the same volume. The PCM volume fraction, melting temperature and properties were found to have critical impact on the storage gains of the HTES. All the parameters must be adjusted such that: (1) the thermal resistance of the storage element is minimized, and (2) most of the energy exchange with the storage element takes place in the latent heat form. The performance of the single-tank HTES was evaluated numerically while operating in a solar thermal domestic hot water (DHW) system for a single-family residence. The PCM parameters were selected to maximize the solar fraction during the operation on a typical spring day in Toronto. The use of the HTES can reduce the tank volume by 50% compared to the matched size of the SHS tank. However, the HTES was found to underperform the SHS when the system was operated in different days with different solar irradiation intensities. The effect of different draw patterns was also investigated. The results indicated that thermal storage is needed only when the energy demand is out-of-phase with the energy supply. For the same daily hot water demand, different consumption profiles; ex. dominant morning, dominant evening, dominant night and dispersed consumptions, showed slight impact on the performance of the system. The concept of multi-tank (cascaded) HTES storage was explored for medium/large scale solar heating applications such as for restaurants, motels, and multi-family residences. The design was based on the series connection of modular tanks through the bottom and top heat exchangers. Each individual tank had a PCM with different melting temperature. The results showed that the cascaded storage system outperformed the single-tank system with the same total volume as a result of the high levels of sequential or tank-to-tank stratification. The use of the cascaded HTES resulted in slight improvement in the solar fraction of the system. / Thesis / Doctor of Philosophy (PhD)

No description available.

Widespread public acceptance of heating and cooling systems utilizing alternative energy sources is largely dependent on their ability to replace conventional systems with no appreciable loss in comfort or convenience. Research was done to determine why current passive solar heating systems and double-shell solar heating/ground cooling systems do not have performance comparable to conventional systems. This information was then utilized to develop the concept for a new multifunction wall system for application with solar heating and ground cooling. The concept of this system is to expand the use of the structure and enclosure elements of a building to function additionally as: The ductwork for the solar heated or earth cooled air, the heat transfer membrane between the heated or cooled air and the living environment of the building, the heat storage medium (in winter), and the temperature leveling and control medium. All these functions are integrated into a single wall construction using a new concrete block and other supporting components. In addition to developing the concept, several critical components of the system were physically tested and analyzed. This paper presents the research, concept development, testing, and conclusions for this new system, a multifunction wall system for application with solar heating and ground cooling. / M. Arch.