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[en] The market potential for active solar thermal systems in the institutional, commercial and industrial sectors of the Canadian economy was investigated, the objective being to identify markets and to prepare action plans as the foundation for developing these markets by Natural Resources Canada and the industry. In the process of researching the market, barriers to market development in these sectors of the economy were also identified as well as actions to overcome these barriers. Nine potential applications were modelled to determine their energy, economic and environmental performance. Of these four attractive applications have been selected for more detailed treatment. Separate action plans have been developed for Natural Resources Canada, the Canadian Solar Industries Association and the active solar thermal industry. The close cooperation of all three partners is considered essential for a successful marketing effort. A marketing plan which gives due consideration to the product, planning, packaging, price and promotion, is also considered to be a vital ingredient, as is a meticulous follow-up on 'leads' created by exposure to the target market. Solarwall'TM' for preheating of ventilation air to new school buildings and solar domestic hot water heating for camp grounds have been identified as the most attractive candidates for marketing at this time. Highlights of marketing plans for these two options are included for purposes of illustrating the essential ingredients of marketing plans. 1 fig
[en] In solar absorption cooling system, the hot water supplied to a single effect absorption chiller comes from a solar collector heat storage. On the other hand, chilled water of the chiller is stored in reservoir and then is supplied to the cooling system due to the daily demand. The size of cooling system components depends on solar daily insulation, daily cooling load and effective working time of the system. In order to optimize the working condition of the system these factors together with their economic aspects should be kept in mind to reach a logical and rational design. In the mentioned parameters to the optimum working condition of an solar absorption cooling system. By using this approach the optimum design of the system would be obtained
[en] Solar systems are able to save an important part of costs for heating, mainly in large objects. During the decision about the possibility to install a solar system to a building, the investor will be interested mainly in the estimation of the costs for the system. One of the main investments is to the absorber a basic part of the solar system. The proper size of the absorber indicates a performance of the whole system but also a significant part of the input investment costs. Nomograms, presented in this project, that were created according the detailed calculation, will significantly speed up stating of the size of the absorber of the solar system. (authors)
[en] Solar powered water heater and water cooler is an important contribution for the reduction of fossil fuel consumptions and harmful emissions to the environment. This study aims to harness the available solar potential of Pakistan and provide an option fulfilling the domestic hot and cold water demands during winter and summer seasons respectively. The system was designed for the tap-water temperature of 65 degree C (149 degree F) and the chilled drinking-water temperature of 14 degree C (57 degree F) that are the recommended temperatures by World Health Organization (WHO). The solar water heater serves one of the facilities of the Department of Mechanical Engineering at NED University of Engineering and Technology whereas, the solar water cooler will provide drinking water to approximately 50 people including both faculty and students. A pair of single glazed flat plate solar collector was installed to convert solar radiations to heat. Hot water storage and supply system was carefully designed and fabricated to obtain the designed tap-water temperature. Vapour-absorption refrigeration system was designed to chill drinking water. Intensity of solar radiations falling on the solar collector, water temperatures at the inlet and outlet of the solar collectors and the tap water temperature were measured and analyzed at different hours of the day and at different days of the month. The results show that the installed solar collector system has potential to feed hot water of temperatures ranging from 65 degree C (149 degree F) to 70 Degree C (158 degree F), that is the required hot water temperature to operate a vapour absorption chilled water production system. (author)
[en] Heat pipes are passive heat transfer devices, of long lives. Material and testing reactors (MTRs) have residual heat after shutdown. Usually MTRs have also spent fuel storage tanks to compromise heat that need to be removed. Gravity assisted two-phase closed heat-pipe loop (GTPHL) covered by removal of decay heat (or heat after shutdown) with evaporator and condenser lengths each 100 m helical coil shape with outer diameter 15 cm and 3 mm thickness as a passive cooling system for a nuclear spent fuel storage pool. This study proposes a completely passive cooling system using thermosyphon loop for cooling and dissipation of the residual heat of wet spent fuel storage by running as main or alternative cooling system. The design focuses on heat removal from the spent fuel storage tank of a research reactor. The model considers natural convection by air for the condenser part of the heat-pipe loop to confine the residual heat. A numerical simulation, using special design of GTPHLs, was used to investigate the thermal performance of the GTPHL. The effects of heat loads were analyzed. Demineralized water was used as the GTPHL working fluid. The atmospheric air was circulated around the condenser as a cooling system. The thermal performance of the GTPHL is evaluated at heat input ranging from 25 to 15 degree kW with filling ratio of the working fluid of 100%. The results show that a good thermal performance is obtained at high evaporator heat load obtained from nuclear spent fuel storage tank.
[en] Actions that can be taken to increase the uptake of technology for solar water heaters and solar buildings are discussed. An overview of existing technology covers solar water heating, solar buildings, space heating, solar cooling, solar drying, solar desalination. Solar water heating, solar buildings and solar crop drying are discussed individually under the sub-headings of (a) the technology; (b) the market; (c) potential; (d) economics and (e) market acceleration strategies. Other subjects discussed are market acceleration, main opportunities, R and D needs and conclusions. The IEA solar heating and solar cooling programme is described
[en] Highlights: ► Two types of solar thermally driven absorption refrigeration machines (ARMs) have been investigated. ► We investigated the influence of the operating conditions on the effectiveness of the ARMs. ► The influence of the flow rate of the work solution on the effectiveness of the ARMs has been tested. ► Two laboratory test plants have been built and tested under different operating conditions. - Abstract: A big increase in the number of solar thermal cooling installations and research efforts could be seen over the last years worldwide. Especially the producers of solar thermal collectors and systems have been looking for thermal chillers in the small capacity range to provide air conditioning for one or two family houses. Furthermore, many developments aim to increase the efficiency of the system and to decrease the specific costs of the produced refrigeration capacity. The growth in the use of solar thermal cooling systems amounted about 860% from 52 units in 2004 to 450 units in 2009 . This tendency is expected to be continuously in the next years. The practical examinations on solar thermally driven absorption machines with refrigeration capacity of 15, 10 and 5 kW have shown that this technology has a good chance to be standardized and to replace partly the conventional one. These systems can save more primary energy at high fraction of solar thermally driving by suitable control and regulation of the system. The investing costs still higher as the conventional one, however, the operating costs are less than the conventional one. The Coefficient of Performance (COP) depends on the kind of the system, work temperatures and conditions as well as the refrigeration capacity of the systems. It lies between 0.4 and 1.2. In the framework of the research on this field, we built, tested and measured two prototypes. After measuring the first prototype, the chillers were redesigned to reduce internal heat losses and make the heat and mass transfer over the surfaces of heat exchangers more effective. Thus, many investigations have been done on some types of heat exchangers for optimization of heat and mass transfer in the system. In this contribution we will show some investigation results on solar thermally driven system in small capacity range. Moreover, we will illustrate an experimental setup for investigation of heat transfer by shell tube heat exchanger consisting of two kinds of tubes. The first one has a smooth outer surface and the other one has a ribbed outer surface. The aim of these investigations is to optimize the whole system.
[en] Solar radiation contains huge amounts of energy and is required for almost all the natural processes on earth. Solar-powered air-conditioning has many advantages when compared to normal electricity system. This paper presents a solar cooling system that has been designed for Malaysia and other tropical regions using evacuated tube solar collector and LiBr absorption system. A modelling and simulation of absorption solar cooling system is modeled in Transient System Simulation (TRNSYS) environment. The typical meteorological year file containing the weather parameters is used to simulate the system. Then a system optimization is carried out in order to select the appropriate type of collector, the optimum size of storage tank, the optimum collector slope and area and the optimum thermostat setting of the auxiliary boiler
[en] Highlights: ► The overall performance of the solar/natural gas chillers is analysed and discussed. ► The system operates in regions with abundant solar energy and cheap natural gas. ► The maximum daily cover of solar energy (between time of day 8 and 17) is about 58%. ► An optimum generator temperature gives a minimum number of flat plate collectors. ► This system compensates the peak-valley load difference and reduces CO2 gas emissions. - Abstract: Solar radiation is a clean form of energy and solar cooling systems is one of the technologies which allow obtaining an important energy saving. Natural gas is a cheaper fuel than oil. It also burns cleaner than oil. Natural gas and renewable energy are complementary and in the future, the alignment of natural gas and renewable energy may be the most effective way to service the demand for clean energy. This paper presents a numerical study of solar/natural gas single effect lithium bromide absorption chillers. The development of this system is based on hot water chiller. As auxiliary power, fire from the natural gas burners is used to heat the hot water on its way to the generator. The overall performance of the absorption chiller system is analysed and discussed. For an evaporator temperature of 5 °C and when the condenser temperature is varied from 28 °C to 36 °C and generator temperatures is varied from 54 to 83 °C the maximum COP is 0.82 and the maximum exergetic efficiency is about 30%. For a given condenser temperature there is an optimum generator temperature for which the number of flat plate collectors is minimum. This optimum generator temperature corresponds to the generator temperature giving the maximum COP and exergy efficiency of the absorption cooling system. The solar/natural gas single effect lithium bromide absorption chillers, using solar energy as the energy source with only limited amount of gas as auxiliary power, not only reduces greatly the cost for electricity and operates in regions where there are abundant solar energy and cheap natural gas resources, but also compensates the peak-valley load difference and reduce CO2 gas emissions. For a refrigeration capacity of 10 kW, the quantity of natural gas used to provide auxiliary load is very small and consequently the CO2 gas emissions is very small (the maximum mass flow rate of CO2 is less than 3 kg h−1).
[en] The knowledge of solar irradiation is important in heating and cooling of buildings architectural engineering, various solar energy utilizations, and for any system design exposed to sun radiation. In the present article, simulation is made to predict solar irradiation over any three-dimensional objects. Special consideration is made to evaluate solar radiation intensity distribution over semi-circular roof and domed roofs. For practical applications, hourly and average daily solar radiation distribution for a series of three Heller type huge cooling towers of Fars Power Plant is also determined