Yearly Energetic and Exergetic Performance of Solar Absorption Refrigeration System in the Region of Northern Sudan (original) (raw)
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Investigation of thermal performance of a solar powered absorption refrigeration system
Energy Conversion and Management, 1996
It is well known that the energy consumption of refrigerating and airconditioning units is as high as heating systems. It is also clear that cooling loads and availability of solar radiation are approximately in phase. Turkey is located in an ideal position to benefit from solar energy for not only water-heating but also cooling. The use of solar powered absorption refrigerating and airconditioning systems will save energy, especially in the summer season. The contribution of these systems to the Turkish energy sector and, consequently, to the economy will be considerably high. In this study, a combined water-heating and cooling system based on absorption refrigeration was designed and constructed. The system consists of four flat plate collectors, an evaporator, an absorber, a generator, a condenser, a solution pump and two heat exchangers. Each part was custom designed to provide 4000 kcal/h cooling load. In this system, a mixture of R22 and DMETEG (DiMethyl Ether Tetra Ethylene Glycol) is used as the working fluid. The R22, which has a less damaging effect on the ozone layer compared to other CFCs, was employed as refrigerant. The thermodynamic results of the experimental system were compared with theoretical calculations, and a reasonably good agreement was found. The results show that the present system is efficient and effective.
Experimental Investigation on Solar Absorption Refrigeration System in Malaysia
Proceedings of the 3rd Wseas Int. Conf. On Renewable Energy Sources, 2009
Abstract:-The experimental investigation of the performance of a solar absorption refrigeration system is described. The influence of generator, evaporator and condenser temperatures on the system performance is studied using evacuated tube solar collectors and ammonia-water as working fluid. It was seen that if higher cooling capacity and also lower evaporator temperature are desired from the system, the generator temperature should be increased considerably. In general, a solar absorption system can work only if ...
Performance Analysis of Solar Absorption Cooling Systems in Iraq
International Journal of Renewable Energy Research, 2020
The feasibleness of using an absorption solar cycle in Najaf, Iraq is evaluated in this study. In the system proposed, a 105,6kW Single Effect Absorption Chiller (SEAC) is powered by Evacuated Tube Collectors (ETC). TRNSYS (version 18) simulation is performed to select the various system parameters and optimize them to increase solar system efficiency, and this simulation develops a solar cooling model that simulates reality and is used effectively for cooling service buildings. The optimized solar air-conditioner for a building consists of a 35 m 2 collector area and number collector in series eight tilted at 32 o for Najaf, Iraq, from the horizontal and 1.5 m 3 HWST. It has been found that in effect, the solar absorption cycle reduces the annual electricity consumption where the solar fraction is high by 79% at Tehran and 77% at Najaf, Iraq. Also Utilizing solar energy can provide further benefits to the governments in the form of CO2 reduction, as the thermal energy generated by...
Improvement of a Solar Powered Absorption Refrigeration System
Background: Over the past few decades, energy is the cornerstone of technology and economic infrastructure. Hence the costs of energy have been increasing exponentially worldwide. Conventional refrigeration is one of the most energy consuming sectors. By developing a solar power refrigeration system, we are not only cutting down the energy costs, but also maintaining our surroundings safe. A huge quantity of energy is available to us from the sunlight and all we need is efficient utilization of this energy. The objective of this paper is to design and study of an environment friendly solar powered ammonia-water absorption refrigeration system. This system does away with reliance on an electric grid, at the same time takes no batteries. Solar refrigerators can be widely used in developing countries, where the power supply is uncertain to mitigate poverty and climate change. This environmentally friendly system is an ideal paragon for vaccine storage or large-scale food preservation. Solar refrigeration system can take on an important role within a sustainable energy system of the future. Materials and Methods: The solar refrigeration system described here is based on the refrigeration cycle of ammonia-water absorption system. The cycle consists of two main steps, 'Generation' and 'Refrigeration'. Generation involves generating ammonia vapor in the generator and ammonia vapor condensation in the condenser. Refrigeration includes ammonia vaporizing in the evaporator and absorbing ammonia vapor into the absorber solution. Ammonia-water (NH 3 /H 2 O) solution is widely used as refrigerant because the solution is extremely stable and functions smoothly at a low temperature. Flat plate solar collectors are widely used for extracting solar energy. These are capable of absorbing direct and diffused solar radiation because of their flat blackened surfaces. As an alternative to flat plate, we may use concentrating collector, a solar collector that uses reflective surfaces to concentrate sunlight onto a smaller area than the reflector. Higher energy flux can be made by this collector and thus providing a higher temperature. But it is more expensive and at the same time complex to operate. Therefore, a flat plate solar collector is our choice for this refrigeration system. Results: The solar refrigerator can save the environment and energy at the same time. Trigenation, the compounding of an absorption refrigeration system with a cogeneration plant to utilize all the generated heat for the production of cooling has become a topic of wide interest in recent years. A trigeneration system can be used in supermarket and food industry to simultaneously satisfy heating, refrigeration and thereby cutting down electricity demands. Conclusion: The solar refrigerator can save the environment and energy at the same time. Trigenation, the compounding of an absorption refrigeration system with a cogeneration plant to utilize all the generated heat for the production of cooling has become a topic of wide interest in recent years. A trigeneration system can be used in supermarket and food industry to simultaneously satisfy heating, refrigeration and thereby cutting down electricity demands.
2015
A solar refrigerator is made of a solar collector and a refrigeration system. This paper concerns the study of a two-stage vapour absorption cycle (heat transformer and refrigerating cycle) employing the refrigerant absorbent combinations of H2O-LiBr and NH3-H2O successively. The system consists of coupling the previous absorption cycle so that the first-stage absorber produces heating water to circulate in the generator of the second stage. It is found that the system can be operated at lower hot source temperatures and, thus, it can be supplied either from flat plate collectors. Résumé Un réfrigérateur solaire est composé d’un capteur solaire et d’un système de réfrigération. Ce papier présente une étude d’une machine frigorifique à absorption ‘NH3-H2O’ alimentée par un thermo transformateur à absorption ‘H2O-LiBr’ de telle manière que l’absorbeur du thermo transformateur produit de la chaleur qui alimentera ensuite le bouilleur de la machine frigorifique. On constate que le systè...
Exergy analysis of solar assisted double effect absorption refrigeration system
Renewable Energy, 1998
Exergy or the available energy is based on the second law of thermodynamics and goes back to Maxwell and Gibbs. It is the exergy content and not the energy content, that truly represents the potential of the substance to cause change. Exergy is the only rational basis for evaluating the system performance. The aim of this project is to study in detail the exergy variation in the solar assisted absorption system. The influence of the cycle parameters are analysed on the basis of first law and second law effectiveness and the results indicated various ways of improving system performance by better design. Also a better quality of the evaporator has more effect on the system performance than the better quality of other components. It was shown that second law analysis quantitatively visualizes losses within a system and gives clear trends for optimization.
A Case Study on Solar Vapour Absorption Refrigeration System
International Journal of Engineering & Technology
Solar refrigeration may have applications in both developed and developing countries. Applications in developing countries such as air-conditioning, vaccine storage or large scale food preservation have been the subject of scientific research. Ammonia-water based system has good COP but generally vapor absorption refrigeration system requires high generator temperature and high circulating ratio aided by a powerful pump. Our objective was to trivialize the role of circulating ratio and simultaneously achieve higher COP. A prototype model was designed, fabricated in laboratory using scrap material and tested; performance of the unit has been analyzed. A parabolic solar trough was used as a source of heat. Various components were modeled in computer and analyzed using ANSYS. The performances and effectiveness of the unit was studied by determining refrigeration effect (RE) and coefficient of performance (COP).
Evaluation of using solar ammonia absorption cooling system for major cities of the Middle East
International Journal of Heat and Technology, 2018
Solar energy is an important source of renewable energy. In this paper, renewable energy is used to cooling purpose in the Middle East. The cooling load is calculated for major cities of the Middle East. An ammonia absorption refrigeration cycle (AARC) is used for cooling purpose. Solar energy is used as the source of high temperature. Codes are written in EES software to analysis the solar cooling cycle. In this analysis, temperature, enthalpy, and other thermodynamic properties are obtained in different cases. Weather properties information such as winter and summer design temperatures of these cities are obtained from HVAC handbooks. The variation of temperature and cooling capacity in different months and different hours of a day is calculated and is shown in different figures. Cooling ability of solar cooling system varies in the different month and different hours. Furthermore, the influence of the efficiency of heat exchanger of solar cooling system on the coefficient of performance of cycle and the cooling capacity is investigated. In this paper, different climates with summer design dry bulb between 32º C and 47º C and solar heat gain between 840 w/m 2 and 890 w/m 2 are considered.
Development of a simple intermittent absorption solar refrigeration system
International Journal of Low-carbon Technologies, 2006
A simple solar energy powered intermittent absorption refrigeration system was designed, fabricated and tested. The system uses a generator charged with ammonia and water. The heat source is a solar radiation collector that collects and radiates solar thermal energy onto a black body generator. The generator drives the refrigerant around the system through a condenser and an evaporator. The system was evaluated by leaving it outside under solar radiation and monitoring temperatures at various points inside the collector, the generator, and the evaporator through the use of thermocouple sensors. The average highest and lowest temperatures inside the solar collector were 100°C and 40°C respectively. The average lowest refrigeration temperature was 4°C. The coefficient of performance (COP) of the system was estimated at 0.487. Keywords solar refrigeration; heat powered cycles; solar thermal applications h c Overall collector efficiency h r Refrigeration efficiency.
A New Aspect in Analysis and Improvement of Standalone Solar-Driven Absorption Refrigeration Systems
Emerging Science Innovation, 2024
Solar-driven absorption refrigeration systems (ARSs) are subjected to work under off-design conditions due to the driving temperature variation. In this study, a model of NH3/H2O ARS with 100-kW cooling capacity has been developed. Energetic and exergetic coefficients of performance (COP, ECOP), besides cooling production (Qeva), have been investigated at off-design conditions. The analysis indicates a reduction in the effectiveness of the generator and solution heat exchanger (SHX) under such conditions. A new method to improve the off-design system's performance by modifying the generator and SHX heat capacities is suggested. Results revealed that an increase in heat capacities of the generator and SHX (UAgen, UASHX) effectively improves the system's performance. Raising the values of UAgen and UASHX by 20% maintains the system's COP, ECOP, and Qeva near their designed values under a wider range of driving temperatures (100 o C to 92 o C). Moreover, this adjustment helps decrease the system's cut-in/off temperature.