An environmental control system utilizing solar energy would generally be more cost-effective if it were used to provide both heating and cooling requirements in the building it serves. Various solar powered heating systems have been tested extensively, but solar powered air-conditioners have received little more than short-term demonstration attention. Solar powered absorption cooling systems can serve both heating and cooling requirements in the building it serves. Many researchers have studied the solar absorption air conditioning system in order to make it economically and technically viable. A number of attempts have been made by researchers to improve the performance of the solar applied air-conditioning subsystems. . This study paper will help many researchers working in this area and provide them with fundamental knowledge on absorption systems, and a detailed review on the past efforts in the field of solar absorption cooling systems with the absorption pair of lithium-bromide and water.
Keywords: Absorption chiller; Air-conditioning; Lithium bromide and water; Solar energy etc
Air-conditioning is a particularly attractive application for solar energy because of the near coincidence of peak cooling loads with the available solar power. Many arrangements or cycles are possible. solar collectors can be used to provide energy for absorption cooling, desiccant cooling, Although a large potential market exists for this technology, existing solar cooling systems are not competitive with electricity-driven or gas-fired air- conditioning systems because of their high first costs. Lowering the cost of components and improving their performance could reduce the cost of solar cooling systems. Improvements such as reduced collector area, because of improved system performance, and reduced collector cost will lower the cost of solar components. The performance coefficient of an absorption air-conditioner, defined as the ratio of the heat transfer rate into the evaporator to the heat transfer rate into the generator, can be calculated as a function of the temperatures identified previously. Solar energy is one of the most available forms of energy on the Earth's surface, besides; it is very promising and generous. The earth's surface receives a daily solar dose of 10E+8 KW-hr, which is equivalent to 500 000 billion oil barrels that is one thousand times any oil reserve known to man. The solar energy is collector area dependent, and is a diluted form of energy and is available for only a fraction of the day. Also, its availability depends on several factors such as latitude and sky clearness. At the same time, its system requires high initial cost. But on the other hand, it has some attractive features such as its system requiring minimum maintenance and operation cost, and it does not have negative effects on the environment. Another important feature of solar energy is its ability to satisfy rural areas where conventional energy systems might be not suitable or uneconomical.
Charters and Chen  had made a comparison study on air-cooled and water-cooled systems. In January 1998, a solar powered two-stage absorption air-conditioning system was installed in China .The system has a cooling power of 100 kW, with collector areas of 500 m2. The nominal generating temperature of the chiller is about 65-750C, and the COP of the chiller is greater than 0.4. This kind of machine was originally suggested by Tanaka, it was first installed at a new building of the Energy Engineering Department of Oita University, Kyushu . After successful operation for a two-year test period, the solar air-conditioning system was operated with steam as the auxiliary fuel. The identical single-double effect absorption chiller was also operated at the Kabe Office Building of the Chugoku Electric Company in Hiroshima.