Solar Absorption air-conditioning system

 

This system has been the basis of most of the experience to date with solar air- conditioning. To begin with, the solar energy is gained through the collector and is accumulated in the storage tank. Then, the hot water in the storage tank is supplied to the generator to boil of water vapor from a solution of lithium bromide+water.

The water vapor is cooled down in the condenser and then passed to the evaporator where it again is evaporated at low pressure, thereby providing cooling to the required space. Meanwhile, the strong solution leaving the generator to the absorber passes through a heat exchanger in order to preheat the weak solution entering the generator. In the absorber, the strong solution absorbs the water vapor leaving the evaporator. Cooling water from the cooling tower removes the heat by mixing and condensation. Since the temperature of the absorber has a higher influence on the efficiency of the system than the condensing temperature, the heat-rejection (cooling water) fluid, is allowed to flow through the absorber first and then to the condenser.

An auxiliary energy source is provided, so that the hot water is supplied to the generator when solar energy is not sufficient to heat the water to the required temperature level needed by the generator. In the solar powered absorption air-conditioning system, it is very much essential to have a hot water storage . It serves as a buffer reservoir to have nearly constant heat input. Similar to the hot water storage tank, a chilled water storage tank is often used in the solar powered air-conditioning system.

 

Figure 2.6 - Solar Absorption air-conditioning system

In the heating season, the hot water is directly provided from the hot water storage to the fan-coil of the air-conditioned space, or/and to places where the heat is used for bathing or other domestic applications.