Energy-efficient heat recovery systems for air conditioning of indoor swimming pools

Analysis of a conventional air-conditioning system for indoor swimming pools during the summer season is presented. The analysis showed that the cooling load is characterized by a large latent heat fraction. As a result, a reheating process must be used downstream of the cooling coil to achieve the proper design comfort condition in the pool area. This, in turn, increases the energy requirement per unit cooling load of the pool. Two heat recovery systems are proposed to reduce this energy. In the first system, ambient air is used for the reheating process in an air-to-air heat exchanger. In the second system, mixed air-recirculated and ambient air is used for the reheating process. Heat recovery efficiency is defined as an index of the energy savings resulting from the use of the heat recovery system compared to that of a conventional air-conditioning system. At a wide range of ambient conditions it is found that the energy savings could be up to 70% of the energy required to operate a conventional air-conditioning system. A parametric study was carried out to size the air-to-air heat exchanger associated with these heat recovery systems, and the results showed that a heat exchanger having an effectiveness of 0.5 would give satisfactory results. The proposed heat recovery systems are also compared to the case of reheating using the heat rejection from the condenser of the refrigeration machine. The comparison showed that the proposed systems save more energy than reheating using the condenser heat. A typical case study is given to demonstrate the savings in energy consumption when these systems are used.