Performance of hybrid air conditioning systems with split condenser and evaporator.

Hybrid air conditioning systems consisting of a standard refrigeration system and a desiccant wheel and managing sensible and latent loads independently present substantial energy-saving potential. However, as these hybrid systems operate at a higher coil temperature, the supply air temperature is also high, leading to an increase in the supply air flow rate for a given room temperature and sensible load. The current study proposes a modified hybrid system with a split evaporator and condenser to reduce the supply air mass flow rate, in addition to the reduction in the compressor power input. In the proposed system, an enthalpy wheel is used to recover energy from the exhaust air stream. A split evaporator and an air-to-air heat exchanger wherein there is a transfer of sensible heat from the dehumidified air stream from the desiccant wheel to the refrigerant and exhaust air stream from the enthalpy wheel respectively, are proposed. With these measures, the supply air temperature, and hence the supply air flow rate reduces substantially. The annual performance of the proposed system with the modifications is compared with that of a conventional system. Results are obtained for a large classroom building and for four Indian cities, representing different climatic conditions of the country. EnergyPlus is used to estimate the dynamic building loads for the summer months. Results show that the proposed hybrid system yields the highest reduction in annual energy consumption of about 49% for the building located in Kolkata, with the lowest reduction of around 16% for Bengaluru. Results also indicate where it is beneficial to use the additional components and where it is not. The study is expected to help in the design of environment-friendly and energy-efficient summer air conditioning systems suitable for different climatic conditions of the country. [ABSTRACT FROM AUTHOR]