Performance investigation of solar energy-aided compression-based building air conditioning strategies for variable climatic regions.

Abstract

Decoupling cooling and ventilation tasks with an existing air conditioning methodology are a promising performance-enhancement technology. In this direction, different configurations of a desiccant-integrated independent ventilation element attached to a conventional cooling system are proposed in this study. This work establishes a quantitative comparative performance analysis among the different process air cooling (obtained through desiccant dehumidification) techniques for three different climates, namely, hot-dry, tropical, and Mediterranean. EnergyPlus simulations have been executed on a small-scale office building of 400-m2 area. The building constructional details and other required simulation input parameters follow benchmark standards. As the chemical dehumidification increases, the process air, i.e., supply air temperature that cannot be sent directly to the room, needs to be cooled. Three approaches for process air cooling have been considered: direct expansion (DX) cooling coil, indirect evaporative cooling (IEC), and sensible heat recovery wheel (SHRW). A solar collector assembly with a supporting heating arrangement is coupled with desiccant unit for regeneration. Outdoor air is used for regeneration in the case of the DX cooling coil and IEC, whereas return air is used in the heat recovery wheel case. Annual simulation results reveal that the SHRW-aided case performs superior than DX coil case for the pertinent climatic conditions, with 9.6 to 45.01% of annual energy savings. For the IEC, energy consumption was 1.8 to 18.38% less than that of DX coil. Also, using return air in this best-suited case reduces the net thermal energy requirement for regeneration by 14.63 to 71.65% with respect to DX coil.