Comparison of two hygroscopic materials for a solar-assisted desiccant-based air handling unit

Abstract

Solar-driven air-conditioning systems are an interesting solution to reduce greenhouse gas emissions as they are essentially powered with a renewable energy source. Among the solar heating and cooling systems, desiccant-based air handling units (AHUs) are a very promising alternative as they require low temperature thermal energy for operation in cooling mode. In this paper the experimental plant of University of Sannio (Benevento, Southern Italy), consisting of an AHU with a desiccant wheel using as hygroscopic material silica gel is coupled with solar thermal collectors. This AHU has been also simulated with a different material for the desiccant wheel, the MIL101@GO-6 (MILGO). It is a composite material, consisting of graphite oxide dispersed in the MIL101 metal organic framework network structure, that shows a better dehumidification effectiveness. The energy and environmental performance of a desiccant-based solar heating and cooling system with this new material have been evaluated with respect to the conventional AHU based on cooling dehumidification. Yearly based dynamic simulations of the plant serving a university classroom located in Benevento have been performed. Furthermore, a comparison with the air-conditioning system equipped the currently adopted material (silica gel) has been carried out too. The optimal plant configuration varying collector type (flat plate and evacuated tube), tilt angle and surface has been found.