Innovative Compact Solar Air Conditioner based on Fixed and Cooled Adsorption Beds and Wet Heat Exchangers

Abstract

In this work, a new all-in-one compact solar air conditioner concept is presented. The system is mainly based on a new DEC process which utilises fixed and cooled adsorption beds operating in a batch process and two wet heat exchangers. The proposed innovative adsorption bed is a fin and tube heat exchanger commonly used in the air conditioning sector, wherein the spaces between the fins are filled with silica gel grains. The main feature of this component is to allow simultaneous dehumidification and cooling of air. Furthermore, since the component hosts a considerable amount of adsorption material, solar energy can be efficiently stored in the desiccant media in terms of accumulated adsorption capacity. This potential can be used when regeneration heat is not available, strongly reducing the need for thermal storage in the solar loop. The indirect evaporative cooling process, operated downstream to the dehumidification, is realized by two wet plate heat exchangers connected in series. The process can be operated at relatively low temperature, allowing supply air temperature to the room of about 20°C.A prototype of the compact solar air conditioner specifically developed for residential application is presented. The main features of the system as well as the thermodynamic cycle are first described. Monitoring results are presented by means of most commonly used performance indicators showing several advantages which can be obtained using the proposed solution.