A NEW HIGH EFFICIENT SORPTION SYSTEM FOR SOLAR ASSISTED AIR DEHUMIDIFICATION (ECOS)

In many climates for controlling the internal built environment - both in industrial and residential sector - air dehumidification is at least as important as temperature control. In this paper a new system concept of a high efficient solar driven air dehumidification is presented. The system can be operated by low temperature heat (lower than 100°C) such as heat produced by selective flat plate solar thermal collectors. The system has been named ECOS: indirect Evaporative COoled Sorptive heat exchanger. The implementation concept of the new cycle is based on an air-to-air heat exchanger technology which presents two sets of channels operating in counter-flow which are physically separated but in thermal contact: sorptive channels and cooling channels. In the sorptive channels, a sorption material is fixed on the surface of the heat exchanger and the process air is dehumidified by adsorption. The sorption process is cooled through continuous indirect evaporative cooling realized through the air stream flowing in the cooling channels. The continuous humidification of the cooling air stream during its way through the heat exchanger leads away the sorption heat and thereby increases the process air dehumidification efficiency. In the paper we present a mathematical model of the cycle which has been developed and used for a wide range of simulations in order to assess the systems performance under different conditions. First experimental results of a laboratory scale test unit underline the functioning of the process. Overall the system has a very high potential for high efficient solar driven air dehumidification and cooling even under conditions with significantly high humidity ratios of the external air (e.g., tropical climates). Therefore it results a significantly promising option for residential and industrial applications.