Experimental analysis of “NAC-wall” for hybrid ventilation mode

Reducing the energy demand for residential cooling systems is crucial in order to limit CO2 emissions, consistently with the EU climate change policy. Within this context, solar DEC (Desiccant, Evaporative Cooling) technologies can represent a valid answer to the energy saving targets. This experimental analysis aims to present the last results of a scientific campaign on a solar DEC prototype, named NAC-wall (Natural Air Conditioning), operating with a hybrid ventilation mode. Heat and mass transfer happens in an innovative dehumidification component, a finned coil coated with a layer of Zeolite SAPO-34, presenting very low pressure drops. Different tests have been performed in the flow regime Reynolds 750-3500 to analyze dehumidification effectiveness. For a better comparison between each test, a preliminary complete regeneration of the adsorbent mean have been always carried out with hot water circulation, produced by a solar thermal system. A theoretical optimized working cycle, i.e. one regeneration stage followed by one adsorption stage, has been studied starting from the experimental results and its performance has been compared with the optimized natural ventilation operating case, reported in a previous work.