Preliminary study of the hybrid solar DEC “NAC wall” system integration in building façades in urban context

A new concept of hybrid/natural air conditioning system, “NAC (Natural Air Conditioning) wall”, with a high level of architectural integration is presented. NAC wall concept is that of a solar DEC (Desiccant Evaporative Cooling) open cycle with very low pressure drops, thus drastically reducing, or even avoiding, the electricity consumption for driving fans. The supply air is dehumidified by an adsorption bed and is cooled indirectly by an evaporative cooler, through a low pressure drop heat exchanger. Adsorption bed is a finned coil heat exchanger coated with a SAPO-34 zeolite layer realizing both heat and mass transfer in a unique component. The assembling of NAC wall components is analysed in order to optimize architectural integration and performances. Experimental data carried out in different operation mode offered promising optimization suggestions to increase the specific cooling power for a better building integration. The integration at a building level would represent an architectural innovation, and the NAC wall production would not impact the supply chain with disruptive changes.