Abstract: The device and method of the invention are adapted to control temperature and humidity of the air in some defined volume such as a room in a house. The device consists of a quantity of hygroscopic material and means for passing air past or through the material. Direct temperature and humidity control occur when air is conditioned (heated and dried by sorption heating, or cooled and humidified by absorption cooling) and sent inside the room; indirect control is also possible, by affecting the temperature of the walls (the sorption material may occupy channels or spaces within the walls, which are then heated/cooled, indirectly heating/cooling the air in the room by conduction). A fan or blower will allow for forced convection of air in a desired path (e.g from outside the house, over/through the sorption material, and into the house, or in the opposite direction). A second fan and valves allow for more complex operations.

Abstract: The innovation uses the disparity between dry and wet conditions of the air, by storing the ‘dryness’ or ‘wetness’ in a hygroscopic material. When the surrounding air is drier or wetter than the hygroscopic material, the potential energy difference between moisture in the air and that in the material can be used as a way of transporting heat from the material to the air and vice versa. A simple way this energy can be used is for heating and cooling of a building. For example, a large storage of adsorbing material can be dried in the hot summer, and allowed to re-adsorb water in the cold winter, thus gaining heat that can be used for domestic heating.