Harvesting energy from fluctuations in humidity

A novel energy system can heat and cool buildings using changes in the humidity of the air

Spotted: Think back to the last time you got out of a swimming pool on a hot day – remember the cooling feeling of the water evaporating off your skin? That coolness came from the transfer of energy from water to air as it evaporates (the same thing happens when we sweat). Now, what if this same principle could be used to cool and heat your house? That is the question that is being answered by Israeli startup ThermoTerra. 

ThermoTerra is developing a renewable energy system that heats and cools using humidity. The system embeds a hydroscopic material such as hempcrete, silica gel, or wood wool inside building walls. When the surrounding air is drier or wetter than the hydroscopic material, the potential energy difference between moisture in the air and the material would transport heat from the material to the air and vice versa.

So, on a hot, dry day, water in the material evaporates, creating a cooling effect. On a cool, wet day, water is re-adsorbed into the material, producing heat. The entire system would be controlled by sensors and smart monitors embedded in the walls.

Other heating and cooling innovations recently spotted by Springwise include a thermal energy storage system that reduces energy bills, a wood-based cooling foam, and an air conditioner that lowers carbon footprint.

Written By: Lisa Magloff