This german company is using silicagel in an air conditioning unit to cool with heat: http://www.sortech.de/sortech/forschung/ http://www.sortech.de/sortech/for

This german company is using silicagel in an air conditioning unit to cool with heat: http://www.sortech.de/sortech/forschung/ http://www.sortech.de/sortech/forschung/ (site unfortunately in german). Edit: I just found another german company using heat for cooling, this one is using zeolite: http://invensor.com/en/technology/zeolite.htm http://invensor.com/en/technology/zeolite.htm