Abstract: A solar operated chemical heat pump useful in both the heating and cooling modes. This system includes an insulated tank containing a fluid which is heated from the exterior. A heat sink in the form of a second tank is also employed. A water-ammonia solution is present in each tank, and conduit means are provided for respectively conducting the vapor of each tank into a bubble plate or similar structure of the remaining tank, this for effecting a thorough dispersion of incoming vapor into the liquid of the respective tanks. Heat from a solar heat source is used to heat the liquid of the first tank to drive off vapor under pressure so that the ammonia gas released can be bubbled through the water of the second tank. This process serves to gradually reduce the ammonium ions in the liquid of the first tank and enables the second tank to serve as a heat sink for the system.