Most efficient way to recover heat from 130 degree F water and transfer this heat to 140 degree F water?
I am making a solar still and I need to recover as much heat as I can from the 130 degree F water (bringing the water temp down to near ambient, 72 degrees F) and then transfer this heat to 140 degree F seawater. I have a limited amount of solar collectors to heat brackish water, send it through an evaporator tower and then a condenser tower to make fresh water. As the fresh water goes through the condenser it gains a great deal of latent heat, thus the 130 degree F water. In order to increase production and regain otherwise lost energy I am trying to recapture a portion of this heat to further warm up the brackish water (currently at 140 degrees after exiting the evaporator tower) before being further heated with the solar collectors. I am operating off grid, so the solution must utilize solar heat or PV panels as the power source.
Does anyone know of a heat pump that operates best in this temp range? What about using TEC (aka TEG, TEP or TEHP) to perform this task? Is there a better or more obvious solution that I am oblivious to? Any advice would be much appreciated.