I was ignoring the insulating effect of CO2 and focussing on the heat system. What I am getting at is we need to find low temperature way of locking up the Sun

I was ignoring the insulating effect of CO2 and focussing on the heat system. What I am getting at is we need to find low temperature way of locking up the Sun's energy. Such that when it is stored it has removed energy from the Earth ecosystem and then when it is released it is at ambient, or below ambient temperature. The thinking behind eutectic salts is about melting something that takes a lot of energy and can be done by the sun's rays. These molten salts could then create steam to drive a steam turbine and produce electricity that can be stored.