Nitinol Free Energy Nickel titanium also known as Nitinol is a metal alloy of nickel and titanium...

You could also use now that it’s 2022 a cavitation heater and or solar water heater and for the cooling either a cooler or cooling device, for the contrast in temperature needed or You could use a condenser like an ac/heater condenser heat one side cold the other or A simple cooler like a seer clay wet sand cooling pot and a simple solar water heater!!! -Nate C Bit