Skytherm roof is better. No need to pump sea water or lake water just put the water in containment on your roof and uncover it as you want solar heating (winter

Skytherm roof is better. No need to pump sea water or lake water just put the water in containment on your roof and uncover it as you want solar heating (winter daytime), radiant cooling (summer nighttime), or cover it if you want thermal capacity heating (winter nighttime) or thermal capacity cooling (summer daytime). http://www.solarmirror.com/fom/fom-serve/cache/30.html http://www.solarmirror.com/fom/fom-serve/cache/30.html