I'm cross-posting this on "Alternative Energy" but its not really alternative, just conservation. I've got a heat pump and we air condition more months that we heat. Question: Why couldn't I run my line in a loop that included passage througha LARGE iunderground tank of water - say a few thousand gallons? At night when it is cooler, I'd chill the water with an evaporator. During the day I could dump heat into the water reserviour before or after entering the condenser coils for more effecient cooling. Essentialy I'd store cheaper energy/cooling in the water.