posted 11 years ago
I'm getting a better picture of what you have in mind, Jason.
That water is a very large thermal mass, and the amount of energy to vent some overly hot air on the warmest days of summer is small in comparison. I take it there are never days where it gets so warm that you have to cool the water, or does it?
I think the best return for your efforts will be spending the time and money to make the water heating as efficient as possible. Things like having the tanks in thermal contact with solar absorbers, using the fish tank water to cool surfaces that regularly get too hot, etc.
Do you have data on how much temperature swing you have in the air and how much the water temperature changes during those swings? You say this is under construction, so maybe not. Maybe after you get it working and have a few months of data, some possible refinements may jump out at you. No matter how much planning goes into engineering before construction, there are always ways to optimize parameters after the thing gets built.