Good question.

We have a three ton geo heatpump (a Tranquility 27) with the desuperheater, but its inclusion was a mistake the installer made. We took it as was with the thought that it would be worthwhile enough after all, but I have not yet hooked it up. We only use the unit about half of the year (we need very little cooling) so I put it off over the summer ... well, you know the drill.

But I am attracted by the vacuum solar tubes, which are claimed to be useful here in western Montana even in overcast and cold conditions. We'd spend close to $3K on such a system, with an anticipated payoff (at current natural gas prices) of about 7 years.

But the desuperheater would cost me almost nothing more to finish installing, even though it added about $300 to my heatpump cost. I could probably recoup that in about three years. Right now it's just a sunk cost.

But "What if", since I already own the desuperheater, I installed it in tandem with the solar tubes? It would be at its most efficient at exactly the time the solar tubes were at their least efficient- when it was very cold. (Or I may be wrong- it may be that the tubes are plenty efficient when it's veryvery cold, as long as it's clear; it may be fog and overcast conditions that I need to worry about concerning the solar tubes.)

Well, I haven't answered your question, but there's my two-bits worth for now, and thanks for bringing the question up. Good luck to you and I hope we both learn something from this!

M

ItÂs a no-brainer. If youÂre already installing geothermal, install the desuperheater too. If youÂre not satisfied with the result, then look to something else.

IMO

SR