How can I use my bathtub as a geothermal heat pump?
Question:We're going through a heatwave and my house goes up to 80 degrees in the daytime. I have almost unlimited cheap access to cool ground water (64 degrees). Is it practically feasible to fill my bathtub and use it as a heat sink? How would I do this?
Answers:
No, it's not practical at all. Simply filling your bathtub with water will do very little to cool your home. Sure it will absorb a little heat, and if you're sitting next to it, you will feel cool due to radiation to the cold water from your body, but this will really have no impact on the temp in your house. This really couldn't even be considered a heat pump anyway. A heat pump works on the principles of the refrigeration cycle. You simply aren't benefiting from that here.
Filling the tub does not in any way distribute the cool water through the house. It will only remove a small amount of sensible heat from the air without removing moisture. In fact, once you cool the air, the relative humidity will go up making you feel less comfortable. Also, the heat removed from the air will cause the water to evaporate from the tub making the humidity rise even more, making you even less comfortable!
The idea of a geothermal heat pump (in cooling mode)is to use the ground as a big heat sink. This can be done by pumping a liquid in a closed loop or via an open loop in a well or pond. The idea is that the water gets returned to where you got it, not sent to the sewer system. It's just a gross waste of potable water.
Having said that, you aren't completely crazy. One project that I helped design had a large irrigation system. They were going to be pumping several thousand gallons a day to water some bushes. In that case we pumped well water through the radiant floor tubing before sending it out to the bushes. This helped take some heat from the house before the fan coil units did the rest of the air conditioning. We only did this because we had a use for the water after. Note that it still required fan coil units to remove the moisture.
think i would get a used car radiator, hoses, tank, small pump or some type of rig and a box fan.. make a chill box.. cool water runs through raidator fan blows through raidator.
are you thinking of filling your in home bath tub with the 64 deg water in order for your interior air to lose its heat to the water in the tub? that takes alot of energy to do that it will not do that just like that. you may want to use that 64 deg water and run it through a fan coil to deliver some cool air but thats about it. that would involve you to purchase a fancoil unit and a pipe that goes to the ground water to the fan coil delivered with a pump. very expensive good luck.
After a hot bath in cold months I leave the water in the tub and in hot months I leave cold water in the tub. In either case it's somewhat effective as there is a blower near the tub. I have to pay for the gas to heat the water but cold water is free for me.
You ain't foolin us, You just wanna start makin beer in your house like the stooges did,
I'm on to you hehe
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