I do not give up easily on an idea, especially when my research shows it is viable. It is just a matter of setting up the right combination of cooling and circulation to create a chilled floor. About a week ago I tried running well water through the floor and that worked to chill the floor slightly. Even though I set up a pump to get the water outside, I felt it was using a LOT of well water. I’m not sure how strong the well is and although it is a relatively wet year, what would happen in a dry year?
Reasoning that a chiller might be more able to chill just the floor pipes and not the storage tank, I bought another chiller, this time from Craigslist. It is a 1/3 horsepower modular chiller from Prime. They no longer market these chillers but it has a reasonable reputation in aquarium forums. The modular chiller is stronger than the 1/3 horsepower tower chiller by the same manufacturer–it is rated to chill 300 gallons at 12-22 gpm flow rate.
I plumbed the chiller into the radiant system and turned off the boiler and closed off the pipes to it. Then I tried just using the Grundfos pump to circulate chilled water but it never got over 3 gpm. That is too low for the chiller to work properly.
So I took out the Taco 011 and hooked it up in series with the Grundfos. Of course the piping leaked a couple of times and had to be redone. I didn’t have all the connections I needed and I had to work around the Home Depot being out of stock of the specific Sharkbite connections that I wanted to use.
I have the chiller running right now at a setpoint of 67 with a current temp of 70 and a 2 degree differential. The Taco pump will continue to run even when the system shuts off.
I will have to figure out how to control it with the thermostats. Currently they open the appropriate zone valve and turn on the Grundfos pump set on cool instead of heat. But when the room meets the set temperature the Grundfos will turn off. I’m not sure how much of a problem that is for the pump if the secondary pump is still operating.
Right now I’m waiting to see if the water will cool the floor and maintain a cooler temperature during the day. Ideally this system is paired with ventilation. If this works, installing ventilation would be the next step, after getting the electrical done of course.
Unfortunately the chiller has the same problem as the others even with a shorter run to chill. The temperature of the water going through the chiller stayed at 70 degrees all night and the refrigeration unit added heat to the utility room so that the whole house did not cool down as much as it had without the chiller or even just water circulation.