Chillers

Wires52

Hi all

I want to install a inline chiller into my radiant floor heating system, the house has 6 zones that I would like to cool down in the summer months. I live in a very dry climate so condensation is not so much of a problem. can it be done and if so what size chiller should I buy .

Brad White

Need a lot more information

Radiated floor area, your sensible cooling load, tube spacing and diameter, etc. In a way you are "back-engineering" the system, taking a given layout and doing a capacity check, basically.  The chiller size comes out of that. A contractor who deals in the major system brands such as Uponor, would have access to their design software which in my opinion is the best if not the only way to nail down your capacity.



Regardless, your water temperatures will have to be regulated above your dewpoint no matter where you live, but also your water temperatures do not want to be so cold that it is uncomfortable to walk on. That conundrum, cool enough to cool and not be cold.



If you have high sensible gains, lots of sun, lights, wide screen TV, abundant marital aids and toaster ovens, you understand that you may just be "taking the edge off" and not performing the full AC effect, right?

bob_46

I have a dream

If a swamp cooler is 100% efficient the temperature of the leaving air and of the water

in the pan will be the wet bulb temperature of the ambient air. If it's 90º F and 10% RH

you get about 58ºF water. My dream is, set a swampy next to the house. Let it suck

outside air and discharge right back to the outside air. Install a heat exchanger (HX) at the swamp cooler with a small pump and pump water from the pan through the HX, pump

the water from your radiant system through the other side of the HX. Dew point and

wet bulb are the same number. (not the same thing) Since the swampy and HX are not

100% efficient the temperature of the slab should stay above DewPoint. If your house has an attic you could blow the discharge air from the swampy through the attic and reduce the load. You need to do some load calculations and enginearin. I believe this

would be a lot cheaper to run than a chiller.

Brad White

Cooling Tower

What you described there, Bob, is a cooling tower. Agreed in a very dry climate, your low wet bulb temperatures will do a lot by evaporation but you also have sensible gains on the water and you will gain a bit by conduction from the ambient air,  enough to negate much of the evaporative effects.



Most practically sized towers in our climate have an approach temperature of about seven degrees (leaving water temperature at say, 85F to entering wet bulb temperature of 78F).



In the desert southwest, yes you can do much better as in your example, but the make-up water out of the ground might well be higher than your wet bulb temperature by a fair degree. May make a good first stage though.