Chilled water loops

George_10

chilled water through and existing hydronic loop on a continuous basis. And assume the boiler was bypassed.
Would you get some cooling effect? Would it be cost efficient.

Constantin

Depends on the source

Consider a couple of things:

• Either you control the humidity/temperature really well or you're going to get condensation. The only folks I know of who do a big business of radiant cooling are the Germans. They get down to monitoring individual windows to see if they're open, and if so, stop the cooling. Otherwise, you'll have some rainfall.
• Overhead ceiling panels seem to work best. The warmer air congregates up there and the radiant "view" of the ceiling is usually not obstructed. Plus, if you're controlling for the dewpoint, the large surface area up there does a great job of removing sensible heat. For example, the Karo system looks intriguing as it can heat and cool a place.
• Other forms of cooling will still be required to remove the latent heat and control humidity. However, the fan and duct systems can be up to 80% smaller than air-only systems. From what I can tell, finding an installer who has done this before though is apt to be a challenge, particularly in the residential market.
• Last but not least, you'll need a chiller instead of using a refrigerant-based system if you don't have a source of cold water handy (like an underground well or a cold lake). A ground-source heat pump also makes for an excellent source of chilled water.

So it appears that it can be done. In fact, one web-site advocates the running of potable water through the radiant system first before being used inside the house. This would allow the use of the local well or municipal water supply to cool your house to a very limited extent for "free". Most plumbers/installers recoil at this thought though (as do I, but I'm just a homeowner) due to the risks and the issues associated with running an open system.

GMcD

Radiant cooling.

Yes, you can do this as long as the fluid temperature did not go below the ambient dewpoint of the room where you are doing this. Lets say your room ambient dewpoint was 60F, then you can run a minimum fluid temperature of 61F and not get condensation on your cool radiant surface. The cooling effect is going to be somewhere between 35-40 watts/sq meter or around 12 btuh/sq. ft. Do a Google search on keywords "floor cooling", "radiant cooling", "Bjarne Olesen", and the like and see what you get. The key is to control your ambient humidity to avoid condensation.