Radiant heat without a buffer tank

Jimpoole

I have some customers that will install a geothermal radiant heat system without a buffer tank.  They will put the whole mass on one zone and install extra tubing to get more fluid in the system for storage.  What are the benefits to this type of install besides lower install cost, less components?  What are the drawbacks?

kcopp

not sure....

it will work very well. I remember a while back john Siegenthler had a Glitch and the Fix article on this very thing.... the buffer tank was a must.

http://www.radiantandhydronics.com/Articles/Glitch_and_Fix/BNP_GUID_9-5-2006_A_10000000000001110120

Zman

Control

I think the biggest drawback will be control over comfort. I guess if it is one big room and the heat loss is very stable (not much solar gain/temp swings) the system should work.Or if it is an area where temperature is not that important like a garage.

Carl

SWEI

geothermal or geo-exchange?

Is there a heat pump involved here?

zacmobile

I wouldn't recommend it but...

I have seen it done, and it seemed to be working fine, it was in a garage/studio. Room thermostat was wired directly to heat pump with no other controls. If you did attempt this I would be inclined to match the heat pumps flow requirements to that of the radiant floor, ie. If a 3 ton heat pump needs 9gpm then design the floor around that, if it means using larger tubing, 5/8" 3/4" etc. Also at the very least I would employ some kind of high limit control, an aquastat in a well on the load out to protect the heat pump in the event of a runaway thermostat or something. In addition, the possibility of short-cycling the heat pump may be a concern, most come with built-in anti short cycling protection but I don't like to rely on that alone, much better to not do that in the first place, a heat pump thermostat will have an adjustable time delay to prevent this.