Use of desuperheater in Winter

3 ton Bosch system, 525 feet bore, 1050 feet loop, near Allentown, PA.
Contractor says they tell people to turn off the desuperheater in the middle of Winter, unless it looks like a mild Winter. Says something about pulling too much heat from loop to heat hot water, wants to make sure water temp is good through Winter to heat the house. I think that's overly conservative. My thought is, the desuperheater is heating the water more efficiently than my hot water heater, so I'm going to use it year round.
Heat loss calc done by BPI/Resnet certified guy showed 30,000 btu/hr max heat loss so in my mind, I have plenty of loop, plenty of capacity and I shouldn't have to worry about the %10 drain on btus from the desuperheater. I should use it year round. Does that make sense? Do you agree?

Thanks

 

I agree with you. The contractor seems mis informed unless he undersized your system.

Do you have a separate buffer tank for the desuperheater?

During the really cold spells, just monitor your EWT to see how the loop is performing under peak loads. Then you can shut off the desuperheater if needed.

 

Yes separate buffer tank. As far as monitoring the EWT, I can't because they don't put gauges on their systems. I thought that was odd. Probably something I should have requested ahead of time as it would be nice to be able to monitor that. I guess there's no way I can use a thermometer and stick it in somewhere to get that info?

 

Is the some pipe insulation that you could slide a meat thermometer under?

 

I'll try that. Thanks

 

Why a 3 ton system for a 30,000 btu load? ....and then no DSH in the winter?
The DSH costs less in reduced heating efficiency then it saves in hotwater production.
Oversized heat pump + myths about winter DSH = stone age (Carter era) geo installer.

 

Ok, thanks. I'll keep the DSH on all Winter. I agree with your comment about stone age installer and they do oversize. However, would you guys be a little more cautious with DSH use this first Winter considering the loop didn't have much time to "charge" this Summer since it was only installed late August and A/C wasn't used much? That was a concern brought up by the installer.

Thanks

 

Monitoring your loop temp is the only way to know if your loop is being over worked.

 

Agree with DeWayne and Joe.

Tape the probe of a Walmart Accurite meat thermometer to the entering water line using metal foil tape and insulate the pipe + probe.

If EWT gets much below 30*F, consider stopping the DSH, but that shouldn't happen in Allentown unless loop is way undersized.

For families with normal hot water use profile, DSH diversion is well below 10% during late night cold snaps since by then buffer tank is all warmed up.

 

Ah thermal banking. I forgot that one. I should have said: Oversized heat pump + myths about winter DSH+ banking heat in the ground in the summer to carry you through winter = stone age (Carter era) geo installer.

Loops may underperform the first year because of compaction, but heat migrates away from loops or to them depending on season. Elevated soil temps may help you for a short while in the fall as lower temps may help you for a day or two in early cooling season.
If heat didn't move to or from loops, you would quickly exceed design temp parameters. For the same reason, storage tanks of thousands of gallons don't work as loops convey to or extract heat from massive amounts of space.

 

Just keep the DSH running, your loop sounds plenty of large compared to your load, and even if the loops dip down to 28F, or 25F in the first year, you loose efficiency a bit, but you will be fine. 10% more load from the DSH will not have much impact at your loops.