De-superheater Q

[mckpickle]

Hi folks, First off let me say what a great website this is. There are so many folks here with lots of great advice.

If someone wouldn't mind I have a question about my Hydron 5 ton heat pump. It has the de-superheater attached. What I don't understand is how it can produce hot water? The way I understand it, the water coming in from my well is about 50 degrees (this time of year anyway in NH) and that is run across a heat exchanger. The air is then compressed which heats it up and blows into the house. My question is where is the heat coming from to then warm water for the 87 gallon tank? I would think that the 50 degree water has been pretty much drained of most of it's "heat" in order to warm the air. What am I missing? Thanks for any response.

[RoBoTeq]

Desuperheaters only produce heat for your water in the summer when the system is cooling. Then, the heat absorbed from your home's air is transferred to your domestic water.

[mckpickle]

Desuperheaters only produce heat for your water in the summer when the system is cooling. Then, the heat absorbed from your home's air is transferred to your domestic water.

Well that certainly make more sense now. And explains the 450$ winter electric bill!

Do you think that since the water is still circulating through the geo system that the hot water in the tank could be assisting the heat pump? I wouldn't think that would be ideal as I'd be using resistance heat to heat the water and run it through the heat exchanger.

[DeltaT]

I have a customer that has two of these systems that are used to heat and cool his home. He has 3 200 gallon water storage tanks in the crawl space of his home for chilled water storage.

Since these systems work both in heating and cooling the extra heating capability is there just about all year round.

[beenthere]

Moved to Residential Geo

[RoBoTeq]

My mistake with such a simplified answer that I gave. A desuperheater "will" work year round, but unless you have an abundance of excess heat, such as in the case that Delta T has described, it is best to turn off the desuperheater in the heating season.

There is only so much heat produced. In the heating season, if the hot water generator takes away from the space heating capacity, the electric auxilliary heaters are going to have to run to make up the difference. Sort of a case of robbing Peter to pay Paul.

[jerryd_2008]

Well that certainly make more sense now. And explains the 450$ winter electric bill!

...

As a HO that almost went with geo, how big is your house and WHAT IS YOUR SUMMER BILL??????

I can't comprehend a bill that high especially with a super efficient geo unless you were using propane in a very cold climate. Between 3-4 of those bills and you would have our total energy bill on a large home here in NW Arkansas using mid 90's single stage HVAC.

[RoBoTeq]

Too many geo systems in northern climes are designed for cooling, as should be for most air to air systems. However, in such climates it is better to size the equipment for cooling but make sure you have enough ground loop to handle the heating with a minimum need for the auxilliary electric heaters.

[drsmith012]

Desuperheaters only produce heat for your water in the summer when the system is cooling. Then, the heat absorbed from your home's air is transferred to your domestic water.

I get far more hot water off of my Waterfurnace in the winter than the summer. According to the contractor who installed it that is normal for R410 systems and oppisite form R22 sytems. Which if you are on city water is ironic as in the winter the incomming water is a lot colder than in the summer but far more benificial. My water heater has been off for about four weeks now but not continously. I have had to feed it some electrons during some of the recent warm spells her in VA. Nice to have it on a remote control. In the summer it just does not produce the quality of heat it does in the winter. I have a single "50" gallon heater connected to a 3 ton WF Envision.

[mckpickle]

As a HO that almost went with geo, how big is your house and WHAT IS YOUR SUMMER BILL??????

I can't comprehend a bill that high especially with a super efficient geo unless you were using propane in a very cold climate. Between 3-4 of those bills and you would have our total energy bill on a large home here in NW Arkansas using mid 90's single stage HVAC.

Just as a comparison, in sep and april the heat pump hardly ever kicks on. During those months the bill is still around 200 bucks. We're on an eletric co-op and it's around 30% higher than other companies....(go figure). When we do use the pump for colling in the summer it only adds about 75 bucks. This july/aug, with a 8 month pregnant wife, we kept the house at 72-74 and it was about 75 bucks anyway. But keep in mind, I'm in NH so 90 degrees here is a crisis!

In the winter the pump really works. I'm starting to wonder if the open loop system where it dumps "chilled" water back into the well was a good idea. Jan/feb my well temp ends up down to about 43-45 degrees. The heat pump is still able to pull plenty of heat out of the water and we've never gone cold, but I grit my teeth when the thing kicks on.
The house is about 3400 sq feet and is wicked tight.

[Evogreen]

Desuperheaters only produce heat for your water in the summer when the system is cooling. Then, the heat absorbed from your home's air is transferred to your domestic water.

i am postive that desuperheaters work both in summer and winter, I agree they do a lot more of the water heating in summer but there is also some heating done in winter too.

Here is a quote from popular mechanics

"A desuperheater is an auxiliary heat-recovery system that provides up to 60 percent of a home's domestic hot water. It's really just a second condenser located in the cabinet and connected to a standard electric water heater via a coaxial fitting. It delivers more heat in summer, but it helps in winter, too. The purchase price is a hefty $500, but again, the cost is misleading. Without a desuperheater, you'd need to install more underground piping to dissipate the extra heat. As you might expect, most units come with desuperheaters."

http://evogreen.ca
for more info on geothermal systems etc.

[RoBoTeq]

I get far more hot water off of my Waterfurnace in the winter than the summer. According to the contractor who installed it that is normal for R410 systems and oppisite form R22 sytems. Which if you are on city water is ironic as in the winter the incomming water is a lot colder than in the summer but far more benificial. My water heater has been off for about four weeks now but not continously. I have had to feed it some electrons during some of the recent warm spells her in VA. Nice to have it on a remote control. In the summer it just does not produce the quality of heat it does in the winter. I have a single "50" gallon heater connected to a 3 ton WF Envision.

None of this makes any sense whatsoever. You can't get more water heating capability in the winter then you do in the summer. There is no difference in the way R410a and R22 systems function.

[RoBoTeq]

i am postive that desuperheaters work both in summer and winter, I agree they do a lot more of the water heating in summer but there is also some heating done in winter too.

Here is a quote from popular mechanics

"A desuperheater is an auxiliary heat-recovery system that provides up to 60 percent of a home's domestic hot water. It's really just a second condenser located in the cabinet and connected to a standard electric water heater via a coaxial fitting. It delivers more heat in summer, but it helps in winter, too. The purchase price is a hefty $500, but again, the cost is misleading. Without a desuperheater, you'd need to install more underground piping to dissipate the extra heat. As you might expect, most units come with desuperheaters."

http://evogreen.ca
for more info on geothermal systems etc.

Was already addressed and corrected. There is only so much heat being absorbed whether for cooling or for heating. Obviously, in the cooling mode, all of the absorbed heat can be put into heating domestic water. In the heating mode, if heat absorbed is used to heat domestic water, it is taking away from the heat required to heat the homes air and may require the more expensive to operate auxilliary heaters to turn on.