Geothermal Water to Water

[Deleted User]

We program it in to the controls. It is a "soft" interface as opposed to a 'hard' interface. The ODR's for the boiler and the GSHP are set to the same starting parameters, but the GSHP pulls up short (max operating temperature of 115 degrees F intentionally) and the mod con takes over. When it does take over, the buffer tank will see a return temp that will shut the GSHP down.

When the GSHP is doing DHW preheat (as it is in 90% of our jobs) then the modcon does nothing because the tank is already preheated to 115 degrees F.

ME

Delmas_2

Geothermal Water to Water - best units?

We are looking into offering geothermal for a radiant application in an existing home.
Are there units that can generate 140 degree water?
I'd love to hear from those of you who have done this as to things to watch for etc.

[Deleted User]

None that I've found...

115 is the normal recommended max. You could probably get 140 out of an indirect unit, but the COP would be low and the life expectancy short.

A direct unit can probably acheive those temps, but they have their own set of issues.

Everyone wants to be real green until they find out how much of their own green it is going to cost to be green, then suddenly they want to be KINDA green, like maybe pale green...

When it comes to applying GSHP, we size it for the AC load, then use that capacity to base load the system and allow a high efficiency mod con boiler to do the rest of the work at design condition.

Also, a ton of GSHP is 12,000 btu's when you are doing AC, except when you're trying to do heat, in which case it is roughly 80% of a ton, or 9,600 btu's.

Although it is technically feasible to do 100% of your heating needs with GSHP, it is VERY expensive initially, and the technology has not proven itself to be reliable enough in my book to warrant the cost. That industry has a LOT of learning to do when it comes to doing hydronics...

JMPO

ME

Rich L.

Climate Master

Climate Master is now offering their Tranquility line which is rated up to 145 degree output temps. It comes from the factory with heat exchangers designed to do domestic as well. Looks like a nice setup. The biggest downfall on this unit in my opinion is that it can not do chilled water, therefore you can't do AC with it as well.

I've gone through 2 winters with a Hydron Module water to water GSHP in my house. I have it limited to 115 degrees and use outdoor reset to control those temps. It's proven very economical to operate and to date has had zero problems.

Wayco Wayne_2

Mark

how do you stage in the mod con into the geo HP system. I've got a job I've looked at that needs a boost. WW

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Darin Cook_5

ME

Funny you should say that about folks wanting to be green. Mark Hunt and myself always said - Folks want to be green till that wallet opens and they see how much green has to come out. (Then it becomes a nice pastel sea foam green).

I would love to do a nice geo system. I went to the Climate Master school and paid the cash to come up to speed on the subject. The problem is that the well guys in our area charge the same for geo boring as they would for a water well. $20.00 a ft plus casing. The majority of the geo cash layout for the HO is for the well guy. It makes it very cost prohibitive for the average joe to afford a system such as this. I also have a issue using HDPE with no O2 barrier and no air elimination device. Sooner or later air will diffuse into the piping and into the system. Of course I was told at the class that no one has EVER had a problem with that!





Darin

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Delmas_2

Geothermal Water to Water

Thanks Mark, and the rest of you who gave your thoughts.the idea of base loading the system and topping off with the boiler sounds liek a great idea.
Delmas