High temperature geothermal heat pump

[Wizeman]

Hello,

I am looking to retrofit my existing residential heating system. It's an old oil-fired hot water system with radiators (not baseboard heaters).

I know that conventional geothermal heat pumps can't reach higher temperatures than 120°F but I was wondering if anyone here has heard about some way to reach 180°F so I can use the existing radiators.

Thanks,

-Vince

 

[zekeman]

No, you would need an airhandler and ductwork for a heatpump; but I would keep the old system for backup heating when the outside temperatures fall below about 30 or whatever the "crossover" temperature would be.

 

[carnage1]

you can hit 180 deg easy with a geothermal system, if you are in an area with geothermal resources you don't need anything other than a geothermal well and a water pump. I assume you aren't in such an area since you mention a 120 deg limit. If you choose to go with 120 deg water it will probably heat your home just fine. (it would take more info to calculate)
the old boiler systems ran so hot because they were quite low flow and the flow was generally from thermal effects with no external pump. So if they were not hot enough you didn't have the flow and hence no heat. If you can cycle 120 degree water through your system so that the return water is not significantly cooler then you should have plenty of heat. Which should be easy if you put an electric pump into the system. I know of some very old systems running effectively off of 140 deg wells with winter temps often in the single digits.

 

[Wizeman]

Thanks for your replies. Like carnage1 says, I don't have geothermal resources (ie.: hot springs) in my area.

However, what you say about flow vs. temperature makes sense. I'm just worried that the radiators will not induce the same convective current as with a higher temperature which could have a negative effect on the heat distribution...

 

[carnage1]

well if convection doesn't move the heat far enough into the room you could always stand closer

 

[Wizeman]

lol, star for you!