ᐅ Experiences with brine heat pumps from IDM?

Created on: 10 Feb 2021 13:42
D
DASI90
Good afternoon everyone,

we have been offered the TERRA SWM 6-17 HGL from IDM. So far, I haven’t been able to find much information about the company IDM. Does anyone have experience with the heat pumps from IDM? From what I have heard and read, the Austrian company IDM has a pretty solid reputation.

Best regards
DASI9015 Feb 2021 17:03
We have very large and numerous windows facing southeast. Do you really think that provides pure buffering up to the stated 11 kW? What happens to the heat pump when the heating load is low? Does it then consume much more electricity?
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T_im_Norden
15 Feb 2021 18:34
If the pump is oversized, it usually wears out faster and operates inefficiently.
Assuming Crink’s data are correct, your pump would run at about 7.8 kW at a design temperature of -9°C (16°F) or whatever you have, which is almost its minimum output. At 0°C (32°F), it might only need about 5 kW, which is already below the minimum output.
This means the pump would have to cycle on and off because it cannot modulate down any further.
face2615 Feb 2021 20:43
Hey, and just think about it—the smaller one goes up to 13 kW, and you don’t even reach 8 kW during the coldest temperatures. Then there are internal gains (appliances, people, etc.) and solar gains as well...
DASI9016 Mar 2021 10:21
The previous heating load comes from the building’s energy balance calculation. The energy consultant also calculated a heating load of around 8 kW for each room.
We have now planned the Terra SWM 3-13 HGL. Accordingly, the drilling company adjusted the borehole depth. We are now 160 m (525 ft) shorter than before. This results in 9 kW from 7.2 kW extraction capacity and 1.8 kW electrical input. Honestly, this makes me a bit uncertain, especially because I heard from an installer that he actually experienced twice now that the borehole froze around the probe due to insufficient drilling depth. What do you think about this? I mean, I have a heat pump with a maximum rated capacity of about 13 kW. But if I can only get a maximum of 9 kW from the borehole, isn’t that contradictory? Or am I missing something? Or if I only need a maximum of 8 kW anyway, does it not matter?
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T_im_Norden
16 Mar 2021 11:44
For me personally, that minimum output is still too high.

2.9–3.2 kW is the smallest that my BWT can manage, and it did not exceed this even at minus 15 degrees Celsius (5°F).
DASI9016 Mar 2021 11:51
You mean you would rather choose a smaller heat pump and a shallower borehole instead?

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