039. Back to the heat pump

There was a misunderstanding somewhere and it appears that the overall cost for the district heating system would exceed that of the version with a heat pump. I still don't understand this clearly so I obviously cannot explain it. So, it's back to the air-source heat pump, though perhaps not the one by Heliotherm.

I'm looking at some of the results of performance tests of these devices done by independent labs[1] to see if I find a favorite. One new issue that I've become aware of is that our technical room[2] is a little on the small side. The heat pump and its associated plumbing will fit, but we really could use the space if we can save it. Also, this type of installation requires large openings from the room to the outside and because this room is partly underground, construction elements called Licht- or Kellerschächte[3] have to be used. I have a great aversion to these things, partly from the maintenance point of view. To circumvent both these problems, I think a unit that is installed outside the house is called for (we had been considering only internal units so far). I have yet to find any indications that they're less effective than the ones installed inside.

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[1] One such facility is in Switzerland → Wärmepumpen-Testzentrum WPZ.

[2] Here's a link to an old sketch → Figure 7g. The lower level.

[3] I'm not sure these things even exist in the same form in the Anglo-world. You can do an image search with the keyword "Kellerschacht" or "Lichtschacht" to see some examples.

038. District heating instead of a heat pump

Back in March (link to the post here), I had written that we would be using a heat pump made by a company called Heliotherm to heat the house and warm water. That model had been suggested to WA by the company that did the first round of energy calculations for us. Since then, there have been some significant changes in the construction elements, and a new energy calculation is being done by a different firm. Also, a new opportunity became available in May, that of district heat[1]. Earlier in the year REFUNA, the company that runs this network, was in the process of adding capacity and they couldn't promise that they could serve us. By May they were able to give us a positive answer.

The advantages of this type of heating system is that they're generally more energy efficient and cleaner than local systems and boilers. They take up less room for installation and are very low maintenance. Wikipedia had a good write up on it, see the link in the footnotes below. In our case, the costs associated with the installation and hook-up should be below that of what it would be for the heat pump system because a lot of the necessary earth removal work will have to be done for the other connections anyway.

I'm actually very pleased about this development as I was not so happy about the air-source heat pump. At very low ambient temperatures, they basically become electric heaters.

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[1] District heat is also known as waste heat, or utility-supplied heat. The term in German is Fernwärme, literally "distance" heat or warmth. REFUNA gets its heat from the waste heat of the nuclear reactor in Beznau near where we'll be. The Wikipedia article mentions this → District heating