TGA planner difficulties, underfloor heating supply temperature + wastewater ventilation

  • Erstellt am 2022-07-15 10:22:47

Pacmansh

2022-09-28 12:15:03
  • #1
Unfortunately, I have no information about that; see below for KfW55 Sounds reasonable. The outdoor temperature is assumed by the planner to be -16 degrees, and the bottleneck is currently not even the bathroom, for whatever reason. According to telephone information, it should be 45W/m². It should be noted that KfW55 is not owed, only communicated later because the subsidy was applied for. However, the energy consultant messed that up/submitted it too late (same engineering office). It is quite possible that it was redesigned back to the minimum standard according to the Building Energy Act. I would have commissioned that myself if I had had enough information. I no longer trust the MEP planner. But he was commissioned by the developer, and I have to try to get the best out of it. The lady does not want to provide me with a room-by-room heating load calculation, but the developer promised me that I can get the documents. I have now requested it through him in the hope that this will bring some more clarity.
 

Alessandro

2022-09-28 12:32:44
  • #2
With this insulation standard, you will probably have to accept the high VLT...
If you now also have a buffer that, by nature, should/must be overloaded by a few °C, you have even higher VLT :-(

Nevertheless. We are probably talking about 10-15% more consumption over the heating period compared to a better insulation standard and lower VLT.
Depending on the size of the house, this is not so bad now.

Have you asked your local utility/EVU if there is a cheaper heat pump tariff?
Maybe a second meter for the heat pump is worth it....
 

Pacmansh

2022-09-28 13:07:54
  • #3
Correct, the net living area is approximately 145 m², you won’t get poor from that. What’s more important to me is that the underfloor heating is planned somewhat reasonably. The current concept is more like "You can just turn down the heating at the thermostat if it gets too warm." I also feel that the rooms don’t really fit together properly, but I’m still hoping for additional information on that.

I checked the heat pump tariff, it is possible. However, I had roughly calculated that the additional meter rental makes the model not so very attractive. Therefore, I initially refrained from it. The electrical installation is not yet final, though. I’ll take another look at it.
 

stjoob_at

2022-10-04 08:28:47
  • #4
The classic with the bathroom. You almost always need additional heating surface (wall/ceiling) or you heat a bit electrically in winter. Heating circuit lengths of 150 m would be too long for me, meanwhile there are circuits that have 1/3 of that length. I would accept a maximum of 30% difference between the longest and shortest circuit here. ERR and buffer tanks should be thrown out anyway. The thing with the room heating load is funny too, it has to be there for the design :confused: I'm curious whether the heat pump will also be nicely oversized.
 

Pacmansh

2022-10-04 09:37:52
  • #5
I would have liked to have the ERR and buffer outside as well, but then I would have had to commission someone myself and for that I would have needed all the necessary data again. I probably would have ended up having to take responsibility for a heat pump potentially arriving too late.

I tried to argue against the nonsense of the ERR, but here is a small example of the rubbish I have to argue against: The picture shows the bedroom with a small dressing room (electrical planning has already been revised). The opening between the dressing room and the bedroom is about 1.20m wide without a door. The planner wanted the thermostat in the dressing room as well because it would be nice to come from the cool bedroom into the warm dressing room.

Regarding the heat pump, I was told that it is just below the required size, so I still have hope.

The room-specific heating load calculation has not arrived yet, but I am still optimistic that it will work.
 

stjoob_at

2022-10-04 10:54:15
  • #6
The ERR can at least still be lowered/disconnected after installation. You still have to pay for it anyway ;) Great logic from the planner, even with a door you wouldn't achieve significant temperature differences. The exterior walls have a much lower U-value than the interior walls. This is no longer like in old buildings. Indoor temperatures equalize much more. Maybe you can still convince her to install only a small buffer in the return flow for the defrost function of the heat pump instead of the heating buffer.
 

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