ᐅ Who should you entrust with the room-by-room heating load calculation?
Created on: 2 Feb 2020 12:23
A
annab377
Hello everyone,
Do heating system installers know that underfloor heating is best sized and planned using a room-by-room heat load calculation?
Is the room-by-room heat load calculation also important for selecting the heat pump (in our case either water-to-water or ground-to-water), or is the "overall heat load calculation" of the entire building according to DIN 12831 sufficient?
If my architect does not offer this, who should I turn to? What should I look for in the phone directory / on the Internet to find a professional who can assist me with this?
From what I have read here in the past months, a room-by-room heat load calculation is very important. A precise calculation can save money because the heat pump selected accordingly will operate more efficiently, allowing the house to be heated more effectively.
Thank you for your answers,
Greetings from BaWü
Ann.
PS: Am I mistaken, or can the overall heat load calculation according to DIN 12831 really be verified or recalculated by oneself (assuming you have all the U-values of the building envelope, of course)? Are there already ready-made templates available on the Internet for this? Maybe also for the room-by-room heat load calculation, or is that usually too complex for the homeowner?
Do heating system installers know that underfloor heating is best sized and planned using a room-by-room heat load calculation?
Is the room-by-room heat load calculation also important for selecting the heat pump (in our case either water-to-water or ground-to-water), or is the "overall heat load calculation" of the entire building according to DIN 12831 sufficient?
If my architect does not offer this, who should I turn to? What should I look for in the phone directory / on the Internet to find a professional who can assist me with this?
From what I have read here in the past months, a room-by-room heat load calculation is very important. A precise calculation can save money because the heat pump selected accordingly will operate more efficiently, allowing the house to be heated more effectively.
Thank you for your answers,
Greetings from BaWü
Ann.
PS: Am I mistaken, or can the overall heat load calculation according to DIN 12831 really be verified or recalculated by oneself (assuming you have all the U-values of the building envelope, of course)? Are there already ready-made templates available on the Internet for this? Maybe also for the room-by-room heat load calculation, or is that usually too complex for the homeowner?
Attention: Many heating load calculations prepared by heating system installers are inaccurate and not precisely tailored to the needs of the building occupants. In practice, the heating load is often overestimated. Heating system installers are rarely the right contact for an accurate heating load calculation. Building services engineers or civil engineers usually provide more precise calculations.
For sizing a heat pump, it is possible to estimate the heating load based on some parameters from the energy-saving regulation calculation. The result typically deviates by less than +/-5% from a heating load calculation according to DIN 12831 and is sufficient for sizing the heat pump and heat source. However, for planning heating surfaces and ventilation, a room-by-room heating load calculation according to DIN 12831 is essential. On the topic of energy-saving regulation heating load from the heat pump consumption database de
hegi___ schrieb:
Using just 5 or 10-unit increments isn’t sufficient.Why?Pinky0301 schrieb:
Why?- All circuits should have a low and preferably similar pressure loss. Therefore, the largest and the smallest circuits must be coordinated with each other.
- The spacing of the pipes should be precisely adapted to the heating load of the room so that the desired temperatures are reached without the need for throttling or regulation. (5 cm (2 inches) spacing does not make much sense. It only increases pressure loss without significant additional output. See attachment)
- The system should be designed for the lowest possible supply temperature.
- The heat pump should run continuously and not cycle on and off. Therefore, it must not be oversized.
The efficiency pump alone can consume between 35 and 90 watts. With 16 hours of runtime per day, that amounts to approximately 55 to 140 € per year just in pump electricity cost difference.
In addition, there are efficiency losses from the actual heat generation, which can be several times higher.
That is why I would always recommend having the design checked by an external expert. The costs add up significantly over the operating lifetime.
Oh dear, I see another topic I need to read up on... Thanks @hegi___! I will ask the energy consultant. We could of course go larger than 10cm (4 inches) or 15cm (6 inches), but I thought that would be too much anyway. Intermediate steps are unfortunately not possible. That’s probably the compromise you have to make when aiming for a low build-up height.
hegi___ schrieb:
The efficiency pump alone can consume between 35-90 watts. With 16 hours of operation per day, that results in a difference in pump electricity costs between 55 and 140 € per year.My heat pump with 6.1 kW, non-modulating, has so far run a maximum of 3 heating cycles of 2-3 hours each per day this winter. Yes, the winter has been mild so far, but that’s the theory of continuous operation of heat pumps and pumps.
Some skeptics even advise against modulating heat pumps for these reasons, since continuously running circulation pumps counteract efficiency. But those are minor issues and just theories.
Outside the heating season, the circulation pump works even less—certainly not 16 hours a day.
So the potential savings of 55 to 140 € are more realistically in the range of 10 to 30 €.
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