Please check - correct heating, ventilation system, etc.?

Hello everyone,

great forum here, I have already read quite a bit and gathered some information. However, I would be happy if someone could take a look at the overall package from us to see if anything still needs to be done or if it is okay as it is.
For your information, we are building a 3-family house with a heat pump (ground surface), controlled residential ventilation, underfloor heating.

Some facts:
Living areas basement, ground floor, and upper floor combined (all 3 units) are about 340 sqm
The heat pump is a Viessmann Vitocal 300G with 10KW. It is planned to lay about 600 sqm of loops in the garden, 6 pipes each 100m long
Hot water storage for the entire house is 390L, supply temperature max 60 degrees
The controlled residential ventilation is a Helios controlled residential ventilation EC 500 W
Kfw 70 standard solid construction is being built, I have the Kfw heating calculation but only understand half of it - so feel free to post info from it if someone tells me what :)

My first question now is whether it is properly dimensioned like this? Correct heating, correct ventilation system, and correct amount of hot water storage?
The second question concerns the ventilation system, specifically the supply air. Since they are still laying the loops for the geothermal heat and digging up the garden, I suggested taking this opportunity to lay a 100m long sloping KG pipe so that the air is preheated/-cooled. Sloping so that any condensate hopefully drains away. The side leading to the house ends in a shaft (there are heating loops there too, no idea why), so that I could flush the pipe if necessary. According to the heating company, the 100m provide a cooling/heating of 10K.

Looking forward to your answers and opinions .... we are already at the plastering stage and the heating will arrive soon, but maybe something can still be changed if we are making a mistake.

....For your information, we are building a 3-party house with a heat pump (ground-surface), controlled residential ventilation, underfloor heating.

The controlled residential ventilation depends on user units according to DIN 1946-6!!! That would be three separate controlled residential ventilation systems with/without heat recovery here. Theoretically also possible with a central system, but only with significantly increased investment for controls etc. In this case, decentralized controlled residential ventilation systems with heat recovery will probably be the most effective solution.

....The heat pump is a Viessmann Vitocal 300G with 10KW. It is planned to lay about 600m of loops in the garden, 6 strands of 100m each ..

What is the heating load considering the controlled residential ventilation with/without heat recovery? What is the actual energy demand for heating and hot water? If unknown, how can one, for example, size/design a source or define a heat generator?

....The hot water storage for the entire house is 390L, ...

That will probably "go badly" if rental of two residential units is intended!

...My first question now would be whether this is dimensioned correctly? Correct heating, correct ventilation system, and correct amount of hot water storage?

Who can answer this reliably since essential basic data are missing?

....According to the heating company, the 100m provide cooling/heating of 10K....

Then just contractually agree on the 10 K.

Best regards.

Hello Euro,

thanks for the reply, unfortunately I can't make much use of the answer yet as it doesn't really help me forward :(

I'll provide a few more details. The three residential units consist of my family (ground floor + upper floor), my parents (ground floor only), and my business (basement only). The business could also be converted into a holiday apartment (toilet, shower, large windows and light well).

Thanks for the info that 390L is not enough, but what would be a reasonable hot water storage volume in your opinion for my conditions? Twice as much? 490L?

For the controlled residential ventilation with heat recovery, I wanted a central system, not a decentralized one. All pipes run together in the technical room and are controlled jointly for the entire house. If the other parties ever find that disturbing, they would have to manage without controlled residential ventilation. Decentralized or separate control was too expensive for me (and I also see no necessity). Is the DIN standard mandatory?

I certainly won't get the 10K for the supply air contractually – but if it only costs me the material price for the basement pipes (the work of digging is done anyway because of geothermal energy), would that be recommendable or still not worth the effort? Or even not advisable due to condensation?

I know I didn’t provide reasonable basic data, I have the document from the engineering office here and can gladly provide some numbers (but as I said, which exactly do you need?). Maybe some data from the part that seem important to me.





[TD="bgcolor: rgb(94.000000%, 94.000000%, 94.000000%)"] Envelope area A 714.26 m2





[TD="bgcolor: rgb(94.000000%, 94.000000%, 94.000000%)"] Reference area AN 405.93 m2





[TD="bgcolor: rgb(94.000000%, 94.000000%, 94.000000%)"] Gross volume Ve 1268.53 m3





[TD="bgcolor: rgb(94.000000%, 94.000000%, 94.000000%)"] Envelope area factor A/Ve 0.56 1/m





[TD="bgcolor: rgb(94.000000%, 94.000000%, 94.000000%)"] Window area Aw 74.85 m2




[TD="bgcolor: rgb(94.000000%, 94.000000%, 94.000000%)"] Area-related transmission heat loss existing H'T,existing 0.330 W / (m2K)




[TD="bgcolor: rgb(94.000000%, 94.000000%, 94.000000%)"] Area-related thermal bridge loss (flat rate) Delta UWB 0.050 W / (m2K)




[TD="bgcolor: rgb(94.000000%, 94.000000%, 94.000000%)"] Area-related transmission heat loss allowable (Energy Saving Ordinance) H'T,allowable 0.500 W / (m2K)




[TD="bgcolor: rgb(94.000000%, 94.000000%, 94.000000%)"] Transmission heat losses existing / allowable (Energy Saving Ordinance) 66.00 %




[TD="bgcolor: rgb(94.000000%, 94.000000%, 94.000000%)"] Area-related transmission heat loss reference building H'T,Ref. 0.395 W / (m2K)




[TD="bgcolor: rgb(94.000000%, 94.000000%, 94.000000%)"] Transmission heat losses existing / reference building 83.54 %




[TD="bgcolor: rgb(94.000000%, 94.000000%, 94.000000%)"] Usable internal gains Q"i 30.03 kWh / (m2a)




[TD="bgcolor: rgb(94.000000%, 94.000000%, 94.000000%)"] Usable solar gains windows Q"s 15.88 kWh / (m2a)




[TD="bgcolor: rgb(94.000000%, 94.000000%, 94.000000%)"] Usable solar gains glass extension Q"ss 0.00 kWh / (m2a)




[TD="bgcolor: rgb(94.000000%, 94.000000%, 94.000000%)"] Usable solar gains TWD Q"TWD 0.00 kWh / (m2a)




[TD="bgcolor: rgb(94.000000%, 94.000000%, 94.000000%)"] Usable total gains Q"g 45.91 kWh / (m2a)




[TD="bgcolor: rgb(94.000000%, 94.000000%, 94.000000%)"] Reduction due to night setback Q"il 2.82 kWh / (m2a)




[TD="bgcolor: rgb(94.000000%, 94.000000%, 94.000000%)"] Ventilation heat losses Q"V 42.50 kWh / (m2a)




[TD="bgcolor: rgb(94.000000%, 94.000000%, 94.000000%)"] Transmission heat losses Q"T 48.91 kWh / (m2a)




[TD="bgcolor: rgb(94.000000%, 94.000000%, 94.000000%)"] Additional losses floor heating Q"FH 0.07 kWh / (m2a)




[TD="bgcolor: rgb(94.000000%, 94.000000%, 94.000000%)"] Heating energy demand Q"h 42.74 kWh / (m2a)




[TD="bgcolor: rgb(94.000000%, 94.000000%, 94.000000%)"] Hot water demand Q"TW 12.50 kWh / (m2a)




[TD="bgcolor: rgb(94.000000%, 94.000000%, 94.000000%)"] System performance factor eP 0.75 -




[TD="bgcolor: rgb(94.000000%, 94.000000%, 94.000000%)"] Primary energy demand existing Q"p,existing 41.56 kWh / (m2a)




[TD="bgcolor: rgb(94.000000%, 94.000000%, 94.000000%)"] Primary energy demand reference building Q"p,Ref. 66.21 kWh / (m2a)




[TD="bgcolor: rgb(94.000000%, 94.000000%, 94.000000%)"] Primary energy demand allowable (Energy Saving Ordinance) Q"p,allowable 66.21 kWh / (m2a)




[TD="bgcolor: rgb(94.000000%, 94.000000%, 94.000000%)"] Primary energy demand existing / reference 62.77 %

Hello,

...Hello Euro, thanks for the answer, unfortunately I can't do much with the answer yet as it doesn't really help me :(

Unfortunately, that is often the case and is not always understood or is misinterpreted by the questioners.
Reliable answers can usually only be given if corresponding data is available. The latter is rarely the case, so an answer would be pure speculation.

...The three residential units consist of my family (ground floor + upper floor), my parents (only ground floor) and my business (only basement). The business could also be converted into a holiday apartment (toilet, shower, large windows, and light well).

Here, the energy demand for hot water would have to be determined first. Individual usage habits play a major role here. Especially with a heat pump as a heat generator, the storage size and heat exchanger surface must be adapted to this supply.

...For the controlled residential ventilation with heat recovery, I wanted a central one, not a decentralized one at all costs.

This is fundamentally the better solution.

...If the other parties ever get disturbed by this, they would have to manage without controlled residential ventilation...Is the DIN standard mandatory?..

The DIN standard generally belongs to the ART (Recognized Rules of Technology) and is intended for residential ventilation. Different conditions apply for commercial premises, so depending on the type of business, a connection based on this alone is prohibited.

...., would that then be advisable or still not worth the effort? Or even inadvisable because of condensate?

It does not cause any damage. However, air preheating and possibly cooling effects are often overestimated. In addition, the efficiency of heat recovery in controlled residential ventilation deteriorates.
Condensate separation in summer and transitional periods is a positive effect.

...I know that I have not provided reasonable basic data, but I have the document from the engineering office here and can gladly provide numbers from it...

These are results of the primary energy verification. They serve exclusively to examine the admissibility of the construction project. It is not permitted to use them for heating dimensioning or consumption estimation.

Best regards.

Hi Euro,

thanks again for the answers.
I understand the missing statements because important information is missing ... I have meanwhile also understood that the primary energy proof is not sufficient for such a statement. I have activated my architect and construction company (turnkey) to take care of it. With a bit of luck, the heating engineer has had a heating load calculation done - but I currently strongly doubt that!

By the way, if you are hesitant to make statements before reliable data is available, I understand that. But of course you raise many questions when you tell me that with a 390L hot water storage it will go wrong if parts are rented out - but you do not say what size range would then be appropriate? :rolleyes:

I’ll see what information I can get - hope for a HLB, and then I’ll get back to you. Thanks in the meantime for the information and tips on the other things! :)

Sorry for the late reply, but the heating load calculation has just arrived here. So, to the experts, how does it look now with my previous questions? :)