ᐅ Heating Load Calculation & Installation Plan According to DIN: Is a New Calculation Required?

Tolentino schrieb:

So, the calculation was done before I decided on the ventilation system, according to the heating specialists, but it is not that important for the individual room analysis either. They say you can account for about 80% of the additional demand from ventilation through heat recovery again in the overall heating demand.


@Mycraft: You mean it doesn’t make much difference for the overall room temperature?

I don’t understand that statement. When a room is ventilated by opening windows, you ventilate with outdoor air temperature, which is included in the calculation as NAT (design outdoor temperature). A minimum air exchange rate of 0.5 times the room volume per hour is assumed.
With a mechanical ventilation system with heat recovery, however, you are not ventilating with the NAT but with a significantly higher air temperature (depending on the level of heat recovery). That means for the same ventilation volume per day, you have a much lower heat loss through ventilation. And yes, this is also calculated for each room individually, depending on the ventilation concept. Usually, in a single-family home bathroom, there is only exhaust air, meaning the incoming air volume has the air temperature of the room supplying the air.
Mechanical ventilation with heat recovery not only changes the total heating load but also the heating load of individual rooms, depending on their function (supply air or exhaust air).
And you don’t have an increased demand but rather a reduced heating demand—unless the windows are always kept closed during window ventilation....

Yes, sure. I basically meant less additional heating demand due to ventilation when using controlled residential ventilation versus manual ventilation...
Thanks for explaining its relevance also for single-room ventilation!
I think he just wants to follow a fixed procedure or not be influenced. That’s why I’m preparing myself here.
So, here’s what I’m noting for myself:
The ventilation concept needs to be finalized (it must have been done or commissioned by him), then based on that, a new room-specific heating load calculation with the specified room temperatures should be done. I will try to have him or the general contractor take care of this, because there is clearly a difference in heating design depending on whether a central controlled residential ventilation system with heat recovery is installed or not.
He knew that I’m interested in a ventilation system, but he shouldn’t have commissioned the calculation before I had definitely decided yes or no for controlled residential ventilation.
Otherwise, he must accept if necessary that I commission another office and he incorporates their planning...

What exactly does 6100 kW heating load mean? That’s not kWh, so how do I convert that into an annual energy demand? Can I use this at all to estimate a rough annual heating electricity demand?

Thanks and regards

Tolentino

Just calculate the bathrooms with 20°C (68°F) instead of 24°C (75°F). Then it should work fine with a 30°C (86°F) supply temperature. If the heating engineer complains, simply argue that the missing 4°C (7°F) will be covered by an electrically powered towel radiator installed by the building owner. This, along with the fact that internal or solar gains are not considered and the oversizing due to the uncontrolled ventilation, ensures that the house will still be warmed adequately.

So you mean I can skip a new calculation? I actually want more than 20°C (68°F) in most living areas...

I know I’m repeating myself, but still.

Do it like OWL suggested: commission the same office that OWL used for the calculation, using your desired temperature settings.

You have a construction project here that will cost you hundreds of thousands, so if you are unsure about the quality of the builder’s calculation, I wouldn’t hesitate to spend a few hundred euros for an independent second opinion.

Yes, I agree. I just need to get confirmation from Heizi that he will build according to the design/calculation.