Hello everyone,
We are building a semi-detached house with a total heated area of approximately 460 sqm (4,951 sq ft). The building will be constructed to KFW 55 standard. Both units will have a central ventilation system from Zehnder with heat recovery. According to our energy certificate, one half of the house has a heating demand of 10 kW and the other 7 kW.
The heated area includes the two basements, which are not occupied but only moderately heated (partly used for storage).
We are producing everything separately except for the boiler, specifically:
A shared Fröling PE1 boiler without a particle filter
and for each unit:
A solar collector with vacuum tubes and a gross surface area of 10 sqm (108 sq ft)
A 1000-liter (264-gallon) hygienic storage tank with two solar coils, one at the top and one at the bottom.
The system will be set up so that the solar collectors heat the respective buffer tanks of each half, and the boiler will only activate when one of the buffer tanks gets too cold and then heat both to the target temperature.
Now the big question is: Which PE1 boiler should we choose? We want to avoid being cold, but at the same time, not oversize the boiler given pellet consumption and wear from frequent cycling.
I am not sure how much emphasis we can put on the figures in the energy certificate and how the domestic hot water consumption needs to be factored in here.
I look forward to your ideas and hope I haven’t forgotten any details. Otherwise, I’m happy to provide more information.
We are building a semi-detached house with a total heated area of approximately 460 sqm (4,951 sq ft). The building will be constructed to KFW 55 standard. Both units will have a central ventilation system from Zehnder with heat recovery. According to our energy certificate, one half of the house has a heating demand of 10 kW and the other 7 kW.
The heated area includes the two basements, which are not occupied but only moderately heated (partly used for storage).
We are producing everything separately except for the boiler, specifically:
A shared Fröling PE1 boiler without a particle filter
and for each unit:
A solar collector with vacuum tubes and a gross surface area of 10 sqm (108 sq ft)
A 1000-liter (264-gallon) hygienic storage tank with two solar coils, one at the top and one at the bottom.
The system will be set up so that the solar collectors heat the respective buffer tanks of each half, and the boiler will only activate when one of the buffer tanks gets too cold and then heat both to the target temperature.
Now the big question is: Which PE1 boiler should we choose? We want to avoid being cold, but at the same time, not oversize the boiler given pellet consumption and wear from frequent cycling.
I am not sure how much emphasis we can put on the figures in the energy certificate and how the domestic hot water consumption needs to be factored in here.
I look forward to your ideas and hope I haven’t forgotten any details. Otherwise, I’m happy to provide more information.
O
Oetzberger2 Oct 2021 10:3120 kW is more than enough. Is there something available around 15 kW? The actual heating demand will be at most in that range.
Oetzberger schrieb:
20kW is more than enough. Is there something in the range of 15kW? The actual heating load should be around that maximum. Oetzberger schrieb:
20kW is more than enough. Is there something in the range of 15kW? The actual heating load should be around that maximum. Thanks in advance for your reply.
Could you explain your statement? Is there a rule of thumb? Do you have the same setup? Are you a heating engineer?
Are there any other opinions?
Consider your usage scenario:
We were away several times in winter for two weeks and set the heating to frost protection (around 4°C (39°F)).
As a result, after returning, warming up the cooled-down building was time-consuming and took more than one day.
The heating system was sized according to DIN standards (here winter-low at -13°C (9°F)).
If you experience this frequently, I would recommend choosing the larger boiler.
We were away several times in winter for two weeks and set the heating to frost protection (around 4°C (39°F)).
As a result, after returning, warming up the cooled-down building was time-consuming and took more than one day.
The heating system was sized according to DIN standards (here winter-low at -13°C (9°F)).
If you experience this frequently, I would recommend choosing the larger boiler.
O
Oetzberger2 Oct 2021 11:23The DIN standard significantly overestimates the heating load, and a calculated maximum heating load of 17kW is in reality closer to 12kW. If quick reheating after a vacation is more important to you than cycling behavior and longevity, then you can of course choose to oversize considerably. What is the lower modulation limit? This is usually more relevant than the maximum value.
Deniz85 schrieb:
The energy performance certificate shows one half of the house with a heating load of 10 kW and the other 7 kW.The values from the energy performance certificate are not related to the heating load. In fact, the calculation should not result in more than about 10 kW (12 kW).Similar topics