merlin667
2013-07-26 20:24:55
- #1
Hello first of all,
We are currently planning a new single-family house and are currently finishing the floor plans. We are quite satisfied so far, but I am a bit unsure about the heating. I am aware that a proper design according to ÖN/ or EN cannot be done here (it’s not just two clicks). The following key data: Gross floor area 188m², gross volume 608m³, building envelope area 448m², compactness (A/V) 0.74, average U-value 0.22, according to the energy certificate building heating load Ptot with 0.5 air changes/h 5.76kW. Heating via underfloor heating, plus there is also a residential ventilation system with a heat exchanger. So, about the location: standard outdoor temperature -12.3°C, heating days 175d, heating degree days 3791Kd, lowest temperature -25.2° in the last 30 years, -20° is regularly reached every winter, we have 122 frost days and 26 ice days per year. Additionally, the other extreme is 37.2 degrees, and in recent years we have had an average of 20 days per year (mostly split into two periods) with daily highs above 30 degrees, and I am seriously considering the option of cooling with the heat pump. Our sticking point is: I am not quite clear which heat pump we will choose. How suitable is a ground collector with such key data? We have 933m² of land. The soil is clayey and wet, as far as I have found out so far, this is actually probably the best for the ground collector, but I have some concerns if the winter lasts longer or when the snow cover is thick (we have already had a few winters in the recent past where we had a continuous snow cover from the end of November to mid-April. Of course, this is combined with extremely low outdoor temperatures over a long period. On the other hand, an air heat pump would also be a consideration, but I have another question there: Is it sensible to aim for monovalence for as long as possible, but choose the heat pump one size larger for that? Is it legitimate to add the output of the preheating coil to the heating capacity—I think yes, but: what about defrosting the evaporator? Not that this causes problems then.
We are currently planning a new single-family house and are currently finishing the floor plans. We are quite satisfied so far, but I am a bit unsure about the heating. I am aware that a proper design according to ÖN/ or EN cannot be done here (it’s not just two clicks). The following key data: Gross floor area 188m², gross volume 608m³, building envelope area 448m², compactness (A/V) 0.74, average U-value 0.22, according to the energy certificate building heating load Ptot with 0.5 air changes/h 5.76kW. Heating via underfloor heating, plus there is also a residential ventilation system with a heat exchanger. So, about the location: standard outdoor temperature -12.3°C, heating days 175d, heating degree days 3791Kd, lowest temperature -25.2° in the last 30 years, -20° is regularly reached every winter, we have 122 frost days and 26 ice days per year. Additionally, the other extreme is 37.2 degrees, and in recent years we have had an average of 20 days per year (mostly split into two periods) with daily highs above 30 degrees, and I am seriously considering the option of cooling with the heat pump. Our sticking point is: I am not quite clear which heat pump we will choose. How suitable is a ground collector with such key data? We have 933m² of land. The soil is clayey and wet, as far as I have found out so far, this is actually probably the best for the ground collector, but I have some concerns if the winter lasts longer or when the snow cover is thick (we have already had a few winters in the recent past where we had a continuous snow cover from the end of November to mid-April. Of course, this is combined with extremely low outdoor temperatures over a long period. On the other hand, an air heat pump would also be a consideration, but I have another question there: Is it sensible to aim for monovalence for as long as possible, but choose the heat pump one size larger for that? Is it legitimate to add the output of the preheating coil to the heating capacity—I think yes, but: what about defrosting the evaporator? Not that this causes problems then.