Determining a heat pump's yearly energy output

[TSN79]

A building needs a certain amount of energy during a year (kWh) for room heating. An air to water heat pump has been installed to provide heat to a radiator system (55/40°C). How do I go about estimating how much of the yearly energy need the heat pump will cover? What confuses me is that the outside air temperature varies from -15 to +20°C during the year, and I don't know how to consider that variable. Not that I would know what to do if the outside temperature was fixed Does one usually use some average yearly temperature? Could anyone provide som basic procedures here? Thank you!

 

[berkeman]

A building needs a certain amount of energy during a year (kWh) for room heating. An air to water heat pump has been installed to provide heat to a radiator system (55/40°C). How do I go about estimating how much of the yearly energy need the heat pump will cover? What confuses me is that the outside air temperature varies from -15 to +20°C during the year, and I don't know how to consider that variable. Not that I would know what to do if the outside temperature was fixed Does one usually use some average yearly temperature? Could anyone provide som basic procedures here? Thank you!

The quality of the insulation in the building walls and roof will be a major factor, as well as what kind of doors are used for ingress and egress (assuming no windows get opened). Do you have any information on the building insulation?

I'll page @russ_watters to get a better reply for you...

 

[TSN79]

Do you have any information on the building insulation?

Not really, but that kind of information has gone into a calculation that sombody else has already done, resulting in a total energy need over a year (for room heating) of about 80 000 kWh.

 

[jrmichler]

A basic procedure:
1) Calculate total heat loss at the outdoor "design temperature", the typical coldest outdoor temperature.
2) Calculate the internal heat gain.
3) The difference is how much heat is needed to heat the building on the coldest day.
4) The OP implies that the heat pump will not provide the amount of heat calculated in step 3. If so, calculate the coldest temperature at which the heat pump will fully heat the building.
5) Find the outdoor temperature history for your area.
6) Calculate the heat required, and the heat provided by the heat pump, for the range of temperatures from the coldest day to coldest temperature at which the heat pump provides 100% of the heat.
7) Add up the results. The total heat from the heat pump, plus the additional heat needed on the coldest days, should add up to about 80,000 kWh. If so, you are done. If not, start over.

 

[russ_watters]

How do I go about estimating how much of the yearly energy need the heat pump will cover?

I don't understand. Why don't you think the answer is simply, "all of it"?