Air to water heating

An air-water heat pump can be an excellent solution for parish community centres of a certain size. In small cemetery facilities and very small parish community centres, investment costs are too large in relation to the heating required here.

The efficiency of an air-water heat pump is slightly lower than for a well dimensioned ground source heat pump. If there is no space for digging down water pipes of a sufficient length, an air-water heat pump is a better solution.

If connecting the buildings to district heating is possible, this is normally recommended rather than installing a heat pump.

Which buildings are suitable?

The building should be reasonably well insulated and have normal density for it to make sense to install a heat pump. To keep costs down, it is very important to keep the flow temperature as low as possible, preferably about 50 - 55 ° C. Underfloor heating in most of the building is preferable, but not a requirement.

If there are radiators, it is important that they are sufficiently dimensioned. This will normally be the case in an older building, which is renovated and reinsulated by newer standards and where the old radiators are preserved.

If the parish community centre is only used occasionally, it may make sense to lower the temperature a few degrees when it is not in use. This, however, adds extra requirements for the degree of insulation and the size of the radiators, because the parish community centre must be heated to normal room temperature in a relatively short time using only ground heat.

Placing the outdoor unit

Outdoor unit placement must be carefully considered, as there are both aesthetic considerations and noise limits to comply with. Regarding neighbours, the Danish Environmental Protection Agency has noise limits, but the municipality may choose to impose other limits. If the building is adjacent to the cemetery, there may be locations that are undesirable due to noise.

It is important that the outdoor unit is placed in the open air, to ensure a good supply of fresh air. Attics or similar places are generally not recommended. If a foreclosure is built for the outdoor unit, it must be very open. If sufficient ventilation isn’t ensured, energy consumption will be unnecessarily large.

Inspection

An annual inspection is mandatory because the system contains over 1 kg of refrigerant.

Economy

When heating the parish community centre with an air-water heat pump, the heating bill is typically 60 to 65 øre per kWh heat. This is a slightly higher price than for a parsonage, because a reduction in electricity tax only applies to private homes (in Denmark). Electricity from a pump in the parish community centre is paid at full cost.

There are other rules for the electricity used in cemetery facilities. A partial refund of VAT and electricity tax can be obtained, if electricity consumption is measured separately using a Submeter.

There will typically be a saving of 40 - 50% when converting to an air-water heat pump from an oil-fired boiler. If heating with natural gas, normally no significant savings will be achieved.

Air to water heat pump at a cemetery facility.
Photo: Carsten Vejborg.