Your choices:
1 Geothermal; 2 Local heating (ind. house); 3 Comfortable indoor climate
| What is your resource? | What do you want to deliver? | What is the service the customer wants? |
| Biomass (digestible sludge) | District cooling | 3 Comfortable indoor climate |
| Biomass (fermentable sludge) | District heating | Electricity |
| Biomass (solid) | Electricity | Process cooling (< 0 °C) |
| 1 Geothermal | Fuel: Gaseous | Process heat/steam (50 - 150 °C) |
| Sunshine | Fuel: Liquid | Process heat (150 - 1000 °C) |
| Water | Fuel: Solid | Process heat (> 1000 °C) |
| Wind | Local cooling (ind. house) | Transport |
| Residual oils/fats etc | 2 Local heating (ind. house) |
The COP of a heat pump increases as the product temperature decreases. The higher the COP, the lower the cost for electricity.
Central heating in single-family houses can be water-borne – which is preferred in the case of heat pumps – or it may be air-borne. In case of water-borne heating, the production of tap water is normally integrated in the same heat pump as for the production of radiator water but – of course – with a separate coil.
For sanitary reasons, tap water must be heated above 50 °C and hence, the COP for the production of tap water cannot exceed a certain value.
However, the temperature of the water used for comfort heating is system dependant: With old, wall-mounted radiators, there may well be a demand that the temperature exceeds 60 °C, with modern, wall mounted radiators 40 °C is enough and with a floor heating system the temperature is further reduced down to 30 °C.
With geothermal heating systems, and if the tap water is produced in a separate unit, these differences will immediately show on the electricity bill.