DID YOU KNOW
When combining a ground source heat pump with underfloor heating efficiencies of 400% can be achieved
Heat pumps with underfloor heating
To get the most efficient operation from a heat pump it’s important that the outlet temperature is kept as low as possible, this lends itself to underfloor heating distribution systems.
With underfloor systems the ideal installation is to mount the underfloor in screed. Using the screed as a thermal mass allows the occupier to run the heat pump on off-peak tariffs further reducing the running costs. For first floor applications the ideal building construction is beam and block with the underfloor and screed laid on top. For suspended floors a dry/sand screed can be used either between or over joists, however with these systems structural and height considerations need to be taken into account. It may also be necessary to run the heat pump at a higher temperature to drive the heat through the overlying chipboard and final floor finish, therefore reducing its efficiency.
Things to consider
Where suspended timber floors are present, any underfloor heating pipework, typically installed within the joist void, would need to be embraced by a steel heat transfer plate, which not only increases cost but also slows the build programme.
Since the flow temperature into these underfloor circuits would need to be increased to around 45ºC (to drive the heat through the overlying chipboard and final floor finish), there is no greater operating efficiency than if the heat pump was serving radiators.
If heat emission plates are used off-peak tariffs cannot be effectively used as there is no thermal storage and again higher temperatures may be required.