Suitability

Installation types

Dimplex SI MER ground source heat pumps are suitable for the following types of application:

• Domestic - The SI MER range uses a single phase electricity supply, making them suitable for installation in UK homes
• Non domestic – for light commercial applications with low heat load demands (i.e. up to 11W).

Multiple heat pumps can be installed in parallel if required.

Heating system types

Dimplex SI MER ground source heat pumps are suitable for use with the following types of heating distribution system:

• Underfloor heating – the ideal choice for use with a heat pump. The larger heating surface area available allows lower water temperatures to be used (i.e. 35ºC - 45ºC), helping to improve the efficiency of the heat pump system.
• Radiators – The SI MER range has a maximum water output temperature of 58ºC, making it possible for use with radiators providing the radiators are correctly sized.

Boiler systems usually run at much higher water output temperatures (75ºC +), therefore for lower water temperatures produced by a heat pump, the size of each radiator has to be approximately doubled to enable the same level of heat output.

Hot water

• Stored hot water - when used with a correctly sized Dimplex hot water cylinder, the SI MER range can produce stored water temperatures of approximately 50ºC.
• Where there is a requirement to store water at higher temperatures, this can be boosted with a supplementary electric heating element installed in the water cylinder and controlled by the heat pump WPM controller.

Cooling

It is possible to use SI MER ground source heat pumps in the following ways for cooling:

• Active cooling – the heat pump process is reversed to provide cooling by extracting heat from within the building and transferring it back into the ground via the ground collector for use later in the year when needed for heating.
• Passive cooling – excess heat can be transferred from the building to the ground via the ground loop circuit with the addition of a retro-fittable passive cooling unit. An additional cooling controller communicates with the heat pump manager to enable a combination of heating and cooling in a single system.

Domestic hot water can still be produced in parallel to the cooling operation as the heat pump compressor is not active in the passive cooling mode.

Passive cooling is only possible with vertical borehole installations.

Either active of passive cooling can be provided in the following ways:

• Silent cooling – using underfloor heating (or other surface heating systems) by passing cool water through them.

Large cooled surfaces reduce the room temperature by approximately 3-5ºC) without draughts or air movement.

• Dynamic cooling – via fan convectors able to cool (or heat) the air in the room according to need.