Pond mats

This section provides details of an example project featuring a cascaded ground source heat pump system fed by a pond mat ground array.

We have provided a ground source heat pump design with schematic drawings, ground source heat pump installation costs and a real-life case study and ground source heat pump reviews to showcase how a cascaded ground source heat pump system architecture fed by pond mats can effectively meet a high commercial heating and hot water load.

For more information, call sales on 0845 680 4328.

Example: Schematic

For illustrative purposes only

Example: Project & Finances

Based on the above schematic, Kensa has calculated example costs below to illustrate the upfront finance required and the expected running costs and income generated via the Non-Domestic Renewable Heat Incentive (RHI) over a 20 year period (the duration of the Non Domestic RHI), compared to an LPG system. For a bespoke quote please click here.

Heat Pump Specification

System architectureCascaded central plant
Total heat pump capacity120kW
Equipment type3x 45kW Plantrooms
Design conditions0/50°C
Potable DHW tempSpace heating only
Integral immersion heatersNo (DNO friendly)
Ground array typePond mats
Pond mats required24 plus header pipework
Lake area required - no flow6000sq/m


Total Project Costs, Savings & Returns vs LPG

 Kensa Ground Source Heat Pump & Ground ArrayLPG Boiler
Lifetime Expectancy: ApplianceUp to 20 yearsUp to 10 years
Lifetime Expectancy: InfrastructureUp to 100 years-
Carbon Saved (over 20 years)800 tonnes0 tonnes
Appliance & Infrastructure Cost*£83K to £100K£7K
Running Costs (over 20 years)**£350K to £400K£450K to £550K
Servicing Costs (over 20 years)***£0K£2K
RHI Income (over 20 years)****£350K - £500KNot eligible
Net cost (after 20 years)*****£0 - £83K£459K - £559K
*Costs are for the supply and installation of the Kensa heat pump and ground array only, and the supply and installation of the LPG boiler equipment only. Costs for supply and installation of internals such as radiators, underfloor and heating controls are not included, please speak to your plumbing contractor. **Based on electric at 15p/kW/hr and COP of 3. Based on LPG at 40p a litre and 85% efficiency ***Ground source heat pumps have no requirement for annual maintenance. However, it is good practice for the heating distribution system to be proactively checked and maintained to ensure optimum performance. ****The NON-DOMESTIC RHI is a 20 year index linked funding stream which assumes inflation at 3%. *****Net cost for LPG does not include an additional LPG boiler, which will likely need to be  factored in during the 20 year comparison period due to the LPG’s 10 year average lifetime expectancy.

Case study: The Old Farmhouse

The owners of the Old Farmhouse in Lancashire replaced their old, inefficient LPG boiler with a cascaded ground source heat pump system from Kensa to provide heating and hot water to three separate dwellings, thus benefiting from the Non Domestic Renewable Heat Incentive (RHI).

Key facts:

  • Working agricultural farm and c1900 farmhouse;
  • Converted barn and stable buildings;
  • Cascaded ground source heat pump system;
  • 1x 24kW Kensa Twin Compact for heating;
  • 1x 21kW Kensa Hybrid for heating and hot water;
  • 12x pond mats submerged in pond.
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