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 schematic drawings, example costs and a real-life case study to showcase how a cascaded ground source heat pump system architecture designed by Kensa can effectively meet a high commercial heating and hot water load.

For more information, call sales on 0845 680 4328.


Schematic drawing*

*For illustrative purposes only

Costed example

Cascaded system utilising pond matsHeat pump architecture
Heat pump architectureCascaded central plant
Total heat pump capacity45kW
Equipment type21kW Hybrid & 24kW Twin
Design conditions0/50°C
Potable DHW temp60°C
Integral immersion heatersNo
Ground array typePond mats
Pond mats required10
Lake area required - no flow2500sq/m
Equipment supply costs*£35-45K
Pond mat installation costs**£5-10K
Comparative external oil installation costs£3-8K
Total 20 year NDRHI funding***£135,000 - £165,000
Estimated heat pump 20 year running costs****£100-120K
Estimated oil running costs*****£130-175K
Heat pump lifetime expectancyHeat pump 20 years - pond mats 80 years
Heat pump annual servicingNot required
Projected carbon saving214 tonnes
* A cost range is depicted here as every project is different and can contain more design features than shown in this example.

**Installation costs for external kit only (costs to install internals equivalent to a traditional system)

***NDHRI is a 20 year index linked funding stream which assumes inflation at 3%

****Based on electric at 15p/kW/hr and COP of 3

*****Based on oil at 45p litre and 85% efficiency

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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