This section provides details of an example project featuring a cascaded ground source heat pump system fed by a borehole 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 designed by Kensa can effectively meet the heating and hot water load of schools and colleges.

For more information, call sales on 0845 680 4328.

Schematic drawing*

*For illustrative purposes only


Costed example

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 System

System architectureCascaded central plant
Total heat pump capacity120kW
Equipment type3x 45kW Plant Rooms
Design conditions0/50°C
Potable DHW tempSpace heating only
Integral immersion heatersNo (DNO friendly)
Ground array typeBoreholes
Boreholes required*2700mtrs
Land area required2000sq/m
*Boreholes based on average ground conductivity

Total Project Costs, Savings & Returns vs LPG

 Self-FinancedFunded Split Ownership 
SystemKensa Ground Source Heat Pump & Ground ArrayLPG Boiler
Lifetime Expectancy: ApplianceUp to 20 yearsUp to 20 yearsUp to 10 years
Lifetime Expectancy: InfrastructureUp to 100 yearsUp to 100 years-
Carbon Saved (over 20 years)800 tonnes800 tonnes0 tonnes
Local NOx emissions*0kg NOx/y0kg NOx/y12.09kg NOx/y
Appliance & Infrastructure Cost**£217K to £232KDetails coming soon!£7K
Running Costs (over 20 years)***£350K to £400K£350K to £400K£450K to £550K
Servicing Costs (over 20 years)****£0£0£2K
RHI Income (over 20 years)*****£350K to £500K£0Not eligible
Net cost (after 20 years)******£132 to £217KDetails coming soon!£459K to £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: Charlestown School

Located next to a busy railway line this school required an efficient heating and cooling system that could operate all year round. The solution was to install an 80 kW cascaded ground source heat pump system connected to ten boreholes located underneath adjacent playing fields. Overall heating costs have been reduced by 75%.

Key facts:

  • Retrofit installation of 1960s building;
  • Cascaded ground source heat pump system;
  • 80kW Kensa Plantroom heat pumps;
  • Providing heating and cooling;
  • 10x boreholes under playing field;
  • 75% reduction in heating costs.
Read more

Related Content

Blog: Cascaded ground source heat pumps

If a commercial premises has a high demand for heating and hot water, then modular cascaded ground source heat pumps provide an effective solution to meet the heat load of the property.