This section provides details of an example project featuring a cascaded ground source heat pump system fed by a slinky 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 slinkies can effectively meet a high commercial heating and hot water load.
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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 architecture||Cascaded central plant|
|Total heat pump capacity||120kW|
|Equipment type||3x 45kW Plant Rooms|
|Potable DHW temp||Space heating only|
|Integral immersion heaters||No (DNO friendly)|
|Ground array type||Slinkies|
|Slinkies required||x24, plus header pipework|
|Land area required||6000sq/m|
Total Project Costs, Savings & Returns vs LPG
| ||Kensa Ground Source Heat Pump & Ground Array||LPG Boiler|
|Lifetime Expectancy: Appliance||Up to 20 years||Up to 10 years|
|Lifetime Expectancy: Infrastructure||Up to 100 years||-|
|Carbon Saved (over 20 years)||800 tonnes||0 tonnes|
|Appliance & Infrastructure Cost*||£87K to £115K||£7K|
|Running Costs (over 20 years)**||£350K to £400K||£450K to £500K|
|Servicing Costs (over 20 years)***||£0K||£2K|
|Non Domestic RHI Income (over 20 years)****||£350K to £500K||Not eligible|
|Net cost (after 20 years)*****||£15K - £87K||£459K - £509K|
*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: Hornsea Garden Centre
Hornsea Garden Centre near Hull has three Kensa Plantroom heat pumps installed in a cascaded system to provide heating and hot water to a large new-build extension with 30,000 sq ft of retail space and a café kitchen.
- New-build extension providing 30,000 sq ft of retail space;
- Main building upgraded to underfloor heating;
- Cascaded system architecture;
- 2x 45kW Plantroom Heat Pump providing space heating;
- 1x 25kW High Temperature Twin Compact Heat Pump providing hot water;
- 24x 50m slinkies located under nearby field;
- System contains 7250 litres of water and 1450 litres of antifreeze.
Case Study: Todridge Farm
The owners of Todridge Farm had four 21kW Kensa Hybrid Heat Pumps installed in a cascaded system to cover the high demand for heating and hot water in their six bedroom farmhouse and four adjacent cottages.
- 6 bedroom farmhouse and 4 cottages – 700m²
- Displacing oil heating
- x4 21kW Kensa Hybrid Heat Pumps
- Cascaded system architecture
- Pipework sunk into flooded marshland
- Funded by the Renewables Finance Loan and Non Domestic RHI
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.