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.
Hornsea Garden Centre near Hull is part of the British Garden Centres Group owned by green-fingered brothers Charles and Robert Stubbs. It is one of the largest garden centres in the group and houses a large selection of plants, landscaping products, pet products, aquatics, furniture, home furnishings, clothing and tools.
The centre has recently undergone some fantastic new development providing an extra 30,000 sq feet of retail space, plus an orangery which brings a new atmosphere to the existing restaurant. Owners Charles and Robert were looking to heat the new extension and upgrade the huge main building to underfloor heating to maximise available floor space.
Maintaining a constant, controllable temperature was not only important for customer comfort, but imperative for maintaining the on-site indoor planting facility and specialist aquatic centre. With kitchen and customer toilet facilities located in the restaurant area, it was also crucial that the building had ample supplies of hot water.
The owner Charles was sold on the environmental benefits and reliability of ground source heat pump technology, plus the payback available through the Non-Domestic Renewable Heat Incentive (RHI) scheme meant that the project made good commercial sense. The heat pump was installed by Lincoln-based installer Steve Robinson, who has experience of commercial applications of ground source heat pump technology.
Cascading Plantroom system
Steve took advantage of Kensa’s MCS Umbrella scheme to get guidance on the sizing of the ground arrays and design of the heat pump system, to ensure that it was compliant with the Microgeneration Certification Scheme (MCS) and therefore eligible for the RHI.
“I’ve worked on successful projects with Kensa in the past and, on the Hornsea Garden Centre job in particular, I was very impressed with the level of their technical sales and support. I like the fact that Kensa is a British manufacturer, plus they are easy to get hold of and good at problem-solving.”
Kensa specified two 45kW Plantroom units to cover the heating and one 25kW High Temperature Twin Compact to provide hot water. Kensa’s Commercial Plantroom heat pumps are designed to be modular, allowing the installer to match the heat pump output to the heat load of a commercial building.
The heat pumps are arranged in a cascaded system, meaning that the customer benefits from the heat provided by multiple heat pump units.
The heat pumps are housed in a plantroom based on a mezzanine level above the main site entrance on reinforced steel sheeting, which can hold a weight of up to four tonnes. From an access point of view, it would have been better to house the plantroom on the ground floor, but this would have taken up valuable floor space. A large ground array consisting of 24 loops of 50m coiled slinky pipe is buried under a field across from the car park.
“We’re very happy with the heating and hot water solution that the ground source heat pumps provide at Hornsea. The building warms up to a cosy 22-23 degrees very quickly and is easily maintained. As well as being energy-efficient, the technology makes perfect business sense compared to radiators or air source which work out more expensive.
“Plus if you factor in the payback from the RHI, this approach is a no-brainer. With the current rate of return we will have paid for the cost of the system in a few years and are projected to have earnt back triple the cost of our investment by the end of the 20 year period.”
The system has been so successful that Charles is considering applying it again in another garden centre that he is building in Durham.