Recent advances in the performance of leading makes of ASHPs mean that they are now capable of producing water which is hot enough simply to be coupled up to existing central heating and hot water systems without costly and disruptive adaptation.

For the ultimate cost reduction, the installation of heat storage (currently large hot water tanks) will enable the production and storage of most of a 24 hour day’s heat requirement using off-peak production on very low cost tariffs, the savings with storage would be some:

• From natural gas to ASHP - 50%
• From Oil or LPG to ASHP - 82%

Heat Pump Case Study – Hostel at Newmarket

Project Overview

In 2010 we were requested to tender for a prestigious project in Newmarket.

The project was the renovation and extension of a hostel to accommodate some 32 international students who attend a 5 month live-in course on racehorse management and care.

Mitsubishi and Dakin were the preferred heat pump suppliers, but they had no models which would match the technical specification, without expensive boosting.

The renovated building required water for sanitary (domestic hot water) use at 60⁰C and heating at 55⁰C at ambient temperatures down to -15⁰C. And that the heating water temperature should be ambient temperature compensated.

It was required that there would be no electric temperature boosting nor double compression.

Our heat pumps turned out to be the only ones to match this specification.

Photo of Hostel

The Design

We designed a modular set up using 4 x 3 phase heat pumps of 14kW each. These would be controlled by the building management computer on a cascade basis for optimum efficiency.

Photo of Installation

The pipework is of reverse return design.

Adjacent to the heat pumps we included a 200 litre inertia tank. This adds necessary volume to the system and reduces cycling and thereby reduces electricity consumption, and unnecessary wear and tear.

Photo of Inertia Tank

We also incorporated a by-pass and shut off valves so that we could start up and test the heat pumps and our controls before the rest of the building was finished. This ensured that once the builder’s heating engineers had completed and tested their work, the heat pumps were immediately ready for service.

The building design required that the heat pumps transfer their heat via a heat exchanger in the plant room. This was a good design as it limited the extent of the heat pump’s water to a closed circuit of about 100 litres plus the inertia tank of 200 litres requiring 60 litres of glycol insertion to provide protection down to -20⁰C.

The installation has been commissioned and met the required temperatures at the hand-over test.

Financials

Cost of the system (excluding civils) £42,000 plus VAT at 5%

Running cost p.a. had the project been on oil at $100 per barrel £12,153

Running cost p.a. on electricity £4,500

Savings p.a. £7,650

Pay back 5.5 years

This installation is available for inspection

The client has recently built a visual shield around the plant –

Photo with wooden surround