Since the 1980s, Woodland Primary School in County Durham, had relied on oil to provide its heating and hot water needs. However, when the school’s oil heating system came to the end of its life, a more sustainable option was needed. With funding secured for the project from the Public Sector Decarbonisation Scheme via the Department of Business, Energy and Industrial Strategy (BEIS), Durham County Council called on the expertise of Vaillant to specify a low carbon heating system that would reduce running costs and improve overall efficiency.

When looking at the specification process behind the aroTHERM plus, it was established early in the project that the oil boiler at Woodland Primary School would be replaced with a heat pump solution. However, with the tight time constraints and additional challenges with the fabric of the building itself, the council called on outside expertise to calculate the size and volume requirements – as well as which type of heat pump would be most suitable.

As a result, the Councill approached Energist Solutions, who recommended Vaillant having favoured its products previously for ease of installation and quality. Supported by an enthusiastic school Office Manager and Head Teacher, the Low Carbon Team at Durham County Council applied to the PSDS through Salix Finance to cover the cost of the project.

The team successfully secured £113,000 of the total £122,000 project costs to upgrade Woodland Primary School, which included the design and installation of the aroTHERM plus heat pump cascade system, 31 ground-mounted solar panels and converting all lighting to Light Emitting Diodes (LEDs).

The school’s existing oil boiler was replaced with four Vaillant aroTHERM plus heat pumps, located away from the main school building. It was deemed that two 12kW units would provide the heating requirements, with an additional two 10kW units being able to alternate between heating and hot water demand. Alongside a large buffer tank and large hot water cylinder, both of which were in the original boiler house.

The rural primary school initially wanted the new heating system to be integrated with the existing Building Management System (BMS). Working with Vaillant and their design team, Energist were able to adapt the legacy BMS system to work with the Vaillant 720/sensoCOMFORT control, to monitor the energy usage for the school whilst ensuring a continuous supply of power via the adaption to a three-phase supply.

By installing the sensoCOMFORT control, the heat demand is continuously monitored and the aroTHERM plus units can switch on automatically as required.

New, ground-mounted solar PV panels were also installed at the rear of Woodland Primary School’s playing fields. There are 31 panels in total, with each panel delivering 455W, resulting in a peak power of 14.1kW. Utilising solar panels has helped to reduce the amount of electricity the heat pumps consume from the grid whilst also generating revenue through selling surplus electricity back to the grid.

From a budgeting perspective, generating energy independently from the grid means the school can better manage their overheads at a time when energy prices are fluctuating more than ever before.

As a result, Woodland Primary School is now the lowest carbon emitting school in County Durham, reducing their carbon emissions from 22.1 tonnes per annum to 4.9 tonnes. These successes have also allowed Durham County Council to scope out more carbon reduction projects in the region, based on the tangible results of Woodland Primary School.

Malcolm Johnson, Energy Conservation Adviser at Durham County Council, said: “The Woodland Primary School project has achieved several ‘firsts’ including the first school in Durham County Council to get air source heat pumps. We embraced the challenges of this project, and the expertise from Vaillant was vital in delivering the heat pump solution. We have been really impressed with the aroTHERM plus heat pumps, and the high level of service we received from Vaillant’s expert team, including their support in the pre-planning, help with designing the plans and consultancy when we ran into any issues.”