Plas Newydd mansion

Renewable energies from the Irish Sea

The stately mansion, the ancestral home of the Marquess of Anglesey, is a listed building together with the surrounding parkland and the nearby stables. Up to now, it was heated by means of two oil-fired boilers. In 2014, UK’s largest marine-source heat pump system was installed - a construction project with many challenges.

The building project

Plas Newydd deserves very special treatment for many reasons: The grounds are located in a designated Area of Outstanding Natural Beauty and the nearby Menai Strait is a Special Area of Conservation. The building has an approximate heated floor area of  5000mover three levels. Apart from living quarters, the remainder of the building has museum accredited status and is used for display purposes and National Trust offices. The surrounding parkland and the nearby stables building are listed buildings

Up to now, it was heated by means of two oil-fired boilers, located in the stables building some 120 metres to the north of the house. Heat was transferred to the wet radiator system from the boiler house via two pairs of underground pipes. Following a tender for a new heating system, which was carried out for reasons of economic efficiency and risk minimisation, those responsible made contact with STIEBEL ELTRON at the end of 2013. An innovative marine-source heat pump system was installed the following year. In this way, the historical monument and its contents keep free of moisture on a year-round basis and CO2-emissions are reduced.

Aside from the sheer scale of the project, the challenges included working around rising and sinking tides and a long list of precautions required to protect the marine conservation area. Great care had to be taken to avoid damage to delicate marine habitats. The pump house, located on the beach and partially recessed into the cliff-side, was constructed with a minimum of wet concrete. On-site refuelling of machinery was strictly prohibited due to the risk of spillage.

Another top priority was preservation of the location’s natural beauty.  The 60 metres of pipes that extend along the seabed out into Menai Strait to suck in seawater are disguised by local rocks.

The technology used: WPF 66 brine | water heat pump

Cutting-edge technology in harmony with nature and listed buildings: A total of four STIEBEL ELTRON brine | water heat pumps were installed in Plas Newydd. How exactly does the technology work? To keep the manor house comfortably warm, heat exchangers extract heat from the seawater. The process can be compared to refrigeration technology, which uses chemicals to draw off heat.

In this case, the heat produced is captured and used to warm water, which is piped 30 metres up a cliff face to the stables building where the heat pumps are located. The temperature achieved is 55 °C, which is ideal for keeping the mansion’s interior temperature constant and preventing the development of moisture.


Award-winning project

Formerly the National Trust’s biggest oil consumer and polluter, Plas Newydd is now one of the cleanest-operating buildings anywhere in the UK.

The heat pump project has been recognised as the Commercial Project of the Year by the Energy Efficiency and Renewables Awards 2014. In addition, it has won the Renewables UK Cymru 2014 Award as Outstanding Renewable Energy Project.

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