Anglesey Abbey - River to heat House
The National Trust has an ambitious target to source 50% of our energy needs from renewable sources by 2020. Two years ago we installed Solar Panels on the roof of our Visitor Centre and now we have now installed a water source heat pump to heat the House and some of our office space. Taken together these two projects provide the Trust with over 230,000 kWhs of renewable energy each year.
How does a water source heat pump work
A heat pump is a device that uses a small amount of energy, in the form of electricity, to move heat from one location ( the ground, air or water) to another, in our case the House. Heat pumps work in a similar way to a fridge, but instead of moving heat out of your fridge they move heat into our buildings.
Using this technology, we now extract heat from Quy Water, which runs along the boundry of Anglesey Abbey. We should be able to extract around 3 - 5 degrees from the water, before returning it to the river further downstream.
Inside the heat pump this heat is transferred via a heat exchanger to a refrigerant which has a very low boiling point and evaporates. This gas is then compressed which increases its temperature (you might notice a similar effect when you use a bicycle pump and it gets warmer).
The temperature is increased through compression cycles to a point where it can be used to heat the House. The heat is then transferred via a second heat exchanger to be pumped round the existing radiator system in the House. The cooled compressed gas passes through an expansion valve and condenses to start the cycle again.
What are the benefits
We used to use oil fired boilers to heat the House, switching to a water source heat pump system has removed the risk of an environmentally damaging oil leak. The new system uses around one third of the energy used by our oil boilers, and this significantly reduces our carbon emissions.
We will save around £12,000 a year in fuel costs, that adds up to nearly a quarter of a million pounds over the 20 year life of the heat pump - that's money that can be used to look after Anglesey Abbey, the collection, and invested in our visitor facilities.
The low temperature background heat provided by the heat pump is also better for looking after our sensitive collections in the House, as opposed to the fluctuating high temperature heat from an oil boiler.