Nancy Astor Water Source Heat Pump

Our new sustainable system provides all of the hot water for the building
Drake's Reservoir
 
The Nancy Astor water source heat pump provides all of the hot water for the building, and is estimated to use approximately half the energy of the previous gas system.
 
 
Students were given a tour of the newly commissioned Water Source Heat Pump in April 2024.
Structure of water source heat pump, Nancy Astor
Pipework for the water source heat pump leading into Drake's reservoir

Heat pump

The heat pump itself is housed in the Nancy Astor basement plant room along with two buffer tanks which act as thermal stores to maximise the carbon savings by storing collected thermal energy.
The heat pump is an electrically-powered heating system. Using the reservoir pipework filled with heat transfer fluid, the system absorbs renewable, low-grade heat energy from the reservoir water. The heat pump then compresses this heat energy to raise its temperature using a R407C refrigerant medium.
Heat exchangers transfer the additional energy from the transfer fluid to the water piped through the buffer vessels to serve the domestic hot water.

External structure

An external structure has been created to route the pipes from the Nancy Astor plant room to the reservoir. Some of the pipes you might be able to see will have outgoing, cold transfer fluid inside headed to the reservoir, whereas the other will have the returning, warmer fluid.
The fluid is Thermox DTX which has been especially formulated for use in Geothermal heating systems and increases the efficiency of the heat transfer process and offers antifreeze characteristics down to -50 oC is non-toxic and biodegradable.
Water source heat pumps have long been regarded as a means to produce affordable and secure heat from a low-carbon source. The return temperature using water source is generally 5-6 oC higher than equivalent ground source type collectors thus increasing the efficiency of the heat pump.

Pipework

The pipework is submerged in the reservoir, laid out in four coils each with a total length of 250m designed to maximise surface area. The pipes form a closed loop system, meaning it is not water from the reservoir itself, but instead it sends thermal transfer fluid around the sealed system.
Heat naturally flows from warmer to cooler places. The water source heat pump exploits these physics by circulating a cold fluid through coil pipework in the water. It absorbs low-grade surrounding energy from body of water.
The ground source heat pump then compresses and condenses this free energy to a higher temperature and transfers it to the hot water system. Having transferred its energy from the reservoir to the heat pump, the fluid continues its circuit back to the submerged pipework to commence the cycle all over again.
 
 

Supporting the UN Sustainable Development Goals

  • SDG 7 graphic full colour

    Powering the growth of renewable energy

  • SDG 11 graphic full colour

    Pioneering energy efficient buildings

  • SDG 13 graphic full colour

    Supporting climate action

 
 
At the University of Plymouth, we are committed to building a sustainable future. This is one of many projects that have been undertaken as part of a plan to reach net-zero carbon emissions.
Funding made available by University capital expenditure and by the Department for Energy Security & Net Zero (DESNZ) through the Government’s Public Sector
Decarbonisation Scheme (PSDS), delivered by Salix Finance. This was secured based on the installation of the water source heat pump, to provide domestic hot water to Nancy Astor Building.