Earlier this year we explored different ways to heat our campus sustainably. Find out what happens next.

Context

The University of Warwick has set a target to be Net Zero for Scope 1 and 2 emissions by 2030. The University’s Energy Strategy, which works towards these targets, has three pillars: Reduce, Decarbonise and Smart. The biggest challenge in the decarbonisation of energy used in our buildings is the replacement of fossil fuel heating systems.

Approaches to Decarbonisation of Heat

There are several technologies that can provide low carbon heating. Some are based on low carbon fuel sources (e.g biomass) and some extract heat directly from the environment (e.g heat pumps). After careful consideration of all of the different options, we have concluded that heat pumps are the best solution for our campus.

Heat Pumps

Heat pumps extract thermal energy from the environment. Sources of thermal energy can be the air, ground or large surface water bodies. Ground source heat pumps are more efficient during the coldest weather because the temperature below the ground is higher than air temperatures.

There are two types of ground source heat pump; closed loop and open loop systems. Open loop boreholes were selected for further investigation at Warwick because, with favourable ground conditions, more heat can be extracted from fewer boreholes.

Drilling Locations

Our decarbonisation plans include a new renewable energy centre to serve our new buildings and a new facility within our existing energy centre at Cryfield to supply low carbon heating to our older buildings through our underground heat network. Due to the variability in geology across our campus, we carried out drilling trials at two different sites.

Between January and July this year we drilled two 350 metre deep boreholes in the ground. The image below shows the Cryfield drilling rig. Drilling was followed by extensive geological and water pumping tests to understand the potential of the boreholes.

Cryfield Rig

Borehole Testing - The results

After analysis of the data from the boreholes, we found that due to the specific nature of the geology and therefore the availability of free-flowing water underground in the locations we tested, the open loop ground source heat pump solution is not currently a suitable option for low carbon heating at the University.

Next Steps

Testing the viability of open loop ground source heating was an important step in the journey of decarbonising heat across the University of Warwick campus and has given us a greater understanding of the options available to us.

We are now developing our designs based on large-scale air source heat pumps. Whilst less efficient in very cold weather, they are a well-established technology that has many benefits and can provide the low carbon heat across campus that we are looking for in our Decarbonisation plan. We are pleased to have selected the right solution for our campus and will now progress the development of our new energy centres on this basis.