About the event

This CPD seminar describes the development of heat pump systems coupled to groundwater, so-called “open loop” groundwater heating and cooling systems in the context of the MoD land portfolio, which serves as a good proxy for other “campus scale” development opportunities.

These systems operate on the premise of extracting groundwater and pumping it through a heat pump or heat exchanger to yield or absorb heat and reinjecting the “spent” water back into the ground. Two decades of implementation across the UK have seen some remarkable successes and rapid accumulation of experience, but there remain several significant flaws in the procurement, implementation and, especially, the management, monitoring and aftercare of such system.

Amidst a growing international consensus of an imminent carbon emergency, there is a pressing need for all nations to reduce their carbon emissions quickly and significantly. In the UK, heating comprises nearly half of all energy usage (DECC, 2011) and has thus become a national priority for carbon reduction.

Easy strategies for achieving this have proved elusive (BEIS, 2018). Electrically powered heat pumps, “hoovering up” low temperature heat from the ground beneath our feet (or from air, sea or rivers) are arguably the most promising technology (Banks and Birks, 2020).

An important measure for comparing operating costs between competing heat pump technologies is “coefficient of performance” (COP) which is essentially the heat output (kW) divided by the electrical energy input (kW). COP vary between competing heat pump technologies. For example, BEIS, 2020 has default values for air source heat pumps, open loop groundwater source heat pumps, and closed loop ground source heat pumps of 2.51, 3.31 and 2.84 respectively.

Army Establishments are typically large and often sited on productive aquifers (water bearing rocks) that are ideal for open loop ground sourced heat pumps. Furthermore, many sites used to pump and supply their own potable water and these existing but now unused deep groundwater extraction wells had yields that could deliver as much as 1 MW of design heat load.

There are other factors at play that align well with open loop groundwater heating and cooling including:-

Large buildings acting as anchor loads
Existing heat networks currently served by oil/gas fired boilers
Many MoD establishments are located on productive aquifers e.g. The Chalk of Southern England and in the Midlands, North and Scotland Permo - Triassic Sandstones.

The Ministry of Defence Estate (Air Force, Navy and Army) is a valid proxy for other large development settings including schools/colleges, airports, local authority land holdings etc where an essential pre requisite for larger heat pump applications is met: large site footprints where distances of several hundred metres are possible between abstraction and recharge locations within the site boundary.

The MoD has announced ambitious decarbonisation targets.

https://www.gov.uk/government/publications/ministry-of-defence-climate-change-and-sustainability-strategic-approach