Heat pumps are becoming the go-to option for healthcare organisations looking to improve the efficiency of heating systems and drive a reduction in carbon emissions

All four UK health services have united to commit to achieving net-zero carbon emissions by 2045 at the latest.

And, with emissions from the NHS estate responsible for over 60% of the total NHS carbon footprint, there are significant opportunities to improve efficiency and make savings.

One of the technologies being widely adopted within the sector is heat pumps.

Unlike traditional gas boilers, heat pumps do not burn fuel to create heat.

Instead, they use refrigerants to transfer heat, which is similar to the technology used in refrigerators.

Choose wisely

There are two main types of heat pump most commonly used within the health sector – ground source and air source.

The air-source heat pump works by transferring heat between the outdoor and indoor air; while ground-source heat pumps, also known as geothermal heat pumps, are used to transfer heat from the ground to a building.

Both offer viable solutions for healthcare estates, but air source heat pumps require less space and are likely to fit within existing plant rooms and space more readily.

And, while ground-source options offer a slightly-more-stable performance throughout the year, air source can be considered for sites where there is less outdoor space, and they are also typically easier to install.

Energy efficient

When operating, the refrigerant within the pump takes in heat from the outside air or ground and the temperature is then raised by compressing it.

This hot gas is passed through a heat exchanger to heat up the water in the central heating system.

And this process means the pump uses less energy.

Dr Samira Saravi, hydronics product manager for Mitsubishi Electric, explains: “As the NHS looks to decarbonise its estate, heating becomes an obvious area to start as it consumes so much energy.

“NHS trusts are actively looking at ways of removing gas systems, and modern heat pumps are available right now that can meet the demand of a large hospital and deliver hot water up to 90°C.

“Heat pumps contribute to much-lower whole-life carbon compared to fossil fuel-based heating system. Also, they offer consistent heating, which is crucial for maintaining optimal temperatures in hospitals.

“For instance, air source heat pumps can provide 90°C sanitary hot water when the outdoor temperature is -5°C. In addition, most need only two water pipe connections and they have lower maintenance costs. This helps to make the long-term operational cost and maintenance financially attractive for NHS trusts.

Temperature control

“And heat pumps can not only help in terms of carbon emission reduction, but also provide precise temperature control.

“As they are powered by electricity, how you source and use that electricity can help adapt operations to save even more money. That may be thermodynamically – by charging storage/buffer vessels with hot water during off-peak and low-demand periods; or electronically – with integration of onsite photovoltaic power generation.”

Advising trusts on choosing the right pump for their estate, she adds: “Both have a place in the hospital sector where they can be applied most effectively, so a key aspect, always, is to understand the individual needs of the site and its operation, including both current uses and future uses.

“Each system will be different as each building and hospital is unique.

“We would advise trusts to consider the feasibility of installing heat pumps based on the characteristics of their particular hospital site, taking into account space availability, requirements, noise considerations, etc.

“The important thing though is to talk to the manufacturer as early in the planning process as possible.”

Mitsubishi has worked with a number of NHS trusts across the country to upgrade and replace outdated heating systems, including Devon Partnership NHS Trust, where its team replaced a heating and  cooling system with three modular heat pumps and two modular chillers.

Working with industry

E.ON Energy has also embarked on a 15-year energy efficiency partnership with Nottingham’s Queen’s Medical Centre (QMC), one of the largest NHS hospitals in the UK.

And the trust’s new energy centre will use four high-efficiency heat pumps to extract heat from the air and 64 boreholes up to 250m deep to draw natural warmth from the earth.

Excess heat can be piped down into these boreholes and stored or preserved for use at a later date.

Any leftover heat can be recycled by the heat pumps, lowering the demand for fossil fuels and in turn reducing energy costs.

Nottingham University Hospitals NHS Trust said the project would cut the hospital’s carbon emissions by 30% a year initially, which would increase to about 43% after its current gas-fired heating system is decommissioned.

Anthony May, chief executive of NUH, said: “This partnership demonstrates our significant commitment to environmental sustainability and offers a creative solution to meeting our energy needs and tackling climate change, while at the same time improving patient and staff comfort by allowing us to better manage temperatures within our buildings.

“Innovative projects like these will play a hugely-important role in helping us meet our ambitious goal of achieving a net zero carbon operation for heating and cooling system emissions by 2040.” 

Making savings

The critical care unit at St Mary’s Hospital in London has also installed a ground source heat pump system to provide heating and cooling.

As a result, the hospital’s carbon emissions have dropped by over 40%, and it expects annual energy savings of around £1m.

And the University Hospital of South Manchester has installed air source heat pumps to provide heating and cooling to the hospital’s outpatient building, reducing emissions by over 30%.

Funding for NHS heat pump technology is primarily coming from the Public Sector Decarbonisation Scheme (PSDS) or via Energy Performance Contracts with manufacturers and suppliers.

Veolia secured £22m from the PSDS to help decarbonise two acute hospitals for the University Hospitals Birmingham NHS Foundation Trust.

Located in Edgbaston, the Queen Elizabeth Hospital Birmingham will lower its carbon footprint by 2,086 tonnes per year through conversion from the use of steam for heating to a hot water system backed by the integration of a 1MW multi-stage heat pump system. And upgrades at the Good Hope Hospital in Sutton Coldfield will see the installation of a 650kW multi-stage heat pump system.