The design and operation of buildings impact the cost of care, resiliency, sustainability, public perception, and — most importantly — patient outcomes. With this in mind, healthcare facilities — perhaps more than any other type of building due to their societal role — should aim to implement the most efficient and sustainable cooling and heating systems. By doing this they will also work towards maximising the efficiencies and the potential of their building.
Innovation in heating and cooling offers hospitals a wide array of mechanisms to decarbonise their buildings while reducing operating costs. These range from large heat pumps for building temperature control, and close temperature control chillers for medical equipment and hospital server rooms, to air-handling units (AHUs) — integral components of heating, ventilation, and air-conditioning (HVAC) systems that regulate indoor air quality, temperature, and humidity. AHUs can play a major role in decarbonising hospitals by adopting sustainable practices, technologies, and materials — such as variable frequency drives (VFDs), high grade filters, and heat recovery devices, which significantly improve energy efficiency. On top of that, innovative heat pump systems enable the electrification of heating and the repurposing of wasted thermal energy, aiding the transition from fossil fuels, and helping to meet ambitious sustainability targets.
Towards Net Zero carbon emissions in healthcare
It is evident that hospitals and healthcare facilities all over the world are eager to change, but they require guidance on what is possible and how to achieve it. Accelerating and scaling the use of combined heating and cooling, advancing system-level efficiency, utilising renewable energy sources, leveraging waste heat recovery technology, and transitioning to next-generation low global warming potential (GWP) refrigerants, are some of the most impactful areas of focus.
The NHS has been a pioneer, becoming the world’s first health service to commit to reaching Net Zero in carbon emissions. This goal not only aims for greater sustainability, but also enhances resilience in the face of fluctuating energy prices. As the NHS accounts for about 4 per cent1 of the UK’s national greenhouse gas emissions, decarbonising healthcare facilities can significantly contribute to the country’s decarbonisation efforts. By 2040, the NHS aims to eliminate net emissions from the sources under its control, with an interim target of 80% reduction by 2032.2 To achieve these objectives, the service launched an ambitious programme encompassing everything from improving building fabrics to replacing outdated lighting with LEDs. However, the most significant contributor to achieving its Net Zero will be the decarbonisation of heating, and the repurposing of wasted thermal energy.
Emissions from hot water and space heating systems reportedly account for 80% of the NHS’s direct greenhouse gas emissions. When gas boilers were first installed, they represented a healthier and more efficient improvement over previous solutions, such as hospital incinerators that provided heat. However, gas boilers are a major source of greenhouse gas emissions, and a large contributor of Nitrogen Oxide (NOx) emissions in the UK, which have been linked to worsening respiratory conditions.
Electrified thermal management systems
The need for greater efficiency, lower emissions, and healthier air quality — while still providing the necessary heat and hot water for hospital operations — has led to the greater adoption of electrified thermal management systems. These innovative heat pump technologies can provide heating and cooling simultaneously, or autonomously. Unlike gas boilers, which burn fossil fuel to generate heat and hot water, heat pumps extract or transfer latent energy from the ground or air in a clean, highly efficient process.
New hospitals are being designed with these modern heating systems from the outset, and many existing facilities are retrofitting heat pumps to replace ageing boilers. Given the diversity of hospitals across the country, tailored solutions can help to meet specific needs. For example, one public hospital replaced a 2,500 kW LPHW boiler with a heat pump system delivering hot water at 80 °C, annually reducing CO2 emissions by 1,300 tonnes. Another hospital in a major city replaced a 1,000 kW steam boiler with a 120 °C heat pump system, cutting CO2 emissions by 550 tonnes per year.
In the Midlands, a third hospital replaced its existing 2,200 kW LPHW boilers and 3,000 kW chillers with an electric thermal management system based on heat pump technology, which provides simultaneous heating and cooling, cutting 1,990 tonnes of CO2 emissions annually.
Simultaneous cooling and heating
Given that chillers are essential equipment for hospitals, and that other cooling needs are increasing as the climate warms, these dual-function systems will become increasingly vital. Thermal management systems that deliver both heating and cooling simultaneously are highly energy-efficient due to their ability to capture and re-purpose energy from one process to another. When the system is in heating mode, it also produces cooling without requiring additional energy. Conversely, while cooling, it generates heat as a by-product that can be utilised for heating purposes.
Simplifying and putting it into perspective: just as electric vehicles use braking to recover energy for acceleration, heat pumps in large buildings can switch between heating and cooling multiple times a day, recovering and recycling energy instead of wasting it. This significantly improves the efficiency of meeting the heating and cooling needs occurring at the same time.
Integrating cooling and heating systems allows for the repurposing of energy, meeting the year-round cooling needs of surgical facilities and vital IT equipment such as MRI scanners, while also providing domestic hot water and heating to keep patients comfortable. Heat recovery chillers can generate hot water as a by-product of the chilled water system, storing cooling energy through ice banks when not simultaneously required.
As extreme heat events become more frequent, prudent hospital estate management is planning for future cooling needs. Simultaneous heat pump systems offer a promising solution to this challenge. While pure heating heat pump solutions require external (sustainable) heat sources such as air or (ground) water, simultaneous heating and cooling applications provide the unique opportunity to reclaim or harvest energy which is available within the same building.
Removing barriers to implementation
A common misconception is that sustainable solutions are prohibitively expensive. In reality, the energy efficiency and CO2 reductions achieved through these technologies often result in short payback periods, sometimes within just two to three years. Another myth is that these systems are complex and only applicable to new buildings. In fact, most existing buildings have poor energy performance that can be significantly improved with smart heating and cooling solutions. Replacing cooling-only machines with those capable of simultaneous heating and cooling makes the incremental cost more manageable.
The UK government recognises the need to decarbonise buildings, providing support and incentives to help public sector buildings, including hospitals, better cope with climate change while reducing emissions.
The Public Sector Decarbonisation Scheme3 is a major enabler for hospitals to make these upgrades, providing over £1.425 bn of grant funding over the financial years 2022—2023 through 2025—2026. The scheme supports the aim of reducing emissions from public sector buildings by 75% by 2037, compared with a 2017 baseline, making it easier to improve building infrastructure and increase use of renewable energy sources, including heat pumps.
We have a clear vision for our cities — a future where renewable energy generation, heating and cooling of buildings, and energy storage, seamlessly work together to create highly energy-efficient buildings. These facilities would produce enough energy to operate independently of the grid, repurposing what would otherwise be wasted, and achieving significant energy efficiencies. If decarbonised buildings became the standard, we could enjoy cleaner air, and live in smarter, healthier, and more resilient cities that are less dependent on fossil fuels.
References
1 National ambition. NHS England. https://tinyurl.com/2p89j4mr.
2 Delivering a ‘Net Zero’ National Health Service report. NHS England. 1 October 2020. https://tinyurl.com/bp76k8k3.
3 Public Sector Decarbonisation Scheme. Department for Energy Security and Net Zero. 1 October 2020. https://tinyurl.com/uzw6adje.