As we transition our portfolio to net zero, we are testing low carbon technologies to accelerate progress. We have proved that air source heating and cooling works in major commercial buildings – reducing gas use by over 80%, moving away from fossil fuels, cutting energy costs for customers and improving thermal comfort. Members of our technical services team reflect on lessons learnt and opportunities for the future.
Embracing new technology
John Gentry: Air source heating and cooling is a renewable energy technology that uses free outside air to heat and cool buildings. We started testing this technology seven years ago, following detailed investigation. At the time, there was apprehension across the industry about whether air source pumps would work for the UK, where commercial buildings traditionally use gas boilers. We went out of our way to understand the equipment, including its limitations.
Our initial pilot at 350 Euston Road proved that the right air source pumps, well managed, can extract enough warmth from outside air to heat workspaces, even on a freezing London day. We have now also installed the technology at 10 Exchange Square and 338 Euston Road, where it is delivering similar results, and consider it as standard on all new developments and for lifecycle replacements in existing buildings.
Debunking scare stories
Matt Beales: One of the scare stories around air source pumps is that, when outside temperatures drop below 10°C, they struggle to generate the heat required. Our experiences debunk that myth. Even through icy spells of -2°C, we generally see zero gas consumption for heating spaces in buildings with air source heat pumps; gas boilers only come on to heat domestic hot water – and we’re now looking at projects to remove that.
Malcolm Webb: Air source pumps are highly efficient. Where gas boilers typically have a coefficient of performance below one (1kW of gas input generates less than 1kW of thermal output), air source heating and cooling can offer a fivefold return, with 1kW of electrical input generating around 5kW of thermal output. Pumps reuse heat from the outside air and recover waste heat from the chillers. Their carbon and cost savings are a showstopper.
Overcoming challenges
John: It’s not a walk in the park though. One of the biggest challenges is the upfront cost, as air source pumps are expensive. So, in the main, we retrofit the technology when existing equipment reaches its end of life. We also look to bring projects forward where the business case stacks up. This includes assets where customers are on long leases, so the payback period works. Concerns around new technology are another challenge. In testing the potential of air source heating, we’ve installed pumps in parallel with existing heating systems.
Malcolm: Air source pumps give a lower grade heat than boilers, only reaching 50°C, whereas gas boilers go to 80°C. However, this is more than adequate if you run buildings smarter. Rather than scheduling everything to start in one go, we now bring on air handling units first to raise temperatures in the space, then fan coil units to condition the air and then calorifiers for hot water. By smoothing demands in this way, the load never exceeds the system capacity.
Matt: With retrofits, you have to fit equipment into the space available, which can be a challenge. Some of our new pumps are positioned with only millimetres to spare. Refrigerant choice affects plant size too, so when space is tight, this limits options. We work closely with manufacturers to identify the best solution.
Lessons learnt
Matt: Customers are at the heart of everything we do. You need occupier support because air source pumps are not a like-for-like replacement. Our customers see being in a low carbon building as a positive and we have good data on the business case, so they tend to be supportive.
Malcolm: As for any major plant, positioning your meters in the right places is important. We’re now on version nine of our metering strategy, constantly improving it. You also need to allow time for seasonal commissioning – demands vary substantially from August to January. And it’s important to integrate control systems. On our first installation, the air source pumps were initially operated via a separate controller. When there was an issue, it took time to get to the bottom of it and gas use went back up as the boilers kicked in. We’ve now integrated the controls into our Building Management System (BMS), so our team can optimise performance through a single platform.
Matt: When you’re leading with new technologies, you need to be able to count on support from the manufacturer, as there isn’t the expertise locally. Otherwise, any defects or control issues take time to resolve. When you build a good relationship with the manufacturer, choose the right equipment for your building (every structure is different), implement a robust control strategy and commission it effectively, you have a recipe for successful air source heating and cooling.
Never standing still
Matt: The technology is evolving so fast. Soon after we installed air source pumps at 10 Exchange Square, a new refrigerant was released with lower Global Warming Potential. We’re always watching for improvements. At the moment, air source pumps are the most efficient heating solution. Outside British Land, I meet engineers hoping to continue using high efficiency boilers or waiting for hydrogen fuel technology to improve. However, in order to hit our net zero target by 2030, we are taking action now. We’re looking for every property to eliminate fossil fuels.
Malcolm: This is an exciting time to be in British Land’s technical services team. British Land encourages us to seek out low carbon innovations. When we installed our first air source pump at Regent’s Place, it was the largest retrofit of its kind in the UK, and we’re continuing to lead the way. Every day is a school day. There’s always a new technology to look into, or a different way to run things. That’s the best thing – though it doesn’t make our lives easier!
John: I’m proud of the team’s willingness to go on this journey. If we hadn’t taken early action on air source heating and cooling, we’d still be debating whether it’s the right thing to do. Instead, we’ve proved that the technology works and influenced the mainstream engineering world. We published our Pathway to Net Zero last year and are now developing pathways for individual buildings – air source heating and cooling is an important part of this.
COP26 highlighted the importance of climate action for many people. Leading by example, as a major property company, we are sharing steps everyone can take. I’d encourage everyone to consider new technologies. Do your due diligence and push the boundaries to achieve those breakthroughs that make a difference. Oh and yes, when it comes to the end of my own gas boiler’s life, I absolutely would replace it with an air source heat pump.
John Gentry is our Head of Technical Services and Sustainability.
Malcolm Webb is Senior Technical Service Manager at Regent’s Place.
Matt Beales is Senior Technical Service Manager at Broadgate.