British Land’s York House will be the blueprint for future energy retrofits
Property giant British Land has set some of the most ambitious carbon-reduction targets in the sector and is leveraging cutting-edge technology and the latest energy management tools to achieve its goals.
The property company manages a portfolio valued at £13bn – of which it owns £8.9bn – and is aiming to achieve net zero carbon by 2030. Central to this ambitious goal is the replacement of gas boilers with heat pump systems in its properties.
The transition from fossil fuels started in 2012 with the installation of a hybrid heat pump system at 350 Euston Road, where heat pumps work in tandem with gas boilers to meet peak heat demand. In its latest project, British Land has replaced four gas boilers with heat pump chillers at its York House headquarters in London and says it will be the blueprint for future energy retrofits.
Template for transition: York House retrofit
Screenshot of the dashboard view of the new heat pump
The retrofit of York House involved the replacement of four gas boilers and chillers with two parallel 4-pipe air source heat pumps, which concurrently supply chilled water and heating to the low-temperature heating system.
‘The benefits of using 4-pipe heat pump chillers is that there’s a year-long cooling load, and we get to use some of the rejected heat from that process to heat the building,’ says Daniel Valente, head of projects at Nationwide Air Conditioning.
Other improvements to the HVAC system included the introduction of indoor air quality (IAQ) controls for ventilation, a full validation of the fan coil units, and confirmation of water flow rates and temperatures.
The previous gas boilers had 1.3MW of heating capacity, while the new heat pumps have a heating capacity of 600kW, with a duty standby arrangement and a combined cooling capacity of 1.2MW.
The project has resulted in a 57% annual decrease in HVAC energy usage, and electrical energy use has reduced from 982MWh in 2019 to 419MWh for the 12 months up to September 2024, even with heating and cooling moving from gas to electric.
An advanced building model, in line with the Nabers UK standard, was built to identify what the peak loads would be.
‘We came up with a proof of principal that we could actually utilise a 95% peak load design to minimise the equipment size, but also to optimise the project costs. It enables us to start controlling the building on a demand-driven strategy,’ says Draper, of Twenty One Engineering. The design was validated by the operational gas profiles of the building, he adds.
The system maintains a temperature of 17°C when the building is unoccupied, says Draper. This reduces the time needed to heat up the building, which maximises the efficiency of the heat pump.
One challenge was to ensure that a flow temperature could be maintained that was hot enough to heat the building at all times, says Valente. ‘We needed to ensure that we were able to increase the flow temperature at periods of high load, so we installed a second-stage water-to-water heat pump,’ he adds.
The unique aspect was that there was no hydraulic separation in the LTHW system, and a much lower heating capacity. ‘The water-to-water heat pump only injected heat when needed to meet the building heating load required during the winter months,’ Valente says.
The benefits of this were higher operational efficiencies, lower initial capital costs, and a simpler installation.
Key to British Land targeting net zero carbon is the adoption of ISO standards 50001 Energy Management and 14001 Environmental Management, as well as the Nabers UK rating scheme, which provide frameworks for measuring and reducing energy use. ISO 50001 Energy Management is used to monitor and improve the energy performance of its buildings, and ISO 14001 Environmental Management to measure and continually improve other areas of sustainability.
‘ISO frameworks demonstrate that we are operating in line with our commitments, and that we have clear objectives and goals that we are working towards,’ says John Gentry, British Land’s head of technical services and sustainability.
CIBSE Certification offers UKAS-accredited certification for ISO 9001, 14001, 45001 and 50001 and, last year, took over from the BRE as the scheme administrator for Nabers UK, the operational energy rating scheme. CIBSE Certification certified British Land’s environmental and energy management systems.
One of two four-pipe heat pump chillers installed at York House
Nabers UK, which has its roots in Australia, has two UK products – Design for Performance (DfP), which drives energy efficiency in new offices, and Nabers Energy for Offices, which measures the energy efficiency of existing offices. British Land is keen to use Nabers Energy for Offices to monitor the performance of existing buildings, including retrofits such as York House. It is using Nabers DfP to accurately predict energy performance of new buildings such as 1 Broadgate.
The strength of the rating is that energy data has to be validated annually, allowing the continuous monitoring of plant, says Matthew Beales, British Land’s head of technical project delivery.
British Land has long invested in sub-metering. This has been key for ISO 50001, which requires metered data to be submitted annually. ‘The system gave us the granularity of data to be able to really drill down into the profiles of our buildings and see how they were being operated – and where we were using energy unnecessarily,’ says Gentry.
The technical capabilities of CIBSE Certification as an independent organisation are fundamental to the integrity of standards such as Nabers UK
British Land’s Credit 360 data management system records, tracks and analyses building data, including energy and water consumption. It can identify anomalies in performance – so, if an occupier’s energy or water use spikes, the system flags it, allowing for investigation and resolution of the underlying issue.
Geoffrey Brophy, British Land technical services manager, is responsible for data quality. ‘I like to know what’s going on in the building that I’m responsible for from an energy point of view,’ he says. ‘I don’t want to sit in front of an occupier and not know what I’m talking about.’
Phil Draper, managing director at Twenty One Engineering, says British Land’s metering and data systems made meeting the ISO requirements relatively straightforward. ‘Most were already within British Land’s culture. It already had internal auditors, for example,’ he says.
Meet the Nabers UK
British Land has a long association with Nabers UK, having been on the working group that established the rating scheme in the UK.
‘We need to look beyond modelled theoretical certifications, such as EPCs and Breeam, and look at actual operational rating targets, such as Nabers UK,’ says Matt Webster, the property company’s head of environmental sustainability.
British Land was the first in the UK to receive a Nabers UK DfP target rating certificate for the 1 Broadgate office in London, which is due for completion this year. ‘In projects such as Broadgate, we can see the benefit of Nabers UK in terms of efficiency, the collaboration between the design team and the property management team, and supply chain,’ says Webster.
The refurbished interior at York House
The detailed energy modelling required by Nabers UK means that British Land has the confidence to use more efficient plant and more sophisticated control philosophies in new and existing buildings, he adds.
While British Land is leading the efficiency drive, there is a growing awareness among its customer base about Nabers UK and building performance, Webster continues.
‘At York House, there are some pretty big occupiers that have set their own climate goals and climate strategies to which the building can then respond,’ he says.
Webster is ‘really pleased’ that CIBSE is now running and administering Nabers UK. ‘The technical capabilities of CIBSE Certification as an independent organisation are fundamental to the integrity of standards such as Nabers UK. It ensures the ratings are properly verified and understood,’ he says. l
For more on Management Systems Certification at CIBSE Certification, including ISO 50001, go to: cibsecertification.co.uk/management-systems
For details of Nabers UK, visit:
cibsecertification.co.uk/nabers-uk
