Mitsubishi lands London heat pump project

UK: Property development and investment company British Land is benefitting from new heat pump technology that has fully replaced the use of gas at its London headquarters.

The HQ, York House, is a five-storey, multi-tenanted office building in Marylebone, which previously relied on gas boilers for heating and requires 24-hour cooling with extended fresh air requirements.

When looking to decarbonise the building, British Land opted for two air-source heat pump chillers and one water-to-water heat pump from Mitsubishi Electric to replace four gas boilers and an old chiller system.

This was part of a wider goal to achieve a 75% reduction in operational carbon and a 25% reduction in energy use by 2030. The result is a building where heat pumps deliver a more than 400kWh reduction in energy use year-on-year. 

“The project at York House is unique because it was the first building where we achieved a full gas removal using heat pump technology,” revealed British Land’s head of technical project delivery Matt Beales. “Our previous projects have been hybrid with gas being retained, but with this one, we really wanted to lead by example as it’s our head office.”

The design of the solution was provided by Essex-based consultancy Twenty One Engineering, and the starting point was identifying the peak load to increase efficiency. 

“We came up with the principle that we could utilise a 95% peak load to minimise the equipment size and optimise the project costs,” explained Twenty One Engineering MD Phil Draper. “We looked at controlling the building on a demand-driven strategy, which means that the building isn’t allowed to get cold, and that reduces the time needed to heat it and maximises the efficiency of the heat pump technology.”

Following the project design, two other main challenges had to be addressed: the limited roof space and installing the new heating system in a fully operational building. A structural survey of the rooftop was carried out, and the installer, Nationwide Air Conditioning, 3-D modelled the pipework and surrounding areas to ensure the units fitted.

“We decided to complete the works within normal office hours, so nearby apartments weren’t disturbed, which meant the office building was fully occupied,” explained Geoff Broughey, senior technical services manager for British Land and York House. “Most of the work occurred on the roof, so the building occupants weren’t aware.”

The Mitsubishi Electric heat pump chillers are also helping British Land to reuse waste heat from the process to heat the building and minimise energy consumption. The four-pipe heat pumps use R513A.

“The unique aspect of this project was that we had no hydronic separation and a much lower capacity on the water-to-water side so that we only injected the amount of heat required to give the building the load required during the winter months,” commented Nationwide Air Conditioning head of projects Daniel Valente.

“The benefits to this were higher operational efficiencies, lower initial capital costs and a simpler installation.”