Buildings that perform in practice
For the potential of a building to achieve high levels of energy efficiency requires more than just good design. It also needs the active involvement of those who use the building, as one of the winners of this year’s CIBSE Building Performance Awards demonstrates.
While every designer would like to believe that their buildings perform as designed, especially in terms of energy efficiency, they know that this often does not happen in practice. Energy-efficient technology is but one side of the equation. How a building is used and operated and problems put right is the other side of that equation.
When the client or building operator takes a real interest in the perforce of their building is when the design intentions can be met — or exceeded.
Even in quite a new office building, large energy savings can be achieved by enlisting the support of the building-management team and the building’s occupiers. A notable case in point is York House in the west end of London, the headquarters of British Land, which occupies 44% of the building, with four other businesses occupying the remaining space. So effective has been the operation of this building in the short time it has been in use that it was chosen as the winner of the category for building operation in CIBSE’s Building Performance Awards for 2011.
York House was completed in 2007 and provides over 8300 m2 of office space, 1000 m2 of retail space and 22 residential units. It is managed by an on-site team from Broadgate Estates, a wholly owned subsidiary of British Land.
The main headline figures are a reduction in energy use controlled by British Land of 32% to save British Land and its occupiers £52 000, and occupiers reducing their electricity consumption by a further 128 MWh, an estimated saving in their energy bills of £11 000 a year and associated reduction in carbon-dioxide emissions of 69 t.
The total amount of energy used at York House was reduced by over 1000 MWh, saving an estimated £63 000 and cutting carbon-dioxide emissions by 416 t.
These successful outcomes were achieved by an environmental working group comprising British Land, Broadgate Estates, the occupiers of offices in York House and consultants hurleypalmerflatt. The group began meeting in 2008 to identify energy-savings opportunities and deliver them. A notable saving was a reduction in gas consumption to a mere 2 kWh over the Summer compared with over 120 000 kWh the previous Summer. That virtual elimination of gas use during the Summer was achieved by a new weather-compensation system to ensure that the boiler would not operate when the outside temperature was above 15°C.
In addition, a new energy-management system and ongoing monitoring services is helping to optimise the operation of central plant for heating and cooling.
The £65 000 investment is expected to be paid back in two years and has already been attributed with savings of £28 000 over an 8-month period. Among the early benefits of the new system was the identification of a broken sensor that had been causing constant gas use for heating. It has also made possible the better use of external air to provide free cooling.
Other initiatives include a new system of smart metering and energy management, with electricity and gas data uploaded automatically to a central system every 15 minutes. That system was provided by EP&T Global, and its remote monitoring service highlights opportunities for optimising the central heating and cooling plant — complete with the financial impact of each action. A monthly report highlights the financial impact of completed measures and provides an ongoing report of outstanding actions.
Lighting energy consumption has been reduced by installing more motion sensors in areas such as next to cycle racks and in stairwells. Further savings have been achieved by adjusting timers on existing sensors so that lights switch off more promptly.
The all-too common practice of heating and cooling working at the same time has been prevented by reducing thermostat deadbands to within ±2 K.
Occupiers were helped to save energy by measures such as installing power-saving software on computers and replacing traditional light bulbs with energy-saving alternatives.
A parallel programme of waste management has seen 98% of all managed waste from the building diverted from landfill through recycling and incineration — equivalent to saving £5400 in landfill taxes. There were two principal measures. One was a new scheme for composting food. The other was the efforts of the staff environmental working group to raise awareness of recycling facilities.
Stuart Bowman, divisional director of energy and sustainability at hurleypalmerflatt is delighted with the outcome of the energy-reduction campaign. He says, ‘The success of the partnership at York House is testament to adopting a managed approach from day one and the tremendous commitment from British Land, Broadgate Estates, hurleypalmerflatt and all of the occupiers. Even buildings that are designed to be energy efficient need to be managed well to optimise savings.’
The judges of the CIBSE Building Performance Awards also expressed appreciation of the way the building is managed: ‘Tenants were engaged in the process of cutting energy use and provided feedback that was acted upon. The reduction in energy use is impressive.’
York House has scored very well in BREEAM ratings. It achieved a ‘Very good’ environmental rating for the management and operation of the building, which was followed by a ‘Very good’ rating for the environmental performance of the design.
