CIBSE AWARD WINNER | INSTITUTE OF PHYSICS 8,180 1,549 Third floor Second floor First floor Large AV screen Ground floor Basement level Section of the IOPs headquarters Aecom used dynamic thermal modelling to determine how much free cooling was available from the ventilation system. We increase the volume of fresh air drawn into the building until it reaches the point where it is more energy efficient to turn down the fans and to use cooling coils, explains Edmondson. In summer, the GSHP supplies chilled water to the AHUs and perimeter coils at a flow temperature of between 9C and 14C, with a return temperature of 17C. Fresh air rates are minimised in summer and winter based on CO2 levels. In addition, the buildings reinforced concrete superstructure has been left exposed on the soffit of each floor to add thermal mass to the spaces and help mitigate peak summer temperatures. In winter, the GSHP is the primary source of heat for the building. It supplies heat at 40C flow (30C return) to the underfloor AHUs and perimeter heaters. Gas-fired boilers (80C flow/60C return) provide top-up heat for cold mornings and heating back-up should the heat pump fail, in addition to heating the domestic hot water. The geothermal system appears to be working well. Summary data for the first years operation show the system has an annualised combined coefficient of performance (COP) of 3.4, although this figure is expected to improve over time as systems are optimised. (See panel, Successful commissioning on page 24.) Use of electricity to generate heating and cooling is prescient given the likely move away from gas for heating non-domestic buildings in forthcoming regulation changes The strategy of no combustion and limited heat rejection makes this building years ahead of its time. Its use of electricity to generate heating and cooling is prescient, given the likely move away from gas as fuel for heating for non-domestic buildings in forthcoming changes to the Building Regulations. At the time the project was designed, the carbon factor for electricity was 0.519kgCO2.kWh-1 in both the London Plan and in the Building Regulations. Now, however, legislation is catching up with decarbonisation of the electricity grid. The carbon factor of grid electricity has recently been lowered in the London Plan to 0.233kgCO2.kWh-1, to reflect the increased contribution made by renewables so, on paper, the Institute of Physics headquarters would appear to perform significantly better now, in terms of carbon emissions, than it did at the time of its design. It is precisely because the building services design is ahead of its time that this is an appropriate headquarters for an organisation with a mission to showcase the value of physics to society. It is also what made the scheme a worthy winner of Commercial/Industrial Project of the Year at the CIBSE Building Performance Awards. CJ 28 May 2020 www.cibsejournal.com CIBSE May20 pp24-26, 28 Supp Institute of Physics.indd 28 24/04/2020 15:54