Building simulation software helps deliver office with highest-ever BREEAM score
Detailed modelling of the energy performance during the design stage of this office building at Leeds contributed to achieving a BREEAM rating of 87.55%.
IES Consulting worked closely with consulting engineers King Shaw Associates (KSA) to provide independent validation of the design for the building that has achieved the highest-ever BREEAM score. The Green Office project at Thorpe Park, Leeds, has achieved a BREEAM score of 87.55%. The design was validated before construction began. This building can accommodate up to 420 people, and its carbon-dioxide emissions are predicted to be less than 22 kg/m2 per year, over 80% less than a typical conventionally air-conditioned building — saving over 350 t of carbon dioxide per year. Richard Roberts of RIO Architects explains, ‘The challenge for the design team was to prototype an energy-efficient building that would stand up to the scrutiny of the institutional funding markets.’ The first stage was an engineering design exercise, led by KSA, to produce an environmentally friendly and commercially sustainable prototype building design, which was then applied to the specific plot at Thorpe Park. IES Consulting then used the IES suite of integrated building-simulation software to test and validate the internal comfort conditions and energy performance of the design. In particular the contribution of the Tarmac TermoDeck system to the thermal performance of the building was subjected to detailed studies, requiring special modelling of the heat exchange within the TermoDeck slabs. This analysis enabled King Shaw Associates to develop an innovative strategy to operating plant — using the thermal storage capacity of the system to maximise plant efficiency. Mechanical cooling is based on an absorption chiller using heat from a CHP plant and heat-recovery air-handling units to store ‘coolth’ in the TermoDeck, which is drawn on at times of high demand. KSA also derived a novel operating strategy for the BMS using a detailed analysis of the data from the simulation. This analysis revealed the inter-relationships between the different heating and cooling loads and the capacity of the building to store energy and was used to identify the optimum operating times for the systems. During the construction stages, as the design was fine tuned and value engineered, IES Consulting kept the simulation up to date, enabling the design team to make decisions informed by the building performance. This helped ensure that the integrity of the building’s performance was maintained without incurring unnecessary extra costs on site. Doug King, principal of KSA, sees even more potential for the approach: ‘In an ideal world, I would have liked to use the tool more fully to rationalise different design options at feasibility stage, which I believe could have added at least another 5% in efficiency.’ KSA Had previously been trialling the suite. Following the success of this project, the practice has purchased the software for use in house. Doug King says, ‘In my opinion, the IES system provides an invaluable tool by which we can evaluate the relative advantages of novel designs without committing our clients to being guinea pigs.’