This year we have worked on possibly our most complex project to date, which has involved advising Lincoln County Council on the overheating risk, energy demand, energy cost, pay-back period and C02 emissions savings available under various refurbishment options of a prominent 1960s office block.
The report, linked below, illustrates heat loss/heat gain balance tables for the winter time period, using several dynamic thermal models as the source data. Space heating loads within the building were assessed to be the highest energy demand, so analysis of wintertime heat loss was of high importance. The heat loss/heat gain balance accurately described how heat was being introduced to the building (space heating system, internal gains, solar gains etc), and how it was being lost (conduction via roof, walls, windows, infiltration etc), to a tolerance of <0.5%. This information allowed the design team to fully understand how the building was gaining and losing heat, and as such, how to target reductions in heat loss with precision accuracy – assigning costs where they are of greatest benefit and maximising the performance of the building for the available budget. The design also assessed the risk of overheating in the context of reducing annual energy demand. Some interesting findings were made in relation to building fabric and M&E services, and how the two interact.
In particular, comments made concerning low-g glass and the impact on natural light and artificial lighting loads were interesting. Architects LOVE GLASS(!). If a client is conscious about avoiding overheating, low-g glass is frequently specified to counterbalance high glazing quotas. If they’re not, they can often end up with real overheating problems on their hands. But how low should you go? In the case of this project, the proposal was to specify low-g glass that was so low it would trigger artificial lighting loads year round – not cost effective! The cost of the assessment works undertaken by Greenlite can easily be recovered by avoiding the need to install costly low-g glass AND benefit from improved natural daylight availability and reduced lighting costs. Only through the use of a quality thermal model though can these parameters be discovered without running the risk of incurring overheating issues.