What to expect, a working example of REM
Metz architects recently utilised Rapid Energy Modelling in the refurbishment of laboratories and offices at the British Geological Survey in Keyworth. Originally constructed using a pre-fabricated, glass reinforced concrete panel system in the 1950’s these buildings performed very poorly both thermally and environmentally. By identifying key areas of weakness within the building fabric, and discussing the problems inherent in the building it was possible to identify a suitable refurbishment solution and demonstrate the potential CO2 reductions offered by that solution.
The process involved the modelling of the existing building and applying an energy analysis to establish the current energy performance of the building. This produced a set of results related to building fabric performance and energy consumption. The model is then re-analysed with the chosen refurbishment options applied, which produces a second set of results. The comparison of these two sets of results then produced data which illustrated the potential energy savings offered by the refurbishment options applied. This exercise can be re-run any number of times until a balance between refurbishment affordability and energy based cost savings is achieved.
The actual refurbishment solution was established through a combination of budget and practicality, based upon the necessity for the labs and offices to remain in operation throughout the works. Identifying the key tasks for refurbishment from the refurbishment options list, enabled a specification to be created for the works to inform the model. Eventually five options were identified for further investigation.
The asterisked options were undertaken:
1. Upgrade insulation to flat roof
2. Replace low specification windows*
3. Externally insulate façade*
4. Review HVAC strategy
5. Review occupancy profiles and fit occupancy sensor for lighting
The Rapid Energy Modelling process identified that the chosen refurbishment option yielded a theoretical combined energy consumption saving of 27% and a reduction in CO2 output of 32 metric tonnes per year equating to a reduction of 37%.
The cost of the refurbishment works was £137,000.00, the gross internal area of the building is 912sq.m thus resulting in a cost per square metre of £150.
The client has achieved nearly half of the total CO2 reduction requirement set down by the Government CRC Energy Efficiency Scheme by 2050 at a cost of £150 per square metre.
Ongoing work at the site includes the installation of sub-metres and environmental monitoring in order to ensure that the predicted cost savings are being achieved. Feedback from the staff has been very positive and the immediate effects of the work resulted in the heating system being switched on much later in the season, and staff more actively controlling their office environment by opening windows and new controls to the heating system.
