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BIM:SAM solves riddle of high energy bills in Manchester building
EVORA EDGE’s innovative BIM:SAM approach (building information modelling for strategic asset management)has helped reduce gas spend by 21% in a building, resulting in savings of more than £20,000 per year.
It has also opened up the potential to achieve a ‘design for performance’ approach relatively quickly and cost-effectively across portfolios of buildings using existing EPC models.
What is BIM:SAM and ‘designing for performance’
BIM:SAM is a decision making tool that helps avoid expensive and time consuming mistakes when managing large and complex buildings.
It starts with a sophisticated computer simulation of a building that reflects its real-world usage and operation. This digital model is then used to test out future scenarios such as extreme weather conditions or different energy management options.
EVORA EDGE’s approach is highly unusual in the UK, where modelling is done only to ensure compliance (such as for energy performance certificates), rather than to demonstrate the real-world operation of a building.
However, it is more common in Australia through the NABERS scheme and is now being championed by the Better Buildings Partnership in its ‘design for performance’ project, currently being tested in the UK.
EVORA EDGE was asked to investigate the high energy spend in a modern office block building in the centre of Manchester. The building had been difficult to benchmark because of its unusual heating, ventilation and air-conditioning system (HVAC) which was described as a ‘ground source heat pump’ in the site’s technical literature. However, the client reasonably expected efficiency savings with this type of installation and was confused as to why this was not happening.
There did not appear to be any obvious fault with the system so EVORA EDGE decided to build a dynamic simulation model (DSM) of the building to try and pinpoint any discrepancies.
There was no time nor the budget to create a DSM from scratch so instead, the EDGE team looked to see if the simple SBEM model, created by another company for energy performance certification, could be converted into a DSM.
This is very rarely done. EPC models are designed to achieve legislative compliance and often contain fundamental gaps compared to the real-world use of a building.
The conversion process was challenging and required an in depth understanding of the modelling software as well as extensive mechanical and electrical engineering knowledge to match it to what was happening on the ground.
However, once done, the DSM model was able to highlight a number of inconsistencies in the data which helped target the on-site investigations.
These revealed that the BMS had been set up incorrectly and was not reflecting the operation of the closed ground water loop system and condenser water circuits.
The solution was remarkably simple and required just a few adjustments to the BMS system.
As a result, there has already been an 8% decrease in costs and a saving of £21,579.70. This equates to a 21% reduction in overall kWh over the comparative period and more than 100 tonnes of CO2 saved.
But what is really exciting is that, although difficult, it is possible for a simple EPC model to be used to develop a highly accurate, digital model of an existing building which can be put to a variety of uses.
For example, the DSM model in this building has already been used again to support a photovoltaic (PV) study. It confirmed that installing PV solar panels would reap an estimated 6% return on investment before the application of predicted energy price inflation. As a result, a 50 kWp PV system has now been installed – further adding to the already impressive sustainable credentials of this building.
The case demonstrates that BIM:SAM is a powerful and flexible tool for asset managers both in day-to-day decision-making as well as for longer-term planning.