Building Performance Case Study preliminary results
“Demand Logic has provided us with enhanced building performance management capabilities and a platform to identify issues that are near impossible to identify on standard BMS software to improve energy efficiency and occupier comfort”
Alasdair Cockbain, Group Estates Manager, Mace
Installing Demand Logic at 155 Moorgate
The headquarters of construction and building services company Mace at 155 Moorgate in London contains 8,000m² of office floor space. With a commitment to responsible business practices and targets for reducing its carbon emissions, as well as a £250,000 annual energy bill, Mace were keen to identify energy efficiency savings in this large commercial building. In May 2017 they contracted Demand Logic to examine the data produced by their Building Management System (BMS) and suggest options for reducing their energy use. Within hours the Demand Logic Data Acquisition Device was installed on-site and feeding data into their data analytics software. As far as the Mace team knew, their demand led strategy heating and cooling plant were set to shut down at 7pm every day, as that is what the BMS software showed. However the Demand Logic team were able to quickly visualise the data representing unexpected out-of-hours operation of the plant and communicate the problem directly to the on-site team to rectify the issue.
Projected Energy Reduction Savings of £25,431
Reducing out of hours operation
BMS systems produce huge volumes of data. This is often used only momentarily to decide whether to turn plant on or off and then it is discarded. Demand Logic extract and save this data so that a historical picture can be developed. It also allows for numerous layers of data to be visualised simultaneously so that the source of issues can be quickly identified. Sometimes plant is not working when it should be, putting excess pressure on other parts of the system and causing uncomfortable working temperatures for occupants. At 155 Moorgate it was identified that a handful of smaller pieces of equipment were faulty and calling for constant cooling unnecessarily. Despite their small size they were overriding the 7pm switch-off, forcing the full cooling system (including chillers, pumps and air handling units) to run continuously as well. This was resulting in significant energy wastage, but with the help of Demand Logic this problem was quickly identified, and interventions such as this are expected to save Mace £25,4311 per year.
Building performance overview - a proxy of how comfortable the building is and how well plant is operating
The image above was taken from the Demand Logic platform and shows 2 weeks of activity at 155 Moorgate. In the section at the bottom, the incorrect operation of the chillers and cooling plant (shown in red) was easily identified. Actions suggested by the Demand Logic team over the week of 17th July and logged in the progress section at the top of the screen were carried out over that weekend by the on-site building management team. The improvements in energy efficiency can be clearly seen with the red sections disappearing the following week. Improvements in occupant thermal comfort are also apparent. The excessive cooling was leading to uncomfortably cold conditions shown in the ‘heat map’ section, but as a result of the changes made the temperature rise back to a comfortable level.
Virtual meter illustrating energy consumption of the two chillers
The image above demonstrates one of the many benefits the data from the BMS provides. By using the flow and return sensors of the primary cooling circuit Demand Logic were able to produce a virtual meter for the chillers. This proved a good overview of the reduced load on the chillers as a result of completed actions. The virtual meter suggests that an estimated 5500 kWh has been reduced per week, leading to a yearly projected estimated energy saving of 125,147 kWh.
Estimated effects of completed actions on energy consumption and spend (annual)
The charts above demonstrate the estimated energy consumption (in kWh and £) prior to installing demand logic and how they reduced post completed actions, in addition to illustrating the subsequent energy spend difference per plant item. These positive amendments to the BMS have resulted in a total estimated reduction of 252,431 kWh (electrical) which subsequently translated into 103 tonnes of CO2 or 103,338 kg of CO2 (conversion factors obtained from defra) if Mace used a standard electricity tariff. That is approximately the equivalent of 234,000 miles worth of emissions produced by an average car, 100 days worth of emissions exhaled by the 857 employees in the building and an estimated 75% of emissions produced as a result of office waste on a site of similar size. Mace does purchase 100% renewable energy in addition to this investment to reduce energy consumption.
Typical Reduction in number of Hot & Cold Calls of 50%
Improved comfort and maintenance
Using Demand Logic’s service not only reduced Mace’s energy bills and carbon footprint, but also reduced temperature complaints from employees. By highlighting issues before they lead to complaints the building management team are now able to focus on ensuring expensive plant is properly maintained, having a positive effect on their life-cycle and reducing capex costs. The tools embedded in the Demand Logic platform help the Mace team to operate a condition-based maintenance strategy, prioritising plant that needs attention rather than running through a predetermined schedule. For example, the operation of terminal units providing hot or cold air to spaces can be compared to room temperatures in order to determine if the temperature asked for by the BMS is actually being achieved. By bringing together multiple layers of data, faulty sensors or valves can be located quickly before they lead to incorrect operation of equipment, excessive operating hours and wasted energy.
Continued engagement between Demand Logic and 155 Moorgate team
Further changes are now planned to improve the maintenance programme and control strategy of the 294 terminal units which will improve comfort conditions for tenants and reduce energy consumption. The engineering team at Mace will be using the Demand Logic system to group rogue units for targeted action. Additionally, the team will look into widening the dead-bands of the terminal units. Demand Logic’s experience at other properties, like 20 Fenchurch Street, has shown this can deliver a reduction in heating and cooling demand of 25%-40% by making similar changes on tenant floors.
