S-BMS Case Study: Energy Efficiency Upgrade at Somerset House
Problem
Somerset House, a Grade I listed Georgian building located in the heart of London, faced significant challenges in terms of heating efficiency and control. The building's existing heating system, a bivalent system combining a CHP system with gas boilers, distributed heat via six VT circuits to approximately 350 rooms across three wings. However, the system lacked individual room control, relying on a rudimentary method of adjusting the VT circuit flow temperature and a single 'representative' space temperature sensor per wing to estimate heating loads. This approach resulted in inefficient heating, discomfort for occupants, and unnecessarily high energy consumption.
Solution
To address these challenges, Somerset House underwent a major heating system upgrade. The upgrade involved the installation of approximately 350 VEXO S-BMS S-IoT room temperature and motion sensors, along with 750 LoRaWAN wireless digital Thermostatic Radiator Valves (TRVs), thereby creating 350 independent control zones. This allowed for the precise control of heating in each office based on actual room temperature and occupancy, rather than crude estimations.
The control strategy was refined to pre-heat rooms to a minimum setback temperature of 18°C during occupied hours (07:00-18:00, seven days a week) and boost this to 21°C for 1 to 2 hours before 09:00 from Monday to Friday, with the system reverting to the minimum comfort setting unless activity was detected.
Additionally, during the summer of 2023, zonal demand feedback was integrated to reduce distribution losses further. This was achieved by aggregating TRV demand data for each VT circuit and using this information to control the VT circuits and primary plant through the legacy Building Management System (BMS) via BACnet, based on actual heating demand.
Results
A preliminary analysis comparing boiler gas energy usage for the heating seasons before and after the control system upgrade showed a significant improvement in energy efficiency. Adjusted for heating degree days, the data revealed an average reduction in boiler gas energy usage of 30%, equivalent to a saving of 730MWh, for the heating season 2022/23 compared to the previous seasons before the upgrade.
The integration of zonal demand feedback during the summer of 2023 aimed to further reduce energy consumption by optimising the operation of the VT circuits based on actual demand, thus minimising distribution losses. A comprehensive analysis of the energy savings for the heating season 2023/24 is anticipated to provide further insights into the full impact of the upgrade on Somerset House's energy efficiency.
This case study exemplifies how VEXO S-BMS integrates advanced IoT controls and demand feedback mechanisms to significantly enhance the energy efficiency of heating systems in historic buildings, leading to substantial energy savings, reduced carbon footprint, and improved occupant comfort.
“The main reason I would recommend it is just the ease of installation, the lack of cabling and the LoRaWAN system, especially in buildings like this. I’ve worked in historic buildings for over 35 years and I know all the problems that we get trying to get technology around these buildings and I just found this so simple, it’s perfect for this sort of environment”.
Mick Figg
Head of Buildings, Somerset House
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