By Marios Tsakiris, Business Analyst – Energy Modelling Expert at ZEB
A Building Management System (BMS) is a system that controls and monitors the building’s mechanical and electrical equipment such as air-conditioning, lighting, fire systems, etc. Its purpose is to control the building’s operation automatically under minimum surveillance and for a variety of different situations which are related to weather conditions, human activity, indoor comfort and security concerns. Furthermore, within the scope of an appropriately designed and specified BMS, lies the operation of the building under optimum performance for the users (visitors) and building assets (equipment) to provide optimal user functionality and maximum value for its owner with minimum energy consumption.
Unfortunately, the capabilities of the system to either respond to real time conditions or to actual changes occurring in the building leads to: a) lower comfort for users, b) higher maintenance costs, c) non-optimized conditions and ultimately loss of revenue for the owner. Most of the time this is due to lack of either appropriate design, specifications, or commissioning of the BMS system and could be totally avoidable.
A case study of an energy upgrade for a 5* hotel with 300 rooms in Greece helps prove the above-mentioned point. The upgrade involved the improvement of the BMS system from Class C to B according to EN 15232. Some of the indicative changes applied were:
- Fresh air supply from time-based to demand-based control (use of CO2 sensors)
- Variable speed controlled pumps with steady DP instead of constant speed
- Integrated room controllers into BMS
- Lighting control with presence sensors and Manual on / Auto off.
The results from the upgrade are:
- Annual energy savings of 146.204€ (-14%) *
- CO2 emission reduction by 749.713kg (-11%) *
- Approximate cost of investment in Building Automation:~200.000€
- Investment Payback Time (ROI): 1.4 years
It is important to point out that increased comfort for the visitors and lower maintenance costs have not even been considered within these benefits!
*acc. to EN15232