Implementation of a building management system
Principle
A building management system (BMS) is a computer-based system that supervises all equipment for one or more buildings. Building management systems cover more than just energy equipment. Other technical systems are also controlled – burglar alarms, fire protection, other electrical devices, elevators – depending on the operator's choice. Energy services are the heart of building management systems, however, for the following reasons:
• Among BMS services, only control of energy equipment can balance costs with comfort and needs.
• Measuring energy expenditure is an objective indicator of the quality of technical services management, even if the systems covers other non-energy services.
Explanations
BMS centralised management and operation of the establishment's equipment. These systems can simplify tasks, but necessitate a precise definition of the expected services and of the qualifications required of staff who run the system. In addition to the operational controls described above, BMS can be used for many reporting functions and analysis of equipment performance and consumption. BMS centralises equipment management functions generally carried out by numerous different intermediary devices:
• Simple timers or preset cycles can automatically turn off equipment devices or set them to a lower regime at certain times of day, of the week, or the year.
• Energy cut-off devices can restrict the power supply to electric heating systems as a function of outdoor temperature. These devices act directly on the electrical circuit. They are designed for rooms where it is not always possible to ensure proper settings for heating equipment (meeting rooms, offices, etc.).
• Presence detectors in little or irregularly used spaces switch on a system or return it to normal service levels when a presence is detected (meeting rooms, etc.) and automatically control lighting in hallways or windowless spaces.
• Window opening detectors are used to avoid wasting energy when windows are opened.
• Time-of-use shunters cut off or reduce the power supply to electrical devices, or transfer them to an internal supply line, according to tariff periods (peak/off-peak hours). Some devices are triggered by tariff signals sent to the subscriber's electricity meter, ensuring proper synchronisation and avoiding problems with clock settings.
• Cycle programmers or circular load controllers are used to reduce operating times for a set of technical devices, so as to reduce load during peak hours.
• Integrating load controllers measure load, then calculate electrical energy for a given time period (1, 5 or 10 minutes on the "yellow" tariff plan, 10 minutes on the "green" tariff plan).
Costs
Installing a BMS can generate energy savings on the order of 20 to 40% compared to a building without this type of system. Of course the results achieved depend a great deal on the hotel's initial situation and capacity to manage the BMS tool.