Keeping control of energy usage in buildings is a key contributing factor in protecting the environment. A building management system such as the Desigo range from Siemens can facilitate this control. It can provide a comfortable working environment for building occupants enhancing productivity, ensure compliance with current energy legislation and contribute significantly to reducing energy usage leading to a smaller carbon footprint. However all too often the capabilities of the BMS itself are not fully utilised and the potential benefits are lost.
An optimum way of ensuring good control is to involve the BMS specialists early in the building design, whether this is a controls manufacturer or a specialist systems house. This early involvement ensures the BMS specialist has a clear understanding of the project and is able to create a solution that fits the needs of the client, rather than the all too familiar scenario where the building design is finished before the control system is even considered. This includes making sure that the user interfaces that allow the occupiers to control their own environment are straightforward and easy to use.
Accurate, reliable measurement of the conditions plays a crucial role. If the values being read by the BMS are inaccurate then it will not be able to control correctly. Meters are required in part L of the building regulations to measure consumption of individual zones allowing fairer cost allocation, and this consumption information can be supplied to the BMS. Too often this data is collected but the information is not analysed and then proactively acted upon. The data should be used to compare different zones or buildings or to see where energy usage is high. Control routines and time schedules can then be altered to improve the situation.
The second element is control. The BMS of today controls many elements of a building intelligently. These will include lighting, security, access, fire, ventilation and heating/cooling. These systems can all interact and the BMS can be used as the device to enable this. This interaction can enable cost efficiencies and energy savings.
A typical example of this type of control is when the last employee of a department swipes out using the access control system this triggers the BMS to switch off the appropriate departmental zone lighting, reduce the heating/cooling and ventilation to a preset night time rate. The simple actions of either turning things off when they are not needed or turning them down is often neglected. A reduction of a heating setpoint by as little as 1ºC for example can make a major difference in the amount of energy used, with little or no difference to the comfort of the occupants.
It is important that the system is commissioned correctly and the performance monitored thereafter to ensure correct control. This can either be carried out on-site or via remote monitoring. A remote centre can be used to interrogate different sites around the country, or even world wide. Web enabled controls can be used to provide a connection with the sites on a 24/7 basis, allowing an expert team to remotely see how each building management system is working, in real time. Data is extracted and the resulting information is analysed to improve energy efficiency. The same access also allows for rapid diagnosis of problems.
The final stage is to implement a regular maintenance program for the BMS. A regularly maintained system will work far more efficiently than one that is not maintained. The systems are installed with the best of intentions but can often be neglected after installation. Any number of things can change. Perhaps the most common is that settings are altered to deal with a particular set of conditions and are never restored to their original values. A systematic, regular, well planned maintenance program can ensure these areas are checked and that the system is run at its most efficient level.
To summarise as a manufacturer and supplier of building management systems it is our role to educate our potential clients in what these systems can actually achieve, and ensure they are being used to their full potential.