Theatre Green Book Two Toolkit – Building management systems

 

Building Management Systems

If applicable to your building, the Building Management System (BMS) should be a primary consideration when assessing your energy usage. The BMS is often seen as a complex black box and left alone, yet it is a key to achieving greater efficiency and more sustainable operations. 

The BMS should be installed so it is able to manage your plant in the most energy efficient way whilst also maintaining occupant comfort and enabling effective operational management of a buildings systems.

Figure 1 – The full value stack of a Building Management System (BMS)

The most efficient BMS is one that utilises demand control techniques to ensure services are only deployed when needed, and so that decisions are made based on the whole building. e.g., heating cannot run simultaneously with cooling, or ventilation turned on by lighting system occupancy sensors. 

An evaluation by a BMS contractor and/or consultant can ascertain the condition of your system and identify improvements that can be made. Improvements in control strategies alone can deliver ~15-20% reductions in energy use. 

You may be able to extract the files from your existing BMS to digitally audit the system. Whilst this isn’t always a conclusive way of assessing energy performance it can be useful to orientate your approach. It can highlight controllers that are in fault, misaligned times schedule and / or control settings which lead to excessive energy consumption.

Figure 2 – BMS assessment tools

The most efficient BMS is one that utilises demand control techniques to ensure services are only deployed when needed, and so that decisions are made based on the whole building. e.g., heating cannot run simultaneously with cooling, or ventilation turned on by lighting system occupancy sensors. 

An evaluation by a BMS contractor and/or consultant can ascertain the condition of your system and identify improvements that can be made. Improvements in control strategies alone can deliver ~15-20% reductions in energy use. 

You may be able to extract the files from your existing BMS to digitally audit the system. Whilst this isn’t always a conclusive way of assessing energy performance it can be useful to orientate your approach. It can highlight controllers that are in fault, misaligned times schedule and / or control settings which lead to excessive energy consumption.

Figure 3 – A buildings energy use will naturally drift unless it is continuously monitored and tuned.

BMS Energy Assessments

Assessment of the energy performance of an existing BMS and its controls can be undertaken using the industry British standard BS 15232. Whilst currently there is no profile within this standard for theatres the standard does allow for building particulars to be adjusted and an aggregated weighting can be applied between other relevant building types.  

An assessment under the standard can be used to reveal the inefficiencies and demonstrate the return on investment for upgrading your BMS.  Companies which provide this assessment have codified this standard and enhanced it with more inputs and calculations such as a forecasting energy savings to make it far easier to work with and demonstrate the potential value to a building and the return on investment.

Figure 4 – British standard BS EN 15232 can be used to understand the current energy and potential improvement of a BMS

Analytics and Diagnostics

New and emerging software tools which can be deployed to analyse the data generated by your BMS. These tools have been shown to be capable of realising energy savings of 15-40% in many existing buildings, as well as demonstrating improvements in comfort and improving the effectiveness of FM teams. This approach can identify significant energy, cost & carbon savings even in a well-managed building.

Questions to ask your BMS contractor:

    1. Are all controlled items working correctly? / Are valves sized correctly?
      It seems obvious but good control is usually inhibited by issues with the equipment. A sensor may only cost ~£10 to replace but if it is reading incorrectly it could cost £100’s possibly £1000’s in annual energy losses. The same applies for all controlled devices. For this reason, regular maintenance checks should be carried out including trending some of the device historical data.
    2. Does each system operate based on the demands of the space or system?
      As mentioned above this is the best way to ensure both efficiency and occupant comfort and can be achieved with simple programming within your BMS, including time scheduling, optimised start / stop, and demand monitoring through additional sensors.
    3. Are the cooling / heating systems integrated to stop simultaneous heating and cooling?
      If systems such as ventilation and heating aren’t interlocked correctly you could be using cooling when there is heating active or increasing ventilation fan speed to offset heating.
    4. Can inverters be installed on any plant to save energy?
      Inverters allow the speed of these items to be ramped up or down to save energy when the demand is low leading to energy savings. A return-on-investment calculation can be carried out to justify the costs of replacement.
    5. Is heat recovery being utilised effectively? Can it be implemented?
      Heat recovery from ventilation air has long been proven to result in significant energy savings in modern buildings. If your current plant is capable.
    6. Can free cooling be utilised?
      Energy can be saved using simple solutions like free cooling, if the outside air is below a certain temperature your AHU’s can be programmed to prioritise fresh air over enabling the cooling system. This can be especially useful in a packed theatre setting during winter months.
    7. Are systems assigned profiles allowing FM staff to switch between modes?
      The ideal system offers an easy-to-use interface which allows theatre staff to easily set and manage time schedules for the systems in use at different events. For example, separate time schedules for reception and foyers, café, administration / offices. In addition, different modes for each space i.e. during a production you may wish to control the rate of air changes based on CO2 levels in the room then during an intermission ramp up the fans to full speed to purge the air.
    8. Are the BMS graphics user friendly? Can they be improved?
      Many of these systems are viewed as complicated to use and the people responsible for the day-to-day operation can find it to be a chore if not set up correctly. The BMS is capable of intuitive user interfaces but this needs to be developed with the staff who are tasked with its use for it to be effective is operations.
    9. Is my BMS data being collected and analysed?
      BMS systems can collect a large amount of data which can be used to show the effectiveness of energy saving strategies. The BMS should be set up for logging of this data in a clear structured way where the data can be accessed by third party tools such as excel.
    10. Are the alarms generated by the system useful?
      Alarms can be a useful tool to identify performance issues in the building. Unfortunately, a poorly commissioned BMS will generate so many alarms that the user is overwhelmed and no longer views them. We recommend alarms are split into the following priority levels for ease of use. 
    • Level 1 – Critical – Automatic email to FM team
    • Level 2 – Medium priority – Visual alarm at PC (Red)
    • Level 3 – Low priority / Maintenance – Visual alarm at PC (Amber)
    • Level 4 – Note for logging