Buildings account for about 40% of total energy consumption and contribute significantly to overall carbon emissions worldwide. Commercial buildings make up a large part of this. In Asia, economic growth and a shift towards service-based economies will expand the need for commercial buildings. This trend provides scope for substantial energy cost savings.
There are a number of different ways companies can reduce the energy consumption of their buildings. Buildings can be designed more efficiently at the planning stage, which whilst ideal is not always an option. Existing buildings can be retrofitted to improve energy efficiency. While this option may have a lasting and significant impact – and is absolutely necessary – it can also be capital intensive and disruptive. Another option is to use software to ensure buildings utilise energy efficiently, and that is where Building Energy Management Systems (BEMS) come into play.
What are ‘Building Energy Management Systems’?
BEMS are computerised systems that enable building operators to monitor and control building systems including heating, ventilation, air conditioning and lighting. They often require minimal capital investment and result in little site disruption. Of specific interest to this article, analytics software can help detect and address many sources of waste such as:
- HVAC (heating, ventilation, and air conditioning) equipment that is simultaneously heating and cooling a given space due to a failed sensor or other fault.
- Default configurations for all systems and pieces of equipment, meaning they run at suboptimal set points and are rarely updated after initial configuration.
- HVAC and lighting systems running at full capacity during periods when buildings are largely unoccupied.
To put energy management systems in context within the larger movement towards greater energy efficiency, there are generally speaking three approaches to making an efficient use of energy.
- Energy conservation: efforts that are made to reduce energy consumption through economy, elimination of waste, or more rational use.
- Energy recovery: the reuse of a byproduct of one system for use as input energy for another system.
- Energy substitution: the substitution of one energy source or fuel type for a more economical or less polluting energy source or fuel type.
Energy management for commercial buildings and offices mainly focuses in the area of energy conservation measures or programs, such as BEMS.
So What Can Be Measured by BEMS?
Older systems were used to simply control the HVAC functionalities, the foundation of all buildings’ energy use. Nowadays, we can monitor and control everything that relates to the building’s mechanical, electrical, and plumbing systems. These systems are composed of sensors which measure temperature, humidity, outside temperature, and much more. Aside from sensors, controllers manage the operation of the equipment monitored, including chillers, boilers, roof top units, fan coil units, heat pumps, variable air volume boxes, and air handling units.
With technology advances, it is now possible to monitor individual pieces of equipment through the placement of ‘sub-meters’, which are more refined than sensors. Sub-meters can be placed on equipment to measure the use of electricity, water, gas, or steam. Lighting monitoring and control is another area where significant energy savings can be realised. As technology improves, more complicated systems allow us to measure air quality at various points within a building, to use outside weather data for anticipating cooling or heating requirements, and even to include demand management in the system to better manage time of use.
Beyond simply monitoring, best practice dictates that a comprehensive energy management system should provide multiple additional capabilities. Primarily, it must gather data from every available source, whether old, new, standalone or integrated. It is also advisable to analyse single-variable data (or multi-variable data) to help identify problems and trends. This data can, in turn, be used to automate responses to different climatic situations. Additionally, the system should be able to provide different kind of alerts for different circumstances, such as energy overuse and mechanical or electrical failures. As such, sources of waste can be clearly identified and fixed, allowing for direct payback on the initial investment.
BEMS are integrated networks of meters, sensors and sub-meters, software, and hardware which provide the tools to add visibility into energy consumption and enable better green building energy management in commercial buildings.