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Angela Reid is a Director and Environmental Engineer of TÜV SÜD’s UK Real Estate division, an international building services engineering consultancy, specialising in sustainable MEP (mechanical, electrical and public health), BIM (Building Information Modelling), lighting design, and vertical transportation.
According to the World Business Council for Sustainable Development (WBCSD), reducing energy use in buildings is not only a climate change imperative, but it also represents a sizable business opportunity. Alongside this, international laws and directives relating to energy use are becoming more stringent. And, as end-users become increasingly conscious of the role that they play in global energy consumption, there is a growing demand for greener buildings amongst tenants. Such buildings also provide more effective control of the internal comfort conditions, delivering other positive impacts such as increased employee productivity and wellbeing. Building owners and operators must therefore move beyond simple energy conservation efforts, towards practices that increases the efficiency of their energy usage and deliver utility savings.
Organisation-wide energy management systems offer the potential to substantially reduce consumption and increase efficiency, whilst improving productivity and driving profitability. More than just a tool for conserving energy, Building Energy Management Systems (BEMS) are therefore being used increasingly as a strategy to reduce both energy consumption and overall operational costs. The industry is now also focusing on performance in use, by seeking ways to close the gap between regulated/predicted/designed energy consumption and what is actually been consumed.
BEMS is a computer-based control system, consisting of a central user interface and a network of components, which include hardware (valves/dampers/actuators), controllers, meters and sensors. These communicate electronically to monitor, measure and control the active systems (heating, ventilation, cooling, hot water and lighting), as well as building performance. This centralised management system gives operators a real-time understanding of how the building is performing and plenty of options for improving energy efficiency. For example, they can set times when plant switches on and off, set temperatures within specific spaces, meter energy consumption, and receive alarms when failures occur.
BEMS delivers a direct benefit to the building operator in terms of reduced utility payments, as energy consumption can be monitored and understood, and therefore controlled effectively to make savings. For example, sub-meters can be used to troubleshoot and pinpoint problems, by detailing the consumption of each individual active system and identifying any high-end consumers. As part of the troubleshooting strategy, buildings can be divided into floors or departments, which allows for sub tenants to be charged accurately for their energy consumption. As the BEMS records historical energy data, this can also be used for longer term comparison and benchmarking purposes.
The optimal level of energy efficiency can be achieved by the BEMS continuously maintaining the correct balance between operating requirements, external and internal environmental conditions, and energy usage. To optimise these benefits, there should usually be a trained building manager who is the single point of responsibility for the operation and upkeep of the BEMS.
The BEMS will allow the building manager to more effectively respond to HVAC-related complaints, as well as optimise energy consumption and thermal comfort conditions. As remote monitoring and control is possible there is also potential for facilities management savings, as potentially fewer operatives will be required to run the building. Indeed, numerous councils are employing offsite third-party companies to test whether systems are needed, both inside and outside known hours of occupancy, and switch plant off to save energy when it is not required.
While BEMS delivers building operators precise control, and enables them to realise valuable cost savings, it is important to remember that it cannot compensate for an inherently inefficient building design. One size doesn’t fit all, so if the design is poor then no amount of monitoring and control will result in significant energy savings. The same would also apply to thermal comfort, if this hasn’t been integrated into the original design.
The BEMS specification should therefore be well thought out at the design stage, and a clear functional specification created, which considers all the necessary requirements. This will ensure that there is capacity within the system to respond to all functionality, so that energy consumption can be effectively monitored and understood. For example, you don’t want to get to the commissioning stage and realise that there aren’t enough points to connect all of the meters that will be used to monitor energy consumption.
To benefit fully from BEMS, there must first be some level of investment to employ and train suitable staff to operate it. At the point of system commissioning, a clear and concise handover to the building manager and team must also be actioned. As these systems are complex, they may require further training, or a level of ongoing support, to give staff the confidence and understanding that is necessary to optimise use and maximise the benefits which BEMS delivers. The user-friendly nature of the system interface is also a very important consideration from the start – what will the programme look like and can users easily navigate through it?
The ability for the BEMS to integrate with other hardware and software should also be considered. Closed protocol systems must therefore be carefully considered and potentially avoided, so that the end-user is not tied to a single manufacturer and the system’s components can communicate freely. This would be especially important on a campus where multiple buildings may be grouped, or where remote access is desired. The ability to interrogate local outstations should also be considered, to allow flexibility and local checking of functional integrity following maintenance action when out working within the building plantrooms.
With the WBCSD estimating that buildings consume more than one-third of total end-use energy, and cause a fifth of total greenhouse gas emissions, there a global drive for improved energy-efficiency. At the same time, building price premiums, regulations and government incentives are spurring on the development of more sustainable buildings. The perception of energy-efficient buildings as a business opportunity is therefore growing.
While the implementation of a BEMS may require investment, it does deliver significant long-term payback by ensuring that a building operates at maximum levels of efficiency, removing uneconomical energy usage and associated costs. Quite simply, if you are not monitoring energy consumption, you cannot manage it effectively, with the result being spiralling building operating costs and decreased occupant comfort.
The Road to Effective Building Energy Usage
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