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Building Energy Management Systems (BEMS)

Managing the energy and other needs in buildings efficiently and intelligently can have considerable benefits. A building energy management system (BEMS) is a sophisticated method to monitor and control the building's energy needs. Next to energy management, the system can control and monitor a large variety of other aspects of the building regardless of whether it is residential or commercial. Examples of these functions are heating, ventilation and air conditioning (HVAC), lighting or security measures. BEMS technology can be applied in both residential and commercial buildings. The teaser image illustrates several of the different functions a BEMS can monitor and control. Video 1 shows the possibilities for a home energy management system.

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Video 1

Illustration of a home energy management system

Introduction top

Buildings’ energy consumption in the EU represents about 30% of total EU energy consumption and between 25 and 40% in OECD countries (OECD, 2003). Developing countries have a less efficient building stock where it is even more important to improve on building energy efficiency. In the EU-25, in 2003 total CO2 emissions amounted to 3.8 Gtonnes of which 479 Mtonnes were household emissions (12%) (EU, 2005). In the UK, the domestic sector represents about 28% of CO2 emissions and within that space heating is 53%, lighting and appliances 22%, and water heating 20%. Cooking contributes only 5% (UK DTI, 2006). Building Energy Management Systems (BEMS) control the functions of the building, allowing a smooth operation and efficient functioning of the building. This description elaborates on the BEMS technology.

The IEA (1997) uses the following description of a BEMS: "an electrical control and monitoring system that has the ability to control monitoring points and an operator terminal. The system can have atrributes from all facets of building control and management functions such as heating, ventilation and air conditioning (HVAC) to lighting, fire alarm system, security, maintenance and energy management. Another common description is that BEMSs are control systems for individual buildings or groups of buildings that use computers and distributed microprocessors for monitoring, data storage and communication (Levermore, 2000). Other terms frequently used for this technology are Building Management System (BMS) and Energy Management System (EMS).

As such, the BEMS technology is a broad concept of building control, and can have a variety of characteristics. However, the term BEMS is limited to use for sophisticated and advanced control systems (IEA, 1997). Therefore, while all buildings require and have some form of control system, BEMS technology is substantially different from previous control systems. The main point in which a BEMS differs from other control systems is the characteristic of communication: information of the processes and functions of the building can be received and controlles at a central, single operating unit. Therefore, decisions can be made based upon the received information (IEA, 1997). This is a critical aspect of a BEMS as it allows for optimization of the system. For instance, the central and single operating unit can receive information of temperature and building occupancy and can make the decision to lower the temperature in parts of the building that are not occupied. These decisions, therefore can increase energy efficiency. Figure 1 illustrates a possible BEMS configuration in which multiple buildings are connected to each other and are connected via the internet to a central operating unit to allow smooth cooperation among the buildings and increase efficiency. Increased cooperation among different buildings through the BEMS allows for additional increased energy efficiency, as functions of the different buildings can be coupled.

illustration © climatetechwiki.org

Figure 1: Possible configuration of a BEMS monitoring and controlling multiple buildings. Source: MOD, 2001.

Feasibility of technology and operational necessities top

Minimal components of a BEMS are: at least one principal operator position (or central station); a connection of the principal operator position to remote outstations also called controllers. The remote outstations can function independently or can be controlled by the principal operator position. The connection is most commonly provided through the internet.; the prinicpal operator position has an interface with the remote outstations and can control various functions of these outstations depending on the client's requirements (for instance, the system can be limited to energy, or can include other functions such as security). Figure 2 illustrates the main components of a BEMS control system.

illustration © climatetechwiki.org

Figure 2: Main components of a BEMS. Source: MOD, 2001.

The IEA (1997) identifies three main objectives of a BEMS: a) to provide a healthy and pleasant indoor climate; b) to ensure the safety of the user and the owner; anc c) to ensure economical running of the building in respect of both energy and personnel. As mentioned, a BEMS can monitor and control many factors within the building, or within a group of buildings. HVAC, lighting, domestic hot water, electrical supply/distribution, energy consumption, vertical transportation, and many others are examples of factors that can be controlled by a BEMS. Figure 3 illustrates a BEMS control system in operation.  .

illustration © climatetechwiki.org

Figure 3: Illustration of the functions of a BEMS. The figure shows a BEMS controller controlling the system based on a timer, external inputs such as temperature, and based on feedback from the system itself. Source: MOD, 2001

The IPCC (2007) notes that commissioning is a key stage in the implementation of the BEMS. Commissioning is the quality control process that begins with the early stages of design. In other words, it is essential to consider the BEMS technology and its required functions in the earliest stages of design to optimize the operation potential and consequently the energy savings of the technology. Basically, it is more practical to incorporate a BEMS into the design of the building compared to retrofit a BEMS into an existing building. For example, considering BEMS functions such as vertical transportation management into the design of the building, is more practical as all essential electronics and wiring can be incorporated into the design. Concluding, the IPCC (2007) notes that the commissioning process ensures clear design intent. Proper commission procedures can result in significant energy savinfs in the buildings operation (See e.g: Claridge et al., 2003). Table 1 illustrates some common functional capabilities of a BEMS. Once constructed, the other key aspect of an advanced control system such as the BEMS is the need to maintain operation efficiency (IPCC, 2007). 

Table 1. Several common functional capabilities of Building Energy Management Systems. Source: MOD, 2001
Optimisation of building and plant operations.
Provision of energy management information
Remote monitoring and control of services and functions of one or several buildings
Possibility of automatic control of services and functions. For instance, automatic switch-on, switch-off of appliances
Monitoring of building status and environmental conditions
Status of the technology and its future market potential top

Since their introduction in the 1960s, BEMSs control systems have become more and more sophisticated. Rapid developments in BEMS hardware, such as sensors and communication highways, and computer processing power have made BEMS a preferred management system (IPCC, 2007; MOD, 2001). Not only have the rapid developments significantly reduced costs of a sophisticated management system, the advances in technology have also increased the possibilities for a BEMS and therefore increased its potential. For instance, advances in information technology makes monitoring via the internet possible. In addition, it is now possible to monitor many buildings at the same time, and integrate functions of several buildings. For instance, heating and cooling requirements can be coupled among buildings resulting in higher energy savings beyond what the energy management optimization of an individual building can accomplish (IPCC, 2007).

The IPCC (2007) notes that the BEMS technology is at a stage at which the technology is economically feasible under specific conditions both for developing countries as well as developed countries. While the IPCC (2007) notes that the technology is expensive, the IPCC also considers the technology effective in both cold and warm climates and in developing and developed countries. In other words, the energy savings the technology is able to achieve, make up for its higher initial costs.

How the technology could contribute to socio-economic development and environmental protection top

When the technology is applied in commercial buildings or in industrial facilities, it can contribute to social development in two ways. By making the workplace safer, and healthier.

First, due to the improved fire, security and other emergency procedures that the technology offers, the workplace will be much safer. The technology can locate potential hazards within the workplace, notify emergency response teams, and inform personnel about the potential danger.

Second, the technology can monitor and control the environmental conditions in the buildings. This capacity of the technology has the potential to make the workplace healthier. Similar to potential fire or security hazards, the technology can monitor factors such as air quality and water quality and can react when value thresholds are crossed. For instance, the system can increase ventilation when the carbon monoxide levels in a facility increase above a level considered safe.

When the technology is applied in residential buildings, it informs residents about their energy consumption. Residents can draw upon this information to apply conservation measures. In addition, the technology can apply certain comfort settings for the residents. The information the technology provides to residents and the actions the technology can perform can therefore contribute to social development by increasing comfort and reducing energy consumption.

While the operation of the technology might be relatively straightforward due to a sohisticated interface, there is still a need for skilled operators of the technology. In addition, the installation of the technology requires training of the installation personnel.

The reduction in overall energy demand due to the use of BEMS results in an increased security of energy supply. In addition, high penetration rates of the technology reduces the need to build additional energy power stations and reduces the demand for import of energy.

One main characteristic of the technology is that it is capable to provide real-time and extensive data on energy consumption to the facility operator. This information can be used to increase energy efficiency of the overall system. Additionally, the BEMS itself improves energy efficiency by streamlining the operation of the machinery it monitors and controls. Improved energy efficiency leads to increased protection of the environment due to the reduced need for resources. For instance, improved efficiency in the electrical requirement of the building directly results in lower carbon dioxide and SO2 emissions when the electricity is provided by a coal powered facility.

For example, according to the IEA, lighting ranks among the major end-uses in global power demand. Lighting represents 650 mtoe of primary energy consumption and 2550 TWh of electricity consumption in 2005.This means that grid-based electric lighting is equivalent to 19% of total global electricity production. The statistics supplied by the IEA report (2006) shows that lighting requires as much electricity as is produced by all gas-fired generation or 1265 power plants. Of this amount the major consumption sector is commercial at 43% followed by residential at 31%, industrial (18%), and outdoor stationary sources at 8%.These statistics refer to on-grid sources. Through the resulting energy efficiency, an installed BEMS, would be able to lower the lighting requirements of the building in which it is installed. For instance, the BEMS can turn off lights in rooms where there are no occupants for a certain period of time. 

Table 2 summarises the main benefits and disadvantages to the BEMS technology.

Table 2. Common benefits from the use of a BEMS (IEA, no date; MOD, 2001)
AdvantagesDisadvantages
Increased energy efficiencyHigher initial costs for design and installation
Improved environmental conditionsOperation and maintenance costs might be higher compared to simpler management systems. However, the BEMS is also capable of reducing overall costs through improved energy efficiency and more efficient use of staff 
More efficient use of staffNeed for a skilled operator
Improved fire, security and other emergency proceduresrequires commitment at all levels throughout its operational life to maintain maximum effectiveness
Improved standards of plant/building functioning
Improved management of the building
Financial requirements and costs top

The IPCC (2007) concludes on the BEMS technology that it is as of yet unclear how much the technology can reduce energy usage and at what costs. Estimates provided on the technology energy savings differ considerably and therefore the technology requires more research and development to determine the financial requirements and costs. For example, Birtles and John (1984) estimate energy savings up to 27 % compared to no BEMS installed, while the IPCC notes estimates between 5 % and 40 % (IPCC, 2007). Additionally Roth et al. (2005) estimate energy savings up to 20 % in space heating energy consumption and 10 % for lighting and ventilation, combining to a 5 % to 20 % overall energy savings range.

Clean Development Mechanism market status top

Currently, no projects in the CDM portfolio are registered regarding the implementation of BEMS technology. However, certain methodologies can be identified which might be used for such a projects. Basically, BEMS technology is an energy efficiency measure, since it streamlines the use of appliances and services in a efficient manner. Since the technology does not generate energy it is therefore a demand side energy efficiency measure. Three CDM methodologies can be identified which might be useful for a project that wants to enter the CDM market.

First, Energy efficiency and fuel switching measures for buildings (Version 10 AMS-II.E.): This methodology comprises any energy efficiency and fuel switching measure implemented at a single building or group of similar buildings. The methodology concerns energy efficiency measures such as energy efficient appliances or an optimal arrangement of appliances. Therefore, when the other criteria of the methdology are met, BEMS technology might be suitable for this methodology. A possible example would be the installation of BEMS in a multiple building appartment complex or hotel. 

Second, a possible methdology to use for a potential CDM project might be Energy efficiency and renewable energy measures in new housing (AMS-III.AE Version 1): Among other technologies such as renewable energy generation, this methodology is also applicable for efficient building design practices. A project which introduces highly efficient BEMSs in new housing might be able to use this methodology to calculate the baseline and the estimated GHG reductions associated with the project.

Finally, Demand-side energy efficiency activities for specific technologies (Version 13 AMS-II.C.): This might be a suitable methodology for a BEMS CDM project. This methodology comprises activities that encourage the adoption of energy-efficient equipment/appliance (e.g., lamps, ballasts, refrigerators, motors, fans, air conditioners, pumping systems) at many sites. Therefore, the BEMS would have to incorporate multiple buildings and would have to be presented as one specific technology. 

While no BEMS related CDM projects are currently registered in the CDM portfolio, there are several CDM projects that relate to energy efficiency in households. The energy efficiency household projects are currently representing 0.1% of the CDM projects in the pipeline. Presently, there are six CDM projects registered in energy efficiency for households - four of them are based on lighting/insulation and two on improved stoves. The lighting/insulation projects are located in India and one in South Africa. The improved stove projects are based in Zambia and Nigeria. For an overview see Energy savings in buildings (Source: UNEP Risoe CDM/JI Pipeline Analysis and Database, February 1st 2010)

General information about how to apply CDM methodologies for GHG accounting can be found at: http://cdm.unfccc.int/methodologies/PAmethodologies/approved.html. 

References top

Claridge, D.E., M. Liu, and W.D. Turner, 2003: Commissioning of existing buildings - state of the technology and its implementation. Proceedings of the International Short Symposium on HVAC Commissioning. Kyoto, Japan.

Levermore, G.J., 2000: Building energy management systems; application to low-energy HVAC and natural ventilation control. Second edition. E&FN Spon, Taylor & Francis Group, London.

UK DTI, 2006. The Energy Challenge: Energy Review. Available at: http://www.dti.gov.uk/energy/review/page31995.html

EU, 2005. Energy and Transport Statistics 2005, EC. Brussels, Belgium. Available at: http://ec.europa.eu/dgs/energy_transport/figures/pocketbook/doc/2005/eti...

OECD, 2003. Environmentally sustainable buildings: Challenges and Policies. Available at: http://www.oecd.org/dataoecd/23/17/8887401.pdf

IEA, 2006. Light’s labours lost, OECD/International Energy Agency, Paris, France.

IEA, 1997. Technical Synthesis Report: A Summary of Annexes 16 & 17 Building Energy Management Systems. Energy Conservation in Buildings and Community Systems. Retrieved 2nd of November 2010 from:  http://www.ecbcs.org/annexes/annex17.htm

MOD, 2001. Building Energy Management Systems. Ministry of Defence: Defence Estates Design and Maintenance Guide 22

IPCC, 2007. Levine, M., D. Ürge-Vorsatz, K. Blok, L. Geng, D. Harvey, S. Lang, G. Levermore, A. Mongameli Mehlwana, S. Mirasgedis, A. Novikova, J. Rilling, H. Yoshino, 2007: Residential and commercial buildings. In Climate Change 2007: Mitigation. Contribution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [B. Metz, O.R. Davidson, P.R. Bosch, R. Dave, L.A. Meyer (eds)], Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.

Birtles, A.B. and R.W. John, 1984: Study of the performance of an energy management system. BSERT, London. Retrieved 2nd of November 2010 from: http://bse.sagepub.com/content/5/4/155.abstract

Roth, K., P. Llana, W. Detlef, and J. Brodrick, 2005: Automated whole building diagnostics. ASHRAE Journal, 47 (5). Retrieved 2nd of November 2010 from: http://www.ashrae.org/publications/page/424