Commercial and residential buildings consume about one-third of the world's energy. If current trends continue, by 2025, buildings worldwide will be the largest consumers of global energy, using as much power as the transportation and industrial sectors combined.  Recent studies have found that improving energy efficiency in buildings is the least costly way to reduce a large quantity of carbon emissions.  By changing energy management practices and instituting technologies that enhance energy efficiency, building owners and managers can reduce energy consumption by up to 35 percent.  Today, office buildings use about 16 percent more energy per square foot than those built 25 years ago.  The total amount of energy used by commercial buildings has risen significantly since the 1980s, reflecting growth in the total amount of office space available and a massive increase in energy consumption per square foot of space.

In an era of volatile energy prices and increasing concern over climate change, the need for the innovative application of technology has become highly acute. Energy costs represent about 30 percent of an office building's total operating costs, providing enormous opportunity for building owners not only to reduce operating costs but also to make significant improvements in the overall environmental performance of their properties.  In order to achieve breakthrough improvements in energy efficiency, it is evident that investments in building automation systems (BAS) and building energy management systems (BEMS) are required.

Buildings with integrated intelligent building technologies can save thousands and even millions of dollars in energy by delivering heating, cooling and lighting more efficiently.  Intelligent buildings are increasingly using solar walls to capture energy from the sun, ventilation systems to recapture and reuse heat, insulation strategies that enable better climate control, high-efficiency lighting systems that enhance illumination with less electricity and automatic systems that control building services based on activity. It is becoming increasingly common in the United States for more advanced, intelligent and green buildings to routinely reduce energy usage by as much as 50 percent over conventional buildings, with the most efficient buildings currently performing up to 70 percent better than conventional properties.  Such green building technologies include building automation systems and building energy management systems.

For this reason, the Continental Automated Buildings Association (www.caba.org) has moved to reduce the environmental impact of buildings by promoting such technologies and undertaking research that documents its benefits.  CABA is a 20-year-old international industry association, composed of about 350 corporate members, dedicated to the advancement of intelligent home and intelligent building technologies.

Building automation systems and building energy management systems are designed to provide centralized oversight and remote control over heating, ventilation and air conditioning (HVAC) systems, lighting and other building systems.  In simple terms, a BAS is a programmed, computerized network of electronic devices that are employed for control and monitoring of systems.  It primarily aims at optimizing the performance, start-up and maintenance of systems and greatly increases the interaction of mechanical subsystems in a building.  BEMS basically perform the same functions as a BAS but vary more in capability and functionality.  Both BAS and BEMS integrate all aspects of a system and take it right up to the user-interface level from where the operational activities in the various subsystems can be monitored.

It is at the bus level, where data is taken from a device to the controller and then taken on the network, that there exists the option of choosing various building automation communication standards.  Standards aim at optimizing the performance of building systems and increase the interaction of mechanical subsystems in the building.  This leads to improved occupant comfort, optimum energy consumption and cost-effective building operation.  All these can be done remotely or from a centralized system with a minimum “human-in-loop” factor.  The lack of the human-in-loop ensures that chances of human error are greatly reduced.

BAS and BEMS are primarily used to improve energy efficiency by monitoring the temperature inside and outside buildings and controlling boilers and coolers.  Essentially, they aim at optimizing energy consumption by employing a control strategy that integrates various energy-consuming units.  Energy management systems help building owners and operators reduce energy costs, while maintaining occupancy comfort.

A typical BAS/BEMS carries out the following functions: the optimization of start/stop of systems; the scheduling of maintenance; predictive fault detection; alarm generation and preventive actions minimizing damage in the case of emergency; and the constant monitoring of systems to detect abnormal operating conditions, in order to take corrective action and bring the system back to normalcy.

BAS and BEMS vary in capability and functionality, but typically consist of sensors, controllers, actuators and software.  Depending on whether a human-in-loop factor is involved, decisions are taken manually or by utilizing embedded intelligence such as decision-making algorithms.

Building automation systems and building energy management systems were mainly introduced in the mid-1980s to optimize the operation of HVAC equipment through computerized monitoring and control of HVAC equipment in large commercial buildings.  The technologies have continuously evolved from the first systems that performed monitoring and simple control via bulky mini-computer based workstations to the latest distributed networks with powerful workstations, wireless Internet-based components and expanded self-tuning control algorithms.  Despite the level of evolution, the performance of BAS historically was drastically challenged over the next two decades, often falling short of the overall potential to improve comfort while reducing energy use.  Most of the problems stem from the difficulties in operating the BAS once they have been installed and commissioned.  Building owners and operators often did not have the necessary dedicated personnel to solve problems.  As a result, there was a tendency to solve building comfort and operational problem through simple triage by disabling BAS control loops or disabling equipment schedules.  The next generation of BAS and BEMS systems however promise to solve these common problems by utilizing embedded intelligence such as decision-making algorithms. The new algorithms perform automated data analysis to identify problems and suggest solutions using built-in expert systems.  The new systems are designed to automatically perform building commissioning on an ongoing basis, but without the time, disruption and cost of a commissioning project.

As many know, building commissioning is the process of ensuring that all building subsystems, including HVAC, plumbing, electrical, fire and life safety, and building security are operating as originally designed by architects and engineers.

Building commissioning is a quality assurance process. Normally, a commissioning firm is involved from project initiation to project completion.  While the service methodology can vary from firm to firm and project to project, the basic formula for successful building commissioning involves a synergy of pre-construction review of design documents for compliance with the owner's performance requirements, periodic site observations during the construction phase, and systems performance testing as the project nears completion. While the practice of building commissioning is still fairly new in the construction industry, it has quickly become common practice as savvy building owners and developers seek substantial returns on their properties.   The ultimate goal for a commissioning provider is therefore to deliver for the owner a project that is on schedule and under budget, and a building with fully operational and optimized systems on the first day of operation.

A key concern however is how to maintain commissioning on an “on-going” go-forward basis, once the building is in place or retrofitted.  A building can always be re-commissioned, but BAS and BEMS technology is emerging that will allow property managers to deploy control strategies to contain costs and create and enhance operational efficiencies for approximately the same cost.

Some of the common control strategies employed include:

• Scheduling: It aims at optimizing equipment performance by automatically switching it on or off depending on a present temperature.  It leads to effective energy saving.
• Resets: A substantial amount of energy is wasted when equipment works at a greater capacity than required.  Resets reduce the wastage of energy by resetting operating parameters.  Examples of building control parameters that can be reset include supply-air and discharge-air temperatures for multi-zone HVAC systems, and heating-water supply temperature.
• Demand limiting: Load shedding or demand-limiting is used to limit energy consumption by limiting the ability of equipment to load again once it has reached a preset point.  Another way to minimize peak demand is to program time delays between the start-up of major pieces of electrical load equipment so that several pieces of equipment do not start simultaneously.
• Diagnostics: It is important to analyze the information associated with operating equipment.  Online performance parameters give a real picture of operating performance of the device.  Parameters such as temperature, flows, pressures, and actuator positions can be used to monitor information.  This has its effects in saving energy as that data will help to determine whether equipment is operating incorrectly or inefficiently and to troubleshoot problems.  A thorough job of building diagnostics typically requires the building operator to monitor more points than the minimum number needed to simply control a building.  This is provided by BAS and BEMS in the form of a continuous building diagnostics program.

A continuous building diagnostics program is designed to monitor any troubles that might arise through smart decision-making algorithms.  The program then allows a property owner or manager to make more informed decisions in order to find appropriate solutions to identified problems that might arise and thereby save money.  It has been estimated that if a BAS or BEMS is incorrectly configured or not calibrated, an estimated 20 percent of a building’s energy can be wasted.  A newer BAS or BEMS installation however can provide energy savings that are similar to what can be achieved through recommissioning, with typical savings ranging from five to 20 percent.  BAS/BEMS systems with smart algorithms should therefore be considered for new commercial building construction projects.

For more information about the benefits of utilizing intelligent, green building technologies to lower overall building costs, consider downloading CABA's comprehensive report on “bright” green buildings. The report features several real-world examples that show how property companies around the world have employed advances in green building and networking technologies to increase profits, lower costs, and help the environment. The report is available for free online at: http://www.caba.org/brightgreen.

CABA recently also released a comprehensive North American market sizing study, examining intelligent and integrated building technology. The study provides an in-depth analysis of the growing North American markets for integrated and converged intelligent building control systems ranging from environmental control technologies, to fire detection, to security to lighting systems to IT convergence. More information about that report is available at: http://www.caba.org/market-size-2010

Rawlson O'Neil King is CABA's Communications Director. He has past experience as a trade journalist, high-tech industry analyst and public relations practitioner. Mr. King holds both a Bachelor of Journalism and a Master of Arts degree in Mass Communication from Carleton University in Ottawa, Canada.