Future of Building Automation Systems

  Future of Building Automation Systems

In addition to the needs of today we are seeing new concerns over global warming, and long term supply of fossil fuels. This combined with the pressure of an aging electrical generation infrastructure, is putting the onus on new programs for high efficiency and even “zero energy” commercial buildings. These programs will have an intelligent, integrated system design as one of their core elements.

In view of the fact that more and more supervisory computer systems are being installed in buildings, one can expect that the demand for integrated systems will rise even more. Further developments in microelectronics will result in even the further distribution of functionality. Control components entering the market, especially sensors and actuators, will be increasingly intelligent and will be designed to become part of larger intelligent systems. Their native communication will be based on open protocols. As control equipment will become more and more commodity its functionality will become more and more standardized and real plug and play capability will become a reality.

Control products will become more and more internet aware, so that supervision and maintenance maybe done from any location in the world. Eventually this development will cause the DDC controller or substation to disappear as its functionality will be taken over by the more intelligent sensors and actuators. The network will become the heart of the DDC control systems of the future.

In General the BAS technology is advancing to offer the following new functionality in the future.

-          Increased multi-system operability

The BAS industry is currently doing extensive research into developing and testing web browser interfaces. BAS designers have recently begun using them for increased multisystem operability and to improve building operators' access to the system. ASHRAE has added web services to BACnet in order to standardize how BACnet systems run web services to exchange data with other computing applications over a network. One initial use of web services is to enable sophisticated functionality such as creating "virtual thermostats" that give users control over the temperature in their own area. Testing is also under way on using web services to integrate BASs with utility systems, which would implement control strategies based on real-time pricing.

-          Lower installation costs with wireless devices

Wireless networks offer future potential cost reductions that are dramatic for the primary controller architecture, because the cost of wiring and conduit is a major budget item. Although they are still relatively expensive, wireless devices are becoming more affordable and reliable with the development of new manufacturing techniques. Also, a new open communication standard, the ZigBee standard, is making possible reliable, low-power, wirelessly networked products that provide much more flexibility than proprietary wireless systems. However, because buildings typically require a large number of sensor nodes (which drives up the cost), designing wireless systems is currently a balance of functionality and cost-effectiveness, with designers cutting costs by removing functions and limiting compatibility with external systems. As costs continue to come down, wireless networks will likely become much more prevalent in BASs.

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Enhanced Automation (EA) and Energy Information Systems

  Enhanced Automation (EA) and Energy Information Systems

Enhanced Automation (EA) increases the capability of your existing energy management or energy billing systems to better manage both the energy use in buildings and the comfort of the building occupants.

Enhanced automation can be accomplished through the installation of control or monitoring EA technologies or simply reprogramming and/or fine tuning your existing equipment control systems. EA systems can manage a variety of building systems, including heating, ventilation and air conditioning (HVAC), lighting, and other systems such as security and building access.

Automation enhancements include adding a new Energy Information System (EIS) or Energy Management System (EMS), as well as re-programming or expanding the network of sensors and control devices on an existing EMS.

In its simplest form, automation consists of a programmable time clock for HVAC and lighting systems. Enhanced automation includes complex networks of sensors and controls for multiple building energy systems. Often EA can be accomplished by simply reprogramming existing systems to maximize their potential.

A comprehensive EA system centralizes control and monitoring of all components within an energy management system (EMS) or an energy information system (EIS) that can also be accessed remotely for building operation control. Integrated systems can receive and automatically respond to energy price signals as well.

Figure (1) shows the individual components of a comprehensive EA system with a combined EMS/EIS. Individual system components can be implemented independently or in a staged, modular approach. Each additional component utilized in building controls offers increased economic and control benefits.

EMS and EIS systems can be integrated, overlap, or be kept as separate systems that communicate with each other and the monitoring and control points in the building. Other building functions can be incorporated into an EMS/EIS system including: security/access, elevator and escalator operation, water usage, and major plug loads (such as computers).

FIG (1)

EIS technologies are designed to provide building information on system-wide performance and energy use. They also enable participation in demand-responsive programs, including load-scheduled, demand-shifted or curtailment-based programs. In many cases, the EIS can provide cost and energy savings expected from program participation at different levels. EIS technologies disseminate information in three levels:

Notification-based systems gather information from the utility meter and signals from external sources. External signals include real-time pricing, electric supply alerts, demand response events, and other information, such as weather forecasts. Notification systems also allow for limited two-way communication, such as accepting a demand response request or providing a bid for demand reduction.

Analysis-based systems provide services, such as data analysis of energy usage and cost, forecasting, and bill consolidation. As with notification-based systems; these systems can provide either periodic or real-time data as needed.

Response systems include the functions of analysis-based systems and typically integrate one or more EMS with two-way communication.

The response relies on the information received from outside signals. The EMS then adjust load through operator-driven or automated programming.

EMS technologies incorporate a wide range of services. EMS are information and control systems that, through a series of sensors, communications, and controllers, allow a building operator to optimize operation of end-use equipment within their facility, often from a centralized operations panel. Direct digital control (DDC) is the most common EMS technology currently being installed. DDC systems consist of microprocessor-based controllers networked to devices that monitor (sense information) or control operations of facility systems and equipment.

Lighting technologies include lighting control and monitoring strategies. These technologies can operate independently or be linked to an EMS/EIS system. Examples include: on/off and reduced lighting controls such bi-level lighting, dimming controls, and occupancy sensors, as well as centralized control strategies that can be programmed into the EMS.

HVAC technologies are automated through control and monitoring strategies usually connected to an EMS. If connected to an EIS, the EMS can automatically adjust the HVAC system to respond to price signals received from the utility. Similar to lighting, these technologies can also operate independently. HVAC technologies include measures for ventilation, temperature control, time control, chillers, thermal storage and air distribution.

 

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Control System Types for Building Automation

        Control System Types for Building Automation

Building control systems largely fall into one of two categories:

         Direct Digital Controls (DDC)

 

 

These systems use electronic signals via computer to process data for direct system control. Although most BASs use electronically powered actuators, today a small proportion of BASs in older buildings use DDCs with outdated pneumatically powered actuators, which use compressed air to control valves and dampers.

        Stand-Alone Controls

Buildings without BASs typically rely on the controls built into individual pieces of large equipment, such as packaged rooftop units and chillers, to maintain comfort conditions and manage energy consumption.

Some of these stand-alone controllers are quite sophisticated and are capable of implementing many of the control strategies described above. However, they fall short of being able to appropriately manage the entire building unless they are "tied-in" to the BAS using a common communications protocol.

        Advantages of DDC Systems Over Stand Alone Systems

In general, full DDC systems offer many more benefits over stand-alone systems that are not tied in to the BAS.

-          Better building feedback

DDC systems typically provide much more information feedback from the building than stand-alone systems. For example, a DDC system could reset variable air volume (VAV) static pressure by scanning all the VAV damper positions and gradually changing the static pressure until only one damper was completely open. At that level of static pressure the fan draws the least amount of power required to distribute sufficient air to all the boxes. Stand-alone controllers usually cannot reset static pressure in this manner, because they typically have no way of sensing VAV damper position.

-          Centralized control  

DDC systems allow for building control and information flows to be centralized at a single location (whereas stand-alone systems don't have the feedback mechanisms necessary for this capability). As a result, operators can readily view and control all building systems from a single computer terminal instead of having to keep track of a variety of different control locations throughout the building.

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Advantages of Building Automation Systems

   Advantages of Building Automation Systems

Building automation systems have become powerful and effective tools and are becoming more and more popular. They help resolve problems quickly, reduce energy use, improve system performance, increase occupant comfort and safety, and help manage maintenance costs. Savings produced by the systems can pay for installation in as little as three to five years. The main advantages of an automated system are discussed below.

         Transparency

Which allow more controllability on the building without need of any new installations, only some intelligent devices are connected with the electromechanical equipments.

         Multi-Functionality

The system can perform many functions at the same time such as: switching, measuring, monitoring, and recording ...etc. without additional cost.

         Flexibility and Extendibility

Changes in programming of device can be allowed and more devices can also be added on the existing system.Wall switches, occupancy sensors, and load controllers have long useful life. However the specific configuration of sensors and loads are likely evolve over time.

Ideally configuration does not need to occur when devices are physically installed. Configuration can occur at any time and be readily changed as needs evolve. A room entry switch or sensor can be reconfigured later to implement functions not envisioned when the sensor was initially installed. 

         Economic Return

A building Automation system may as well be called an energy management system that is because is controls energy consuming equipment in a building to make is operate more efficiently while maintaining a comfortable environment. As a result it could save a lot of wasted energy which in return saves a lot of money.

         Energy Efficient

The automation system represents a parasitic energy load placing great value on maximizing functionality while reducing energy consumption of the automation system itself.

         Open Specifications

Open standards assure healthy competition and compatibility among multiple players reducing risk of obsolete or orphaned equipment.

Open stands encourage niche players to market specialty devices increasing the likelihood special needs can be met with off the shelf equipment.

  

         ZigBee Advantage

New wireless command and control technologies such as ZigBee IEEEE 802.15 are well suited to automation systems. The radios are optimized for reliable short burst low latency traffic. ZigBee radios have very low power consumption making them ideal for battery power wireless sensors. Battery life in years is possible.

Radio based networks dramatically reduce cost, especially in retrofit situations. Using a radio-based system eliminates the functional distinction between fixed location and portable devices. This minimizes development cost and maximizes reusability. The same basic radio and firmware can be used in a fixed location light switch and hand held A/V remote control.

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