Central Monitoring and Control Systems

• Introduction
• CMCS/DDC Development
• CMCS/DDC Systems and Software
• CMCS/DDC System Management
• CMCS/DDC Networking and Intelligent Buildings
• Appendix A

Introduction

This chapter will discuss central monitoring systems and direct digital control (CMCS/DDC) for college and university facilities. If properly installed, operated, and maintained, CMCS/DDC systems can greatly improve and maintain levels of comfort and greatly reduce overall building energy consumption and waste. In addition, these systems can reduce time spent on routine inspections and troubleshooting, speed the accuracy of the service response, and greatly improve the overall operation of campus buildings.

CMCS/DDC systems cover a considerable range of technical and managerial issues. They bring high demands for quality design, installation, operation, and repair. CMCS/DDC systems have become the primary tool for operating many campus building systems. Managing them has become one of the most challenging tasks in any facilities management department. College and university facilities generally have larger and more complex HVAC and building support systems than average institutional or commercial buildings. These systems are used by people who are technologically sophisticated, who have very high standards, and who are quite vocal about their needs and expectations. Because of this, campuses can be tough environments for facilities managers who are inexperienced or mechanics who are poorly trained. In addition, as building systems advance in sophistication and complexity, there are more chances for error. Systems currently are sized and built to computer precision and therefore are less tolerant of misapplication, operating ignorance, and neglect. In addition, these systems now serve a customer who has grown to expect more quality especially at the workplace. Facilities managers know how easily even a brief mechanical or electrical problem (e.g., an air handler loss on a warm day, a blown fuse in a laboratory or to a computer) can swiftly wipe out any memory of the many days of trouble-free operation that preceded the failure.

With complexity of the current building technology and the growing intolerance of building and equipment malfunctions, it is imperative that the quality of design, installation, and training for the operation and maintenance of all building systems be more rigorous than ever before. None, however, is as critical as the CMCS/DDC.

Fortunately, despite their increased sophistication, steady improvements in CMCS/DDCs have made them much more reliable and easier to use in many ways. Many provide improved equipment condition monitoring features such as equipment diagnostics, trend graphing, performance reporting in third-party software such as Microsoft Excel, and so forth. Many systems provide considerable levels of self-diagnostics for troubleshooting the CMCS/DDC itself such as controller hardware, software, and CMCS/DDC communications networks.

As an example of improvements in recent years, most new CMCS installations now provide temperatures and air volumes from a digital controller located in almost every room served by the HVAC system. Comfort and room occupancy can be easily monitored directly from a computer-aided design (CAD) based floor plan showing these values in real time. This information gives console operators and system technicians and mechanics total system monitoring and troubleshooting down to the individual room terminal devices (e.g., reheat and radiation values and VAV box dampers). If necessary, features can be enabled and changes can be made to current thermostat set points, occupant adjustment ranges, occupant override, and time schedules from the central operator's console or from the room itself. Advanced systems are being installed that sense occupancy and turn on lights as well as the room's terminal unit and the necessary central equipment. Sometimes, occupancy sensors restart equipment only outside of prescheduled equipment run times.

With total DDC networks to the room terminal controller level, and the sensor-actuator level, advanced programming also can be installed to optimize the entire HVAC system like never before. By optimally readjusting system-wide set points for supplying air temperature, fan and duct static pressure, and volume to the exact requirements of all of the rooms, a new level of efficiency in HVAC can be achieved.

Most new CMCS/DDC systems come with built-in self-calibration loop tuning and continuous self-diagnostics. In addition, most new systems can integrate building access and security control, fire and smoke management, laboratory environmental pressurization, and fume hood controls.

Advanced systems such as these take careful planning, excellent design, and considerable attention to detail during installation and acceptance if they are to work reliably and provide the comfort and efficiencies described. This chapter will serve as a guide through the development of a new CMCS system by providing explanations and advice in planning, developing purchase justification if necessary, writing requests for information and proposals, and preparing for the new system.