Problem perceivedThe building has 22 rooftop electric cooling/natural gas heating units that were originally installed by the developer as part of the core shell. Each of these constant air volume, single-zone units was equipped with thermostat controls. In addition, Northrop Grumman added three 20-ton computer room air conditioning (CRAC) units to cool critical equipment in this 48,000-sq-ft, single-story, flat-roof building.
Performance Building Services (PBS), a Denver mechanical engineering and contracting firm, provides planned maintenance and emergency repair services for the facility's HVAC. Candace Morales, PBS account manager, cautioned Northrop Grumman that, with the original thermostatic control arrangements, some part of the HVAC system could go down, jeopardizing data storage and damaging costly electronics before anyone knew about it. She suggested an integrated control system to monitor and operate this critical HVAC equipment.
During discussions with Northrop Grumman's JeannMarie Paradise, site manager, and facility manager David Chansilp, Morales learned that many of the 110 employees in the building periodically felt the need to control the thermostat in their work areas, leading to constant squabbles and inefficient operation of the HVAC equipment.
Chansilp expressed a desire for a system that would eliminate the thermostats and enable temperatures to be set from a single location, while at the same time providing equipment monitoring and equipment failure alarms. "When you have a situation like that," said Chansilp, "it forces you to go to an area to determine what the temperature is, what the environment is, and make your adjustments. Then, you have to move on to the next area to determine what to do, whether you must increase or decrease your setpoints. That's a big pain."
Simple SolutionAlthough there are any number of integrated monitoring and control systems for large buildings with central heating and cooling plants and zoned systems, most smaller buildings with self-contained equipment like rooftop air conditioning, heat pumps, or fancoils "make do" with thermostatic control.
To assist in preparing a proposal for Northrop Grumman, Morales turned to Setpoint Technology Center, a Novar Technology Center (NTC) and master distributor of HVAC equipment. One of the most significant concerns addressed in the proposal was the need to minimize disruption of this 24/7 occupied space during changeover from the existing thermostatic control system.
Working closely with Setpoint's Neil Gifford, account manager, Morales proposed a Novar Controls IQ-SBS™ integrated control system to cover the HVAC system and to provide monitoring and remote alarming for the critical computer room A/C units that can't afford downtime. The IQ-SBS system integrates dedicated control modules for each HVAC and CRAC unit via a LAN. The system includes a color touchscreen local control interface (LCI) for local monitoring and setpoint adjustments and an Internet data server that provides e-mail alarm notification and Web browser access for system monitoring and diagnostics from anywhere in the world.
Each IQ-SBS HVAC controller is responsible for an electric cooling/natural gas heating unit, including monitoring and controlling the supply fan, monitoring the discharge temperature, and monitoring the space temperature. There is also a controller for each CRAC unit. While the controllers communicate over a network, the units are independently - and effectively - "zoning" the building.
Since PBS is responsible for planned maintenance and 24/7 emergency service, the company needs to know about any alarms in the building, even before Northrop Grumman does. With the Web browser access, the PBS technician on call receives an e-mail notifying them of a temperature alarm or disenabled unit. They are able to respond, either by getting on the Web and accessing the system or dispatching a technician to the site.