Pneumatics (Almost) Out, Ddc In At MSU
Several years ago, the COT decided it was necessary to replace an outdated hvac system and install a fully automated system in order to manage the school’s control devices. The college also wanted to monitor and manage its energy usage more effectively and be able to access the system via the Internet.
In April 2000, Electro Controls, a systems integrator also located in Billings, bid on the project and was awarded the contract. The original contract called for integrating all of the LonWorks devices and allowing the maintenance staff to access and control those devices at anytime, from anywhere.
The college had never really considered the integration of the four rooftop hvac units, which have BACnet controls. But as the project headed toward the finish line, Electro Controls was able to integrate both systems easily.
NEW SYSTEM INThe college definitely needed some help saving energy. Its air handlers ran all the time, 24 hrs a day, seven days a week. The chiller was the only equipment that was locked-out pneumatically.
One of the two boilers was retrofitted from steam to hot water, and additional pumps had been installed, but there was no real control over the boilers. In fact, as soon as the temperature dropped below a certain outside air setpoint, the boilers ran, even on weekends.
The college was also looking for the new communication aspects of a ddc system, so they would know what was going on.
To address all those needs, the retrofit was divided into two phases. The first phase called for changing out some equipment in the north building on the COT campus, which primarily consists of technical classrooms and shops for auto body, diesel mechanics, auto mechanics, and welding. These shops contain large overhead garages, and some classes are held down the corridor.
The second phase concerned the south building on the COT campus, which had an existing system consisting of a large air handler that was pneumatically controlled. “What we did first was put in Lon-based controllers on the air handler and on all the vav boxes. All the existing pneumatic actuation could stay, so it was a hybrid job,” says Jon Fry, general manager, Electro Controls. A variable-frequency drive was later added to the air handler.
The building also had four rooftop units, three of which were vav air handler types and a single-zone rooftop unit. Electro Controls basically bid to supply those rooftops with manufacturers’ controls, which would have Ethernet capabilities and be a BACnet or a Lon type of control system.
The result is that MSU has a Lon-based system with Tridium’s “Niagara Framework” operating it on the front end. A Trane “Summit” system runs the air handlers; the Tridium system talks to Summit through a BACnet interface. Of the Lon-based system, there are 108 nodes from four manufacturers of Lon products.
BIG AND SMALL CHANGESWhen Electro Controls was awarded the contract, one of the parts of the job concerned installing radiant heat panels in the overhead garages. The specification called for a programmable thermostat to control the 18 or so radiant heaters and unit heaters, but the company decided on a substitution instead.
“We found a Lon-based thermostat made by Smart Controls which allowed those radiant heat panels to be part of the system, so building operators could see their temperatures, do their setpoints, do all their scheduling instead of having to walk through and do it,” says Fry.
“We had a little more labor running Lon trunks out to those thermostats, but it was pretty much a wash. We decided to bring everything into one place on the system.”
The COT also wanted to have a facilities management workstation that could talk to all the building systems. Electro Controls bid on that proposal as well, but was unsuccessful. Originally Electro Controls had bid that project as flat Lon, and was going to put in some Echelon-type routers to handle all the energy management functions at a central workstation.
Near the end of the job, the maintenance supervisor at COT, Ray Carl, was not convinced that the systems could talk to one another. Fry then thought of Tridium’s framework, which has both Lon and BACnet capabilities right out of the box, and he wondered what it would take to bring in that system.
“The Tridium framework has a BACnet utility, and I was able to bring in all the points and create all the objects and all the programming for me in less than one minute. From there, we drew up some graphics in the next day or so. Basically we took two systems that were totally separate from each other and integrated them all into one framework — sharing information from the vav’s that we were controlling to the vav air handlers, being able to schedule them all the same way, being able to change setpoints and command points off and on. Ray was tickled pink,” says Fry.
The result is that the COT has a system that saves energy and has other capabilities, such as Internet accessibility. A competitor had stated that Electro Controls wouldn’t be able to do the job, so the company was under scrutiny during the entire project.
“The first day I brought the front end on line and showed Ray his air handler and all the things about how he could change the settings, all doubts went away. And he can hop on any computer to check things out or troubleshoot a problem,” says Fry. “We were able to integrate not only the Lon system but also the BACnet system.”
As for energy savings, the college experienced a 20% reduction in its energy consumption last winter.