Success in HVAC Systems

The Contemporary Controls Skorpion Switch Solves Network Communication in the System's Controllers

One of the many published documents by the EPA, IAQ Tools for Schools clearly states that "Good indoor air quality (IAQ) contributes to a favorable learning environment for students, productivity for teachers and staff, and a sense of comfort, health, and well-being." A school that has a properly commissioned and maintained HVAC system significantly eliminates any problems with indoor air quality. This is the case for Berkeley Community College in California with an enrollment of more than 4,000 students.

School officials contracted Emcor Service, Mesa Energy Systems (Hayward) headquartered in Irvine, California to install the new HVAC Delta Control system in this six-floor structure. Jonathan Garcia, Project Coordinator with Mesa, said the Delta System is highly reliable and would meet the college's energy conservation requirements and keep maintenance and operating expenses within the budget. In addition, the comfort zone of the college would be at optimal levels—meaning there are no IAQ complaints.

Mesa selected BACnet/IP® as the interface of choice to integrate the HVAC system with other building systems. The HVAC system is controlled through DSCs (Delta System Controllers) located on the building's floors. The DSC is a fully programmable, Native BACnet Building Controller that communicates on Twisted-Pair Ethernet 10BASE-T. It is suitable for controlling equipment such as AHUs, Boilers, Chillers and a variety of HVAC control systems.

The System Workstation, located on the ground floor, is connected to the network through an Ethernet switch, specifically Contemporary Controls® five-port, industrial-grade Skorpion switch. The EISK5-100T is marketed under the CTRLink® trade name by this networking manufacturer in Downers Grove, Illinois. Garcia said the EISK5-100T serves as one of the main doors to communicating with other devices in the network. "That's why it's vital for Mesa to have a consistent supply," he said. "This is highly important—communication on a Local Area Network makes our systems run. The switches provide our floor-to-floor communication as well as building-to-building and last system-to-system communication. These devices allow us to tie into our control network at higher speeds than point-to-point with system controllers. Our technicians are able to connect through the switch to do tasks such as system commissioning (VAC, AHU, HWS, and CHWS) or to troubleshoot the control network. This will enable our staff to effectively diagnose and remedy equipment malfunctions before catastrophic failure occurs."

On each floor of the building, the Skorpion is DIN-rail mounted in a control panel next to the HVAC system controller. Garcia said he values the product's small size (only 1" W x 3.9" H) and design. "The Skorpion unlike other industrial switches has easy access ports as well as a thin body that allows more panel space for other equipment," he explained. "According to our electricians, this product's mechanical structure is an advantage as well. The ports seem to be designed better allowing for easier connection with the CAT-5 cable; a better grip is used for the wire." Skorpion switches are intended for sub-panel mounting and can be powered from the same control transformer that is used to power the other industrial equipment, making the installation neat and rugged.

Each panel containing a switch is daisy-chained via CAT-5 cable from the roof down to the first floor connecting all the HVAC equipment (the controllers, the routers, the VAV controllers, the repeaters, the lighting controllers, the terminators, the return fans, the cooling towers and the cool water pumps) to the network.

Garcia said the well-engineered system exceeded the expectations of the school officials; a system that was designed with the Contemporary Controls product backed by excellent technical assistance. Garcia adds that the company's products, good prices, and quick response to orders make them a top choice among suppliers.