A change is in the air

Air Change turns to ABB PLC to add safety and operational efficiency to its standard indoor air-conditioning units.
When Air Change Australia required a PLC solution to control its Standard Rooftop Packaged (RTP) reverse-cycle air-conditioning units, it turned to electrical control and automation engineering firm High Technology Control (HTC) – an ABB Authorised Value Provider, headquartered in Padstow, Sydney.

Air Change – Based in Milperra, New South Wales – specialises in indoor heat and energy recovery solutions that integrate patented heat exchanger technology and other energy-efficient components with control technology, reducing outside air load by up to 75 percent.

"Our standard RTP is an air-conditioning unit packed with a direct expansion system; it is designed to handle high-fresh-air quantities, and offers heat recovery ability," explained Air Change engineer, Ben Zhang.

"We previously sold these units without a PLC, however in order to add functionality and safety to the machine, we required a dedicated controller for the fan, compressor and reversing valve.

"The ABB PLC has saved us both time and money spent on wiring the control board, and has also helped eliminate some electrical components such as mechanical timers."

According to Zhang, Air Change chose ABB as the supplier offers "a global brand with the reputation of high-end quality and support". Air Change had also previously worked with ABB on a successful application for the Ulladulla Civic Centre in Ulladulla, New South Wales.

"An Air Change unit with ABB PLC was supplied to maintain the pool at optimum temperatures; normally, the air temperature surrounding the swimming pool is higher than the water temperature, so water does not lose heat to the air – since heating air costs much less than heating water," recalled Zhang.

Air Change's RTP units now incorporate ABB AC500 eCo PLCs, which the company purchases through an ongoing supply agreement with HTC.

According to the ABB in Australia business development manager for PLCs, Juan Carrizales, the AC500 eCo model ensures efficient operation of the RTP units, and also allows Air Change to continue offering the package as a cost-effective option.

"Air Change's basic requirements were reduction of power consumption, and accurate control using a variable speed drive – so the objective was to select a small and low-price PLC, with serial communications, in order to provide a flexible solution," Carrizales explained.

"The AC500 eCo is easy-to-configure, offers commissioning, and also offers an ethernet port with a 'web-enable' feature as an option for future expansions, and to receive technical support from the vendor.

"In order to develop the engineering, the customer requested training and technical assistance for the first developments. In this particular project, the PLC has communication with other devices via serial port.

"In communication with a drive, the PLC now helps reduce energy consumption. Plus, for future projects this PLC can be expanded to communicate with management and control systems."

Carrizales says this same PLC product was also used in Air Change's Ulladulla Civic Centre project: "The HVAC system is used as a pool heating system, whereby the PLC controls the compressors, and has communication with the Building Management System," he said.

ABB's PLC model AC500 eCo ensures efficient operation of the Air Change Standard Roof Top Package reverse-cycle air-conditioning unit