HVAC optimisation provides energy savings at shopping centre

Mount Pleasant Shopping Centre, one of two major retail centres serving the city of Mackay, Queensland, was facing significant energy-efficiency issues. The hot, humid climate, ageing buildings and relatively inefficient HVAC technology presented a challenge in lowering the carbon footprint of its retail facilities. To reduce the cost of operations, Mount Pleasant management selected BuildingIQ.

The shopping centre includes more than 65 retail stores, which together occupy some 23,000 m² of commercial space. Pedestrian traffic flowing through the centre averages 4 million person-trips per year.

The overriding challenge was to establish a strong working relationship and technology buy-in by the owner and operator whereby BuildingIQ would connect indirectly with the metering system through the SkyFoundry interface. The HVAC system used by the shopping centre employed direct expansion (DX) technology, which involves distributed cooling plants rather than central cooling with distributed air. DX systems are typically less efficient and less effective than centralised, chilled water (CHW) systems. As a result, operational improvements with DX technologies were much harder to come by and were typically much smaller than those possible with CHW systems.

Mount Pleasant’s management chose BuildingIQ for its energy-efficiency and Predictive Energy Optimization (PEO) systems, and because the PEO model can engage seamlessly with virtually any building management system (BMS). The strategy for implementation employed by BuildingIQ was that of an individualised zone-temperature target system. The optimisation sequence had to be varied throughout the centre because of the heavy foot traffic and thermal loading in key areas, such as the food court, where comfort is a critical factor in the customer’s dining experience, and where the allowable temperature band is relatively tight.

The BMS which BuildingIQ’s PEO was eventually linked to is an Airmaster system, using Tridium R2 at the front end. Although the initial interface took the better part of a year because of the interface creation with the R2 version, early results have been encouraging, with savings up to 10%.

Once the BMS interface was complete, BuildingIQ was able to tap into the historical metering database to begin charging the PEO model. The transitional learning phase accelerated, and within 2-3 weeks, the optimisation procedures were initiated.  Energy savings were immediate, positive and growing. Typically, the algorithms underlying optimisation become more astute as the PEO model masters the thermal dynamics of the buildings.

The central challenge of establishing a solid working relationship with the management of Mount Pleasant was successful, largely because of good will, team dedication, the successful integration of vendors and the demonstration of immediate savings with the promise of greater rewards ahead. The implementation at Mount Pleasant was done in early 2014, and after just 30 days of implementation the centre saved more than 10%.