Smart Thermostat Trial Case Study
People tend to dress for the seasons and the weather. However, air conditioning within office buildings is typically set to provide a 21.5 + 1°C temperature range, regardless of outdoor conditions. This is not only a waste of energy, but reduces relative comfort for building occupants.
Over the 2006/07 summer period, Investa collaborated with the CSIRO and Sustainability Victoria to study how temperature variance could be managed better to improve tenant comfort and save energy. Experiments were performed by the CSIRO's Energy Technology Division on the HVAC (Heating, Ventilation and Air Conditioning) system in one of Investa's commercial buildings in Melbourne. The results of the experiments showed that it is feasible to reduce electricity consumption by up to 15% on a hot summer's day through intelligent control of the building's thermostats.
Conventional air conditioning systems use one thermostat setting that generally stays constant the whole year round. The problem, and opportunity, with this is that HVAC systems run much more efficiently if the thermostat setting can be changed slightly depending on the outside temperature. Simply increasing the thermostat temperature by 1ºC will allow the air conditioner to work a lot less hard in summer, but would make the system (in heating mode) work much harder in winter.
The CSIRO implemented new software for the air conditioning control system that, depending on the outside temperature, made slight changes to the thermostat setting. The effects of these changes on the electricity consumption were calculated through data analysis from power meters fitted to the HVAC system.
The graphs below illustrate the impact on power consumption when allowing smart thermostats to control building temperature. The first graph depicts 'business as usual' operation:
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while the second graph illustrates energy savings when lifting the temperature setpoint by 1°C:
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The power savings recorded of up to 15% on the days of the trial were much better that the initial modelling predicted. Plans are now underway to investigate the implementation of this smart thermostat technology across Investa's commercial property portfolio, multiplying the value of this trial.
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