Alternative strategies for supply air temperature control in office buildings

• Energy savings through supply air temperature control was investigated.
• Three low-complexity strategies were simulated in two types of office buildings.
• There is a large potential of reducing energy usage by revised control.
• Simple strategies can perform almost equally well as more complex ones.

A key element for a reduced energy usage in the building sector is to improve the systems for indoor climate control. But, it is important that such measures are fairly simple and easy to implement in order to facilitate a widespread utilization. In this work, four alternative strategies for supply air temperature control in offices were investigated through simulations. Their level of complexity stretches from linear SISO (single-input, single-output) structures with standard inputs to an optimal algorithm with information about the entire set of disturbances acting on the building. The study was conducted with a conventional outdoor-air-temperature based method as benchmark, and two different heating, ventilation and air-conditioning (HVAC) systems as well as two types of building structures were taken into account. Compared to the benchmark, all alternative strategies resulted in lower energy usages while thermal comfort and indoor air quality were satisfied, and simple strategies could perform almost equally well as more complex. But, it was also shown that the benefits were highly dependent on the considered HVAC system and somewhat dependent on the considered building structures.