Improved HVAC commissioning using wireless sensor networks

Abstract

Commercial buildings present a significant potential for energy saving, in particular through the operation of their air-conditioning systems. Regulations and policies are driving to- wards better energy efficiency, but are mainly focused on the design stages. In practice, there is a performance gap between design and operation of new buildings. One of the causes of this gap is the failure to commission buildings for energy efficiency and comfort. Historically commissioning is limited to design compliance and security checks and would need to scale up to account for the necessity of reducing new buildings’ energy foot- print. However, due to inevitable delays in the construction process, commissioning tends to stop when the building reaches ‘practical completion’. It is thus difficult to increase the commissioning scope pre-handover. Additionally, currently available measurements are not suitable to go through the remaining ‘snag’ list or understand comfort and energy issues. This thesis examines the potential and practicality of using wireless sensor networks (WSN) to perform a post occupancy commissioning (PO-Cx) process for energy and occu- pants’ comfort performance. Requirements for such a WSN are determined from analysing building commissioning practices and the faults they fail to identify. An ad hoc WSN prototype is developed and verified. A proof of concept is established through a six-month deployment on a newly refurbished university building. It is concluded that WSN is a key tool to integrate energy performance and comfort to the commissioning of new buildings. The possibility to install them with minimum disruption of an occupied building and to analysis the data remotely means that it is easy to perform additional commissioning tasks post-handover. Recommendations to develop a commercial WSN for PO-Cx application are given and general strategies for PO-Cx are discussed based on the experience acquired.