Comparative building performance evaluation of a ‘sustainable’ community centre and a public library building

Abstract

This paper uses a forensic building performance evaluation approach to undertake a comparative evaluation of the in-use energy and environmental performance data (collected over two years) of two civic buildings located in Southeast England-a small community centre (<1000m 2) and a medium-sized public library building (~4500m 2), which are designed to high sustainability standards (EPC A rating) and low heating demand met by on-site low/zero carbon technologies. Although both buildings achieved measured air-permeability rates of ~5m3/hr.m2, they encountered similar issues related to poor documentation of 'as-built' drawings, poor handover and guidance, problems with integrating and maintaining new technologies (heat pumps, biomass boilers and solar thermal), lack of calibration of sub-meters, and issues with automatic window controls. However the actual carbon emissions of the community centre are 2 double the predicted, while they are almost five times in the case of library building. This is because the community centre management team overcame some of the issues through their continuous engagement and interest in the building's performance, whereas the management team of the Library building failed to engage with energy management, resulting in disuse of the biomass boiler and solar thermal system. Practical application Comparative building performance evaluation (BPE) systematically reveals the similarities and differences in the actual energy and environmental performance of two 'sustainable' civic buildings. Careful management of heating and electricity loads, good occupant control over the indoor environment and high performance of low-carbon technologies in the Community Centre result in the building performing better than good practice benchmark. Regular changes in FM staff result in inadequate energy management and control over heating, ventilation and lighting, that undermines occupant comfort and leads to excessive energy use in the library building. For civic buildings to perform as designed, it is vital that metering, sub-metering and controls are set up, commissioned and used properly by the FM team. Design teams should ensure that easy-to-understand user guides are made available before handover for FM and occupants.

Developing a new framework to bring consistency and flexibility in evaluating actual building performance

“…Project 2: BPE study of Angmering Community Centre building, UK (Gupta et al, 2017) The performance evaluation of the Angmering Community Centre is part of a UK Government Funded program on BPE. The project commenced at initial occupation and ran for two years, covering the review of the handover, assessment of energy use, in-use monitoring, fabric testing, walkthroughs and qualitative feedback.…”

The Post-Occupancy Dilemma in Green-Rated Buildings: A Performance Gap Analysis

“…Moreover, a previous study indicates that green building is encountering similar issues related to poor as-built drawings, poor handover and guidance, problems with integrating and maintaining new technologies (heat pumps, biomass boilers, and solar thermal), lack of calibration of sub-meters, and issues with automatic window controls [57]. Hence, due to the lack of training and understanding of energy management, issues with improper installation, commissioning, and maintenance lead to a higher risk of performance failure [11].…”

The Role of Occupants in Buildings’ Energy Performance Gap: Myth or Reality?

“…Indoor conditions were monitored in 20% of the selected studies to evaluate discrepancies between assumed and actual indoor conditions. Air temperature was the most commonly monitored indoor parameter to investigate the performance gap, followed by the relative humidity [7,10,12,[14][15][16]49,72] and the CO 2 concentration levels [10,[14][15][16]27,35,53,54,83,91], which were often used as a proxy for occupancy. Indoor environmental conditions were usually monitored via sensors placed in dwellings, but rarely in non-residential buildings.…”

“…Occupants opened windows more frequently or for longer periods (as compared to model assumptions) [5,6,12,14,18,22,28,32,37,45,52,54,55,58,67,72,77,79,82,89,95] Occupants turned off the installed MVHR (mechanical ventilation with heat recovery) and used windows instead for ventilation [6,14,49] Discrepancies between assumed and actual operation of shading devices resulting in the deviation of actual solar gains from model assumptions [5,21,22,89] Mechanical systems Set-point temperature, thermostat settings, system operating schedules and settings Higher actual indoor temperatures than those assumed in the model [6,9,11,14,15,18,29,37,53,55,58,75,79,82,90,101,104,107,…”