An appraisal of the performance of a 'green' office building

Abstract

The challenges of a `greener' future are now a responsibility for everyone and particularly for the built environment, where sustainable building design is no longer an innovative option but more of a legislative must. Unfortunately significant differences are often found between the design and measured performance of buildings, with many factors contributing towards these discrepancies. This thesis investigates, using Post Occupancy Evaluation (POE) techniques, the credibility gap between design and measured performance of a partially occupied `green' office building selected as the case study. The results found that the measured energy consumption was over three times the design estimates, and the performance compared poorly against good practice benchmarks for similar buildings. The study's POE also revealed inefficient control settings, high out-of-hours energy consumption and ineffective building management. This study goes beyond a typical POE as it also includes investigations into how the occupancy variations, and the management strategies applied under these conditions, can impact on building energy performance through the use of simulation modelling techniques. This is an area where very little research has previously been carried out. At the current 50% occupancy levels, potential annual savings of over £30,000 in utility bills and 60% in energy consumption were estimated if more effective management and control was implemented. Social-related aspects of building performance are also investigated. Occupant surveys were conducted and the results were compared to previous findings. The perceived comfort and satisfaction with temperature was the most disappointing finding from the survey, however overall the building was comparable to the average benchmarks, but did not perform well when compared to other `green' office buildings. The study revealed that there is potential for the building to be fine-tuned to perform more efficiently than it currently is, however there must be suitably skilled Facility Management to ensure this is delivered.