Environmental Performance Evaluation of Heating and Cooling Between Sustainable and Conventional Office Building

Abstract

The aim of the study was to evaluate the long-term environmental performance effectiveness of heating and cooling systems between ‘sustainable’ and conventional office buildings. The key research question that this study tried to answear is, ‘To what extent do sustainable office buildings remain sustainable in the long run?’ On this basis, two hypotheses (HP) were tested:
 HP1: Sustainable buildings remain sustainable in the long run.
 HP2: Current indicators fulfil the role for determining long term sustainability.
From the sustainability point of view, this study focused only on the environmental aspect. The word ‘sustainable’ has been used for identifying office buildings where environmental aspects have been taken into consideration through sustainability approaches. In order to address the first hypothesis, initially this study used a case study comparison approach to compare ‘sustainable’ with conventional office buildings, by comparing building design and heating-cooling system characteristics. This helped to raise understanding of the environmental characteristics that classify an office building as sustainable. Two case studies were used:
 The first case study comparison consists of a new ‘sustainable’ BREEAM excellent certified office building from 2009 and a conventional office building from the 1960s that had no refurbishments.
 The second case study comparison consists of a refurbished ‘sustainable’ BREEAM excellent certified office building compared to a conventional office building from the 1950s that had an upgrade in the heating system.
The study then focused on assessing the current environmental performance of heating and cooling between the case study buildings. Therefore Post Occupancy Evaluation (POE) methods were used including site visits, interviews, recording of heating and cooling systems, collection of heating-cooling consumption data, conducting thermographic surveys, applying Heating Degree Data (HDD) Evaluation and undertaking Life Cycle Assessment (LCA).
LCA has played a key role in evaluating the long run environmental performance of heating and cooling systems. The LCA evaluated two performance indicators: a) energy consumption of heating and cooling for 2 years of operation and b) the raw-material consumption of heating and cooling system production. Further, hypothetical long run scenarios were developed to consider the consequences of the existing operational and embodied raw-material emissions in the long run. Sensitivity LCA analysis was also used in order to evaluate the environmental impacts of alternative scenarios of different low/zero carbon technologies if they were installed in the case study buildings. Uncertainty analysis was used to assess the significance of uncertainty in the data evaluated.
The key outcome of this study was the need for developing a new Sustainability Indicator that can be used to support environment decision making in evaluating the long run environmental performance of heating and cooling systems in office buildings. The new indicator brings together all the research methods used in this study by developing further the existing energy indicator already integrated in existing Sustainable Assessment Methods (SAMs) and by developing a new indicator for raw-materials of heating and cooling systems. Suggestions for their integration on existing SAMs are also discussed. Finally the study ends with key conclusions and suggestions for further research.