The Physical Environment and Occupant Thermal Perceptions in Office Buildings An Evaluation of Sampled Data from Five European Countries
Doctoral thesis, 2001
The results from a large field study of thermal comfort in European office buildings are reported. Measurements of physical environmental conditions and occupant perceptions were collected over sixteen months from twenty-six different office buildings located in France, Greece, Portugal, Sweden and the UK. This thesis focuses on the physical environmental measurements and occupant thermal perceptions; however, additional variables with connections to environmental satisfaction are also examined.
An overview of human comfort theory is presented to help place this thesis in appropriate context. The overview presents thermal comfort issues within a broad framework of human response to the environment including physical, physiological, behavioural, psychological and other variables. A more narrowly focused overview of current thermal comfort research is also included.
The work attempts to show relationships and produce useful information from the data set using graphical methods, especially lowess, a locally weighted regression based scatter plot smoothing technique. The objective of using this approach is to literally show the relationships visually. This approach allows the data set itself to illustrate the actual thermal conditions in European office buildings and the occupant perceptions of those conditions along with illustrating relationships. The data are examined in some detail with key relationships identified and explored. Significant differences between countries, both for the physical conditions and the perceptions of those conditions are identified. In addition, the variation over the course of the year for each country is explored. The relationship of daily average outdoor temperatures to indoor temperatures and indoor temperature perceptions is found to be critically important. The relationships, which appear to drive perceptions of thermal comfort, occur in complex ways, making simple, all encompassing explanations impossible. The nature and size of the variations means that the application of simple European wide models of thermal comfort is questionable. It appears that individuals in different Europe countries have different expectations for their indoor office thermal environment.