Energy consumption and thermal comfort in office building

Abstract

The existence of buildings, whether these serve as spaces to live in or as working places, aim to assists the human activity, as well as it provides protection from exterior weather conditions. However, very often in the interior of the buildings are presented problems with regard to the thermic conditions that prevail. The results of problem have direct impact not only in the conditions of comfortable existence in the buildings but also in the health of their users. It is rendered therefore obvious that the appearance of phenomena of thermic dissatisfaction of users in the buildings is by definition opposite with the reason of their existence. Examining each building as a separate sub-system of the exterior environment and given the interaction between each other, the significance of the conditions indoor climate is unbreakably connected with the characteristics of manufacture and operation of building. The more general regard of problem concerns the internal environment globally. Apart from the evaluation of the thermic conditions, are evaluated also other factors such as the quality of internal air, the noise and the lighting. The additional factors that are imported with this more general regard influence the health, the comfort and the performance of residents of the building. The complexities of the problems that are related with the thermic comfort are increased, if we import also the factor of cost. The buildings constitute investments of intensity of capital, with high initial cost and with big duration of life. Meaning that this we are committed to pay is the compensation for any omission, negligence or failure in the planning and the manufacture for entire decades. The Greek legislation included for the first time regulations relative with the buildings heat insulation in 1979, with the Regulation of Heat insulation of Buildings, which was influenced from the corresponding German DIN 4108 and the method of calculation of thermic needs of DIN 4701. The most recent regulation became in 2010, when was also published the Regulation of Energy Attribution of Buildings. The KENAK substantially renewed the Regulation of Heat insulation, incorporating the relative with of the buildings sector provisions of Community Directive 2007 in regard to the targets of reducing the emission of greenhouse gases at 20%, production of energy in percentage 20% from RES and increase of energy output at 20% until year 2020 (known and as “20-20-20”). The energy renovation of buildings can constitute motive force for rebooting the sector, while the specialized work of renovations and energy upgrades occupies indirectly mechanics, technicians and researchers in the sectors of chemistry, minerals and technical equipment. This work concerns the 2/3 globally occupied in the sector, that in the first place work in small to medium-sized companies, giving thus the possibility to increase their contribution in the RES. Finally, the affair the thermic comfort and more generally the indoor climate it depends from the human factor. The use of building from his residents, can lead to improvement of internal environment or to its revalorization. In the evaluation indoor climate and particularly with regard to the conditions of comfort, subjective criteria influence the result of evaluation. Any study round the internal environment of building should take into consideration the users, which conceive differently each one the indoor climate. Consequently the issue of thermic comfort receives also the human component, as for the evaluation and the solution. The building that we will study in this thesis concerns office buildings. The energy consumption of office buildings in Greece varies in connection with their energy installations (being air-conditioned or not), their way of use and their age. With energy data base from many hundreds of buildings in Greece, has resulted the distribution of energy consumption as well as the classification of this buildings in three energy categories, and concretely: - The energy formal building, that corresponds in the 50% of sample of office buildings. - The most optimal building, that corresponds in the 20% of the best energy office buildings and - The passive building, that corresponds in the 5% of the best energy office buildings. As a result, the formal air-conditioned office building consumes almost 138 kWh/m2/year, (final consumption), where: - the air conditioning represent almost 35 kWh/m2/year and - Heating almost 85 kWh/m2/year. The average consumption of the not air-conditioned office buildings it oscillates around 75 kWh/m2/year, from which the 57 kWh/m2/year are consumed for thermic reasons.