Energy Analysis And Cost Efficiency of External Partitions In Low Energy Buildings

Energy efficiency is a very important factor in the construction sector. Construction consumes about 40% of total energy consumption in the world. New buildings in Poland and other European countries are designed according to strict requirements. An important aspect is to ensure thermal protection of the external partitions. To meet the requirements of thermal protection, the heat transfer coefficient of the building barriers must be at the appropriate level, specified in the Technical Conditions. Calculation of heat transfer coefficients of external walls, however, do not assume dynamic influence of external and internal environment conditions. The dynamic influences of environments on both sides of the barrier affect the thermal resistance, and thus the energy consumption and heating costs. In the experimental building of the Malopolska Laboratory of Energy Efficient Building, located on the campus of the Cracow University of Technology, experiments are carried out to describe the phenomena occurring in the partitions. The building has over 3000 temperature sensors built into its construction. Many temperature sensors are placed in the external walls. At the same time, measurements of temperature, humidity and solar radiation are recorded. These data will allow the analysis of phenomena occurring in the external wall under various weather conditions.

Temperature sensors were placed in the construction layer. Subsequent sensors are arranged between the insulation layers, which are arranged in four layers of 5 cm. The last sensors were located on two sides of the ventilated slot. The gap is similar to external conditions. The experiment is to provide an answer to the extent to which wind, sun or rain affect the deterioration or improvement of the thermal resistance of the external wall. The results from the measurements will be compared with the calculated temperatures in the partition. This experiment will allow assessing whether the methodology for calculating the thermal resistance and temperature drops in the partition is accurate. In the second part, the Authors will analyse the purposefulness of using modern thermal insulation materials such as aerogels in terms of cost.