Abstract. The field study was carried out during the heating season in two Lithuanian office buildings with large glazed areas. The methodology was prepared for evaluating indoor microclimate parameters while using objective and subjective evaluation. The results show that the average temperature in all tested offices was in the range of optimal zones, but in some offices the average temperature was not in compliance with the recommended temperature for offices. During the subjective evaluation, respondents working in these offices identified complains because of too high temperatures, stuffy air and irritation in eyes. The average relative humidity measured in all tested offices was not in compliance with the optimal requirements. Such SBS symptoms as irritation in eyes, cough and dry skin of the hands were identified as the most frequent symptoms in the second tested building. Main indoor microclimate problems arising in buildings with large glazed areas were related to overheating indoor spaces because of the direct sun and improper ventilation.

No abstract

Abstract:In order to fulfil the European Energy Performance of Buildings Directive (EPBD) requirements for the reduction of energy consumption, European national requirements have been created for building envelope thermal properties and calculation methodology to determine if building energy efficiency is created. This is however not true in all methodologies. The necessity of building air tightness appears only for new A class buildings, and there are no requirements for air tightness for other building classes. Therefore, the aim of this work is to improve the methodology for the calculation of energy efficiency of buildings, while taking into account the air tightness of the buildings. In order to achieve this aim, the sum energy consumption of investigated buildings was calculated, energy efficiency classes were determined, air tightness of the buildings was measured, and reasons for insufficient air tightness were analyzed. Investigation results show that the average value of air tightness of A energy efficiency class buildings is 0.6 h −1 . The results of other investigated buildings, corresponding to B and C energy efficiency classes, show insufficient air tightness (the average n 50 value is 6 h −1 ); herewith, energy consumption for heating is higher than calculated, according to the energy efficiency methodology. This paper provides an energy performance evaluation scheme, under which performed evaluation of energy performance of buildings ensures high quality construction work, building durability, and the reliability of heat-loss calculations. OPEN ACCESSEnergies 2014, 7 4973

Windows, which have a U-value that is governed by an insulating glass unit (IGU) U-value, must be a building’s only enclosure element, which has no design value concept. The declared U-value, which is calculated or measured with 0 °C of external ambient temperature, is used instead of the design value. For most of a building’s elements, its thermal transmittance with a decrease in the external temperature diminishes a little, i.e., improves. However, for modern window IGUs with Low-E coatings, it is the opposite: the thermal transmittance with a lowering external temperature increases. Therefore, for calculating the peak power for the heating of buildings it is necessary to pay attention to this phenomenon and, therefore, it would be wise to introduce the concept of design U-value for windows, recalculation rules, or affix their declared U-values. This is especially the case in modern times with the prevailing architectural tendencies for enlargement of transparent building elements. For IGUs with Low-E coatings and inert gas fillers, the thermal transmittance depends on the temperature difference between warm and cold environments. When the external temperature is −30 °C instead of 0 °C, the thermal transmittance of the IGU can increase by up to 35%. This study presents the thermal properties of windows’ IGUs depending on the changes in outdoor temperatures by using guarded a hot box climate chamber and presents the proposed simplified methodology for determining the thermal properties of windows’ glass units. The accuracy of the composed simplified methods, comparing the calculated thermal transmittances of IGUs with those measured in the “hot box”, were up to 1.25%.

It is important to develop research on sealing materials in order to find effective solutions to ensure the energy efficiency of buildings. The aim of this study is to investigate the peel adhesion of single-sided self-adhesive tapes to different construction surfaces and to determine the change in this characteristic due to climatic effects. Different construction tapes, mostly used externally in buildings, are glued to different substrates. The artificial aging of test samples was carried out, simulating the effects of moisture, heat, and cold; the intensity, duration, and sequence of the cyclic effects were determined, taking into account the statistical climatological data of the middle-latitude climate zone. The peel adhesion of the tapes was determined before and after different numbers of artificial aging cycles. The results show that the peel adhesion range is very wide, from 11 to 61 N/24 mm. In most cases, a lower-rated peeling adhesion was obtained by peeling the tape from plastered cement–sawdust board. The change in peel adhesion depends more on the surface to which the tape is glued than it does on the number of climatic exposure cycles selected for the test.