This paper presents a case study of a single-family house, where the effect of using thermal energy storage integrated in the floor is evaluated regarding GHG-emissions during the life cycle. The house has a lightweight wood frame construction, is well insulated, and fulfils the Norwegian energy regulations from 2010. Different floor configurations have been studied, both regarding energy demand and emissions. Floors with PCM panels have been compared with a reference case without thermal energy storage integrated in the floor, and have also been compared with concrete and wood as replacement for the PCM panels. The effect of changing the thickness of the PCM, concrete and wood has also been investigated (5 mm, 25 mm and 50 mm), as well as the effect of changing the emission factor of the energy supply to the building. The simulations have been carried out with three different climates: Oslo in Norway, Prague in the Czech Republic and Rome in Italy.
In this work, the thermal performance of three different wall configurations was examined by hot box measurements and numerical simulations. Vacuum insulation panels were sandwiched between traditional insulation in walls where the load-bearing elements were standard 36-mm-thick wooden studs, I-profiled studs and U-profiled studs. The measured mean values of the thermal transmittance (U-value) were 0.09 W/m2·K with 36-mm-thick wooden studs, 0.10 W/m2·K with U-profiled studs and 0.11 W/m2·K with I-profiled studs. The comparison of the three wall structures has shown that with such low U-values, the numerical simulations are more sensitive to the accuracy of the dimensions and thermal conductivities used as input. This required measurements of the thermal resistance of the fibreboard in two directions, the thickness and thermal resistance of the vacuum insulation panels and the thermal resistance of the 36-mm-thick wooden studs and the mineral wool.
Phase change materials (PCMs) have opened a new door towards the renewable energy future due to their effective thermal energy storage capabilities. Several products have recently found their way to the market, using various types of PCMs. This paper focuses on one particular wall-board product, integrated in a well-insulated wall constructed of an interior gypsum board, PCM layer, vapor barrier, mineral wool, and a wind barrier. The wall is tested with and without the PCM layer in order to get comparative results. Experiments are conducted in a traditional guarded hot box. The hot box is composed of two full-scale test chambers, where the tested wall is located between those two chambers. There are two heaters inside the metering box: heater 1 functions as a thermostat which is used to maintain a constant air temperature (of about 20 ºC) in the metering box, while heater 2 is a normal electrical heater that provides a constant heating power when turned on. The cold chamber has a fixed temperature equal to –20 ºC. The experiments are arranged in a comparative way, i.e. comparing walls with and without a PCM layer. Temperature, heat flux, air velocity, and electrical power are recorded during testing. By applying well-distributed thermocouples, the influences of the PCM layer on the interior temperatures can be shown. Furthermore, with attached heat flux meters, the energy storage effect and convective heat flows can be determined. Finally, with the electrical power meter, the energy saving effect can also be calculated. In this paper, initial experimental results are presented, showing the indoor air and surface wall temperatures. The experiments show that inclusion of the PCM layer in the wall reduces the interior air and wall temperatures by a maximum of about 2 ºC compared to a wall without PCM. The results also show that increasing the air velocity over the interior surface during the heating period lowers the maximum air and surface temperatures by the end of the heating period.