Kalamees, T.
2006
Thesis, Tallinn University of Technology
| This study determined indoor and outdoor boundary conditions as design values for hygrothermal design and indoor climate and energy simulations. They include moisture reference year, test reference year, internal moisture excess, temperature factor, and longterm indoor temperature and humidity conditions. For these analyzes, data of the Estonian climate were retrieved from six weather stations, covering a 31-year period, from 1970 to 2000. Indoor climate was measured from 27 detached houses and 13 apartments in Estonia, and in 101 detached ho uses in Finland.
Two different hygrothermally critical years were chosen on the basis of the saturation deficit method and the mould index method. These years are to be used for design and assessment of the hygrothermal performance of the building envelope and they represent critical years for the risk of water vapour condensation and the risk of mould growth. Test Reference Year (TRY) was constructed for heating and cooling energy calculations and indoor climate simulations with slightly modified ISO15927-4:2005 standard method. The TRY contains months from a number of calendar years. For a simplified estimation of annual heating demand, the average number of heating degree-days was calculated from long-term data for six locations.
Long term measurements of indoor climate in measured dwellings were used to determine average and critical temperature and humidity conditions which were used also in moisture excess analysis. The average indoor temperature during winter was +21.6 ˇăC and the average relative humidity 27 %. Despite this almost ideal winter temperatures, the variations in temperature was larger than expected to be produced by modern heating systems and well insulated envelopes. Large variations in temperature indicated that problems existed with temperature control of the heating systems. The average indoor temperature during summer seasons was +24.6 ˇăC and relative humidity 52 %. However, the results showed an extensive period of high indoor temperatures during summer indicating that thermal comfor t was not considered in the original design.
For the calculation of indoor humidity loads in the design of building envelopes, critical values of moisture excess were determined. The design curve on the 10 % critical level is +4 g/m3 during the cold period (outdoor temperature +5 ˇăC) and +1.5 g/m3 during the warm period (outdoor temperature +15 ˇăC) for detached houses and +6 g/m3 during the cold period and +2.5 g/m3 during the warm period for apartments. Between these levels, moisture excess decr eases linearly.
The design values of the temperature factor were determined for Estonian houses and apartments to be used for building design and building inspections. In apartment buildings, temperature factor shall be 0.80 according to mould growth criterion and 0.70 according to surface condensation criterion. In detached houses, these values are lower, 0.65 and 0 .55 respectively. |
