Ljudisolering i prefabricerade betongstommar. En fältmätning av luft- och stegljudsisolering.
FältstudieLuftljudsisoleringStegljudsisoleringPrefabricerade betongstommarLuftljudsmätningStegljudsmätningAkustikLjudtransmissionReduktionstalStegljudsnivånLjudklasser.
Two elementary schools are now being built in Gråbo (in the municipality of Lerum),Röselidsskolan and Ljungviksskolan, which are both designed with solar thermalcollectors for the schools domestic water heating. During the summer while thelargest amount of solar heat can be generated, the activity hence the domestic wateruse in the schools are heavily reduced. Both schools are connected to the local districtheating system which makes it possible to use the solar collectors to deliver heat tothe district heating.The purpose of this thesis is to evaluate the two systems mentioned above and todetermine which system is more suitable to apply on a school. The building whichconditions were used for this evaluation is Röselidsskolan.A solar heating plant of each system type was dimensioned from the expected andknown conditions of the building. The purpose with the dimensioning was to makethe solar plants replace the ordinary energy source as much as possible. The solarplant for domestic water heating was dimensioned to cover 50 % of the annual energyconsumption for heating domestic water. The plant for delivering heat to the districtheating system was dimensioned from available space on the roof of the building andthe summer load of the district heating system. The dimensioning resulted in thefollowing systems:? Domestic water heating system: 35 m2 collector3 area, 2.6 m3accumulation tank volume? Delivery to the district heating: 300 m2 collector areaThe solar plant which is built on Röselidsskolan has 126 m2 collector area and 4 m3accumulation tank volume. The reason for the size of this system being this muchlarger than that dimensioned in this thesis is that the dimensioning for the built systemwas based on a estimated consumption of domestic water, much higher than thatestimated in this thesis. The built system was dimensioned from an expected hot waterconsumption of 15 kWh/m2 per year, compare to 3 ? 5,5 kWh/m2 per year that wasfound for this thesis by reweaving available statistics. However, the statistics fordomestic hot water consumption in schools are very poor.3 Aperture areaIVThe option of connecting the built solar collectors to the district heating is alsoevaluated in this thesis. This gives two additional systems:? Domestic water heating system: 126 m2 collector area, 4 m3 accumulation tankvolume? Delivery to the district heating: 126 m2 collector areaThe four solar plants mentioned above have been simulated with computer softwarecalled Polysun. Due to the uncertainty of the domestic water consumption, the twosystems for domestic water heating was simulated with three different heating loadswithin the span 3 ? 5,5 kWh/m2,year. The yearly water consumption is distributedover the schools active time with a reduction by 20 % during the school holidays.Furthermore, the average cost for the solar energy for each solar plant is calculatedwith the annuity formula. The investment cost for a complete system where, with noregard to size, set to be 10000 kr/m2 solar collector for the domestic water heatingsystems and 7000 kr/m2 solar collector for the systems with delivery to the districtheating. The investment cost, and the reasonable assumption of 20 years depreciationtime and a cost of capital at 5 %, gave a relatively high cost for the solar energy.The most important results are:4? The plant with 35 m2 collector area and 2.6 m3 accumulation tank volume isexpected to generate 9 (12) MWh per year, and 260 (345) kWh/m2 collector areaand year. The energy cost was calculated to 3,1 (2,3) kr/kWh.? The plant with 300 m2 collector area for delivery to the district heating is expectedto generate 84 MWh per year, and 280 kWh/m2 collector area and year. The energycost was calculated to 2,0 kr/kWh.? The plant which is built on Röselidskolan is expected to generate 13 (21) MWh peryear, and 100 (165) kWh/m2 collector area and year. The energy cost was calculatedto 8,0 (4,9) kr/kWh.? If the plant which is built on Röselidskolan instead was to deliver heat to the districtheating it was calculated to generate 34 MWh per year.Following conclusions can be drawn:? For the alternative where the solar collectors deliver heat to the district heating, thepotential for replacing the ordinary energy source is 6 to 9 times higher than thealternative to heat the domestic water supply.? The solar plant built on Röselidsskolan has been calculated to cover 70 to 80percentage of the energy needed for hot water heating. This high coverage and the low hot water demand in the school during the summer makes the solar plantinefficient. If the plant instead was connected to deliver heat to the district heating it is expected to generate 65 to 170 percentage more useful energy.