analysis of the influences of solar radiation and façade glazing ...

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4.1 Summary 100 and determine the most important factors, especially solar radiation, affecting energy consumption was carried out. Special attention was focused on the heat transfer through windows. One of the main goals of the current work was the determination and comparison of the gain and loss of thermal energy through the building fenestration. Glazed openings are very important elements in building design. Windows provide natural day-light into rooms to reduce the use of electric lights and allow heat gain from solar radiation. The type of glazing materials used in a building construction makes a significant contribution to the annual energy consumption. For this reason, it was decided to examine twelve cases of fenestration products with different types of low-e coatings and different configurations of optical filters on a glass surface. The parameters of the developed glazing systems such as visible transmittances, U-factor, solar heat gain and shading coefficients were determined with help of the computer program WINDOW 5.2. The simulation results as indexes of building energy consumption, heating and cooling energy demand were used to select the optimal window performance. Combinations of thermal and optical properties of the recommended glazing system should provide low energy consumption throughout the winter months due to the highest passive solar transmission. Large areas of glazing in each facade of the developed buildings may result both in the increase of heat losses in winter and the deterioration of thermal comfort conditions for the occupants by overheating during the summer. So, that is why the optimization procedure was presented and an optimal value of window-to-wall ratio that leads to a minimum energy consumption for space heating was determined. The current work reports energy balance of glazing system for north, south, west and east face of the developed building. Simulations were conducted for the following five locations in Germany: Hannover, Berlin, Düsseldorf, Frankfurt and Hamburg with different weather conditions. The variability of passive solar gains connected to the windows height above the ground level for heating and warm periods separately was the next problem resolved by the author. The research results concerning an analysis of the thermal environment in the living apartments during the warm period were presented as well. The building indoor environment was described by using an operative temperature and a PMV index. A reduction of gains from solar radiation during the summer was performed by different combinations of protection shields made by movable glass parts printed with various patterns and internal alternatively external window shades with highly reflective parameters. In order to reduce the internal air temperature, we used intensive mechanical ventilation when the outdoor temperature was lower than the air temperature in rooms. The next series of calculations were performed to investigate how variable air volume system influences the thermal environment in living spaces.
4.2 Comments and conclusions 101 Solar radiation can be converted into thermal energy by using technical solutions too. In order to compile the energy balance of the analyzed building, the operation of a solar domestic hot water system was also investigated. The developed DHW system was composed of solar collectors, storage tanks and an auxiliary water heater. The heat transfer performance for tilt angles of solar panels changing from 0° to 90° for Hannover latitude was simulated. Another factor that strongly influences the conversion efficiency was heat loss to the ambient caused by convection, conduction and infrared radiation. The flux of heat loss from the solar panels was also estimated and discussed. Another important question in the design of a DHW system is the optimal volume of a storage tank. Calculations were performed for a storage volume ranging between 1 m 3 to 12 m 3 . The capability of a developed solar active system for supporting the heating central system was also verified and reported. General comments and conclusions that could be drawn are summarized in this research. 4.2 Comments and conclusions Based on the analysis of extensive results obtained from this study the following conclusions can be made. � It is proposed to find a procedure for determining the optimal value of window-towall ratio. This estimation technique consists of the following steps: - calculation of the energy balance for the windows on each side of the building separately, - increase an area of the windows with the positive energy balance to the maximum limit, - reduce the size of windows with negative energy balances to the minimal value (or remove), which depends on the floor space for all living rooms. This developed procedure is universal and can be used for any dwelling house. As it turned out, the optimal value of the window-to-wall ratio for the whole considered building was equal to 22 %. The total glazing area can be reduced by over 46 % in comparison to the original version. But the area of the south facing windows can be enlarged to 58 % of the façade size. It is crucial to note that the optimal value of WWR can provide a reduction in heating energy consumption significantly, i.e. over 30 %. Therefore, it can be concluded that the hypothesis, which is raised in this dissertation, has been proven.
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ANALYSIS OF THE INFLUENCES OF SOLAR
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than the inner air temperature. It
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4.1 SUMMARY .......................
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Subscripts σ - Stefan-Boltzmann co
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1.1 Introduction 9 Another problem,
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1.2 Background and literature revie
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2.1 Building energy simulation soft
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2.2 Experimental research methods 4
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Page 55 and 56: 3.1 Building description 55 All int
Page 57 and 58: 3.1 Building description 57 Case B5
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Page 61 and 62: 3.1 Building description 61 Outside
Page 63 and 64: 3.1 Building description 63 In orde
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Page 105 and 106: References 105 Beausoleil-Morrison,
Page 107 and 108: References 107 Hendron, R., et al.
Page 109 and 110: References 109 Rees, S. and Haves,
Page 111 and 112: References 111 Yohanis, Y.G., et al
Page 113 and 114: Appendix 1 113 Fig. A1.1 VASATI 2.0
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Page 125 and 126: Appendix 2 125 0.035, !- Conductivi
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Page 129 and 130: Appendix 2 129 Discrete; !- Numeric
Page 131 and 132: Appendix 2 131 Fraction, !- Schedul
Page 133 and 134: Appendix 2 133 Air Conditioner:Wind
Page 135 and 136: Appendix 2 135 , !- Sensible Heat F
Page 137 and 138: Appendix 2 137 281, !- Lighting Lev
Page 139 and 140: Appendix 2 139 OG2 InfilTRATION, !-
Page 141 and 142: Appendix 2 141 OG3, !- Zone Name 16
Page 143 and 144: Appendix 2 143 0.004, !- Zone Heati
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Appendix 2 151 Zone 9 Outlet Node;
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Appendix 2 153 Stand Alone ERV 16,
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Appendix 2 155 ZoneHVAC:WindowAirCo
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Appendix 2 157 ZoneHVAC:Baseboard:C
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Appendix 2 159 Zone Control Type Sc
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Appendix 2 161 WindACPLFFPLR, !- Pa
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Appendix 2 163 Stand Alone ERV Supp
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Appendix 2 165 0.03001, !- Maximum
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Appendix 2 167 0.81, !- Sensible Ef
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Appendix 2 169 !- == ALL OBJECTS IN
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