Young Cities Developing Energy-Efficient Urban Fabric in the Tehran-Karaj Region

Transcription

1 Young Cities Developing Energy-Efficient Urban Fabric in the Tehran-Karaj Region Window Area in Office Buildings from the Viewpoint of Energy Efficiency Dr. Eng. MA Farshad Nasrollahi Berlin University of Technology Building Technology and Design, A project sponsored by the Funding programme: The urban transition - Sustainable development of megacities of tomorrow oung Cities - New Towns in Iran

2 INTRODUCTION YOUNG CITIES Aim of the Project Planning and building sustainable and energy efficient mass housing settlements in arid and semi-arid regions in order to lead to a significant enhancement of energy efficiency of buildings, neighbourhoods and towns Source: Young Cities / 35

3 INTRODUCTION LOCATION Hashtgerd New Town (60km west of Tehran, Iran) Coordinates: 36 1 N E 10 km Source: Young Cities / 35

4 INTRODUCTION CLIMATE Warm and dry climatic region o Summer: Warm and dry o Winter: Cold Hashtgerd Source: Kasmaei / 35

5 INTRODUCTION BUILDING ENERGY SIMULATION Playing a decisive role in research on energy efficiency and optimization of energy performance of buildings Powerful analytical method for building energy research and evaluation of architectural design Cost and time saving device Mathematical model that represents all energy flow paths in a building as well as their interactions Building Energy Simulation Evaluation of performance of Building Optimization of Building energy performance 5/ 35

6 INTRODUCTION ENERGY SIMULATION OF OFFICE BUILDING Calculation of the energy consumption of office building Optimization of energy performance of office building Analytical evaluative process dealling with different architectural and constructional factors: Orientation Opening orientation and ratio Sun shading Airchange rate Thermal mass Insulation material etc. Window area and type of shading devices are key factors for building energy performance 6/ 35

7 INTRODUCTION RESEARCH GOAL Study the effect of window area on energy consumption of office building Finding optimal window area for office building With shading devices Without shading devices TOOLS Hashtgerd Climate Data Analysis DesignBuilder as a developed dynamic simulation software Hourly weather data of Hashtgerd New Town 7/ 35

8 INTRODUCTION METHOD Simulation of office buildings with different window area Comparison of the energy consumption of the buildings Total Energy consumption is the sum of heating, cooling and lighting energy consumption Analyzing of the results OPTIMAL MEASURE FOR WINDOWS OF OFFICE BUILDINGS Simulation Condition Same climatic, constructional and architectural conditions Different window areas + Different shading devices BUILDING MODEL A 3-floor cell office building South-facing orientation, east-west axis elongation Building Model for Energy Simulation 8/ 35

9 INTRODUCTION SIMULATION ASPECTS Energy Simulation of Office Building Windows Shading devices Windows without t shading devices Overhang Windows with external blinds External blind Windows in all orientations North-facing windows East and west-facing windows 9 / 35

10 WINDOW WINDOW Optimum window ratio from the viewpoint of energy efficiency by simulation of different office buildings Simulation Condition same window/wall ratio in all orientations 0 % 50 % 100 % 0 % 0 % 50 % 50 % 100 % 100 % 0 % 50 % 100 % 0 % Window Ratio 50 % Window Ratio 100 % Window Ratio 10 / 35

11 WINDOW WINDOWS WITHOUT SHADING DEVICES Simulation of 11 buildings with different window/wall ratio Same window/wall ration in all orientations Windows without shading devices 0 % 100 % 0 % 0 % 100 % 100 % 0 % 100 % Facade section 0 % Window Ratio 100 % Window Ratio 11 / 35

12 WINDOW WINDOWS WITHOUT SHADING DEVICES 120 Heating, Cooling, Lighting and Total Energy Consumption of Office Buildings with different Window Ratio 100 kwh/m²a Window Area / Wall Area (%) Heating Cooling Lighting Total Energy Consumption Heating Energy Consumption The heating energy consumption decreases by increasing the window area from 10 to 80% window/wall ratio The heating energy consumption increases a bit by the window to wall ration from 80 to 100% Cooling Energy Consumption The cooling energy consumption increases by increasing the window area from 10 to 100% window/wall ratio 12 / 35

13 WINDOW WINDOWS WITHOUT SHADING DEVICES 120 Heating, Cooling, Lighting and Total Energy Consumption of Office Buildings with different Window Ratio 100 kwh/m²a Window Area / Wall Area (%) Heating Cooling Lighting Total Energy Consumption Lighting Energy Consumption Reduction of lighting energy consumption is very high from 0 to 30% window/wall area After 30% the lighting energy consumption will be decreased very slowly 30% window/wall ratio is the optimal ration when only lighting is concerned Total Energy Consumption Increasing the window area from 0 to 50% window/wall ratio will decrease the total energy consumption Increasing the window area from 50 to 100% window to wall area increases the total energy consumption 13 / 35

14 WINDOW WINDOWS WITHOUT SHADING DEVICES 120 Heating, Cooling, Lighting and Total Energy Consumption of Office Buildings with different Window Ratio 100 kwh/m²a % 50 % 50 % 50 % Window Area / Wall Area (%) Heating Cooling Lighting Total Energy Consumption 50 % Window Ratio Result For office buildings with the same window/wall ratio and without shading devices the optimum ration is 50% 14 / 35

15 WINDOW WINDOWS WITH EXTERNAL BLIND Simulation i of 11 buildings with different window/wall ratio Same window/wall ratio in all orientations Windows with external blinds 0 % 100 % 0 % 0 % 100 % 100 % 0 % 100 % Facade section 0 % Window Ratio 100 % Window Ratio 15 / 35

16 WINDOW WINDOWS WITH EXTERNAL BLIND 120 Heating, Cooling, Lighting and Total Energy Consumption of Office Buildings with different Window Ratio 100 kwh/m²a Window Area / Wall Area (%) Heating Cooling Lighting Total Energy Consumption Heating Energy Consumption Increasing the window area from 0 to 20% window/wall ratio will increase the heating energy consumption Increasing the window to wall ratio from 20 to 80% decreases the heating energy demand Increasing the window to wall ration from 80 to 100% increases a bit the heating energy consumption Cooling Energy Consumption The cooling energy consumption increases by increasing the window area from 10 to 100% window/wall ratio 16 / 35

17 WINDOW WINDOWS WITH EXTERNAL BLIND 120 Heating, Cooling, Lighting and Total Energy Consumption of Office Buildings with different Window Ratio 100 kwh/m²a Window Area / Wall Area (%) Heating Cooling Lighting Total Energy Consumption Lighting Energy Consumption Increasing the window area from 0 to 100% window/wall reduces the lighting energy consumption Reduction of lighting energy consumption is very high from 0 to 40% window/wall area After 40% the lighting energy consumption decreases very slowly Total Energy Consumption Increasing the window area from 0 to 60% window/wall ratio decreases the total energy consumption Increasing the window area from 60 to 100% window/wall ratio increases the total energy consumption 17 / 35

18 WINDOW WINDOWS WITH EXTERNAL BLIND 120 Heating, Cooling, Lighting and Total Energy Consumption of Office Buildings with different Window Ratio 100 kwh/m²a Window Area / Wall Area (%) Heating Cooling Lighting Total Energy Consumption Window Ratio Result For office buildings with the same window/wall ratio and with external blinds the optimum window/wall ratio is 60% 18 / 35

19 WINDOW NORTH-FACING WINDOW Based on the last results, 60% window ratio in all orientations is the optimum window area? Simulation of different office buildings with 60% south, east and west-facing window ratio and various north-facing window ratio 19 / 35

20 WINDOW NORTH-FACING WINDOW kwh/m²a Energy Consumption of Office Buildings with different North-Facing Window Ratio Window Area / Wall Area (%) Heating Cooling Lighting Total Energy Consumption Heating Energy Consumption The heating energy consumption increases with the increasing of the north-facing window area Cooling Energy Consumption The cooling energy demand decreases from 0 to 20% window/wall ratio Increasing the window area over 20% will increase the cooling energy demand The effect of the north-facing window area on cooling energy consumption is very low 20 / 35

21 WINDOW NORTH-FACING WINDOW kwh/m²a Energy Consumption of Office Buildings with different North-Facing Window Ratio Window Area / Wall Area (%) Heating Cooling Lighting Total Energy Consumption Lighting Energy Consumption Increasing the north-facing windows decreases the lighting energy consumption Decreasing the lighting energy consumption after 20 and 30% is very low Total Energy Consumption Total energy consumption decreases with increasing the north-facing window ratio from 0 to 20% window area to wall area Increasing the north-facing window area over 20% increases the total energy consumption 21 / 35

22 WINDOW NORTH-FACING WINDOW 90 Energy Consumption of Office Buildings with different North-Facing Window Ratio kwh/m²a % Window Area / Wall Area (%) Heating Cooling Lighting Total Energy Consumption Result For office buildings with 60% south, east and west-facing window ratio the optimum window area for north-facing facade is 20% (up to 30%) 22 / 35

23 WINDOW EAST AND WEST-FACING WINDOW Based on the last results 60% window ratio in southfacing facade and 20% window in north-facing one are the optimum window area? 20 %? Simulation of different office buildings with 60% south-facing windows and 20% north-facing windows and various east and west-facing window ratio 23 / 35

24 WINDOW EAST AND WEST-FACING WINDOW kwh/m²a Energy Consumption of Office Buildings with different East and West-Facing Window Ratio Window Area / Wall Area (%) Heating Cooling Lighting Total Energy Consumption Heating Energy Consumption The heating energy consumption decreases with increasing the east and west-facing window area Cooling Energy Consumption The cooling energy demand increases by increasing the east and west facing windows The east and west-facing windows have very high solar gain in summer and very little in winter 24 / 35

25 WINDOW EAST AND WEST-FACING WINDOW kwh/m²a Energy Consumption of Office Buildings with different East and West-Facing Window Ratio Window Area / Wall Area (%) Heating Cooling Lighting Total Energy Consumption Lighting Energy Consumption Increasing the east and west-facing windows decreases the lighting energy consumption The effect of east and west-facing windows on lighting energy is very low Total Energy Consumption Total energy consumption increases by increasing the north-facing window ratio The building with 10% east and west-facing window is very little more than the building with no east and west-facing windows 25 / 35

26 WINDOW EAST AND WEST-FACING WINDOW 80 Energy Consumption of Office Buildings with different East and West-Facing Window Ratio kwh/m²a % 20 % 10 % Window Area / Wall Area (%) Heating Cooling Lighting Total Energy Consumption Result East and west-facing windows are weakness of buildings from the viewpoint of energy efficiency Because of importance of daylighting, g, the optimum window ratio for east & west-facing facades is 10% 26 / 35

27 SHADING DEVICES OVERHANG An office building with optimum window area and different overhang projection size is simulated The windows in all orientations have similar overhangs with the same projection size 20 % 10 % 10 % Facade section Optimum Window Ratio 27 / 35

28 SHADING DEVICES OVERHANG kwh/m²a Energy Consumption of Office Building with Different Overhang Projection Overhang Projection (m) Heating Cooling Lighting Total energy Consumption Result Having overhang and increasing of their projection size increase the heating energy demand Having and increasing the projection size of overhangs reduce the cooling energy consumption Overhangs increase the lighting energy consumption Using overhang for windows of office buildings in all orientations and also increasing of the projection size of overhangs increases their total energy consumption 28 / 35

29 SHADING DEVICES EXTERNAL BLIND Simulation of an office building with external blind with different type of controlling the blinds The optimum window ratio (60% south-facing, 20% north-facing and 10% east/west-facing facade) 20 % 10 % 10 % Facade section Optimum Window Ratio 29 / 35

30 SHADING DEVICES EXTERNAL BLIND 90 Energy Consumption of Office Building with different Control Type of External Blinds kw Wh/m²a Control Type of External Blinds Heating Cooling Lighting Heating withouth Blind Cooling withouth Blind Lighting withouth Blind Total withouth Blind Heating Energy Consumption External blinds often increase the heating energy consumption Cooling Energy Consumption External blinds often decrease the cooling energy consumption 30 / 35

31 SHADING DEVICES EXTERNAL BLIND 90 Energy Consumption of Office Building with different Control Type of External Blinds kw Wh/m²a Control Type of External Blinds Heating Cooling Lighting Heating withouth Blind Cooling withouth Blind Lighting withouth Blind Total withouth Blind Lighting Energy Consumption External blinds often increase the lighting g energy consumption Total Energy Consumption The effect of external blind on decreasing the total t energy consumption is generally verylittle 31 / 35

32 SHADING DEVICES EXTERNAL BLIND Winter and Summer Solstice in the Climate of Hashtgerd Result Little effect of shading devices on energy consumption of office buildings in Hashtgerd High solar altitude in Hashtgerd in summer Short work time of office buildings in Iran (and Hashtgerd) Situation of a big part of work time before noon 32 / 35

33 CONCLUSION CONCLUSION Same window ratio in all orientations without shading devices Optimum window Area: 50 % Heating 80% Cooling 10% Lighting 40% 50 % 50 % 50 % For reduction of total energy consumption the optimum window to wall ratio is 50% The behavior of buildings with external blinds is a bit different in comparison with buildings without shading devices Buildings with external blinds Optimum window Area: Heating 80% Cooling 10% Lighting 50% For reduction of total energy consumption the optimum window to wall ratio is 60% 33 / 35

34 CONCLUSION CONCLUSION Buildings with different window ratio in different 10 % orientations, optimum window ratio: South-facing 60% North-facing 20%-30% East/West-facing 10% 20 % 10 % Overhangs increase the total energy consumption of office buildings The type of controlling the external blinds is the key factor for their effect on energy consumption of office buildings 34 / 35

35 Thank You for Your Attention Berlin University of Technology Young Cities Research Project Building Technology and Design Tel: Fax: / 35