1. 1 Sustainable Buildings Activity 1 Introduction to sustainable building Activity 2 Don’t heat me up! Activity 3 Investigating the energy efficiency of the buildings around you Activity 4 Why sustainable buildings? (Click the links to access the activities.)

2. 2 Activity 1 Introduction to Sustainable Building

3. 3 Do you know the names of these buildings? How do they look different from ordinary buildings?

4. 4 These buildings are three of the most well known Sustainable Buildings / Green Buildings in Hong Kong. One Peking Road Kadoorie Biological Sciences Building, The University of Hong Kong Hong Kong Science Park

5. 5 The term “Sustainable Building” comes from “Sustainable Development” In 1987, the Prime Minister of Norway, Dr. Gro Harlem Brundtland created the landmark definition of Sustainable Development in the Brundtland Report Our Common Future Dr. Gro Harlem Brundtland is an international leader in sustainable development. “Development that meets the needs of the present without compromising the ability of future generations to meet their own needs.”

6. 6 Discussion time Do you understand what Dr. Gro Harlem Brundtland said in 1987? Try to brainstorm some essential features of a sustainable building based on:  the landmark definition of “Sustainable Development”  what you may have learned in environmental education  your common sense

7. 7 Sustainable Buildings are … Energy efficient Non-wasteful and non-polluting e.g. minimise CO 2 emission and Ozone depletion. Highly flexible and adaptable for long-term functionality Easy to operate and maintain Support the well-being of the occupants Be fair to the next generation The buildings contain sustainable designs that will not exhaust the world’s natural resources. (Response to Dr. Gro Harlem Brundtland’s message about Sustainable Development in the world) Energy efficiency is our main focus in this package

8. 8 Discussion time How is energy used in a building? Among the uses of energy you mentioned, which consume the largest amounts of energy?

9. 9 For residential buildings … Source: Electrical and Mechanical Services Department (EMSD), 2005 Air conditioning consumes the largest proportion of energy

10. 10 For commercial buildings … Source: Electrical and Mechanical Services Department (EMSD), 2005 Air conditioning consumes the largest proportion of energy

11. 11 Discussion time The technology of air conditioning gives us a more comfortable environment during summer but it also brings us some negative impacts. Can you list some? Technology has pros and cons. Can you give more examples?

12. 12 Technology is a two-edged sword! Technology can improve our quality of living, but it may also bring us adverse impacts

13. 13 How can we reduce the amount of energy used for air conditioning? We will look into it in Activity 2 – “Don’t heat me up!” We will investigate the designs and measures for improving the energy performance of a building in Activity 3: “Investigating the energy efficiency of the buildings around you” Based on the context of sustainable building, we will have a discussion on the relationship between science, technology, society and environment in Activity 4: Why sustainable building?

14. 14 Activity 2 Don’t heat me up!

15. 15 Conduction - transfer of vibrational energy from one molecule/atom to another Radiation - all objects emit electromagnetic radiation - hotter objects emit radiation with shorter wavelength Convection - transfer of heat by currents due to density differences within liquids and gases (fluids) Quick revision: How is heat transferred?

16. 16 According to activity 1, a large amount of energy is used in air conditioning because the space inside a building is heated up by sunlight. We are going to investigate how different kinds of building materials can help to reduce the heat gain of indoor space.

17. 17 Building materials We can normally divide building materials into two types: Glass and Non-glass. GlassNon-glass

18. 18 Single glass vs Double-glazed glass Single glass: single piece of glass Double-glazed glass: Two pieces of glass with an air-gap between the pieces. Single glass Double-glazed glass Air-gap

19. 19 Demonstration: Single or double-glazed glass is a better conductor of heat? Your teacher will show you a video demonstrating which type of glass performs better in conduction of heat. The setup is shown below: Hot water bath Single glass (20mm thick) Double-glazed glass (20mm thick) Data logger and computer Temperature sensors contacting the upper surface of the Single glass and double-glazed glass Temperature Sensor

20. 20 Click the screen to watch the demonstration

21. 21 Result: The temperature of the upper surface of the single glass rises much faster than double-glazed glass. Conclusion: Double-glazed glass can effectively slow down the heat transferring through it by conduction. Double-glazed glass (20mm thick) Single glass (20mm thick)

22. 22 Design an experiment Goal: To find out whether single or double-glazed glass can better slow down the heat gain of the air inside the building by sunlight. Materials given: Wooden boards, thermometer / data-logger with temperature sensors, single glass, double-glazed glass, light bulb. Write down your answer on the worksheet with the drawing of the experimental setup and suitable labels.

23. 23 Suggested design (hot box test) How does it work? When the 200W light bulb glows, the temperatures of the test materials surrounding the hot box will rise. Thermometers or temperature sensors are used to measure the temperature rise. A simplified view of hot box test setup

24. 24 The setup can test 1-3 pieces of material each time. The temperature of the test materials can be measured with either -A data logger (with temperature sensors) or -Mercury thermometers Measurement

25. 25 If using a data logger to do the measurements, a real time graph can be plotted based on the temperature rise of the temperature sensors. Data Recording If using thermometers to do the measurements, record the temperature on the surface of each material at 30-second interval after the light bulb is switched on. Time (seconds) 0306090120150180210240270300 Test Material 1 Test Material 2 Test Material 3 Temperature ( o C) at 30-second intervals

26. 26 To find out whether single or double-glazed glass can better slow down the heating of the air inside the building by sunlight. Light bulb Temperature sensor Single glass (20mm thick) We simulate the sun by the light bulb. The temperature sensor reads the temperature inside the room. “ ” indicates the direction of heat flow Notes: All thermometers/temperature sensors should be at the same distance (around several cm) away from the test materials. Temperature sensor Double-glazed glass (20mm thick)

27. 27 Which glass (single glass or double-glazed glass) can better slow down the heat gain of the room? Result: Almost no difference! Single glass (20mm thick) Double-glazed glass (20mm thick)

28. 28 Result: Almost no difference! What is the reason? Answer: Over 95% of the heat is transferred from the sun to the room by radiation because both the single glass and double-glazed glass are transparent to most solar radiation. > 95% radiation

29. 29 Blocking radiation is important ! The previous investigation’s result demonstrates that it is very important to minimize the amount of radiation transferred through the glasses from sunlight to indoor space in order to reduce the energy consumption of air-conditioning. Now we investigate two types of glass with special measures to block solar radiation.

30. 30 Testing materials for blocking radiation Repeat the hot box test with the following three types of glass. 1.Clear glass (6mm thick) 2.Glass coated with Sun Control Film (6mm thick) 3.Low-emission Glass (6mm thick) (coated with metallic oxide reflecting layer on the glass)

31. 31 Result… The result agrees with our prediction this time. Sun control film and low-emission glass are widely used in buildings to block solar radiation. Clear glass (6mm thick) Glass with sun control film (6mm thick) Low–e glass (6mm thick)

32. 32 Suggested further investigation: Visibility Slightly modify the hot box test by replacing the temperature sensor with a light intensity sensor. This change can test the visibility ( 透光度 ) of the glasses. Glass Light intensity sensor Bulb

33. 33 Testing non-glass materials Repeat the hot box test with the following three types of non-glass materials: 1.High-density polystyrene board (6mm thick) (used as an insulating layer in roofing) 2.Ceramic tile (6mm thick) (used in kitchen/bathroom wall insulation and on building exteriors) 3.Wood (6mm thick) (used in walls of buildings overseas)

34. 34 Which type of material can better slow down the heat gain of the room? Result: Temperature of 3 materials rises very slowly, Temp. of polystyrene board rises slightly faster High-density polystyrene board (6mm thick) Ceramic tile (6mm thick) Wooden board (6mm thick)

35. 35 Result: Temperature rises very slowly. Temperature of polystyrene board rises slightly faster. What is the reason? Answers: Since the materials tested are not transparent / only slightly transparent to solar radiation, radiation cannot reach the other side of the materials effectively. As a result, the temperature rises slowly. Polystyrene is slightly transparent and allows small amount of solar radiation to pass through it. Thus, its temperature rises slightly faster than the other two. How is heat transferred from sun to space inside the building through non-transparent materials?

36. 36 Combined Heat Transfer How is heat transferred from the sun to the space inside building? 1.Sunlight falls onto the exterior of the wall by radiation. 2.Heat is transferred from external side of the wall to internal side of the wall by conduction. 3.Heat is spread by air currents from the surface of the wall to the indoor space by convection. The whole process is called Combined Heat Transfer. Radiation Conduction Convection

37. 37 Special building materials - Fire-resistant glass There are many types of specially made building materials and glass serving different needs in buildings. Fire-resistant glass: a kind of glass that is widely used in buildings for safety purposes. Can you think of some features of this type of glass that can enable it to have “fire- resistant” properties? Read the second part of the Appendix 1 of your worksheet for more details of this type of glass.

38. 38 Activity 3 Investigating the energy efficiency of the buildings around you

39. 39 Apart from the use of carefully selected building materials, what other design and operational measures can be used to reduce a building’s energy use? Can you find any of them in your school building and/or home building? Set up an investigation plan to check it out!

40. 40 Activity 4 Why sustainable buildings?

41. 41 Why do we need sustainable building? What are the benefits? Who are the beneficiaries? In the context of sustainable building, can you illustrate the Interconnections between Science, Technology, Society and the Environment (STSE)? Further discussions