Sustainable Buildings for China

1. Sustainable Buildings for China Professors Leon Glicksman1, Yi Jiang2, and Qingyan (Yan) Chen1 1Massachusetts Institute of Technology, USA 2Tsinghua University, Beijing, China January 7, 1999

2. Background • Increased purchasing power due to economy growth • Demand for improved living standards • Winter heating • Summer cooling • Larger floor area per person • Largest producer of air conditioners

3. Background Winter Heating: • 130 million tons standard coal for urban heating • 248-260 million tons standard coal for rural heating • 30% of Chinese total energy consumption • Heating region is expanded to Shanghai and Wuhan (below Yangtze River)

4. Background Summer Cooling: • 35% of residential buildings in Beijing • 65% of residential buildings in Shanghai • 50% of residential buildings in Guangzhou • 20%-25% annual increase in sales

5. Problems • High demand for electricity in summer • Heat and noise pollution in micro-climate • Effect on the environment Future growth (American level?)

6. U.S. Buildings • 1/3 of total energy • 1/2 of electricity • 90% of time spent indoors • Major health problems: indoor climate

7. Basic Deficiencies • Very poor windows, single glazed, poorly fitted • Little or no insulation • Absence of summer shading • Poor maintenance • Rapid deterioration

8. Current Chinese Housing Policy • Will turn to market system in 1999 • Will encourage the housing industry to absorb public savings • Will maintain economic growth Consequences: • High speed growth in housing industry • Demand for high quality housing

9. Current Proposed Strategies for Energy Conservation in Chinese Housing • Insulation of building fabrics • Improvement of windows to reduce infiltration • Improvement of district heating systems • Metering system for heating • Improvement of lighting systems

10. Problems Remaining in Chinese Housing • Little consideration for summer cooling • Little consideration of natural ventilation • Little consideration of building forms • Little consideration of indoor air quality • No alternative for room air-conditioners

11. An Example of Current Design: A 30 cm (12 inch) concrete wall

12. Identify and Develop Solutions for Urban Buildings in China • Energy efficient • Simple and generic • Appropriate for local area • Cost effective • Acceptable by local people • Use of local material and labor

13. 18093 28823 2812 1017 6123 10355 695 3979 7068 Energy Global Warming Energy Global Warming Acid Rain Energy Global Warming Acid Rain Acid Rain [MJ] [kg CO2 equiv.] [kg SO2 equiv.] Environmental Impacts of 1m2 Brick Wallover 40 years, for Beijing Climate coal fired district heating embodied in wall structure and insulation % of zero insulation case 37cm 37cm 37cm 10cm 5cm

14. Global Warming from Heating kg CO2 equiv. over 40 years 5,000 4,000 3,000 2,000 1,000 0 no insulation 5cm insulation 10cm insulation 69 Building Insulation and Heat Pump (1m2 of Block Wall, for Beijing Climate) Heating Costs, heat-pump COP 3, electricity from coal, total of 40 years, discount-rate 7% 150 US$ 100 106 50 Initial Investment in Insulation 20 11 36 37 0 0 Investment Costs for Power Generation 20 25 Net Savings 150 US$ 100 Generation Capacity Savings 50 62 56 7 13 0 no insulation 5cm insulation 10cm insulation

15. Provide healthy and comfortable living space with little or no energy consumption in summer Key Point:

16. The Team • Technology Development, Design, Evaluation, and Training • MIT, USA • Tsinghua University, China • Tongji University, China • Construction (Demonstration projects) • Beijing: Vanke Property Development Co. 万科房地产发展公司 • 5-floor luxury housing • 12-floor affordable housing • 30-32 floor middle-class housing • Shanghai (To be identified)

17. Technologies to Improve Building Design • Ventilation • Natural ventilation • Night cooling and thermal storage walls • Advanced mechanical ventilation systems • Shading devices and passive solar • Heat pumps • Desiccants dehumidification

18. Possible Solutions • Natural ventilation to replace air conditioning • Thermal mass and night cooling • Ground coupled heating and cooling systems • Centralized energy systems • Improved windows • Application of vernacular technologies • Overall building design • Incentives for adoption of energy efficient designs

19. Improvement of Windows • Double glazing • New types of frame • Better insulation • Lower infiltration with acceptable indoor air quality

20. Improvement of District Heating • High efficiency by CHP • Large scale network with multi-heat sources • High reliability by loop network combined with computer added fault detection system • Special control policy to make buildings being heated equally • Energy reduced from 50 W/m2K to 30 W/m2K

21. Metering System for Heating • Largest potential saving in heating • 25% - 40% savings in test buildings • Difficulties: • Strongly related to the housing reform • Indoor system has to be changed • High cost for installation

22. Energy Savings • 30% of energy saving by improving the fabric • Additional 20% of energy saving by better control of the district heating system • Additional 20% of energy saving by use of metering systems for heating

23. A Study in Beijing:Results from 83 apartments • Measurements of the room air temperatures over a two-month period • Shading by device • Shading by vegetation • Ventilation • Building layout

24. Low and Middle Rise Housing

25. High Rise Housing

26. Thermal Environment kitchen Bedroom North Entrance Living room WC RHLog Door Bedroom Bedroom Window Balcony

27. Shading Comparison

28. Shading Comparison No shading Shaded

29. Vegetation Comparison

30. Vegetation Comparison Little vegetation Lots of vegetation

31. Use of Vegetation • Reduction on solar radiation • Direct radiation on the building surfaces • Reflection from the ground • Improvement in building micro climate • Reduction of outdoor air temperature • Change of air movement • Improvement on air quality • Decrease of noise

32. Balcony Other’s room Bed room Entrance North Living room Bed room WC Kitchen Comparison between Mechanical and Natural Ventilation

33. Comparison between Mechanical and Natural Ventilation Natural Mechanical

34. Different Natural Ventilation Designs Bad design Good design

35. Different apartments in the same flat can result in 300% difference in cooling load Careful arrangement of the kitchen, bathroom and corridor can greatly reduce cooling demand Comparison of Different Apartment Layouts

36. Use of Air Conditioners:A survey over 300 apartments

37. Results from the Survey Why like AC: 1. Cool 40% 2. Modern Technology 34% 3. Climate control 23% 4. Others 3% Why dislike AC: 1. Separated with the nature 47% 2. Draft and noise 26% 3. Energy and first costs 23% 4. Others 4%

38. Preliminary Understandings:The survey results • Comfort does not mean a low air temperature in summer • Air-conditioning may not be necessary in Beijing with acceptable comfort • The use of air-conditioning can be reduced greatly in southern China

39. Sustainable Housing for China • Be comfortable • Be healthy • Be energy efficient • Be economic • Be flexible and integral to the culture

40. Building Energy Distribution (Winter) Current Building

41. Window and Wall Insulation (Winter)

42. Building Energy Distribution (Summer)

43. Window and Wall Insulation (Summer)

44. Natural Ventilation:Building design

45. Natural Ventilation Design

46. Natural Ventilation

47. Natural ventilation: Airflow at MIT campus

48. Comfort Hours with Natural Ventilation

49. Comfort Hours with Natural Ventilation

50. Night Time Day Time Walls Absorb Heat Gains Minimum Ventilation Walls Release Heat Maximum Ventilation Natural Ventilation:Night cooling