Sustainable Buildings for China Professors Leon Glicksman 1, Yi Jiang 2, and Qingyan (Yan) Chen 1 1 Massachusetts Institute of Technology, USA 2 Tsinghua University, Beijing, China January 7, 1999

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

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

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

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

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

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

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

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

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

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

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

Environmental Impacts of 1m 2 Brick Wall over 40 years, for Beijing Climate coal fired district heating embodied in wall structure and insulation % of zero insulation case 37cm 5cm 10cm EnergyGlobal Warming Acid Rain Energy Global Warming Global Warming Acid Rain Acid Rain [kg CO 2 equiv.] [MJ] [kg SO 2 equiv.]

Building Insulation and Heat Pump (1m 2 of Block Wall, for Beijing Climate) no insulation 10cm insulation Generation Capacity Savings Investment Costs for Power Generation US$ US$ Global Warming from Heating kg CO2 equiv. over 40 years 0 1,000 2,000 3,000 4,000 5,000 no insulation 5cm insulation 10cm insulation Heating Costs, heat-pump COP 3, electricity from coal, total of 40 years, discount-rate 7% Initial Investment in Insulation Net Savings 25 5cm insulation

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

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

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

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

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

Improvement of District Heating ä High efficiency by CHP ä Large scale network with multi-heat sources ä High reliability by loop network combined with computer added fault detection system ä Special control policy to make buildings being heated equally ä Energy reduced from 50 W/m 2 K to 30 W/m 2 K

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

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

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

Low and Middle Rise Housing

High Rise Housing

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

Shading Comparison

No shading Shaded

Vegetation Comparison

Little vegetation Lots of vegetation

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

Comparison between Mechanical and Natural Ventilation Living room Balcony Bed room WCKitchen Entrance Other’s room North

Comparison between Mechanical and Natural Ventilation Natural Mechanical

Different Natural Ventilation Designs Bad design Good design

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

Use of Air Conditioners: A survey over 300 apartments

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%

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

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

Current Building Building Energy Distribution (Winter)

Window and Wall Insulation (Winter)

Building Energy Distribution (Summer)

Window and Wall Insulation (Summer)

Natural Ventilation: Building design

Natural Ventilation Design

Natural Ventilation

Natural ventilation: Airflow at MIT campus

Comfort Hours with Natural Ventilation

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

Shading Devices (Summer)

Dense Rock kW/mK3.46  kg/m C p J/kg836  m 2 /s1.3E-06 average heat extraction /year: 50MJ/m 2 Ground Temperature Changes with Heat Pump

Room Small Chiller Cooling coil Heat exchanger Desiccant adsorption sun Desiccant regeneration Outdoor Cooling tower air Operation of Desiccant System Desiccant dehumidification + Cooling Tower Outdoor air Desiccant System

Desiccant Cooling

Support ä MIT Kann-Rasmussen Foundation ($200,000/year) ä Tsinghua University National Natural Science Foundation (RMB 1,000,000)

Objective ä Identify energy efficient and sustainable designs and technologies ä Use economic and appropriate solutions for China ä Build demonstration buildings ä Publicize results to public, designers, officials, and industry ä Prepare design guidelines ä Train designers and planners

Milestones ä Background data, energy use of residential buildings ä First order evaluation of promising systems for energy efficiency ä In-depth study of several most promising ä Prototype design studies, model, evaluations ä Full-scale demonstrations ä Development of design guidelines