DETAILED RESEARCH PLAN
This project focuses on construction and
evaluation of demonstration buildings that incorporate energy-conservation
features. We will continue to use the methods expanded upon in the
Formation of partnerships.
The faculty at MIT has already had several exchanges
with Chinese colleagues. Over the last year five MIT faculty members
have made three visits to China, visiting Beijing, Shanghai, and
Shenzhen. The MIT and Tsinghua faculty held a one-day seminar at
Beijing for interested designers, developers, equipment suppliers
and researchers. New sustainable design and technologies were described
and discussed. Meetings were held with members of major design institutes
at Tsinghua University in Beijing and at Tongji University in Shanghai.
These institutes are responsible for the design of many large building
projects in China. An agreement was reached between MIT faculty,
engineering colleagues at Tsinghua University and Tongji University,
and the two design institutes to develop demonstration projects
for sustainable buildings. Last spring, faculty from Tongji University
in Shanghai traveled to the U.S., supported on AGS funds.
Selection of target sites.
Currently, target sites comprise a diverse group,
with the most promising site located in Shenzhen, The site is comprised
of 2 hectares, with a floor area ration of 1.5. We have recently
submitted the schematic design to Vanke Architecture Technology
Research Center and hope to take an active role in the next few
months during the detailed design and construction document phases.
We have targeted a second site outside of Beijing,
in a development called Hui Long Gong. The total land size is seven
square kilometers. MIT and Tsinghua University have been asked to
develop a plot of land of about 10 hectares. This is a model where
urban factors and construction techniques, in addition to technologies
explored in other projects, should be investigated due to the size
of the project. The inclusion of faculty and students from Tsinghua
University in this project will facilitate close planning of the
demonstration and proper evaluation of proposed designs. In addition,
the collaboration also will encourage considerations such as building
codes and buyer acceptability, and careful monitoring of the demonstration
after it is built and occupied.
Evaluation of building
density, size, and shape.
Many new residential construction projects in
urban areas in China favor high-rise buildings. Pressures on land
use and code requirements for distances between buildings are often
cited as reasons for this choice, which runs counter to widespread
acknowledgment that buildings of lower height provide more enjoyable
living conditions and are more easily shaded with vegetation. MIT
will explore and evaluate alternative siting and sizing of buildings,
using the various test sites as a starting point. Results will be
shared with all team members and will be important for investigation
of airflows around buildings (UT and ETH) and for weighing land
and building construction costs.
To protect from cold winter winds, several measures
are proposed that have to do with building shape, orientation, clustering,
and the immediate surrounding. Moreover, to keep houses cool in
summer, advanced natural ventilation is recommended. For both design
tasks, a detailed knowledge of external aerodynamics is required.
It is insufficient to consult tables with typical surface pressures.
Instead, computational fluid dynamics predictions of the velocity
field in the immediate surroundings can provide detailed information
about the interaction of wind and building geometry. Roof slopes,
edges and shape of the building envelope, placement of windows,
smoke stacks, and vents, and clustering or joining of residential
units can be optimized. Exhaust openings in the roof with passive
Venturi suction driven by wind, can be designed and properly shaped.
Hot updraft on south-facing facades of high-rise residences can
be simulated, and consequences for open windows clarified.
For residential buildings in the climate as
in Beijing, buffer zones such as terraces enclosed by glass windows
or winter gardens are effective to reduce heating loads during the
winter by collecting solar energy. When solar irradiation is intense
and the elevation of the sun high, the terraces provide shade to
the inner zone. During the period when natural ventilation works
well, these spaces should be open to the outdoors. The impacts of
these "half-open spaces" on the air movement and heat transfer in
and around buildings need careful attention. In the proposed research,
ETH and UT will use CFD to investigate these mechanisms and to provide
information for optimum design of these spaces.
Evaluation of specific technologies.
Technologies will focus on natural ventilation
as an alternative to mechanical cooling and on selected other strategies
for passive heating and cooling. These appear to be the most promising
approaches for sustainable Chinese housing. There are a number of
generic issues that must be considered to insure that such systems
will have a substantial impact on the building performance. Within
this work we will consider the major implications of such systems
and develop general design rules.
Chinese designers would like to include natural
ventilation in the design of their new buildings. This is a complicated
issue that involves the design of building interiors and window
placement to facilitate airflow. In addition, the proximity of neighboring
buildings and the building shape will influence air circulation
outside the building and in turn natural circulation throughout
the building. There is the desire to include natural ventilation
in high-rise buildings, a difficulty compounded by the interaction
of buoyancy and wind driven flows. If natural ventilation could
properly be designed in a building, our initial simulations suggest
that natural ventilation combined with nighttime cooling and thermal
storage in the walls would eliminate most of the need for air conditioning
in Beijing on an average summer day.
The research team would consider the general
issue of natural ventilation from a variety of viewpoints:
- Air flow around building exteriors: UT, ETH
- Advanced ventilation concepts: UT
- Natural ventilation within buildings: MIT,
- Evaluation of sustainability: EPFL, MIT
- Integration into Building Design: MIT, Tsinghua
In a similar fashion, the research team will
consider generic new designs and technologies to include solar heating,
dehumidification, shading techniques (U of Tokyo), and other passive
measures (Tsinghua U.). The practicality, impact on sustainability
and general design rules will be considered. The sustainability
guidelines developed by EPFL will be used to carry out the evaluation.
Promising systems will be considered for inclusion in demonstrations.
Tool for evaluation of buildings by assessment
of health impact of the indoor air quality.
Indoor Air Quality (IAQ) is closely linked to
energy consumption and therefore is relevant to sustainability of
buildings. There are often trade-offs between improving IAQ, reducing
energy consumption, and maintaining thermal comfort. IAQ is one
of the important factors that affects welfare and health of occupants.
Therefore, a prediction model that can simultaneously treat various
factors is desired to realize good design of sustainable buildings.
The model will be able to evaluate effects of natural ventilation
or thermal storage capacity of buildings, taking unsteady-state
phenomena into account.
ETHZ will develop a simplified natural ventilation
assessment technique. This method would serve to evaluate the effects
of various factors such as ventilation methods (natural ventilation,
mechanical ventilation, etc.) and materials on IAQ. The envisaged
tool can evaluate energy consumption, thermal environment (air temperature
and radiative temperature), and IAQ simultaneously. This computer
model can be employed to quantify overall effects of the measures
taken in the construction project. A concept of occupant contaminant
inhalation will be used for a long-term assessment of health impact
of IAQ. The design tool will help to create buildings with low energy
consumption without compromising comfort and occupant health.
MIT architecture faculty and students, assisted
by engineering faculty and students, will begin to prepare a series
of design alternatives for the demonstration buildings in the Beijing
Tian Hong project. In addition, MIT will act as consultants for
the design development and construction documents phase for the
design of the Shenzhen project, researching more aspects of detailed
Development of final
MIT, Tsinghua and Tongji Universities will take
an active role in the design development of both Shenzhen and Tian
Hong projects. This will involve frequent contact with architects
Tsinghua University will document key aspects
of building construction as they relate to energy-efficiency features.
For example, fixed shading of windows may require more complicated
concrete formwork. MIT will begin to catalog specific materials
that are readily available in China, and will look into finding
Chinese manufacturers and suppliers.
After construction, Tsinghua University and MIT
will document the performance of the demonstration buildings, including
apartment-level energy consumption; temperature, lighting levels,
airflow and insulation measurements; and occupant thermal comfort
surveys. University of Tokyo will design methods for monitoring.
Preparation of guidelines
for future demonstrations and wide-scale adoption.
All of the institutions participating in this
project will collaborate in preparing guidelines for future demonstrations,
based on lessons learned from the first building. With support from
Tsinghua University, MIT will conduct a series of workshops intended
to educate both developers and architects in China as to technologies
and design approaches utilized during this project.
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