200 Braddell Road Singapore 579700
Building and Construction Authority
Energy Efficient Building Facades for Thermal Comfort Environment
- Project Key Words:
- Residential façade, indoor thermal comfort; Residential Envelope Transmittance Value (RETV), different generations of façade design.
- PI:
- Prof. Wong Nyuk Hien
- Organization:National University of Singapore
- Designation:Professor
- Collaborators:
- Prof Steve Kardinal Jusuf/ Assistant Professor/ Singapore Institute of Technology
- Project Period:
- 01/07/2016 To 30/09/2018
- Project Description:
In Singapore’s residential buildings, air-conditioners are the largest contributors of building energy use. The concept of passive design to improve the indoor thermal comfort is an important strategy in reducing the energy use in residential sector. The building envelope separating the indoor space from the outdoor environment plays an important role in the passive control, because it acts as a modifier of the direct effects of climate variables, such as the outdoor temperature, humidity, wind, solar radiation and rain.
Currently, the existing public high-rise residential buildings in Singapore (i.e. HDB apartments) have passive design features such as: north-south orientation of windows, extended canopies to provide sun-shading and casement windows to promote natural ventilation. On the other hand, private high-rise residential buildings (i.e. condominiums) which cater to higher-income residents seem to have less emphasis on promoting the natural ventilation and passive design strategies. For example, implementation of a full height glass façade is common in many condominiums, as they are deemed to offer better views and create a luxurious building appearance. Based on observations, this design trend seems to have been adopted in several recent HDB designs.
BCA has implemented the RETV regulation to reduce the heat gain into interior spaces and consequently, air-conditioning energy use. Several design parameters to reduce RETV include window-to-wall ratio (WWR), glass shading coefficient, U-value of wall, and external shading device. While RETV serves to reduce heat flow into residential buildings, it is uncertain if this has adequately addressed the issue of thermal comfort for naturally-ventilated spaces. In addition, after implementing RETV for several years, it is relevant to evaluate the thermal performance of current residential building envelopes and see how this can be further improved.
The objectives of this project are:a. To understand the impact of façade design parameters and material properties on the indoor environment as well as façade thermal and wind performance;b. To evaluate the façade design under existing RETV regulations;
c. To develop façade design guidelines that reduce solar heat gain and promote passive design for natural ventilation to achieve indoor thermal comfort.
- Lead Organization:
- National University of Singapore (NUS)
- Project Impact
- The research findings in this project will be translated into façade design guidelines, which might be further incorporated into the building envelope code and/or Green Mark scheme. The developed guidelines serve to educate and guide the industry practitioners to design the residential façade with adequate concerns to improve the building energy efficiency and thermal comfort in the naturally ventilated spaces.
- Project status:
- On-Going Completed Terminated
- Project Outcomes:
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The key deliverables of this project include:a. A written report on:• Quantitative assessment of the thermal performance of existing residential facades and indoor thermal comfort, analysing the impact of façade design parameters on building thermal performance;• Impact of different types of shading devices on incoming wind flow for natural ventilation and reducing solar heat gain;• The assessment of residents’ indoor thermal comfort and preference, and the development of the new thermal comfort index (TCI) prediction model;• Relationship between the façade design parameter, façade thermal performance and RETV value.b. Façade design guidelines for building industry to minimise solar heat gain and achieve indoor thermal comfort for naturally-ventilated residential spaces.
