| Author: | Wu, Tingfeng |
| Title: | Investigation on energy saving potential of novel coating cool roof for buildings in China |
| Advisors: | Lu, Lin (BSE) |
| Degree: | M.Eng. |
| Year: | 2020 |
| Subject: | Roofs Buildings -- Energy conservation -- China Roofing paint Protective coatings Hong Kong Polytechnic University -- Dissertations |
| Department: | Department of Building Services Engineering |
| Pages: | ix, 88 pages : color illustrations |
| Language: | English |
| Abstract: | Nowadays, the worldwide demand for energy conservation and environmental protection has increased significantly, especially the energy consumption of the air-conditioning system, which can account for up to one-fifth of the total energy consumption of a building. Passive cooling is a method to maintain the building environment with less energy consumption without mechanical machinery. How to reduce the energy cost naturally? Reducing the heat gain or heat loss through the building roof is one of the key methods of passive cooling, which always occupies a considerable percentage for space cooling or heating, around 36.7%. Thermal reflective coating is a kind of exterior coating that has a solar reflectance so that it reflects the heat of sunlight. The concept of a roof covered with highly reflective paint can be a certain kind of cool roof, which usually does many effects in the field of passive cooling. It is common in China, and many researches on passive cooling roofs in China have been carried out in the past few years, mainly focusing on the field experiments of several types of coatings. Some national and local building standards for energy efficiency in China also recognize its importance but there is no requirement of its application on cooling of building roofs. This project aims to examine the energy saving potentials of cool roof coating in buildings in China by simulating a certain residential building prototype that meets the Chinese standards in three cities (Beijing, Shanghai, and Guangzhou). EnergyPlus is used as the simulation tool. Each city represents a typical climate zone in eastern and southern China. The cooling roof covered with a highly reflective paint with a reflectivity from 0.2 to 1.0 is chosen to generate the annual heating/cooling load, roof reflection and energy savings in all summer cities with hot summer and cold winter zone, hot summer and warm winter zone, and cold zone. The simulation results show that for China's hot summer/warm winter and hot summer/cold winter zone or even in cold zone, a cool roof covered with reflective coatings should be considered as one requirement of achieving building energy efficiency standards. For the air-conditioned residential building applied during the simulation, the energy performance of three selected coatings, one typical city and overall three typical cities separately from the three zones mentioned above, all are proved to be effective in energy saving. First, for roof temperature reduction, while changing the location of the building and keeping the solar\reflectance of the roof at the same time, the roof surface temperature will still increase according to the location moving to the south, and forms two peak temperatures during a day. While changing the solar reflectance to the three aged version, the energy saving in total will be influenced in positive correlation. Second, the factors according to one city can release several impacts due to the change of the cool roof. The net and total energy analysis can indicate the energy consumption by increasing the reflectance ratio of the roof. The electronic consumption and end use percentage parameters are supposed to show the occupied energy delivering from the outside, so that the energy saved by the roof can be illustrated. Third, compared with the simulation results in Guangzhou, Beijing and Shanghai, we can learn that the energy saving performance become apparently effective when the solar reflectance is rising without any other factors' disturbance. To conclude, the cool roof coatings have a good prospect of building energy saving in China's construction industry. |
| Rights: | All rights reserved |
| Access: | restricted access |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| 5345.pdf | For All Users (off-campus access for PolyU Staff & Students only) | 2.1 MB | Adobe PDF | View/Open |
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