| Author: | Liu, Shengnan |
| Title: | Control of a direct expansion air conditioning system with adaptive predicted mean vote as regulator |
| Advisors: | Deng, Shiming (BSE) |
| Degree: | M.Eng. |
| Year: | 2018 |
| Subject: | Hong Kong Polytechnic University -- Dissertations Air conditioning -- Design and construction Buildings -- Energy conservation |
| Department: | Department of Building Services Engineering |
| Pages: | x, 80 pages : color illustrations |
| Language: | English |
| Abstract: | The traditional air conditioning (A/C) system only control the indoor air temperature as the control object. As a result, the A/C system not only cannot provide a thermal environment that meets the user' thermal comfort requirements, but also often overlooks the energy saving potential of the system. To solve this problem, an improved control strategy with thermal comfort index as regulator was presented. In this project, the adaptive predicted mean vote (aPMV), which is a comprehensive thermal comfort index considering seven parameters (air temperature, relative humidity, mean radiant temperature, clothing insulation, active level and adaptive coefficient), was applied as the controlled variable in the direct expansion air condition system. And a previous established fuzzy logic controller was simplified and improved for its real application. Test results demonstrated that improved controller with aPMV as the regulator could control and adjust the indoor thermal comfort well, with better control accuracy and sensitivity. In addition, a local fan as personalized ventilation was installed in the conditioned space. It was shown that at the same thermal comfort level, about 4% -7.6% energy saving of the A/C system could be achieved when a higher local fan speed was applied. The improved control strategy with aPMV as regulator presented in this project not only could realize the improvement of indoor thermal comfort but also fulfill the reduction of energy consumption. The traditional air conditioning (A/C) system only control the indoor air temperature as the control object. As a result, the A/C system not only cannot provide a thermal environment that meets the user' thermal comfort requirements, but also often overlooks the energy saving potential of the system. To solve this problem, an improved control strategy with thermal comfort index as regulator was presented. In this project, the adaptive predicted mean vote (aPMV), which is a comprehensive thermal comfort index considering seven parameters (air temperature, relative humidity, mean radiant temperature, clothing insulation, active level and adaptive coefficient), was applied as the controlled variable in the direct expansion air condition system. And a previous established fuzzy logic controller was simplified and improved for its real application. Test results demonstrated that improved controller with aPMV as the regulator could control and adjust the indoor thermal comfort well, with better control accuracy and sensitivity. In addition, a local fan as personalized ventilation was installed in the conditioned space. It was shown that at the same thermal comfort level, about 4% -7.6% energy saving of the A/C system could be achieved when a higher local fan speed was applied. The improved control strategy with aPMV as regulator presented in this project not only could realize the improvement of indoor thermal comfort but also fulfill the reduction of energy consumption. |
| Rights: | All rights reserved |
| Access: | restricted access |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| 991022168751903411.pdf | For All Users (off-campus access for PolyU Staff & Students only) | 4.06 MB | Adobe PDF | View/Open |
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