Full metadata record
| DC Field | Value | Language |
|---|---|---|
| dc.contributor | Department of Building Environment and Energy Engineering | en_US |
| dc.contributor.advisor | Wang, Shengwei (BEEE) | en_US |
| dc.creator | Li, Xinyue | - |
| dc.identifier.uri | https://theses.lib.polyu.edu.hk/handle/200/13416 | - |
| dc.language | English | en_US |
| dc.publisher | Hong Kong Polytechnic University | en_US |
| dc.rights | All rights reserved | en_US |
| dc.title | Design and optimization field-level process control for air-conditioning system implemented in IoT environments | en_US |
| dcterms.abstract | Internet of Things (IoT) technologies attracted great attention and have increased applications in various industrial sectors, including smart buildings and building automation (BA) fields. Additionally, the emerging wireless network technologies have opened up a new and attractive alternative for the real-time energy management in the wireless manner, owing to the new features including ultra-reliable and low-latency communication in the networks. However, the functionality of IoT technologies in buildings applications are still very limited, as they are mostly used for monitoring and data collection, while data processing and control decisions are typically made centrally or remotely. With regard to building controls, as one of the fundamental tasks of building automation, the IoT technologies are only applied to those less or not time-critical tasks. The feasibility of IoT technologies applied to time-critical tasks, such as field-level process controls, still needs further investigations. Thus, a new control architecture is needed that adopts IoT and emerging network technologies, providing an alternative option for future BA systems to fully reap their benefits in applications of building automation and smart buildings with more flexibility. | en_US |
| dcterms.abstract | This PhD study, therefore, aims to design and develop an appropriate architecture of networked field-level process control for air-conditioning systems implemented in IoT environments, with systematic analysis of the impacts of network uncertainties and component-level device characteristics. The optimization methods by different aspects are also proposed to optimize the performance of networked field-level process control considering network uncertainties. | en_US |
| dcterms.abstract | An IoT-enabled control architecture of networked building field-level process control in IoT environments is designed and the essential field-level smart IoT devices are developed. The feasibility and applicability of adopting IoT technologies and wireless networks for heating, ventilation, and air-conditioning (HVAC) process controls at field level are investigated experimentally. The control adopted the proposed control architecture under the good network condition shows almost the same performance compared with that using conventional direct digital controllers (DDC), which are widely used in current BA systems. The experimental comparison proves the feasibility of adopting IoT technologies and the wireless network in networked field-level process controls. | en_US |
| dcterms.abstract | The impacts of network constraints and component-level characteristics of HVAC devices as well as their interaction on networked field-level control are investigated. A IoT-enabled networked building field-level control simulation platform is developed for assessing such impacts, where a typical field-level HVAC process control is implemented. The component-level characteristics of the actuator and major network constraints in the networked control loop are taken into account. The results show that network constraints can significantly enlarge the faults caused by unfavorable component-level characteristics. The increased response time resulting from network delay may lead the actuator reaching the dead band. Packet loss can significantly enlarge the overshoot caused by dead band and hysteresis. | en_US |
| dcterms.abstract | Based on the proposed control architecture and analyzing the key factors affecting network performance, different optimization methods are proposed to enhance the performance of networked field-level control in buildings. These methods include: 1) an enhanced networked control strategy proposed for control optimization by considering control design; 2) a method developed by adopting 4th generation/5th generation (4G/5G) industrial cellular networks for control optimization by using advanced network technologies; and 3) a robust networked control scheme proposed for control optimization by using compensation methods. | en_US |
| dcterms.abstract | For the first method, the enhanced networked control strategy is proposed to enhance the networked control performance and robustness by optimizing control design. The task decomposition and distributed deployment of this strategy can significantly reduce the impacts of transmission delay and packet loss, and properly balance the different response speeds of two processes. The proposed enhanced networked control strategy has better steady-state performance in the IoT environment under different network conditions compared to the conventional strategy. It can provide stable control output even in the high dynamic region of the controlled process. | en_US |
| dcterms.abstract | For the second method, the 4G/5G industrial cellular networks are implemented into networked field-level process control. The capability and performance of the cellular networks when applied for time-critical building control tasks, as well as the coverage and connection performance are assessed. The experimental test results show that the cellular network is capable of supporting time-critical control tasks with good control performance even in the deep area of the building. The 5G-standalone network shows attractive performance in the conditions concerned. | en_US |
| dcterms.abstract | For the third method, the robust networked control scheme is proposed to enhance the networked control performance and improve robustness by using compensation methods. The proposed control scheme consists of a predictor and a compensator, aiming to predict the states of the networked control process when packet loss happened. The test results show that the proposed robust networked control scheme is validated as an effective option to mitigate the impacts of network constraints on control when using IoT technologies. Using the proposed control scheme, the deviation can be reduced from 13.7K to 5.8K (57.7%) under the same period of continuous packet loss. | en_US |
| dcterms.abstract | To conclude, this PhD study confirms the feasibility and applicability of adopting IoT technologies and wireless networks for field-level process controls in buildings. An IoT-enabled control architecture is designed and proposed as a recommendable alternative for building process controls in the next-generation of building automation systems. Considering the future development with deeper penetration of IoT technologies, the proposed architecture opens up a possibility for building automation systems to implement process controls using integrated smart IoT devices at field level with a “plug-and-play” manner. The deployment of such system could be cost-effective, as it reduces the cost associated with wiring, calibration, and configuration. Having the ability to conduct field-level building process controls in this manner, IoT technologies could play more essential role in building automation systems and have high impacts in future BA system development. | en_US |
| dcterms.extent | xx, 123 pages : color illustrations | en_US |
| dcterms.isPartOf | PolyU Electronic Theses | en_US |
| dcterms.issued | 2024 | en_US |
| dcterms.educationalLevel | Ph.D. | en_US |
| dcterms.educationalLevel | All Doctorate | en_US |
| dcterms.LCSH | Intelligent buildings | en_US |
| dcterms.LCSH | Air conditioning -- Control | en_US |
| dcterms.LCSH | Heating -- Control | en_US |
| dcterms.LCSH | Ventilation -- Control | en_US |
| dcterms.LCSH | Internet of things | en_US |
| dcterms.LCSH | Hong Kong Polytechnic University -- Dissertations | en_US |
| dcterms.accessRights | open access | en_US |
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