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A platform for research: civil engineering, architecture and urbanism
An online model for predicting dynamic response of a packed liquid desiccant dehumidifier
Abstract Liquid desiccant dehumidification systems show significant energy-saving potential in HVAC applications. The dynamic characteristics of a liquid desiccant dehumidifier attract increasing attentions in recent years, which are essential for designing appropriate controllers for it. However, due to the complicate coupling of heat and mass transfer inside the dehumidifier, there are few models have been developed for predicting the dynamic characteristics of a packed liquid desiccant dehumidifier. In this paper, an online model was proposed, which predicted the dynamic response of a packed dehumidifier mainly based on the air outlet humidity ratio rather than the inlet parameters of the dehumidifier. The online model was derived from the heat and mass transfer principle and can be described by an exponential function. The dynamic response can be divided into two stages taking the maximum air outlet humidity ratio changing rate as a dividing point. The two unknown parameters (the maximum air outlet humidity ratio changing rate and the time coefficient) in the online model were determined by the first stage of dynamic response, and then the online model predicted the dynamic response of the packed dehumidifier at the second stage. The online model agreed well with the experimental data, casting a new light on learning the internal relation of the dynamic processes of a packed dehumidifier. Furthermore, the relation between the variation of inlets and dynamic response of air outlet humidity ratio could be predicted quickly using the proposed model, contributing to control algorithm development. And a preliminary idea about how to construct an appropriate controller based on the proposed model is presented, which provides a reference for further study.
An online model for predicting dynamic response of a packed liquid desiccant dehumidifier
Abstract Liquid desiccant dehumidification systems show significant energy-saving potential in HVAC applications. The dynamic characteristics of a liquid desiccant dehumidifier attract increasing attentions in recent years, which are essential for designing appropriate controllers for it. However, due to the complicate coupling of heat and mass transfer inside the dehumidifier, there are few models have been developed for predicting the dynamic characteristics of a packed liquid desiccant dehumidifier. In this paper, an online model was proposed, which predicted the dynamic response of a packed dehumidifier mainly based on the air outlet humidity ratio rather than the inlet parameters of the dehumidifier. The online model was derived from the heat and mass transfer principle and can be described by an exponential function. The dynamic response can be divided into two stages taking the maximum air outlet humidity ratio changing rate as a dividing point. The two unknown parameters (the maximum air outlet humidity ratio changing rate and the time coefficient) in the online model were determined by the first stage of dynamic response, and then the online model predicted the dynamic response of the packed dehumidifier at the second stage. The online model agreed well with the experimental data, casting a new light on learning the internal relation of the dynamic processes of a packed dehumidifier. Furthermore, the relation between the variation of inlets and dynamic response of air outlet humidity ratio could be predicted quickly using the proposed model, contributing to control algorithm development. And a preliminary idea about how to construct an appropriate controller based on the proposed model is presented, which provides a reference for further study.
An online model for predicting dynamic response of a packed liquid desiccant dehumidifier
Zhang, Xiaobo (author) / Xu, Xiangguo (author) / Zhu, Yuxian (author)
Energy and Buildings ; 224
2020-06-04
Article (Journal)
Electronic Resource
English
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