Performance investigation of a counter-flow heat pump driven liquid desiccant dehumidification system

Xie, Ying; Zhang, Tao; Liu, Xiaohua

doi:10.1016/j.energy.2016.09.037

Cited by 52 publications

(13 citation statements)

References 28 publications

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“…On the other hand, the waster block temperatures at the cooling or heating sides of the TEM heat pump should be maintained constantly under a given operating condition; therefore, in theory, one might also estimate the outlet water temperatures using Equation (13) with the assumption that the water was cooled or heated through the pipe with a constant surface temperature (13) [24].…”

Section: Model Validationmentioning

confidence: 99%

“…Interestingly, one can also see that the outlet water temperatures predicted by the theoretical condenser equation were also well matched with the measured data within 2% error bounds. On the other hand, the waster block temperatures at the cooling or heating sides of the TEM heat pump should be maintained constantly under a given operating condition; therefore, in theory, one might also estimate the outlet water temperatures using Equation (13) with the assumption that the water was cooled or heated through the pipe with a constant surface temperature (13) [24]. = − − exp(− ) (13) In Figure 6, the predicted outlet water temperatures that were acquired from the proposed empirical models and from the theoretical equation (Equation (13)) for the convection heat transfer of the internal flow in a pipe at constant surface temperature were compared with the actual outlet water temperatures measured in the additional experiments.…”

Section: Model Validationmentioning

confidence: 99%

“…It seems that the heat generation by the Joule's effect in the TEMs offset the heat loss to the cold side, so that the predicted outlet temperatures at the hot side using proposed model and Equation (13) agreed better. However, the heat transferred by conduction [4] from hot side to cold side reduced the cooling effect at the cold side of the thermoelectric heat pump, which caused discrepancy between the outlet water temperatures at the cold side predicted by the proposed model and those that were determined by Equation (13). From this observation, one can conclude that the undesirable heat transfer between the hot side and cold side in the TEM heat pump has less negative impact on the heating effect at the hot side when compared with the cooling effect at the cold side.…”

Section: Model Validationmentioning

confidence: 99%

“…Also, the models were developed to analyze the thermal and energy performances. However, most studies in the field of TEM have not dealt with simultaneous using of cooling and heating such as in the field of conventional vapor compression heat pump [13,14]. There are some literatures investigating TEM applications providing simultaneous cooling and heating of working fluids.…”

Section: Introductionmentioning

confidence: 99%

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Empirical Analysis for the Heat Exchange Effectiveness of a Thermoelectric Liquid Cooling and Heating Unit

2018

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This study aims to estimate the performance of thermoelectric module (TEM) heat pump for simultaneous liquid cooling and heating and propose empirical models for predicting the heat exchange effectiveness. The experiments were conducted to investigate and collect the performance data of TEM heat pump where the working fluid was water. A total of 57 sets of experimental data were statistically analyzed to estimate the effects of each independent variable on the heat exchange effectiveness using analysis of variance (ANOVA). To develop the empirical model, the six design parameters were measured: the number of transfer units (NTU) of the heat exchangers (i.e., water blocks), the inlet water temperatures and temperatures of water blocks at the cold and hot sides of the TEM. As a result, two polynomial equations predicting heat exchange effectiveness at the cold and hot sides of the TEM heat pump were derived as a function of the six selected design parameters. Also, the proposed models and theoretical model of conventional condenser and evaporator for heat exchange effectiveness were compared with the additional measurement data to validate the reliability of the proposed models. Consequently, two conclusions have been made: (1) the possibility of using the TEM heat pump for simultaneous cooling and heating was examined with the maximum temperature difference of 30 • C between cold and hot side of TEM, and (2) it is revealed that TEM heat pump has difference with the conventional evaporator and condenser from the comparison results between the proposed models and theoretical model due to the heat conduction and Joule effect in TEM.

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Section: Model Validationmentioning

confidence: 99%

Section: Model Validationmentioning

confidence: 99%

Section: Model Validationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Empirical Analysis for the Heat Exchange Effectiveness of a Thermoelectric Liquid Cooling and Heating Unit

2018

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“…In the aspects of system level improvements, Xie et al [45] used a two-stage heat pump cycle to improve the energy efficiency of the system. Niu et al [46] discussed the interactions between LDDS and heat pump, and proposed that a hybrid system with double-condenser was a reasonable arrangement.…”

Section: Improvement Of System Structurementioning

confidence: 99%

Modeling and control of dehumidifier in distributed operating liquid desiccant dehumidification system

Wu¹

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Liquid Desiccant Dehumidification System (LDDS) achieves low humidity level with relatively low energy consumption, which is an outstanding alternative to conventional airconditioning system in removing the moisture in the air. In industrial or commercial buildings, dehumidifiers of LDDS are usually located at different floors in a distributed manner, while the heat source utilized for regeneration such as the waste heat or solar energy are in the plant room or on the rooftop in a centralized form. Conventional LDDSs regulate the solution concentration in the dehumidifier by continuously exchanging the desiccant solution between dehumidifier and regenerator, which limits LDDS to a one dehumidifier vs. one regenerator arrangement. To take full advantage of the building recourses, a scheme of multiple dehumidifiers working with one regenerator is more efficient. Meanwhile, new technical issues have been raised together with this mechanism, such as detecting and maintaining solution concentration and the solution transfer among the components of a system with multiple terminals. Therefore, this thesis tries to provide some deep discussions on the questions generated from the distributed operating manner to further popularize LDDS in building application. The major contributions are as follows: A buffer integrated dehumidifier has been proposed to realize the distributed operation, and new mathematical model has been developed and validated to describe the dynamic profiles of the dehumidification and concentration variation process during the system operating, including the moisture absorption, strong solution charging, solution mixing, circulating and excavating. A concentration regulation strategy has been developed to control the working solution concentration in the dehumidifier. Model-based soft-sensors are designed to detect the working solution concentrations of dehumidifier and regenerator to provide the concentration information of the two towers for the regulation strategy. Experimental studies on an actual system have been carried out to further verify the efficiency of this concentration regulation strategy with the assistance of the soft-sensors.

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Performance evaluation of enhanced geothermal-based desiccant cooling and heating systems for an office building

Borji

Ziapour

2022

Int. J. Environ. Sci. Technol.

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Performance investigation of a counter-flow heat pump driven liquid desiccant dehumidification system

Cited by 52 publications

References 28 publications

Empirical Analysis for the Heat Exchange Effectiveness of a Thermoelectric Liquid Cooling and Heating Unit

Empirical Analysis for the Heat Exchange Effectiveness of a Thermoelectric Liquid Cooling and Heating Unit

Modeling and control of dehumidifier in distributed operating liquid desiccant dehumidification system

Performance evaluation of enhanced geothermal-based desiccant cooling and heating systems for an office building

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