Performance comparisons of desiccant wheels for air dehumidification and enthalpy recovery

Zhang, Li‐Zhi; Niu, Jianlei

doi:10.1016/s1359-4311(02)00050-9

Cited by 219 publications

(66 citation statements)

References 11 publications

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“…Performing an energy analysis of the desiccant wheel requires adopting a numerical model to predict the state of the streams leaving the wheel. Models in the literature largely fall into two categories: (1) coupled partial differential equation models accounting for the dynamic processes occurring within the wheel [44][45][46] and (2) simplified models based on correlations derived empirically. 47 More recently, Fu et al 48 presented a micro-scale molecular dynamics sub-model coupled to a macro-scale heat and mass transfer sub-model.…”

Section: Model Developmentmentioning

confidence: 99%

Next-generation HVAC: Prospects for and limitations of desiccant and membrane-based dehumidification and cooling

et al. 2017

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Recently, next-generation HVAC technologies have gained attention as potential alternatives to the conventional vapor-compression system (VCS) for dehumidification and cooling. Previous studies have primarily focused on analyzing a specific technology or its application to a particular climate. A comparison of these technologies is necessary to elucidate the reasons and conditions under which one technology might outperform the rest. In this study, we apply a uniform framework based on fundamental thermodynamic principles to assess and compare different HVAC technologies fromGeneration HVAC: Prospects for and Limitations of Desiccant and Membrane-Based Dehumidification and Cooling," Applied Energy, 200:330-346, 15 August 2017.an energy conversion standpoint. The thermodynamic least work of dehumidification and cooling is formally defined as a thermodynamic benchmark, while VCS performance is chosen as the industry benchmark against which other technologies, namely desiccant-based cooling system (DCS) and membrane-based cooling system (MCS), are compared. The effect of outdoor temperature and humidity on device performance is investigated, and key insights underlying the dehumidification and cooling process are elucidated. In spite of the great potential of DCS and MCS technologies, our results underscore the need for improved system-level design and integration if DCS or MCS are to compete with VCS. Our findings have significant implications for the design and operation of next-generation HVAC technologies and shed light on potential avenues to achieve higher efficiencies in dehumidification and cooling applications.

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Section: Model Developmentmentioning

confidence: 99%

Next-generation HVAC: Prospects for and limitations of desiccant and membrane-based dehumidification and cooling

et al. 2017

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“…The dehumidification efficiency of the solid desiccant modules η was determined as the ratio of the transient moisture removal to the humidity ratio of the inlet airflow, as in Equation (2) [19].…”

Section: Methodsmentioning

confidence: 99%

Performance Investigation of the Novel Solar-Powered Dehumidification Window for Residential Buildings

et al. 2017

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Abstract:In this paper, a solar-powered dehumidification window (SPDW), combining a conventional double-glazed building window with a solid desiccant packed bed and a photovoltaic panel, has been proposed to dehumidify the air supplied to a residential building in an energy-saving way. The solid desiccant packed bed was installed between the double layers of the residential window to achieve the compact building-integrated window-dehumidifying system that could be regenerated by solar energy, and the photovoltaic panel was used to compensate the electricity for the operation of the fans to supply the air to the building. To investigate the dehumidification and regeneration performance of the SPDW, the transient moisture removal, dehumidification efficiency, temperature difference between the building inlet and outlet air, heat transfer characteristics, desiccant temperature, regeneration rate, and the power of the fans and the photovoltaic panel were analysed for different inlet air conditions and simulated solar radiation. It was found that, for the system operated under an inlet air temperature of 19.2 • C and a relative humidity of 86.1% during the dehumidification process, the system performed with a maximum transient moisture removal of 7.1 g/kg, a maximum dehumidification efficiency of 58.60%, a maximum temperature difference between the inlet and outlet air of 10.7 • C, and a maximum released adsorption heat absorbed by the dehumidified air of 89.66%. In the regeneration process, the system performed with a maximum desiccant temperature of 35.3 • C, a maximum regeneration rate of 153 g/h, and a maximum power of the photovoltaic panels of 39.83 W under the simulated solar radiation of 900 W/m 2 . The results from the established semi-empirical model agreed well with the testing results, and the model could be used to predict the water content ratio of the desiccant modules during the dehumidification process under different conditions, which will be helpful in the analysis and application of the SPDW in the future.

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“…Figure 11 presents the variation of the speed of dehumidification with time [25]. From the figure it can be seen that the maximum speed of dehumidification occurred at the beginning of the dehumidification process since the water vapour pressure difference between the silica gel and the inlet air was greatest at this stage, resulting in the maximum speed of dehumidification.…”

Section: Speed Of Dehumidificationmentioning

confidence: 97%

Performance Study of a Novel Solar Solid Dehumidification/Regeneration Bed for Use in Buildings Air Conditioning Systems

et al. 2017

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Abstract:In this paper, a novel solar solid dehumidification/regeneration bed has been proposed, and its three regeneration methods, i.e., simulated solar radiation regeneration, microwave regeneration, and combined regeneration of the microwave and simulated solar radiation, were experimentally investigated and compared, as well as the dehumidification performance. The degree of regeneration of the proposed system under the regeneration method combining both microwave irradiation and simulated solar radiation could reach 77.7%, which was 3.77 times higher than that of the system under the simulated solar regeneration method and 1.05 times higher than that of the system under the microwave regeneration. The maximum energy efficiency of the proposed system under the combined regeneration method was 21.7%, while it was only 19.4% for the system under microwave regeneration. All these proved that the combined regeneration method of the simulated solar and microwave radiation not only improved the regeneration efficiency of the system, but also enhanced the energy efficiency. For the dehumidification performance, the maximum transient moisture removal was 14.1 g/kg, the maximum dehumidification efficiency was 68.0% and the maximum speed of dehumidification was 0.294 g/(kg·s) when the inlet air temperature was at 26.09 • C and the air relative humidity was at 89.23%. By comparing the testing results with the semi-empirical results from the Page model, it was indicated that the Page model can predict the regeneration characteristics of the novel solar solid dehumidification/regeneration bed under the combined method of microwave and simulated solar regeneration. The results of this research should prove useful to researchers and engineers to exploit the potential of solar technologies in buildings worldwide.

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Performance comparisons of desiccant wheels for air dehumidification and enthalpy recovery

Cited by 219 publications

References 11 publications

Next-generation HVAC: Prospects for and limitations of desiccant and membrane-based dehumidification and cooling

Next-generation HVAC: Prospects for and limitations of desiccant and membrane-based dehumidification and cooling

Performance Investigation of the Novel Solar-Powered Dehumidification Window for Residential Buildings

Performance Study of a Novel Solar Solid Dehumidification/Regeneration Bed for Use in Buildings Air Conditioning Systems

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