Experimental research on the cooling performance of a new regenerative dew point indirect evaporative cooler

Chu, Junjie; Xu, Wei; Fu, Yijun; Huo, Huimin

doi:10.1016/j.jobe.2021.102921

Cited by 12 publications

(4 citation statements)

References 12 publications

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“…The heated air stream then passes through the desiccant wheel (7-8) and removes the absorbed water. In the HDH desalination cycle, the inlet air (10) consists of the moist waste air from the rotary desiccant wheel (8) and the M-cycle cooler (9). This mixed air is sent to the humidifier, where it is further humidified and heated by the heated brine (10)(11).…”

Section: Ventilation Modementioning

confidence: 99%

“…This technology eliminates the need for chemical refrigerants and mechanical compressors, as the cooling process is completed by water evaporation [7]. In 2002, a novel thermodynamic cycle of IEC was developed by Maisotsenko, also known as the M-cycle [8]. In this cycle, a fraction of the pre-cooled supply air is redirected to wet channels as the working air, allowing the product air to be cooled below the WBT and towards the dew point temperature (DPT) of the incoming air at a constant humidity level [9,10].…”

Section: Introductionmentioning

confidence: 99%

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Cooling and Water Production in a Hybrid Desiccant M-Cycle Evaporative Cooling System with HDH Desalination: A Comparison of Operational Modes

et al. 2023

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In this paper, the cooling and freshwater generation performance of a novel hybrid configuration of a solid desiccant-based M-cycle cooling system (SDM) combined with a humidification–dehumidification (HDH) desalination unit is analysed and compared in three operational modes: ventilation, recirculation, and half recirculation. The HDH unit in this system recycles the moist waste air sourced from the M-cycle cooler and rotary desiccant wheel of the SDM system to enhance water production. A mathematical model was established and solved using TRNSYS and EES software. The results of this study indicate that the recirculation mode exhibited superior cooling performance compared to the other two modes, producing up to 7.91 kW of cooling load and maintaining a supply air temperature below 20.85 °C and humidity of 12.72 g/kg under various ambient conditions. All the operational modes showed similar water production rates of around 52.74 kg/h, 52.43 kg/h, and 52.14 kg/h for the recirculation, half-recirculation and ventilation modes, respectively, across a range of operating temperatures. The recirculation mode also exhibited a higher COP compared to the other modes, as the environmental temperature and relative humidity were above 35 °C and 50%. However, it should be noted that the implementation of the recirculation mode resulted in a higher water consumption rate, with a maximum value of 5.52 kg/h when the inlet air reached 45 °C, which partially offset the benefits of this mode.

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Section: Ventilation Modementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Cooling and Water Production in a Hybrid Desiccant M-Cycle Evaporative Cooling System with HDH Desalination: A Comparison of Operational Modes

et al. 2023

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“…DIEC heat exchangers, such as traditional IEC systems, can operate in counter-flow and cross-flow configurations, but the counter-flow arrangement is the most common one. As the DIEC technology appears to be very promising, its performance have been thoroughly studied by means of in-depth experimental investigations [57,58], by performing an energy and exergy analysis [59], and also through the artificial neural network method [60]. Moreover, new types of coatings [61] and geometries [62] of the plates have been investigated, and the DIEC system has been integrated into other more complex heat exchangers [63,64], in order to improve its performance.…”

Section: Diec Systemsmentioning

confidence: 99%

Modeling of Indirect Evaporative Cooling Systems: A Review

Caruana,

De Antonellis,

Marocco

et al. 2023

Fluids

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Air-to-air indirect evaporative cooling (IEC) systems are particular heat exchangers that use the latent heat of evaporation of water to cool down an air stream, without increasing its specific humidity, thus guaranteeing adequate thermohygrometric conditions in the refrigerated environment with low energy consumption. Dew-point indirect evaporative cooling (DIEC) systems are based on the IEC technology, but they recirculate a part of the air taken from the room to be refrigerated, in order to possibly achieve a lower air temperature. IEC and DIEC systems are becoming increasingly common these years, as they can ensure a good efficiency, minimizing the environmental impact of the air-conditioning system. Consequently, it has been necessary to develop models, both analytical and numerical, to quickly and accurately design this type of system and to predict their performance. This paper presents a review of the analytical and numerical models developed specifically for IEC and DIEC systems, highlighting their method, main innovations and advantages, and possible limitations. From this analysis, it emerged that analytical models have been developed since the late 1990s and only few of them are suitable for DIEC heat exchangers, while numerical models for both IEC and DIEC systems are gaining popularity in recent years. Almost all the analyzed models have been validated by comparison with numerical and/or experimental data, showing a maximum discrepancy within 10% in the majority of the cases. However, the validations were performed for a few specific cases, so in real applications it might be difficult to associate the model boundary conditions and the heat exchangers operating conditions, such as nozzles orientations, plates materials, water flow rates, and configurations. Another common limitation concerns the modeling of some properties, as wettability factor and air density, which might affect the accuracy of the results.

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“…Its condensation method is not enough to achieve the dehumidification goal [7]. Chu et al [8] found that the heat transfer performance of a regenerative indirect evaporative cooler (RIEC) is not prominent in wet areas. On the other hand, the reduced vapor pressure difference of LDD at high temperatures compromises its dehumidification efficacy [9].…”

Section: Introductionmentioning

confidence: 99%

Optimization of the Liquid Desiccant Cooling Systems in Hot and Humid Areas

Zhang,

Yang

et al. 2023

Sustainability

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Air-conditioning systems in hot and humid regions account for over 50% of total energy usage. Integrating an indirect evaporative cooling (IEC) and a liquid desiccant dehumidifier (LDD) as the liquid desiccant cooling system (LDCS) presents an energy-saving and emission-reducing solution to replace traditional mechanical vapor compression refrigeration (MVCR) systems. This integration overcomes the regional limitations of IEC in hot and humid areas. The newly developed LDCS uses exhaust air as the working air source and solar energy as the heat source for desiccant solution regeneration. This study aims to develop an empirical model for the outlet parameters of the LDCS, propose an optimization strategy for its operating parameters, and assess the potential and energy performance through parameter analysis and multifactor optimization. By conducting sensitivity analysis and optimizing six critical parameters based on a response surface model (RSM), the system outlet temperature, relative humidity, and coefficient of performance (COP) are improved as the optimization objectives. The regional capability is demonstrated in three selected hot and humid cities. The results indicate that the LDCS can significantly increase the COP by 57.3%. Additionally, it can meet the dehumidification demand when operating with 25% of the air extracted in the RIEC during months with high humidity and temperature. This study will facilitate the application of IEC and LDD technologies, guide the design and operation scheme of the system, and promote energy-saving and emission-reducing solutions in hot and humid regions.

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Experimental research on the cooling performance of a new regenerative dew point indirect evaporative cooler

Cited by 12 publications

References 12 publications

Cooling and Water Production in a Hybrid Desiccant M-Cycle Evaporative Cooling System with HDH Desalination: A Comparison of Operational Modes

Cooling and Water Production in a Hybrid Desiccant M-Cycle Evaporative Cooling System with HDH Desalination: A Comparison of Operational Modes

Modeling of Indirect Evaporative Cooling Systems: A Review

Optimization of the Liquid Desiccant Cooling Systems in Hot and Humid Areas

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