Numerical study on the performance of an air—Multiple PCMs unit for free cooling and ventilation

Liu, Shuli; Iten, Muriel; Shukla, Ashish

doi:10.1016/j.enbuild.2017.07.005

Cited by 46 publications

(13 citation statements)

References 17 publications

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“…Conventional TES in an A‐CAES system composed of one heat storage medium (such as phase change material or sand, et al) is difficult to meet the changing needs of temperature. Thus, a TES that can store thermal energy at different temperatures is necessary …”

Section: Thermodynamic Modelmentioning

confidence: 99%

“…[2,33] However, we expect that the thermal oil enters the intercooler (IC1, IC2, and IC3) at as low of at emperature as possible to absorb much more heat during the charge process.C onventional TES in an A-CAES system composed of one heat storage medium (such as phase changem aterial or sand, et al)i sd ifficult to meet the changing needs of temperature.T hus,a TES that can store thermal energy at different temperatures is necessary. [34] To improve the thermal energy storage capacity,t he TES is composed of several phase changem aterials (PCMs) separated by the heating-insulting layers to create alternating compartments of each material. Each compartment is filled up with one material and the heat transfer can be assumed at ar apid rate to store much more thermal energy.D ifferent PCMs can capture thermal energy in different temperatures during charge stage and can releaset he stored energy in different temperatures during discharge stage,w hich can well match the changing temperature of hot oil, resulting in the less exergyd estruction than that of one material TES.…”

Section: Thermalenergy Storagementioning

confidence: 99%

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Thermo‐Economic Analysis and Optimization of Adiabatic Compressed Air Energy Storage (A‐CAES) System Coupled with a Kalina Cycle

Wang

2018

Energy Tech

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An adiabatic compressed air energy storage system (A‐CAES) can improve the energy storage potential, compared with conventional CAES systems, by capturing the heat generated during the charge stage. However, a challenge remains in the utilization step of the stored thermal energy due to the energy loss from the thermal energy storage vessel, which has hindered commercialization of A‐CAES. To utilize the thermal energy produced by a compressor during the charge process efficiently, a novel system that couples A‐CAES system with the Kalina cycle (KC) is designed to recover the loss of heat. In the new system, which is characterized by a higher and more stable power output, a Kalina cycle and the expander absorb the heat released from thermal energy storage units to generate electricity. Theoretical thermodynamic analysis shows that the novel combined system can achieve more efficient operation than a single A‐CAES system. By examining the effects of key thermodynamic parameters on the exergy efficiency and overall capital cost, a Pareto frontier obtained shows the tradeoff between exergy efficiency and overall capital cost of the system, where 47.17 % and 1.455 k$ kW−1 are determined as the optimum values for the two objectives from the optimum design solutions.

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Section: Thermodynamic Modelmentioning

confidence: 99%

Section: Thermalenergy Storagementioning

confidence: 99%

Thermo‐Economic Analysis and Optimization of Adiabatic Compressed Air Energy Storage (A‐CAES) System Coupled with a Kalina Cycle

Wang

2018

Energy Tech

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“…[9][10][11][12] Methods for LHS performance enhancement include extending heat transfer surface, [13][14][15][16][17][18][19] improving process uniformity 7,20 and enhancing PCM conductivity. [9][10][11][12] Methods for LHS performance enhancement include extending heat transfer surface, [13][14][15][16][17][18][19] improving process uniformity 7,20 and enhancing PCM conductivity.…”

Section: Introductionmentioning

confidence: 99%

“…In order to improve the performance of latent heat storage systems, researchers have conducted a large number of studies. [9][10][11][12] Methods for LHS performance enhancement include extending heat transfer surface, [13][14][15][16][17][18][19] improving process uniformity 7,20 and enhancing PCM conductivity. [21][22][23][24][25][26][27][28][29] Lohrasbi et al 13 and Kabbara et al 14 used axially fins and radially fins, respectively, to extend the heat transfer surface area.…”

mentioning

confidence: 99%

“…In the past decade, multiple PCMs were extensively used for improving process uniformity that is essential in the consideration of the thermal performance enhancement of energy systems. Narasimhan 7 and Liu et al 20 investigated the heat transfer behaviors of multiple PCM modules and assessed the improvement of the thermal storage systems. It was revealed that thermal performance was significantly improved due to the more uniform temperature field caused by the arrangement of cascaded PCMs.…”

mentioning

confidence: 99%

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Conduction paths of backbones for thermal enhancement of nanocomposite phase change materials

Zhou

Zhao

et al. 2019

Int J Energy Res

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Thermal energy storage (TES) based on phase change materials (PCMs) has become a research hot spot due to its high energy storage density and maintained operating temperature during the phase change. However, as PCM has a poor thermal conductivity that can be as low as 0.2~0.5 W/m·K, the charging/discharging processes of PCM modules are significantly restrained, which severely affects the application of the TES technology in industrial sectors. This study concerns the improvement of the effective thermal conductivity of composite PCM formed by adding nanoparticles with high thermal conductivity into different PCMs. A theoretical model is established to reveal the intrinsic mechanism for the promotion of thermal conductivity of composite PCM consisting of nanoparticles. The results show that aggregation and interfacial thermal resistance are the main reasons for the change of the thermal conductivity. By forming effective conduction paths composed of backbones in the composite PCM, the average thermal conductivity can be improved significantly, which can be as high as 10~50 W/m·K with a wide range of volume fraction of the additives.

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Effect of phase change material plates' arrangements on charging and discharging of energy storage in building air free cooling

2020

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Previous examinations of building air free cooling using phase change material (PCM) plates were numerically conducted for specific arrangements/configurations of PCMs plates. Experimental investigation for models validations and comparison between the different configurations of PCMs are the shortages of these studies. The present research experimentally investigates the effects of the PCM plate's arrangements on the thermal characteristics of the charging and discharging processes. Parallel and staggered arrangements of different spaces between the plates were tested. The effect of plates' arrangements on the discharging time and quantity of PCM needed to fulfill the required free cooling are also investigated. The results showed that (a) in parallel arrangement, the discharge time decreases with decreasing spaces between PCM plates; (b) the discharge time in staggered arrangement is longer than that of parallel arrangement by 63%; (c) putting PCM plates on large numbers of rows increases the discharge time; (d) in staggered arrangement, the discharge time increases with decreasing spacing between PCMs plates; (e) the needed quantity of PCMs plates in staggered arrangement is lower than that of parallel arrangement by about 67%; and (f) generally, staggered arrangement with low spaces between PCMs plates is the optimum arrangement for air free cooling as it has the longest discharge time.

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Numerical study on the performance of an air—Multiple PCMs unit for free cooling and ventilation

Cited by 46 publications

References 17 publications

Thermo‐Economic Analysis and Optimization of Adiabatic Compressed Air Energy Storage (A‐CAES) System Coupled with a Kalina Cycle

Thermo‐Economic Analysis and Optimization of Adiabatic Compressed Air Energy Storage (A‐CAES) System Coupled with a Kalina Cycle

Conduction paths of backbones for thermal enhancement of nanocomposite phase change materials

Effect of phase change material plates' arrangements on charging and discharging of energy storage in building air free cooling

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