A modeling study on the heat storage and release characteristics of a phase change material based double-spiral coiled heat exchanger in an air source heat pump for defrosting

This communication extends the thermodynamic analysis of latent heat storage in a shell-and-tube heat exchanger, developed recently, to the complete heat storage-removal cycle. Conditions for the cyclic operation of this system are formulated within the quasi-steady approximation for the axisymmetric two-dimensional conduction-controlled phase change. Explicit expressions for the overall number of entropy generation units that account for heat transfer and pressure drop irreversibilities are derived. Optimization of this figure of merit with respect to the freezing point of the phase-change material and with respect to the number of heat transfer units is analyzed. When the frictional irreversibilities of the heat removal stage are negligible, the results of these studies are in agreement with those developed recently by De Lucia and Bejan (1991) for a one-dimensional latent heat storage system.

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Performance analysis of heat storage of direct-contact heat exchanger with phase-change material

Applied Thermal Engineering ◽

10.1016/j.applthermaleng.2013.03.041 ◽

2013 ◽

Vol 58 (1-2) ◽

pp. 108-113 ◽

Cited By ~ 25

Author(s):

Takahiro Nomura ◽

Masakatsu Tsubota ◽

Akihito Sagara ◽

Noriyuki Okinaka ◽

Tomohiro Akiyama

Keyword(s):

Heat Exchanger ◽

Performance Analysis ◽

Phase Change ◽

Phase Change Material ◽

Direct Contact ◽

Heat Storage ◽

Contact Heat ◽

Direct Contact Heat Exchanger ◽

Change Material

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Experimental demonstration of an air-source heat pump application using an integrated phase change material storage as a desuperheater for domestic hot water generation

Applied Energy ◽

10.1016/j.apenergy.2021.117890 ◽

2022 ◽

Vol 305 ◽

pp. 117890

Author(s):

Johann Emhofer ◽

Klemens Marx ◽

Andreas Sporr ◽

Tilman Barz ◽

Birgo Nitsch ◽

...

Keyword(s):

Phase Change ◽

Phase Change Material ◽

Heat Pump ◽

Hot Water ◽

Experimental Demonstration ◽

Domestic Hot Water ◽

Air Source Heat Pump ◽

Change Material

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Heat storage in direct-contact heat exchanger with phase change material

Applied Thermal Engineering ◽

10.1016/j.applthermaleng.2012.04.062 ◽

2013 ◽

Vol 50 (1) ◽

pp. 26-34 ◽

Cited By ~ 44

Author(s):

Takahiro Nomura ◽

Masakatsu Tsubota ◽

Teppei Oya ◽

Noriyuki Okinaka ◽

Tomohiro Akiyama

Keyword(s):

Heat Exchanger ◽

Phase Change ◽

Phase Change Material ◽

Direct Contact ◽

Heat Storage ◽

Contact Heat ◽

Direct Contact Heat Exchanger ◽

Change Material

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Defrosting Performance Improvement of Air-Source Heat Pump Combined Refrigerant Direct-Condensation Radiant Floor Heating System with Phase Change Material

Energies ◽

10.3390/en13184594 ◽

2020 ◽

Vol 13 (18) ◽

pp. 4594 ◽

Cited By ~ 1

Author(s):

Chenxiao Zheng ◽

Shijun You ◽

Huan Zhang ◽

Zeqin Liu ◽

Wandong Zheng ◽

...

Keyword(s):

Phase Change ◽

Phase Change Material ◽

Heat Pump ◽

Heating System ◽

Air Source Heat Pump ◽

Composite Phase Change Material ◽

Radiant Floor Heating System ◽

Radiant Floor Heating ◽

Change Material ◽

Floor Heating

Traditional defrosting methods applied to solve frosting problems of air-source heat pumps operating in cold periods may reduce heat capacity of the system and decrease indoor thermal comfort. In order to improve the performance of air-source heat pump (ASHP) and maintain indoor temperature in defrosting conditions, an air-source heat pump combined with a refrigerant direct-condensation radiant floor heating system with phase change material is proposed and evaluated in this study. Two radiant floor heating terminals with and without composite phase change material modules were compared through experiments. A composite phase change material based on dodecanoic acid-tetradecanol-hexadecanol mixture and expanded graphite was investigated for this application. Experimental results indicate that both heat fluxes of two comparing terminals are higher than 70 W/m2 in heating condition. At the same time, the floor surface temperature, indoor air temperature, and heating capacity of the terminal with composite phase change material modules are higher than those without composite phase change material modules in defrosting condition. This suggests that the proposed system with composite phase change material modules can improve indoor thermal comfort in defrosting condition as well as satisfy the heating requirement in heating condition.

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Dynamic numerical study on phase change thermal storage heat transfer

Thermal Science ◽

10.2298/tsci2106171c ◽

2021 ◽

Vol 25 (6 Part A) ◽

pp. 4171-4179

Author(s):

Jie Cui ◽

Guofeng Wang ◽

Zhitang Guo ◽

Shuo Yang ◽

Honggang Pan ◽

...

Keyword(s):

Heat Transfer ◽

Heat Exchanger ◽

Heat Exchange ◽

Phase Change ◽

Phase Change Material ◽

Heat Storage ◽

Thermal Storage ◽

Transfer Effect ◽

Fin Spacing ◽

Change Material

Targeted at the poor heat transfer effect of the phase change thermal storage heat exchanger due to the low thermal conductivity of the phase change material, a fin-tube type phase change thermal storage heat exchanger has been proposed in the study. A 2-D model of the phase-change heat storage unit was established, and the dynamic heat transfer law of the melting and solidification of the phase change material, and the influence of the fin structure size on the heat storage/release performance of the heat exchanger were numerically analyzed. The results show that in the area close to the tube wall, the smaller the fin spacing, the larger the thickness, the faster the phase change heat storage/release speed, and the better heat transfer effect. In the central area of the phase change material, the greater the fin spacing and thickness, and the better the heat transfer effect of the phase change heat storage/release. The area close to the outer wall has the smallest temperature change, and the heat storage/release effect is the worst. Therefore, the use of energy storage heat exchangers with gradual fin thickness and spacing is an effective method to improve the heat transfer efficiency of existing equipment. In addition, in order to improve the heat exchange effect of the edge area of the phase change, its structure could be changed or the heat exchange form can be increased.

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