Experimental study of closed‐loop thermosyphon with a different evaporator geometry

Aljuboori, Adeeb A. A.; Ahmed, Saba Y.; Jabbar, Mohammed Y.

doi:10.1002/htj.21887

Cited by 2 publications

(3 citation statements)

References 36 publications

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“…Also, investigated numerical and an experimental of the TPCT charged with working fluids (ethanol, acetone, butanol, water, R-134a, and methanol) and filling ratios (40% to 100%). (Adeeb, A., et al, 2021), investigated the thermal performance of CLT with various evaporator geometry. The water was used only as a working fluid, with different FR=50,70 and 100 %.The heat load and cooling flow rate were constant with magnitudes (185 W, 2 L/min.)…”

Section: Table1mentioning

confidence: 99%

Parametric Study of a Two-Phase Closed Thermosyphon Loop

Obaid

Sarsam

2022

jcoeng

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A theoretical and experimental investigation was carried out to study the behavior of a two-phase closed thermosyphon loop (TPCTL) during steady-state operation using different working fluids. Three working fluids were investigated, i.e., distilled water, methanol, and ethanol. The TPCTL was constructed from an evaporator, condenser, and two pipelines (riser and downcomer). The driving force is the difference in pressure between the evaporator and condenser sections and the fluid returns to the heating section by gravity. In this study, the significant parameters used in the experiments were filling ratios (FR%) of 50%, 75%, and 100% and heat-input range at the evaporator section of 215-860.2 W. When the loop reached to the steady-state, the wall-temperature was recorded at various positions along the thermosyphon loop. Results showed that the thermal performance with water was better than methanol and ethanol with same condition. The experimental values of the heat transfer coefficient at the evaporator section were measured for the three working fluids. The results were estimated with the nucleate boiling correlation using engineering equation solver (ESS) program. In addition, a comparison between the experimental ( ) and theoretical ( values of heat transfer coefficient in the evaporator section showed good agreement with a maximum difference of 16%.

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Section: Table1mentioning

confidence: 99%

Parametric Study of a Two-Phase Closed Thermosyphon Loop

Obaid

Sarsam

2022

jcoeng

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“…2,[9][10][11] These HPHEs have very good features like nonrequirement of input power, operational even at a very small temperature difference between the source and sink streams, have less maintenance problems due to the absence of any moving parts, and the two gas streams are not cross-contaminated. 12,13 These encouraging features boost the focus toward further detailed investigation on the thermal performance of HPHEs. [9][10][11] Heat pipes are heat recovery devices that transfer heat from one airstream to another using the following processes: evaporation of the working fluid in the evaporator section; flow of vapor to the condenser section; condensation of vapor in the condenser section; and return of the condensate to the evaporator section.…”

Section: Introductionmentioning

confidence: 99%

“…Accordingly, heat pipe heat exchangers (HPHEs) are one of the devices that can be effectively used to recover energy in decentralized ventilation systems by transferring heat between two gas streams, such as the exhaust and fresh air streams in the ventilation units of the air‐conditioning systems 2,9–11 . These HPHEs have very good features like nonrequirement of input power, operational even at a very small temperature difference between the source and sink streams, have less maintenance problems due to the absence of any moving parts, and the two gas streams are not cross‐contaminated 12,13 . These encouraging features boost the focus toward further detailed investigation on the thermal performance of HPHEs 9–11 …”

Section: Introductionmentioning

confidence: 99%

Theoretical and experimental investigation of a heat pipe heat exchanger for energy recovery of exhaust air

Ali

Sarsam

2022

Heat Trans

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Heat pipes and two‐phase thermosyphon systems are passive heat transfer systems that employ a two‐phase cycle of a working fluid within a completely sealed system. Consequently, heat exchangers based on heat pipes have low thermal resistance and high effective thermal conductivity, which can reach up to the order of (105 W/(m K)). In energy recovery systems where the two streams should be unmixed, such as air‐conditioning systems of biological laboratories and operating rooms in hospitals, heat pipe heat exchangers (HPHEs) are recommended. In this study, an experimental and theoretical study was carried out on the thermal performance of an air‐to‐air HPHE filled with two refrigerants as working fluids, R22 and R407c. The heat pipe heat exchanger used was composed of two rows of copper heat pipes in a staggered manner, with 11 pipes per row. Tests were conducted at different airflow rates of 0.14, 0.18, and 0.22 m3/h, evaporator inlet‐air temperatures of 40, 44, and 50°C, filling ratios of 45%, 70%, and 100%, and ratios of heat capacity rate of the evaporator to condenser sections (Ce/Cc) of 1 and 1.5. For HPHE's steady‐state operation, a mathematical model for heat‐transfer performance was set and solved using MATLAB. Results illustrated that the heat transfer rate was in direct proportion with the evaporator inlet‐air temperature and flow rate. The highest HPHE's effectiveness was obtained at a 100% filling ratio and (Ce/Cc) of 1.5. The predicted and experimental values of condenser outlet‐air temperature were in good agreement, with a maximum difference of 3%. HPHE's effectiveness was found to increase with the increase in evaporator inlet‐air temperature and number of transfer units (NTU) and with the decrease in airflow rate, up to 33% and 20% for refrigerants R22 and R407c, respectively. Refrigerant R22 was the superior of the two refrigerants investigated.

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Experimental study of closed‐loop thermosyphon with a different evaporator geometry

Cited by 2 publications

References 36 publications

Parametric Study of a Two-Phase Closed Thermosyphon Loop

Parametric Study of a Two-Phase Closed Thermosyphon Loop

Theoretical and experimental investigation of a heat pipe heat exchanger for energy recovery of exhaust air

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