Effect of Flow Resistance in Adiabatic Part on the Thermal Performance of CO2, R134a, and R410A Two-phase Thermosyphon Loops
Journal of RefrigerationVol. 45, Issue 4, Pages: 28-35(2024)
作者机构:
青岛理工大学环境与市政工程学院 青岛 266033
作者简介:
Tong Zhen, female, associate professor, School of Environmental and Municipal Engineering, Qingdao University of Technology, 86-13791977035, E-mail: tong-tong@foxmail.com. Research fields: data center cooling technology, two-phase thermosyphon loop (TPTL) technology.
基金信息:
the National Natural Science Foundation of China(51906118)
Tong Zhen, Wen Xinran, Han Zekun, et al. Effect of Flow Resistance in Adiabatic Part on the Thermal Performance of CO2, R134a, and R410A Two-phase Thermosyphon Loops[J]. Journal of refrigeration, 2024, 45(4): 28-35.
DOI:
Tong Zhen, Wen Xinran, Han Zekun, et al. Effect of Flow Resistance in Adiabatic Part on the Thermal Performance of CO2, R134a, and R410A Two-phase Thermosyphon Loops[J]. Journal of refrigeration, 2024, 45(4): 28-35. DOI: 10.3969/j.issn.0253-4339.2024.04.028.
Effect of Flow Resistance in Adiabatic Part on the Thermal Performance of CO2, R134a, and R410A Two-phase Thermosyphon Loops
This study experimentally investigates the impact of flow resistance in risers and downcomers on the heat transfer performance of two-phase thermosyphon loops (TPTLs) with CO
2
R134a
and R410A refrigerants. Variations in the heat transfer limit and thermal resistance of the TPTLs were analyzed. The results show that the three TPTLs respond differently to changes in flow resistance. For the CO
2
TPTL
the effects of the riser and condenser resistances on thermal performance are similar. When the opening angle of the riser or condenser valve decreases from 90° to 30°
the heat transfer limit of the CO
2
TPTL decreases from 1 200 W to 700 W. For the R134a and R410A TPTLs
when the opening angle of the riser valve decreases from 90° to 30°
the heat transfer limit of the R410A TPTL decreases from 1 300 W to 700 W
and the R134a TPTL does not
reach normal operating conditions
resulting in substantial superheating and subcooling inside the pipes and a substantial increase in thermal resistance for both types. An increase in the condenser resistance has little effect on the thermal performances of the R134a and R410A TPTLs. For practical design considerations
the same or similar diameters should be used for the riser and downcomer of a CO
2
TPTL. However
for R134a and R410A TPTLs
the riser diameter should be significantly larger than the downcomer diameter to achieve material cost savings.