Experimental and numerical investigation of thermosyphone performance in HVAC system applications

Eidan, Adel A.; Najim, Saleh E.; Jalil, Jalal M.

doi:10.1007/s00231-016-1800-y

Cited by 28 publications

(14 citation statements)

References 17 publications

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“…Six nodes are located radially in the section, a mesh size of 14,175 Quad is selected for good simulation analysis. The assumptions used in the development of the model of the TPCT are slug flow and geyser effect phenomenon were not considered from the pool, heat losses to the environment are negligible, the working fluid is at the saturated temperature which is determined by experiments and the rate of evaporation is equal to the rate of condensation [11].…”

Section: Simulation Of Heat and Mass Transfer During The Computationamentioning

confidence: 99%

“…The Water, Methanol, Ethanol, R134a, Acetone and Butanol were chosen because they were able to function as a working fluid in the range of (-20 to 120) ºC. The best filling ratio (FR) for each working fluid and the charging method, measurements, calibrations was obtained experimentally from an earlier work [11], the volume of working fluid required was calculated under the assumption that the manifold volume and all 3 and 4 tubes in a row would be filled to a depth of (90-150) mm. Also, a film thickness of 0.1 mm was assumed for the internal wetted surface volume above the liquid level.…”

Section: Experimental Test Apparatusmentioning

confidence: 99%

“…The DBT and the THEs surface temperatures were measured using 20T-type thermocouples distributed at various locations on the test rig and THE surface. The output signals from the temperature sensors were recorded in a data logging system [11].…”

Section: Experimental Test Apparatusmentioning

confidence: 99%

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An experimental and a numerical investigation of HVAC system using thermosyphon heat exchangers for sub-tropical climates

Eidan

Najim

Jalil

2017

Applied Thermal Engineering

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Section: Simulation Of Heat and Mass Transfer During The Computationamentioning

confidence: 99%

Section: Experimental Test Apparatusmentioning

confidence: 99%

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An experimental and a numerical investigation of HVAC system using thermosyphon heat exchangers for sub-tropical climates

Eidan

Najim

Jalil

2017

Applied Thermal Engineering

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“…A heat pipe is one of the most efficient and passive heat transfer devices that can transport heat from a source (evaporator) to a sink (condenser) over relatively long distances via the latent heat of vaporization of a working fluid. Heat pipes are used in various applications such as solar and waste material energy devices [1][2][3], cooling of electronic devices [4], air conditioning applications for building environmental control [5,6], space and satellite missions [7,8], and thermal management of gas turbine blades [9]. A heat pipe is a closed pipe with a vacuum that consists of three sections, namely, an evaporator, an adiabatic, and a condenser that is partially filled with a working fluid (de-ionized water was used in this study).…”

Section: Introductionmentioning

confidence: 99%

Study of Heat Pipe Thermal Performance with Internal Modified Geometry

Temimy¹,

Abdulrasool

Hamad

2021

Fluids

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The aim of this study was to investigate the effect of inserting a new internal tube packing (TP) on the thermal performance of a thermosyphon heat pipe (THP). The THP pipe was made from copper with an inner diameter of 17.4 mm and length of 600 mm. The new internal tube packing (TP) had a central copper disc with two copper tubes soldered onto both sides to transport vapor and condensate. The upper tube or riser had an inner diameter of 8.3 mm and was 300 mm long; it was connected to a hole in the disc from the upper side to transport the steam to the condenser section. The lower tube or downcomer had an inner diameter of 5 mm, was 225 mm long and was connected to the lower side of the disc to collect the condensate and transport it to the evaporator. The TP was inserted inside the THP to complete the design of the improved heat pipe (TPTHP). Experimental results showed that the TPTHP reduces the transit time from 16 to 11 min and the thermal resistance by 17–62% based on the input power and depending on the conditions of the THP. The results also showed that the inclination angle and filling ratio have no effect on the thermal resistance of the TPTHP.

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“…It has been confirmed that nanofluids added to water could significantly increase the TPCT performance. Eidan et al [7] have experimentally and numerically worked on wickless heat-pipe-dedicated applications in HVAC systems. They have investigated a thermosyphon filled with different working fluids (water, methanol, ethanol, acetone, butanol, and R134a) and with different FRs (0.4, 0.5, 0.6, 0.7, and 1.0).…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation of the Thermal Performance of a Wickless Heat Pipe Operating with Different Fluids: Water, Ethanol, and SES36. Analysis of Influences of Instability Processes at Working Operation Parameters

Andrzejczyk

2018

Energies

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In this study, the influences of different parameters on performance of a wickless heat pipe have been presented. Experiments have been carried out for an input power range from 50 W to 300 W, constant cooling water mass flow rate of 0.01 kg/s, and constant temperature at the inlet to condenser of 10 °C. Three working fluids have been tested: water, ethanol, and SES36 (1,1,1,3,3-Pentafluorobutane) with different filling ratios (0.32, 0.51, 1.0). The wall temperature in different locations (evaporation section, adiabatic section, and condenser section), as well as operating pressure inside two phase closed thermosyphon have been monitored. The wickless heat pipe was made of 0.01 m diameter copper tube, which consists of an evaporator, adiabatic, and condensation sections with the same length (0.4 m). For all working fluids, a dynamic start-up effect caused by heat conduction towards the liquid pool was observed. Only the thermosyphon filled with SES36 was observed to have operation limitation caused by achieving the boiling limit in TPCTs (two-phase closed thermosyphons). The geyser boiling effect has been observed only for thermosyphon filled with ethanol and for a high filling ratio. The performance of the thermosyphon determined the form of the heat transfer resistance of the TPCT and it was found to be dependent of input power and filling ratio, as well as the type of working fluid and AR (aspect ratio). Comparison with other authors would seem to indicate that lower AR results in higher resistance; however, the ratio of condenser section length to inside diameter of pipe is also a very important parameter. Generally, performance of the presented thermosyphon is comparable to other constructions.

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Experimental and numerical investigation of thermosyphone performance in HVAC system applications

Cited by 28 publications

References 17 publications

An experimental and a numerical investigation of HVAC system using thermosyphon heat exchangers for sub-tropical climates

An experimental and a numerical investigation of HVAC system using thermosyphon heat exchangers for sub-tropical climates

Study of Heat Pipe Thermal Performance with Internal Modified Geometry

Experimental Investigation of the Thermal Performance of a Wickless Heat Pipe Operating with Different Fluids: Water, Ethanol, and SES36. Analysis of Influences of Instability Processes at Working Operation Parameters

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