Heat pipe heat exchangers and heat sinks: Opportunities, challenges, applications, analysis, and state of the art

Shabgard, Hamidreza; Allen, Michael J.; Sharifi, Nourouddin; Benn, Steven P.; Faghri, Amir; Bergman, T. L.

doi:10.1016/j.ijheatmasstransfer.2015.05.020

Cited by 233 publications

(87 citation statements)

References 71 publications

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“…When the RH of supply fresh air is 25% (normally occurring during a summer days, when the DBT is high), the THEs evaporator section is subjected to higher heat flux. Thus, we could expect dry out phenomenon [3,18] to occur in the evaporator section since the THEs effectiveness decreases.…”

Section: Sensible and Total Effectivenessmentioning

confidence: 99%

“…Therefore, a significant part of energy savings can be achieved if heat recovery technologies are incorporated into the HVAC systems. The benefits of THEs over conventional heat exchangers are: lower initial cost (because of higher effectiveness per unit area of heat exchanger), reduced air-side pressure drop (fewer rows), lower maintenance costs (no moving parts), and lower operating costs (no external power) [1][2][3].…”

Section: Introductionmentioning

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: Sensible and Total Effectivenessmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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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“…An alkali metal heat pipe could achieve passive heat transfer function with many distinct advantages, including high thermal conductivity, no single point failure, small pressure, no moving parts and high reliability. It can efficiently transfer large quantities of heat with good isothermality through the vapor‐liquid phase transition . Heat pipes are considered an excellent choice for passive heat transfer, especially in space.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigations on start‐up performance of static nuclear reactor thermal prototype

et al. 2020

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Summary Nuclear power is most suited to satisfy the energy demands of future deep space exploration. In this paper, we propose a static nuclear reactor (the nuclear static thermoelectric reactor [NUSTER]), which offers the advantages of superior modularization, simplification, a fully static state, and passive operation. Based on the conceptual design of a static nuclear reactor, an electrical heating principle prototype was designed and fabricated to validate the feasibility of the fully static passive energy conversion concept. Skutterudite thermoelectric generators (TEGs) were used for static energy conversion, and potassium heat pipes were employed for passive heat transfer. The system start‐up performance, restart performance, and thermoelectric performance were investigated using the thermal principle prototype. We proposed a new approach to analyze the heat pipe start‐up process based on the heat transfer performance. The experimental results indicated that the restart process can be used to reduce the start‐up time, because the low heat flux stage is avoided. During the start‐up process, the TEGs hot side heat flux and temperature difference were gradually established, and the TEGs open circuit voltage and power density gradually increased. A maximum open circuit voltage and power density of 38.2 V and 0.92 W/cm2, respectively, were achieved when the TEGs temperature difference reached 575°C. The high performance of the thermal principle prototype demonstrated the feasibility of the NUSTER conceptual design, and the experimental data can serve as a valuable reference for optimization of static reactor designs.

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“…Several experimental and numerical investigations into using heat pipes for TES at CSP plants have been conducted [30,31]. Sharifi et al [32] compared the melting rate of a vertical cylindrical PCM heated by a rod or heat pipe at the center of the PCM, and their results show that the use of heat pipes resulted in a higher melting rate.…”

Section: Introductionmentioning

confidence: 99%

Development of an Integrated Thermal Energy Storage and Free-Piston Stirling Generator for a Concentrating Solar Power System

2017

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Incorporating thermal energy storage (TES) into a concentrating solar power (CSP) system extends the power production hours, eliminating intermittency and reducing the Levelized Cost of the Energy (LCOE). The designed TES system was integrated with a 3 kW free-piston Stirling convertor. A NaF-NaCl eutectic salt was chosen as the phase change material (PCM) with a melting temperature of 680 • C. This eutectic salt has an energy density that is 5 to 10 times that of a typical molten salt PCM. In order to overcome the drawbacks of the material having a low thermal conductivity, heat pipes were embedded into the PCM to enhance the heat transfer rate within the system. Since the dish collector tracks the sun over the course of the day, two operational extremes were tested on the system; horizontal (zero solar elevation at sunrise/sunset) and vertical (solar noon). Although the system's performance was below the expectations due to improperly sized wicks in the secondary heat pipes, the results indicated that the Stirling engine was able to produce 1.3 kWh of electricity by extracting latent heat energy from the PCM; thus, the concept of the design was validated.

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Heat pipe heat exchangers and heat sinks: Opportunities, challenges, applications, analysis, and state of the art

Cited by 233 publications

References 71 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

Experimental investigations on start‐up performance of static nuclear reactor thermal prototype

Development of an Integrated Thermal Energy Storage and Free-Piston Stirling Generator for a Concentrating Solar Power System

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