Opportunities, challenges, and state of the art of flexible heat‐pipe heat exchangers: A comprehensive review

Abstract

Heat pipes (HPs) play a pivotal role in efficiently managing the thermal challenges posed by high heat flux devices. To facilitate their operation at extremely low temperatures, specialized working fluids with low‐boiling points are a necessity. HPs serve as efficient heat exchanger (HEX) in diverse applications, such as heat pumps and heat‐transfer components. In the realm of space applications, HP is indispensable for cooling electronic components within two‐phase thermal control systems. Notably, the recent significant reduction in HP production costs has paved the way for synergizing HP with HEX, promising substantial energy savings. This comprehensive review centers its focus on the advancements in HEX‐based flexible HP systems. It critically evaluates various performance models and investigates key findings from a multitude of literature papers that pertain to HEX applications. The review encompasses a wide spectrum of innovations, including conventional, pulsating, and thermosyphons (gravity‐assisted) in HEX. It further explores studies on recuperative and regenerative HEX configurations. The surveyed literature underscores the critical role played by the choice of operating fluid and heat load in significantly influencing HP performance. This study offers a comprehensive understanding of key outcomes, strengths, limitations, and specific applications of HP and HEX. The review also highlights the significance of operating fluid selection and considerations related to heat load while outlining exciting opportunities for future research in this domain. Moreover, it introduces several novel concepts for future studies in pertinent domains, offering promising directions for further exploration within this field.