Vapor-Chamber Performance Evaluation: The Challenge of Impartial Cross-Platform Comparison

The worldwide power electronics market is expected to expand at an annual growth rate of 4.7% from USD 35.1 billion in 2020 to USD 44.2 billion by 2025 [1]. This rise is fueled by the use of renewable energy sources throughout the world, and the increasing utilization of power electronics in the production of electric vehicles. The expanding implementation of power electronics in consumer products is another key driver of the market's growth. The most significant impediment in the electronic systems is their thermal management. Two-phase cooling is currently the standard thermal-management solution in all its forms, including heat pipes, vapor chambers, thermosyphons, and so on. But comparing the performance of different systems poses many challenges, thus making decision making difficult in the absence of complete information for each device.In this study, a list of ten critical elements or parameters required to unambiguously characterize the design and performance of a promising two-phase heat-transfer system for future deployment and development, namely the vapor chamber, is presented. This "Decalogue" is inspired by three main factors. First, the rising demand for better and more effective vapor chamber assemblies, which has prompted both industry and academia to invest substantially in related R&D. Second, this investment has resulted in a plethora of new systems (i.e. [2] –[6] etc.) where each design has been accompanied with insufficient description, making it difficult, if not impossible, to perform detailed comparisons across different designs/approaches. Third, the need to develop a common set of standards for describing such systems so that similar designs/philosophies may be compared successfully by researchers and developers seeking to duplicate results and improve on previous performance, especially in commercialized systems.We seek to gather all criteria needed to characterize each vapor chamber system, while exhibiting all benefits and limitations of its design, and illustrating what type of technical application the design may be helpful for, using a simple tabular method. The suggested approach might serve as a reference point or a standard way of accurately representing this type of heat transfer component. This description should benefit researchers in the area by clearly stating what the actual measurements/attributes of each system are, while also emphasizing the relevance/importance of each design by simply comparing it to others. The ten (deca) points presented here merely illustrate the most essential aspects of the design and performance of any vapor chamber.

I. INTRODUCTION

Designing electronic components that are safer, smaller, and more powerful is a necessity for the future. More heat must be dispersed from a reduced area, and the system must be dependable in long-term operation. Effective heat regulation and dissipation from electronic apparatuses is a struggle that has stymied technological innovation in recent years [7] –[9]. The development of appropriate thermal management solutions has become a hurdle, particularly under the light of the ever-increasing demands on electronic-systems performance [10] –[12]. Conventional Vapor Chambers (VC) have a simple design that comprises of an evaporator, a condenser, and a capillary structure, commonly known as the wick, as seen in Figure 1 (bottom). The phase change is taking place at the evaporator and condenser sides of the system, with the evaporator being directly connected to the heater. The working fluid is gasified at the evaporator, and the produced vapor flows to the condenser section, where it releases its latent heat and condenses to liquid owing to the induced vapor pressure gradient. Driven by capillary pressure, the liquid condensate then returns to the evaporator via the capillary structure. These mass and energy transfer cycles continue until the vapor chamber's upper limit of heat dissipation is achieved [13]. VC can disperse heat in two dimensions, whereas heat pipes can only transport heat in the lengthwise dimension. Because the heat input and output are the same, while the heat-applied area is larger, VCs are essentially serving as heat-flux transformers, resulting in a lower heat flux after the VC apparatus and so paving the way for the heat to be more efficiently dissipated by a prespecified component (i.e., heat sink with fan, cold plate, etc.). Thus, VCs are thermal-management components that can provide the needed solution to dissipate the excess heat and to protect delicate electronic equipment from overheating. Two-phase passive heat spreading systems, such as the VC, are an essential component for electronics cooling and have been utilized over the previous two decades, after originating as flat-plate heat pipes [14].