Electrically Isolated Hybrid Two-Phase Cooling System

Advanced Cooling Technologies, Inc. (ACT) proposes to continue development and commercialization of an innovative hybrid two-phase cooling system (HTPCS) that combines the unique benefits of mechanically pumped two-phase systems with capillary-driven two-phase cooling. In Phase II, ACT successfully fabricated, tested, and delivered a hybid two-phase evaporator. During Phase II, we began discussing potential applications with partners that supply power electronics to commercial and military markets. The purpose of the proposed Phase II-B is to develop Engineering Demonstration Units (EDU) for each of these markets while also addressing fabrication issues that we encountered during Phase II. At the end of Phase II-B, ACT will deliver these EDUs to our partners for further testing. We will continue to work with them after this phase to move towards commercialization of this technology. The HTPCS has several unique evaporator features that separate this system from traditional two-phase cooling systems. First, electronics are mounted to a plate that is in direct contact with a region that promotes thin film evaporation on the opposite side of each transistor. Thin film evaporation is one of the most effective heat transfer mechanisms and is capable of reaching heat transfer coefficients near 100,000 W/cm2. This arrangement greatly reduces the thermal resistance between the electronics and coolant, which allows for high power and high heat flux management without a large temperature potential, while the selected materials provide electrical isolation between the electronics to prevent losses from parasitic capacitance. In addition, all materials are Coefficient of Thermal Expansion (CTE) matched. This prevents stress at the joint between the electronics and evaporator as the electronics increase in temperature during operation. Stress at this joint can cause the electronics to become detached from the cold plate and quickly overheat. In Phase II, ACT demonstrated the removal of heat loads >300W/cm² while maintaining device temperatures below 80°C. Heat transfer coefficients of 60,000 W/m²•K and greater were achieved, which is considerably higher compared to typical refrigerant-based pumped two-phase cooling systems. ACT sees great potential in further developing this technology and has connected with companies within the power electronics industry to assist in the commercialization of this technology. At the end of Phase I, ACT applied for a provisional patent of the proposed device and a full patent in Phase II, Application Number 17/003,539. We have been informed by the Patent Office that the award will occur by July, 2022. The research proposed in this narrative focuses on completing technical tasks that, upon completion, will prepare the technology for a successful introduction into the market.