One of the main concerns in the world is rising energy demand, which forces industries to introduce the products with the lowest energy consumption. Cooling systems often employ single-phase flow and gas-liquid two-phase flow in many applications. These types are well-demonstrated that have lower cooling performance than liquid-liquid two-phase flow. Therefore, customers would pay more as the electricity price goes up. Another pain that customers experience is a higher maintenance cost to keep the product in good condition. Our solution is a new viable liquid-liquid microchannel approach that would provide high cooling performance resulting in a more sustainable cooling system. A unique design for the discharge tank is required to separate both operating liquids in a practical way before pumping through the loop. This novel design would provide a continuous flow of each phase before joining each other at a Tee junction to establish a slug flow. Then, metal lab-on-a-chip microchannels with rectangular cross-sectional areas transfer thermal energy to the coolant. The rectangular cross-section of the channel would also have different aspect ratios to give an optimized cross-section where the highest heat transfer rate occurs.