Expansion valves and control
Current domestic cooling appliances primarily use capillary tubes, which are robust, cost-effective. However, micro-expansion valves have been introduced, offering energy savings of 4-9% compared to capillary tubes, especially when paired with optimized heat exchangers. Micro-expansion valves use advanced control strategies like superheat and subcooling control to adapt refrigerant flow dynamically, improving efficiency across variable conditions. Innovative controllers, including predictive and adaptive systems, outperform conventional PID controllers by handling nonlinear behavior and optimizing energy consumption. Further enhancements in compressor speed control also contribute to reduced energy usage, demonstrating the potential of micro-expansion valves for higher efficiency and adaptability in domestic cooling systems.
Expansion valves are being developed and tested, minimizing pressure drop and ensuring subcritical flow by keeping flow velocity below the speed of sound. Current simulations showing potential energy savings of 5-10% under steady-state conditions.
Experimental investigations will focus on precision testing, evaluating various operating conditions like door openings, temperature changes, and fan speed variations, along with acoustic monitoring. The results will support the development of a 1D simulation model for further applications such as refrigerators, freezers, and heat pumps.
