Self-optimizing subcooler control
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Solution Overview
Problem
Refrigeration systems with subcoolers often consume excessive power due to constant liquid outlet temperature settings, which can lead to overcooling or undercooling, reducing efficiency and requiring costly and complex dual expansion valves.
Innovation Solution
A refrigeration system with a subcooler that uses a single valve to control vapor outlet superheat and liquid outlet temperature setpoints dynamically based on ambient conditions and load, optimizing subcooling to minimize power consumption and eliminate the need for two expansion valves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If constant liquid outlet temperature is provided throughout the year, then the subcooler maintains stable operation, but power consumption increases and efficiency decreases due to overcooling or undercooling
Solution Approach 1:
The patent implements dynamic control of the subcooler by adjusting the expansion valve position based on ambient temperature and system load conditions. Instead of maintaining a fixed liquid outlet temperature, the system continuously adapts the subcooling level to match changing operational requirements, thereby avoiding unnecessary energy consumption while maintaining stable refrigeration performance
Solution Approach 2:
The system changes the liquid outlet temperature parameter dynamically based on ambient conditions and load requirements. The controller adjusts the setpoint temperature according to external factors, allowing the subcooler to operate efficiently across different seasonal and operational conditions rather than maintaining a constant temperature that leads to overcooling or undercooling
2Measurement precision
If two expansion valves are used to control vapor outlet superheat and liquid outlet temperature, then precise control is achieved, but device complexity and cost increase
Solution Approach 1:
The patent merges the functions of two separate expansion valves into a single expansion valve. By combining the control of vapor outlet superheat and liquid outlet temperature into one valve, the system reduces component count and complexity while maintaining precise temperature control through advanced control algorithm that coordinates both parameters through the single valve actuator
Solution Approach 2:
The single expansion valve is designed to perform multiple functions simultaneously - controlling both the vapor outlet superheat and the liquid outlet temperature of the subcooler. This multi-functional approach eliminates the need for separate dedicated valves for each control parameter, reducing system complexity while preserving control precision
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces power consumption, enhances system efficiency, and lowers costs by adjusting subcooling optimally in response to changing conditions, maintaining optimal performance without the complexity of dual valves.
Implementation Method 1
The first path is adapted to cool a refrigerant of the second path by an exchange of heat
Data Source
AI summary
According to certain embodiments, a method comprises determining a liquid outlet temperature setpoint for refrigerant discharged from a liquid outlet of a subcooler. The liquid outlet corresponds to a hot-side path of the subcooler that receives refrigerant directly from a tank, cools the refrigerant by an exchange of heat with a cold-side path of the subcooler that receives the refrigerant from the tank via an inlet expansion valve, and discharges the refrigerant to an evaporator via an outlet expansion valve. The method further comprises determining a superheat setpoint for the refrigerant discharged to a compressor via a vapor outlet of the cold-side path. The superheat setpoint is determined based on the liquid outlet temperature setpoint. The method further comprises adjusting a temperature of the refrigerant discharged to the compressor based on the superheat setpoint.