A system having an optimised subcooler and a method of operating the system
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Solution Overview
Problem
Refrigeration systems with subcoolers often face inefficiencies due to constant liquid outlet temperatures, leading to overcooling or undercooling, which diminish system capacity and increase power consumption, and the use of two expansion valves adds cost and complexity.
Innovation Solution
A system and method that utilize 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 a second expansion valve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If constant liquid outlet temperature is maintained in subcooler, then system stability is improved, but power consumption increases and system capacity diminishes
Solution Approach 1:
The patent implements dynamic control of the subcooler liquid outlet temperature setpoint based on ambient conditions and system load. The controller adjusts the setpoint dynamically rather than maintaining a constant temperature, allowing the system to adapt to changing conditions and optimize power consumption while maintaining adequate subcooling performance.
2Manufacturing precision
If two expansion valves are used to control vapor outlet superheat and liquid outlet temperature, then control precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent merges the control functions of two separate expansion valves into a single expansion valve. The controller compensates for the reduced mechanical control capability by implementing dynamic setpoint adjustment and coordinated control strategies, thereby maintaining temperature control precision while reducing system complexity and eliminating the need for a second expansion valve.
Solution Approach 2:
The single expansion valve is designed to perform multiple functions: controlling vapor outlet superheat, regulating liquid outlet temperature, and managing refrigerant flow distribution. The controller enables this multi-functional valve to achieve precise temperature control through dynamic setpoint adjustment and coordinated operation.
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 responsiveness to changing conditions, and conserves costs by optimizing refrigerant handling and eliminating the complexity of dual valves, thereby improving overall efficiency and reducing energy waste.
Implementation Method 1
a subcooler comprising a first path and a second path, the first path adapted to cool refrigerant of the second path by an exchange of heat
Implementation Method 2
the evaporator, wherein the evaporator is adapted to cool a load by evaporating the refrigerant
Implementation Method 3
The evaporator uses the refrigerant to cool a space proximate the loads by absorbing heat
Implementation Method 4
the compressor, wherein the compressor is adapted to receive the refrigerant from the evaporator and apply pressure to the refrigerant; The compressor compresses the refrigerant to concentrate the absorbed heat
Implementation Method 5
a condenser adapted to receive the refrigerant from the compressor, cool the refrigerant, and discharge the refrigerant to the tank; The refrigerant is then directed to the compressor. The compressor compresses the refrigerant to concentrate the absorbed heat so that the condenser can more easily remove the heat from the refrigerant
Data Source
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AI summary
According to certain embodiments, a method comprises determining a liquid outlet temperature setpoint for refrigerant discharged from a liquid outlet (128) of a subcooler (106). The liquid outlet (128) corresponds to a hot-side path (110) of the subcooler (106) that receives refrigerant directly from a tank (102), cools the refrigerant by an exchange of heat with a cold-side path (108) of the subcooler (106) that receives the refrigerant from the tank (102) via an inlet expansion valve (104), and discharges the refrigerant to an evaporator (116) via an outlet expansion valve (114). The method further comprises determining a superheat setpoint for the refrigerant discharged to a compressor (118) via a vapor outlet (126) of the cold-side path (108). 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.