Refrigerant Compressor Inlet Pressure Control Using Purge Valve Bypass
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Refrigeration units in trailers lack sufficient power and variable speed capability from electric motors to efficiently operate components like compressors at high loads, leading to reduced efficiency and potential damage due to excessive vacuum in the suction inlet.
Innovation Solution
A refrigeration unit design incorporating a diesel engine and a single-speed electric motor with a compressor, featuring a purge valve to inject liquid refrigerant into the suction inlet and a hot gas bypass valve to mix heated gas with injected liquid, controlled by a controller to manage pressure and prevent frost buildup, allowing for efficient operation and extended component life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a smaller electric motor is used to meet spatial constraints, then the device size is reduced, but the motor lacks sufficient power output to operate compressor and other components at high loads
Solution Approach 1:
The patent employs variable-speed control of the compressor motor, allowing it to operate at different speeds depending on load requirements. This dynamic operation enables a smaller motor to deliver high power output when needed (at high speeds) while maintaining compact size for spatial constraints.
Solution Approach 2:
The system changes operational parameters by controlling motor speed variabley rather than operating at fixed speed. This allows the motor to adapt its power output to match varying load conditions, effectively providing high power capability without requiring a larger motor size.
2Productivity
If the compressor operates at high speed with insufficient suction pressure, then productivity is improved, but excessive vacuum causes harmful effects on the compressor
Solution Approach 1:
The patent introduces a suction pressure regulator valve as an intermediary device between the evaporator outlet and compressor suction inlet. This valve actively controls and maintains suction pressure within optimal ranges, preventing excessive vacuum conditions that would harm the compressor while allowing high-speed operation for productivity.
Solution Approach 2:
The system implements pressure sensing and control feedback mechanisms where suction pressure is monitored and the regulator valve adjusts accordingly to maintain pressure within safe operating limits, preventing harmful excessive vacuum conditions during high-speed compressor operation.
3Stress or pressure
If liquid refrigerant is injected into the suction inlet to increase pressure, then suction pressure is improved, but frost formation creates harmful effects
Solution Approach 1:
The suction pressure regulator valve serves as an intermediary that controls liquid refrigerant injection into the suction inlet. It regulates the amount and timing of injection to increase suction pressure while preventing conditions that would lead to frost formation on the evaporator or suction line.
Solution Approach 2:
The system changes the physical state and flow parameters of refrigerant through controlled injection and regulation. By carefully managing injection rate, pressure, and temperature parameters, the system increases suction pressure without creating the temperature conditions that would cause frost formation.
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
The solution effectively manages suction pressure and prevents frost formation, enhancing the refrigeration unit's efficiency and extending the compressor's lifespan by ensuring balanced operation and reduced vacuum levels.
Implementation Method 1
The purge valve is operable to selectively divert liquid refrigerant from the condenser to the suction inlet to increase the pressure in the suction inlet
Implementation Method 2
The hot gas bypass valve is operable to selectively divert pressurized, gaseous refrigerant from the discharge outlet to the suction inlet to increase the temperature of the refrigerant in the suction inlet
Implementation Method 3
a condenser in fluid communication with the discharge outlet through which pressurized, gaseous refrigerant is condensed
Data Source
AI summary
A refrigeration unit includes an engine, a motor capable of producing a similar power output as the engine, and a compressor driven by one of the engine and the motor. The compressor includes a suction inlet and a discharge outlet. The refrigeration unit also includes a condenser in fluid communication with the discharge outlet through which pressurized, gaseous refrigerant is condensed, an evaporator in fluid communication with the condenser to receive liquid refrigerant and return gaseous refrigerant to the suction inlet, a passageway having a first end in fluid communication with an outlet of the condenser, and a second end in fluid communication with the suction inlet, and a purge valve defining at least a portion of the passageway between the first and second ends. The purge valve is operable to selectively divert liquid refrigerant from the condenser to the suction inlet to increase the pressure in the suction inlet.