Trim Compressor Unloading Control Without Gas Bypass Loss
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Solution Overview
Problem
Conventional refrigeration systems waste energy by recirculating compressed refrigerant back to the suction side during unloading, reducing overall efficiency and increasing operating costs, as they often operate at peak load for only a few hours a year.
Innovation Solution
A refrigeration system with a trim compressor and control valves that regulate refrigerant flow to fewer cylinders, using a variable unloading controller to adjust the compressor capacity based on load demands, allowing for efficient modulation of refrigerant output without wasting energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a gas bypass system is used to unload compressors, then compressor capacity can be reduced, but energy is wasted by recirculating compressed refrigerant back to the suction side
Solution Approach 1:
The patent extracts and eliminates the gas bypass recirculation path from the system. Instead of recirculating compressed refrigerant back to the suction side, the system allows the compressor to discharge compressed refrigerant directly to the condenser, removing the energy-wasting recirculation loop while maintaining compressor unloading capability through other means.
Solution Approach 2:
The patent inverts the conventional unloading approach by preventing compressed refrigerant from being sent back to the suction side. Rather than using a bypass to redirect flow, the system inverts the flow path so that compressed refrigerant follows the normal discharge path to the condenser even during unloading conditions, thereby eliminating the energy waste associated with recirculation.
2Reliability
If multiple compressors are installed to accommodate peak load, then peak load capacity is sufficient, but system operates inefficiently at loads below peak capacity
Solution Approach 1:
The patent implements dynamic capacity modulation of the compressor through control of discharge valves. The compressor can adjust its effective capacity by controlling whether discharge valves are open or closed, allowing the system to match compressor output to actual load requirements rather than operating at fixed peak capacity, thereby improving energy efficiency during non-peak periods.
Solution Approach 2:
The patent changes the operational parameters of the compressor by controlling the state (open/closed) of discharge valves. This parameter control allows the compressor to modulate its effective capacity and operate efficiently across a range of load conditions, eliminating the need to run multiple compressors or operate inefficiently at partial load.
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 system effectively reduces energy waste and operating costs by allowing the refrigeration system to adjust capacity according to changing loads, maintaining efficiency and reducing energy expenditure during non-peak periods.
Implementation Method 1
at least one control valve for regulating a flow of refrigerant to fewer than all of the plurality of cylinders, the at least one control valve configured to transition between open and closed positions and located in a cylinder head of the trim compressor
Implementation Method 2
a plurality of compressors configured to circulate refrigerant through the refrigeration circuit, wherein the plurality of refrigerant compressors includes a trim compressor having a plurality of cylinders, in which refrigerant is compressed
Data Source
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AI summary
A refrigeration system (300) comprising: a refrigeration circuit including an evaporator and a condenser; a plurality of compressors configured to circulate refrigerant through the refrigeration circuit, wherein the plurality of refrigerant compressors includes a trim compressor (302) having a plurality of cylinders, in which refrigerant is compressed, and at least one control valve (118) for regulating a flow of refrigerant to fewer than all of the plurality of cylinders, the at least one control valve (118) configured to transition between open and closed positions and located in a cylinder head of the trim compressor (302); a refrigeration system controller (215) configured to regulate a rate of total refrigerant output from the plurality of refrigerant compressors; a variable unloading controller (214) configured to receive a control signal from the refrigeration system controller, and to transmit a control signal to the at least one control valve (118) to vary a rate of refrigerant output from the trim compressor (302).