Refrigeration apparatuses and operating method thereof
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Solution Overview
Problem
Refrigeration units face inefficiencies when the amount of refrigerant directed to the compressor is insufficient to cool its components, leading to potential overheating and malfunction.
Innovation Solution
A refrigeration apparatus with a refrigerant circuit that includes a compressor, condenser, sub-cooler, expansion valve, and evaporator, featuring a bypass line and valves to control refrigerant flow, and a controller to monitor pressure parameters and adjust the bypass valve to ensure adequate refrigerant delivery to the compressor, thereby maintaining efficient cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If refrigerant flow to the compressor is increased to ensure adequate cooling, then compressor cooling reliability is improved, but system efficiency deteriorates due to deviation from optimal operating conditions
Solution Approach 1:
The refrigerant flow path is segmented into multiple controllable branches: a first branch leading to the sub-cooler and a second branch leading to the compressor. This segmentation allows independent control of refrigerant flow to different components, enabling adequate compressor cooling without compromising overall system efficiency by deviating from optimal operating conditions.
Solution Approach 2:
The system employs dynamic control through the second expansion valve to adjust refrigerant flow distribution in real-time based on compressor cooling requirements. This dynamic adjustment ensures the compressor receives sufficient refrigerant for cooling while maintaining optimal system efficiency under varying operating conditions.
2Reliability
If a bypass line is added to control refrigerant flow distribution, then refrigerant delivery to compressor is improved, but device complexity increases
Solution Approach 1:
The second expansion valve serves multiple functions: it controls refrigerant flow to the compressor for cooling purposes and simultaneously regulates the bypass line flow distribution. This multi-functionality reduces the need for additional dedicated components, thereby limiting the increase in device complexity while improving refrigerant delivery reliability.
Solution Approach 2:
The bypass line acts as an intermediary pathway that allows flexible redistribution of refrigerant flow between the sub-cooler and compressor. This intermediary structure enables precise control of refrigerant delivery to the compressor without requiring complete redesign of the main refrigerant circuit, thus balancing reliability improvement with acceptable complexity increase.
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 ensures consistent and efficient cooling of compressor components, preventing overheating and potential damage by dynamically adjusting refrigerant flow based on pressure parameters, thus maintaining optimal operation even under varying ambient conditions.
Implementation Method 1
a condensing device disposed downstream of the compressor, the condensing device comprising a condenser and a sub-cooler
Implementation Method 2
a motor cooling line comprising a motor cooling valve, the motor cooling line fluidically connecting the sub-cooler to the motor to tap refrigerant from the main refrigerant line to cool the motor
Implementation Method 3
a compressor comprising a compressor fan and a motor to drive the compressor fan
Implementation Method 4
air or water to be cooled flows over the evaporator to transfer heat to the refrigerant in the evaporator, to thereby cool the air
Data Source
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AI summary
There is disclosed a refrigeration apparatus comprising a refrigerant circuit, the refrigerant circuit comprising a compressor comprising a compressor fan and a motor to drive the compressor fan; a condensing device disposed downstream of the compressor, the condensing device comprising a condenser and a sub-cooler; an expansion valve disposed downstream of the condensing device; an evaporator disposed between the expansion valve and the compressor; and a main refrigerant line fluidically connecting, in a loop in series: the compressor, condensing device, expansion valve and evaporator. A motor cooling line comprising a motor cooling valve fluidically connects the sub-cooler to the motor to tap refrigerant from the main refrigerant line to cool the motor and is further connected to the main refrigerant line at a return point which is upstream of the compressor fan to return refrigerant to the main refrigerant line at the compressor fan. A bypass line fluidically connects an outlet of the condenser to the expansion valve to bypass the sub-cooler, wherein the bypass line comprises a bypass valve to selectively permit refrigerant in the main refrigerant line to bypass the sub-cooler.