Refrigerant Cooling Control for Casing Protection Without Liquid Compression
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Solution Overview
Problem
Existing refrigeration apparatuses face reliability issues due to the risk of liquid compression when refrigerant is supplied to cooling heat exchangers, leading to inadequate cooling of the casing in heat source units, which can increase temperatures and affect work environments.
Innovation Solution
A refrigeration apparatus with a controller that assesses the state of the refrigerant before supplying it to the cooling heat exchanger, determining whether to open or close the valve based on whether the refrigerant becomes wet or entirely gaseous, and using pressure differences and temperature measurements to ensure reliable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the refrigerant is supplied to the cooling heat exchanger to cool the interior of the casing, then the cooling effect is improved, but the risk of liquid compression increases
Solution Approach 1:
The controller performs preliminary assessment of refrigerant state (temperature and pressure) before opening the valve to supply refrigerant to the cooling heat exchanger. This preliminary action ensures that refrigerant is only supplied when conditions indicate it will remain gaseous, preventing liquid compression before it can occur.
Solution Approach 2:
The system uses temperature and pressure sensors to continuously monitor refrigerant state and provides feedback to the controller. The controller adjusts valve operation based on this feedback, opening the valve only when refrigerant temperature and pressure indicate a gaseous state, thereby preventing liquid compression while maintaining effective cooling.
2Productivity
If the valve is opened to supply refrigerant to the cooling heat exchanger, then the cooling performance is improved, but the possibility of liquid compression occurs
Solution Approach 1:
Before opening the valve, the controller assesses refrigerant conditions using temperature and pressure data. This preliminary evaluation ensures that the valve is opened only when refrigerant is in a safe gaseous state, maintaining cooling performance while preventing liquid compression.
Solution Approach 2:
The controller continuously monitors refrigerant temperature and pressure and uses this feedback to control valve operation. The valve is opened only when feedback indicates appropriate conditions (refrigerant in gaseous state), ensuring both cooling performance and prevention of liquid compression.
3Reliability
If sensors are installed to detect wet state of refrigerant, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The controller performs dual functions: it not only controls the valve operation but also assesses refrigerant state by processing data from temperature and pressure sensors. This multi-functionality reduces the need for separate dedicated detection systems, maintaining reliability while limiting complexity increase.
Solution Approach 2:
The existing temperature and pressure sensors serve dual purposes: monitoring system conditions for control purposes and providing data for refrigerant state assessment. This self-service approach enables liquid compression detection without requiring additional dedicated sensors, thus improving reliability with minimal 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
This configuration reduces the occurrence of liquid compression, ensuring effective cooling of the casing and maintaining a stable temperature, thereby enhancing the reliability and efficiency of the refrigeration apparatus.
Implementation Method 1
the cooling heat exchanger is supplied with the refrigerant to cool the interior of the casing
Implementation Method 2
The compressor compresses a refrigerant
Implementation Method 3
The main heat exchanger causes heat exchange between the refrigerant and a heat source
Data Source
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AI summary
The invention provides a highly reliable refrigeration apparatus configured to cool the interior of a casing of a heat source unit by means of a refrigerant and can reduce a possibility that liquid compression is caused by supply of the refrigerant to a heat exchanger for cooling the interior of the casing. An air conditioner (10) includes a heat source unit (100), a utilization unit (300) having a utilization heat exchanger (310) and constituting a refrigerant circuit (50) along with the heat source unit, and a controller. The heat source unit includes a compressor (110), a heat source-side heat exchanger (140) configured to cause heat exchange between a refrigerant and a heat source, a casing, a cooling heat exchanger (160) supplied with the refrigerant and configured to cool the interior of the casing, and a valve (162) configured to switch to supply or not to supply the cooling heat exchanger with the refrigerant. The controller configured to open or close the valve assesses, before the refrigerant is supplied to the cooling heat exchanger, whether or not the refrigerant flowing from the cooling heat exchanger toward the compressor comes into a wet state when the refrigerant is supplied, and determines whether or not to open the valve in accordance with an assessment result.