Refrigeration cycle device
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Solution Overview
Problem
In refrigeration cycle systems, excessive cooling of controllers can lead to dew condensation due to clogged expansion devices, causing reliability issues and inefficient operation.
Innovation Solution
A refrigeration cycle apparatus with a second expansion device in the bypass pipe, controlled by a controller to regulate refrigerant flow and prevent excessive cooling, includes a foreign substance release mechanism to address clogging and maintain normal operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the expansion device is controlled to regulate refrigerant flow rate for cooling the controller, then the controller temperature is reduced, but foreign substances may clog the expansion device causing excessive cooling and dew condensation
Solution Approach 1:
The expansion device performs periodic full-opening operations at predetermined time intervals to prevent foreign substance clogging. This periodic action clears accumulated debris by allowing high-velocity refrigerant flow through the fully opened valve, thereby maintaining reliable cooling operation without continuous manual intervention.
Solution Approach 2:
The system performs preliminary full-opening of the expansion device before clogging occurs to prevent foreign substance accumulation. By proactively opening the valve at predetermined intervals, the system prevents debris buildup that would otherwise lead to excessive cooling and dew condensation on the controller.
2Reliability
If the expansion device opening degree is increased to prevent clogging, then foreign substances are released, but the controller may be excessively cooled causing dew condensation
Solution Approach 1:
The expansion device is opened fully only at predetermined time intervals for brief periods to clear foreign substances, then returns to its normal regulated opening degree. This periodic full-opening prevents clogging while limiting excessive cooling duration, thereby preventing dew condensation on the controller during normal operation.
Solution Approach 2:
The expansion device dynamically adjusts its opening degree between two states: a regulated opening degree for normal cooling control, and a fully opened state for periodic foreign substance removal. This dynamic adjustment allows the system to maintain reliable operation while preventing harmful dew condensation through controlled temporal variation.
3Temperature
If the refrigerant flow rate is continuously high to ensure cooling, then the controller is adequately cooled, but foreign substance clogging increases
Solution Approach 1:
The system maintains adequate cooling by regulating the expansion device at a normal opening degree during most operation periods, and periodically fully opens it to clear foreign substances. This periodic maintenance approach prevents clogging buildup without requiring continuously high refrigerant flow rates, simplifying the system's operational complexity.
Solution Approach 2:
The expansion device performs self-maintenance by periodically fully opening to clear its own foreign substance accumulations. This self-cleaning function prevents clogging without requiring external intervention or complex additional components, maintaining simple system design while reducing clogging risk.
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 prevents excessive cooling of the controller, suppressing dew condensation and ensuring reliable operation by detecting and addressing foreign substance clogs in the expansion device.
Implementation Method 1
the refrigerant that has rejected heat is caused to flow through a refrigerant cooler to exchange heat with the controller, thus cooling the controller
Implementation Method 2
an expansion device that controls a refrigerant flow rate in the refrigerant cooler
Implementation Method 3
a compressor
Implementation Method 4
a heat-source-side heat exchanger and a load-side heat exchanger
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A refrigeration cycle apparatus includes a refrigerant circuit, a controller, a bypass pipe, a refrigerant cooler, a second expansion device, and a controller temperature sensor. In a case where a temperature measured by the controller temperature sensor is lower than or equal to a set temperature in a state where an opening degree of the second expansion device is controlled to an instruction opening degree that is lower than or equal to a set opening degree, the controller is configured to perform foreign substance release control where the controller is configured to increase the opening degree of the second expansion device and then is configured to return the opening degree of the second expansion device to the instruction opening degree.