Refrigeration cycle device
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Solution Overview
Problem
Conventional refrigeration cycle apparatuses face issues with pressure tolerance when upgrading from low-pressure to high-pressure refrigerants, leading to potential pipe pressure exceedance and increased installation costs due to the need for thicker piping and larger refrigerant storage tanks.
Innovation Solution
A refrigeration cycle apparatus design that includes a refrigerant storage tank with an inlet-side electromagnetic valve and a valve apparatus that allows high-pressure liquid refrigerant to flow in during stoppages, while delaying the shut-off to discharge gaseous refrigerant, preventing pressure buildup and allowing for the use of existing piping, even with high-pressure refrigerants like CO2.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If crossover piping from a refrigeration cycle apparatus that uses an R-404A refrigerant is reused as crossover piping for a refrigeration cycle apparatus that uses an R-410A refrigerant, then simplicity of construction work and reductions in parts costs are achieved, but the pressure of the refrigerant may exceed a pressure tolerance reference value of the crossover piping
Solution Approach 1:
A refrigerant storage tank is introduced as an intermediary component between the liquid-side refrigerant piping and the liquid-side crossover piping. This tank temporarily stores high-pressure liquid refrigerant during stoppages, acting as a buffer that prevents pressure transmission to the crossover piping. The tank enables the use of thinner-walled crossover piping designed for lower pressure ratings while safely handling high-pressure refrigerants like R-410A.
2Adaptability or versatility
If the entire length of the crossover piping reaches 100 m for outdoor units installed in locations distant from indoor units, then installation flexibility is improved, but installation time is longer and installation costs are increased
Solution Approach 1:
The invention changes the pressure parameter rating of the crossover piping by introducing the refrigerant storage tank system. This allows the use of piping with lower pressure ratings (thinner walls) that is easier to install over long distances, while the tank system maintains safety by managing the actual high-pressure refrigerant. The result is reduced installation time and cost while maintaining the ability to install over 100m distances.
3Reliability
If a refrigerant storage tank is used to store high-pressure liquid refrigerant during stoppages, then pressure tolerance issues in crossover piping are suppressed, but the refrigerant storage tank may become larger to accommodate gaseous refrigerant
Solution Approach 1:
The system employs periodic action through the delayed shut-off of the valve apparatus. During stoppages, the inlet-side electromagnetic valve opens to allow liquid refrigerant to enter the storage tank while the valve apparatus remains open for a delayed period to discharge gaseous refrigerant. This periodic opening/closing sequence allows the tank to handle both liquid and gas phases efficiently, optimizing tank volume while maintaining pressure safety.
Solution Approach 2:
The valve apparatus is designed with dynamic delayed shut-off functionality, where the valve remains open for a specified period after the inlet-side electromagnetic valve closes. This dynamic timing allows gaseous refrigerant to be discharged from the tank before the valve closes, preventing pressure buildup and enabling a more compact tank design while maintaining safety.
4Productivity
If the inlet-side electromagnetic valve is opened during stoppages to allow high-pressure liquid refrigerant to flow in, then refrigerant recovery is improved, but gaseous refrigerant may build up pressure in the tank
Solution Approach 1:
The system implements feedback control through the delayed shut-off mechanism of the valve apparatus. When the inlet-side electromagnetic valve closes, the valve apparatus continues to remain open for a delayed period, allowing gaseous refrigerant to escape from the tank. This feedback-based timing ensures that pressure does not build up in the tank while maximizing refrigerant recovery during the stoppage period.
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 design suppresses pressure tolerance issues, reduces installation time and costs, and allows for a more compact refrigerant storage tank, enabling efficient refrigerant recovery and reuse without requiring thicker piping or larger tanks.
Implementation Method 1
an inlet-side electromagnetic valve that is opened when there is no passage of electric current
Implementation Method 2
a valve apparatus that is opened during passage of electric current to the inlet-side electromagnetic valve, and of which the shut-off is delayed after passage of electric current to the inlet-side electromagnetic valve is stopped
Implementation Method 3
a refrigerant storage tank that stores the refrigerant, an intake side thereof being connected to the liquid-side connection piping, and a discharge side thereof being connected to the gas-side connection piping
Implementation Method 4
an inlet-side check valve that is disposed on the liquid-side connection piping, and that allows the refrigerant to flow only toward the refrigerant storage tank
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
An object of the present invention is to provide a refrigeration cycle apparatus that can collect refrigerant inside liquid-side crossover piping when stopped even if liquid-side crossover piping for low-pressure refrigerant is used, enabling the occurrence of problems with pressure tolerance in the liquid-side crossover piping to be suppressed, shortening installation time, and enabling installation costs to be reduced, and that can also make a refrigerant storage tank more compact. The refrigeration cycle apparatus according to the present invention includes: liquid-side connection piping that extends from liquid-side refrigerant piping; gas-side connection piping that extends from gas-side refrigerant piping; a refrigerant storage tank that stores refrigerant, an intake side thereof being connected to the liquid-side connection piping, and a discharge side thereof being connected to the gas-side connection piping; an inlet-side electromagnetic valve that is disposed on the liquid-side connection piping, and that is opened when there is no passage of electric current; an inlet-side check valve that is disposed on the liquid-side connection piping, and that allows the refrigerant to flow only toward the refrigerant storage tank; and a valve apparatus that is disposed on the gas-side connection piping, that is opened during passage of electric current to the inlet-side electromagnetic valve, and that is delayed before being shut off after passage of electric current to the inlet-side electromagnetic valve is stopped.