Air-Conditioning Refrigerant Bypass Storage for Pump-Down Capacity
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Solution Overview
Problem
The existing refrigeration apparatus experiences a decrease in refrigeration capacity due to refrigerant storage in a large-diameter tube at the outlet of the heat source side heat exchanger, leading to increased manufacturing costs and environmental concerns from refrigerant leakage, especially with flammable refrigerants, which are limited by International Electrotechnical Commission standards.
Innovation Solution
An air-conditioning apparatus with a refrigerant circuit including a compressor, heat source side heat exchanger, and expansion valve connected by pipes, featuring a first on-off valve and a bypass that directs refrigerant to a storage unit during pump down operations, allowing for efficient refrigerant storage without increasing the refrigerant fill amount.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large-diameter tube is disposed at the outlet of the heat source side heat exchanger to store refrigerant during pump down operation, then refrigerant can be stored during pump down operation, but refrigeration capacity decreases due to refrigerant stored in the large-diameter tube during cooling operation
Solution Approach 1:
The invention divides the refrigerant storage function from the main refrigerant circuit by introducing a separate storage tank connected through a bypass line. This segmentation allows refrigerant to be stored in the tank during pump down operation without being stored in the large-diameter tube at the heat source side heat exchanger outlet, thereby preventing refrigeration capacity decrease while maintaining reliable refrigerant storage capability.
Solution Approach 2:
The invention introduces a bypass line with a bypass valve as an intermediary pathway between the expansion valve outlet and the heat source side heat exchanger inlet. This bypass allows refrigerant to be diverted to the storage tank during pump down operation, preventing refrigerant accumulation in the large-diameter tube and maintaining normal refrigerant circulation during cooling operation.
2Productivity
If the amount of filling refrigerant is increased to compensate for refrigerant stored in the large-diameter tube, then refrigeration capacity is maintained, but manufacturing cost increases and environmental impact from refrigerant leakage increases
Solution Approach 1:
The invention extracts the refrigerant storage function from the main refrigerant circuit components (heat source side heat exchanger and large-diameter tube) and relocates it to a dedicated storage tank. This allows the main refrigerant circuit to contain only the necessary amount of refrigerant for normal operation, reducing the total refrigerant fill amount while maintaining refrigeration capacity, thereby reducing manufacturing costs and environmental impact.
3Productivity
If the amount of filling refrigerant is increased to compensate for refrigerant stored in the large-diameter tube, then refrigeration capacity is maintained, but manufacturing cost increases
Solution Approach 1:
The invention extracts the refrigerant storage function from the main refrigerant circuit and relocates it to a dedicated storage tank. This allows the main refrigerant circuit to contain only the necessary amount of refrigerant for normal operation, reducing the total refrigerant fill amount while maintaining refrigeration capacity, thereby reducing manufacturing costs.
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 suppresses refrigeration capacity decrease and reduces environmental impact by minimizing refrigerant usage and leakage risks, maintaining performance without increasing the refrigerant fill amount.
Implementation Method 1
a bypass branching from a pipe between the expansion valve and the first on-off valve or a pipe between the heat source side heat exchanger and the expansion valve and connected to a pipe on a suction side of the compressor
Implementation Method 2
a refrigerant storage unit configured to store the refrigerant having passed through the bypass
Implementation Method 3
when the large-diameter tube is disposed at an outlet of the heat source side heat exchanger (a condenser)
Implementation Method 4
a compressor, a heat source side heat exchanger, an expansion valve, and a use side heat exchanger are connected by pipes, and refrigerant circulates
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
Provided is an air-conditioning apparatus configured so that a decrease in a refrigeration capacity can be suppressed without increasing the amount of refrigerant with which a refrigerant circuit is filled and that refrigerant can be suitably stored during a pump down operation. The air-conditioning apparatus includes a first on-off valve 11 provided at a pipe between an expansion valve 7 and a use side heat exchanger 6, a bypass 20 branching from a pipe between the expansion valve 7 and the first on-off valve 11 and connected to a pipe at a suction-side of a compressor 3, and a refrigerant storage unit configured to store the refrigerant having passed through the bypass 20. In a pump down operation in which the compressor 3 operates with the first on-off valve 11 being in a closed state, the refrigerant having flowed out from the heat source side heat exchanger 9 flows into the bypass 20, and then, is stored in the refrigerant storage unit.