Air Conditioner Bypass Pipe Design for Refrigerant Leakage Containment
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Solution Overview
Problem
Existing air-conditioning apparatuses fail to fully utilize the accumulator volume for refrigerant collection during leakage detection, leading to insufficient containment of refrigerant within the outdoor unit.
Innovation Solution
An air-conditioning apparatus with a circuit comprising a compressor, flow switching device, heat source-side heat exchanger, expansion unit, accumulator, bypass pipe, and leakage detection unit, where the control unit switches the flow switching device to connect the compressor's discharge side with the heat source-side heat exchanger and opens the bypass opening and closing device upon leakage detection, ensuring refrigerant flows into the accumulator and is trapped there.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the electromagnetic expansion valve is closed to collect refrigerant, then refrigerant leakage into indoor space is reduced, but the accumulator volume is not fully utilized for refrigerant collection
Solution Approach 1:
The bypass opening/closing device is opened in advance before closing the electromagnetic expansion valve, creating a predetermined refrigerant flow path that directs refrigerant toward the accumulator. This preliminary action ensures that when refrigerant collection begins, the flow path is already optimized to utilize the accumulator volume effectively, rather than relying solely on the upstream heat exchanger.
Solution Approach 2:
The bypass pipe acts as an intermediary element that connects the downstream side of the heat source-side heat exchanger with the upstream side of the accumulator. This intermediary path allows refrigerant to be redirected from the normal flow path through the expansion valve into the accumulator, enabling effective utilization of the accumulator volume for refrigerant collection while preventing leakage into indoor spaces.
2Device complexity
If refrigerant is collected mainly into the outdoor heat exchanger, then refrigerant flow control is simplified, but the collection capacity is insufficient due to limited heat exchanger volume
Solution Approach 1:
Instead of relying solely on the vertical dimension of the outdoor heat exchanger for refrigerant collection, the invention adds another dimension by introducing the bypass pipe that leads to the accumulator. This creates an additional spatial pathway and storage volume, effectively expanding the refrigerant collection capacity from a single heat exchanger to a combined system of heat exchanger plus accumulator.
Solution Approach 2:
The refrigerant collection function is segmented between two components: the outdoor heat exchanger handles initial refrigerant flow control, while the accumulator provides additional storage capacity. By dividing the collection function across these two components connected via the bypass pipe, the system achieves both simplified flow control and increased collection capacity.
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 effectively utilizes the accumulator's volume for refrigerant collection, reducing leakage into indoor spaces by ensuring a large amount of refrigerant is trapped within the accumulator.
Implementation Method 1
opens the bypass opening and closing device, refrigerant flows into the accumulator
Implementation Method 2
a compressor that compresses refrigerant
Implementation Method 3
heat source-side heat exchanger that acts as an evaporator in a heating operation
Implementation Method 4
an expansion unit that reduces pressure of the refrigerant
Implementation Method 5
load-side heat exchanger that acts as a condenser in a cooling operation
Implementation Method 6
an accumulator, a bypass pipe that connects a position between the heat source-side heat exchanger and the expansion unit with the upstream side of the accumulator
Data Source
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AI summary
An air-conditioning apparatus includes a circuit, a bypass pipe that connects a position between a heat source-side heat exchanger and an expansion unit, with the upstream side of an accumulator, a bypass opening and closing device provided to the bypass pipe to control the flow rate of refrigerant flowing in the bypass pipe, a leakage detection unit that detects refrigerant leakage, and a control unit that switches the flow switching device to switch between a cooling operation and a heating operation, the cooling operation being an operation in which the heat source-side heat exchanger acts as a condenser, the heating operation being an operation in which the heat source-side heat exchanger acts as an evaporator. The control unit includes a first controller that, in response to detection of refrigerant leakage by the leakage detection unit, switches the flow switching device to connect the discharge side of the compressor with the heat source-side heat exchanger, closes the expansion unit, and opens the bypass opening and closing device, and a second controller that, after the end of operation of the first controller, switches the flow switching device to connect the discharge side of the compressor with the load-side heat exchanger, and stops the compressor.