Heat Medium Circuit Leak Detection in Plate Heat Exchanger Air Conditioners
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Solution Overview
Problem
Existing air-conditioning devices using heat exchangers with leakage detection mechanisms based on refrigerant volume expansion fail to early detect refrigerant inflow into heat medium circuits, especially when using plate heat exchangers, leading to delayed detection of refrigerant leakage.
Innovation Solution
An air-conditioning device with a refrigerant circuit and a heat medium circuit, including a compressor, heat source-side and intermediate heat exchangers, a discharge unit, a refrigerant detection device, and a controller that activates a notification system upon detecting excessive refrigerant concentration, allowing for early detection and prevention of refrigerant inflow into the heat medium circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a heat exchanger with a leakage detection groove is used to detect refrigerant leakage through liquid pushing out, then refrigerant leakage can be detected, but the structure becomes complex and refrigerant inflow into the heat medium circuit cannot be early detected
Solution Approach 1:
The invention extracts the refrigerant leakage detection function from the heat exchanger structure itself and places it in a separate detection groove located in the outlet pipe of the heat medium circuit. This separation simplifies the heat exchanger structure while maintaining detection capability. The detection groove contains liquid that is pushed out when refrigerant leaks, providing a simple and effective detection mechanism without complicating the heat exchanger design.
Solution Approach 2:
The invention introduces liquid as an intermediary substance in the detection groove. When refrigerant leaks into the heat medium circuit, the expanding refrigerant pushes the liquid out of the detection groove, providing a visible indication of leakage. This intermediary mechanism enables reliable detection while keeping the overall structure simple and avoiding direct complexity in the heat exchanger itself.
2Productivity
If a plate heat exchanger is used to exchange heat between refrigerant and heat medium, then heat exchange efficiency is improved, but refrigerant inflow into the heat medium circuit cannot be early detected
Solution Approach 1:
The invention implements preliminary action by detecting refrigerant leakage at the outlet of the heat medium circuit before the refrigerant can cause harmful effects. The detection groove is positioned to capture refrigerant expansion effects early in the heat medium circuit, allowing for timely detection and response. This preliminary detection approach maintains high heat exchange efficiency while providing early warning of refrigerant inflow.
3Duration of action of stationary object
If refrigerant leaks into the heat medium circuit, then heat exchange continues, but the leakage cannot be detected until later stages
Solution Approach 1:
The invention implements feedback by continuously monitoring the outlet of the heat medium circuit for signs of refrigerant leakage. The detection groove provides real-time feedback when refrigerant expands and pushes liquid out, allowing immediate detection and response. This feedback mechanism ensures that heat exchange operation can be maintained safely with prompt detection of any refrigerant inflow, eliminating detection delays.
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
Enables early detection and notification of refrigerant leakage, preventing refrigerant from entering the heat medium circuit and reducing the risk of accidents such as fires, even when using slightly flammable or flammable refrigerants.
Implementation Method 1
a discharge unit connected downstream of the intermediate heat exchanger in the heat medium circuit and configured to discharge fluid flowing through the heat medium pipe, to outside of the heat medium pipe, depending on pressure of the fluid
Implementation Method 2
a refrigerant detection device configured to detect concentration of the refrigerant contained in the fluid discharged from the discharge unit
Implementation Method 3
a heat source-side heat exchanger, an expansion unit, and an intermediate heat exchanger that are connected by a refrigerant pipe, and through which refrigerant circulates, the heat source-side heat exchanger exchanging heat between air and the refrigerant, the intermediate heat exchanger exchanging heat between the refrigerant and heat medium
Data Source
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AI summary
An air-conditioning device includes a refrigerant circuit including a compressor, a heat source-side heat exchanger, an expansion unit, and an intermediate heat exchanger that are connected by a refrigerant pipe, and through which refrigerant circulates, the heat source-side heat exchanger exchanging heat between air and the refrigerant, the intermediate heat exchanger exchanging heat between the refrigerant and heat medium; a heat medium circuit including a pump, the intermediate heat exchanger, and a load-side heat exchanger that are connected by a heat medium pipe, and through which the heat medium circulates, the load-side heat exchanger exchanging heat between air in an air-conditioned space and the heat medium; a discharge unit connected downstream of the intermediate heat exchanger in the heat medium circuit and configured to discharge fluid flowing through the heat medium pipe, to outside of the heat medium pipe, depending on pressure of the fluid; a refrigerant detection device configured to detect concentration of the refrigerant contained in the fluid discharged from the discharge unit; a notification device configured to notify leakage of the refrigerant; and a controller configured to activate the notification device depending on the concentration of the refrigerant detected by the refrigerant detection device.