Vehicle AC Bypass Circuit for Cold-Weather Dehumidifying Heat
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Solution Overview
Problem
Conventional air conditioning devices for vehicles face challenges in dehumidifying the interior at cold outside temperatures and heating the vehicle interior efficiently due to the temperature mismatch between the condenser and evaporator, leading to moisture freezing and slow heating.
Innovation Solution
The air conditioning system includes a switchable bypass path and a connecting branch that allows the second evaporator to function as a condenser, decoupling the main condenser and second expansion element, enabling the second evaporator to operate at a higher temperature for effective dehumidification and heating by redirecting the refrigerant flow, and incorporating a third expansion element for rapid heating during cold starts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the main condenser is used to cool the refrigerant at cold outside temperatures, then the refrigerant temperature is reduced, but the evaporator cannot dehumidify effectively because the temperature difference is insufficient and moisture freezes
Solution Approach 1:
The system divides the refrigerant cooling function into two separate paths: the main condenser handles primary refrigerant cooling, while the second evaporator (operating in condenser mode) provides additional cooling specifically for dehumidification. This segmentation allows each component to operate at optimized temperature levels, preventing moisture freezing while maintaining dehumidification capability.
Solution Approach 2:
The second evaporator is designed to serve dual functions: it acts as an evaporator during normal cooling operations and as a condenser during cold-weather dehumidification operations. By switching its function through the bypass path, the system gains additional cooling capacity without adding a separate condenser, enabling effective dehumidification at cold temperatures.
2Speed
If the compressor heats the refrigerant for rapid heating mode, then heating speed increases, but dehumidification cannot be performed simultaneously
Solution Approach 1:
The system separates the heating and dehumidification functions into two independent refrigerant circuits. The first circuit (compressor → second evaporator → first expansion element → first evaporator) provides rapid heating, while the second circuit (compressor → main condenser → second expansion element → second evaporator) provides dehumidification. This allows both functions to operate simultaneously without interference.
Solution Approach 2:
The bypass path acts as an intermediary mechanism that directs refrigerant flow to different components based on operational requirements. By opening or closing the bypass path, the system can switch between heating mode, dehumidification mode, or simultaneous operation of both functions, providing flexible control over the air conditioning system's behavior.
3Device complexity
If the conventional refrigerant flow path is used, then the system structure is simple, but heating of the vehicle interior is slow at very low outside temperatures
Solution Approach 1:
The system incorporates dynamic flow control through the bypass path and switching valves that allow the refrigerant circulation path to be reconfigured in real-time. This enables the system to switch between conventional operation and rapid heating mode, optimizing heating speed according to external temperature conditions while maintaining a relatively simple base structure.
Solution Approach 2:
The bypass path is pre-configured to enable rapid heating mode when needed. By having the infrastructure in place beforehand (the bypass path and switching mechanisms), the system can immediately switch to high-speed heating when cold temperatures are detected, without requiring structural modifications or additional components during operation.
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 allows for effective dehumidification without moisture freezing and rapid heating of the vehicle interior, even at low outside temperatures, by optimizing the use of evaporators and condensers as heat exchangers, improving comfort and convenience.
Implementation Method 1
Gaseous refrigerant is compressed and heated in the compressor
Implementation Method 2
In the downstream condenser, the compressed refrigerant is liquefied, with the heat generated by the compression and the condensation heat being given off
Implementation Method 3
the compressed refrigerant is liquefied, with the heat generated by the compression and the condensation heat being given off
Implementation Method 4
Downstream of the condenser is an expansion device in which the liquefied refrigerant is expanded
Implementation Method 5
flows to the downstream evaporator, in which it evaporates with the release of evaporative cold
Implementation Method 6
the evaporator is designed as a heat exchanger through which an air flow to be cooled flows
Data Source
Figure 1a~1b
Figure 1a
Figure 2~3
AI summary
The air conditioning device has a line system (10) for refrigerant and multiple air conditioning elements, such as compressor (12), a main condenser (14) fluidly connected downstream the compressor and a vaporizer (161a) with a fluidic upstream connected an expansion element in a conditioning branch of the line system. A valve arrangement is provided, by which another conditioning branch is selectively blocked or opened. The line system has a switchable bypass path, by which the output of the compressor is directly connected with the input of another vaporizer (161b) while bypassing the main condenser in the open condition of the bypass path. An independent claim is included for a method for operating an air conditioning device.