Vehicle Heat Pump Refrigerant Circuit Bypassing Frozen Evaporator
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Solution Overview
Problem
Heating and cooling systems in electric or hybrid vehicles face challenges in efficiently controlling temperature, especially at extreme temperatures, due to limited availability of heat sources and sinks, leading to increased energy consumption and reduced vehicle range.
Innovation Solution
A refrigerant circuit with a four-way valve for reversing flow direction, coupled with separate coolant circuits and an internal refrigerant heat exchanger, allows for efficient heating and cooling by bypassing the evaporator at low temperatures, utilizing waste heat from the compressor motor, and decoupling non-functional coolant circuits to conserve energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the refrigerant flows through the evaporator to cool the vehicle interior, then cooling performance is improved, but at extremely low outside temperatures the evaporator becomes frozen and is no longer available for heat exchange
Solution Approach 1:
The system divides the refrigerant flow path into separate controllable branches using a multi-position valve. The refrigerant circuit is segmented so that flow can be directed through different heat exchangers (evaporator, condenser, bypass paths) independently, allowing the evaporator to be isolated when frozen while other components remain operational.
Solution Approach 2:
The system dynamically switches the refrigerant flow configuration based on operating conditions using a multi-position valve. At extremely low temperatures, the valve redirects refrigerant flow to bypass the frozen evaporator, preventing further freezing and maintaining system functionality. This dynamic adaptation resolves the contradiction between cooling performance and evaporator availability.
2Reliability
If additional heating is provided during defrosting operations, then defrosting performance is improved, but energy consumption increases and vehicle range decreases
Solution Approach 1:
The system converts the harmful cold environment into a beneficial resource by using the cold ambient air to cool the condenser while simultaneously using the condenser's heat output to defrost the evaporator. The multi-position valve creates a thermal bridge where heat extracted from the condenser directly warms the evaporator, eliminating the need for additional heating energy while maintaining defrosting capability.
Solution Approach 2:
The system merges the cooling and heating functions into a single integrated process. During defrosting, the refrigerant circuit simultaneously performs condensation (releasing heat) and evaporation (absorbing heat) in different locations, with the heat from condensation directly applied to defrost the evaporator. This combined approach eliminates separate heating requirements and reduces overall energy consumption.
3Adaptability or versatility
If the refrigerant circuit is designed to handle extreme temperature variations, then adaptability is improved, but system complexity increases
Solution Approach 1:
The system uses a multi-position valve that provides multiple flow configurations within a single component, making the refrigerant circuit universally adaptable to different operating conditions (cooling, heating, defrosting, extreme cold) without requiring separate dedicated circuits for each function. This single valve handles multiple functions that would otherwise require complex separate systems.
Solution Approach 2:
The system inverts the traditional refrigerant flow configuration by allowing the refrigerant to flow in reverse directions through different heat exchangers based on operating conditions. The multi-position valve enables the evaporator and condenser to swap functional roles when needed, providing adaptability to extreme temperatures without adding complex separate systems.
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 rapid and efficient temperature control of vehicle interiors and units without additional heating or cooling, reducing energy consumption and extending vehicle range by optimizing heat transfer and minimizing refrigerant usage.
Implementation Method 1
The evaporator can be coupled to a second coolant circuit, so that the refrigerant of the refrigerant circuit can absorb heat from the second coolant circuit in the evaporator and can release heat to a first coolant circuit in the condenser
Implementation Method 2
The refrigerant circuit has an internal refrigerant heat exchanger, which is coupled on both sides to the refrigerant of the refrigerant circuit... the refrigerant in a specific area of the refrigerant circuit transfers heat to the refrigerant in another area of the refrigerant circuit
Implementation Method 3
The refrigerant circuit includes at least one compressor... the refrigerant is conveyed from the compressor through the four-way valve to the condenser
Implementation Method 4
an expansion device or expansion valve... the refrigerant is conveyed through the condenser, the expansion device, and the evaporator
Data Source
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AI summary
The invention relates to a heating/cooling system (1) for motor vehicles, comprising a refrigerant circuit (10) embodied as a heat pump (50) and/or as a refrigerating machine, which comprises at least one main line (30) through which a refrigerant (100) can flow, a compressor (11), a condenser (12), an evaporator (13) and at least one expansion device (14, 15). Said condenser (12) can be coupled to a first refrigerant circuit (21) and the evaporator (13) can be coupled to a second refrigerant circuit (22). Said evaporator (13) of the refrigerant circuit (10) can be surrounded on the refrigerant side by means of a bypass line (33).