Evaporator Heat Exchanger Defrosting via Switchable Coolant Path
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Solution Overview
Problem
The existing refrigeration systems in vehicles face inefficiencies due to ice formation on heat exchangers in evaporator mode, which reduces heat transfer efficiency and requires energy-intensive reverse operation to defrost, especially in hybrid and electric vehicles where additional energy consumption shortens the vehicle range.
Innovation Solution
A device and method for defrosting the heat exchanger in evaporator mode using a separate coolant circuit that can be switched on and off, allowing for heat exchange with the heat exchanger to remove ice without reversing the refrigeration system's operation, utilizing a heat exchanger device in thermally conductive contact with the heat exchanger to supply heat for defrosting, potentially using waste heat from vehicle components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the refrigeration system operates in evaporator mode to absorb heat from the environment, then heat transfer efficiency is improved, but ice formation on the heat exchanger occurs which reduces efficiency and blocks air paths
Solution Approach 1:
The system applies preliminary anti-action by using the condenser to actively prevent ice formation on the evaporator through heat transfer. The condenser, which generates heat during compression, is used to melt ice on the evaporator surface before it can block air paths and reduce heat transfer efficiency, thereby preventing the harmful effect rather than just removing it after occurrence
Solution Approach 2:
The patent merges the functions of the condenser and evaporator by establishing a direct heat transfer relationship between them. The condenser serves dual purposes: cooling the refrigerant and simultaneously heating the evaporator to prevent ice formation. This integration allows one component to counteract the harmful effect produced by another, resolving the contradiction between maintaining low evaporator temperatures for heat absorption and preventing ice accumulation
2Object-affected harmful factors
If reverse mode operation is used to defrost the heat exchanger, then ice removal is achieved, but additional energy consumption occurs which reduces vehicle range
Solution Approach 1:
The system converts the harmful waste heat generated by the condenser into a beneficial resource for defrosting the evaporator. Instead of allowing this heat to be wasted or requiring additional energy input for defrosting, the patent directs the condenser's heat output to melt ice on the evaporator. This transforms a potentially harmful thermal effect into a useful function, eliminating the need for energy-intensive reverse mode operation and thereby extending vehicle range
Solution Approach 2:
The refrigeration system performs self-service by using its own operational components to resolve the ice formation problem. The condenser, which is already operating as part of the refrigeration cycle, automatically provides the necessary heat for defrosting the evaporator. This self-contained approach eliminates the need for external energy sources or additional defrosting equipment, reducing overall energy consumption and maintaining vehicle range
3Productivity
If the heat exchanger surface temperature is lowered below freezing point to enable heat absorption in winter, then heat pump functionality is improved, but ice shell development occurs which insulates and reduces efficiency
Solution Approach 1:
The patent introduces the condenser as an intermediary element between the refrigerant compression process and the evaporator. This intermediary transfers heat from the condenser to the evaporator surface, acting as a thermal bridge that prevents ice formation while maintaining the low temperature necessary for heat absorption. The intermediary resolves the contradiction by providing localized heating exactly where needed without disrupting the overall heat pump functionality
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 approach enables energy-efficient defrosting of heat exchangers in evaporator mode, reducing the need for reverse operation and minimizing energy consumption, thereby extending the vehicle's range and maintaining efficiency in both cooling and heating modes.
Implementation Method 1
a heat exchanger device (55) which is arranged in a second coolant circuit or a separate, on and off path of the at least one first coolant circuit and in heat exchange with the heat exchanger (20) in evaporator mode
Data Source
AI summary
In order to deice a heat exchanger in evaporator operation of a cooling system (1), which heat exchanger was iced at low evaporation temperatures, wherein refrigerant (30) can flow or flows through the heat exchanger in evaporator operation (20), a device for deicing such a heat exchanger in evaporator operation (20) is a heat exchanger device (12, 55) which is situated in a second coolant circuit or a separate, connectable and disconnectable path of the at least one first coolant circuit (65) and can be provided or is provided in heat exchange with the heat exchanger in evaporator operation (20). In a vehicle (100), in particular a land vehicle, having at least one electric drive (50) and/or at least one traction battery (59) and having at least one cooling system (1) which can be or is operated in heat pump mode and which has at least one heat exchanger in evaporator operation (20) which, as part of a refrigerant circuit (66), can have or has refrigerant (30) flowing through it, and having at least one first coolant circuit (65), at least one heat exchanger device (12, 55), which is provided in a second coolant circuit or a separate, connectable and disconnectable path of the at least one first coolant circuit (65), is placed in heat-conducting contact with the heat exchanger in evaporator operation (20) for deicing the heat exchanger in evaporator operation.