EV Air Conditioning Condenser Placement for Cabin Heating
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Solution Overview
Problem
The existing air conditioning systems in electric vehicles face challenges in achieving sufficient counterheating, particularly at cold temperatures, due to the limited capacity of the coolant circuit and the inefficiency of electric heaters.
Innovation Solution
The introduction of a third heat exchanger operating as a condenser in the refrigerant circuit, which can be strategically positioned between the first and second heat exchangers, or vertically segmented heat exchangers allowing for dual functionality of heating and cooling, enhances counterheating performance by utilizing waste heat from the condenser for heating purposes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a coolant circuit-based heating system is used in electric vehicles, then heating function is provided, but the heating capacity is insufficient due to limited coolant circuit capacity
Solution Approach 1:
The refrigerant circuit serves dual purposes: cooling during normal operation and heating during cold conditions. The condenser, originally designed for cooling, is repurposed to provide heating by transferring heat to the air flow, making the system self-sufficient for both temperature control needs without requiring separate heating infrastructure
Solution Approach 2:
The heat exchanger (condenser) performs multiple functions: it cools the air flow during warm conditions and heats the air flow during cold conditions. The same physical component and refrigerant circuit are used for both heating and cooling, maximizing the utility of the limited coolant circuit capacity
2Temperature
If electric resistance heaters are used for counterheating, then heating function is provided, but energy efficiency is poor
Solution Approach 1:
The system converts the waste heat generated by the refrigerant condensation process into useful heating energy. Instead of dissipating heat as waste during the cooling cycle, the condenser captures this heat and transfers it to the air flow, turning what would be a loss into a beneficial heating source that improves overall energy efficiency
Solution Approach 2:
The system changes the operational parameters of the refrigerant circuit to enable heating mode. By adjusting the refrigerant flow and condenser operation, the same system can switch between cooling and heating functions, optimizing energy usage based on environmental conditions
3Temperature
If the condenser is positioned between the evaporator and air outlet, then waste heat can be utilized for heating, but the device complexity increases
Solution Approach 1:
The condenser is integrated into the existing air flow path between the evaporator and the air outlet, merging the heating function into the existing cooling system architecture. This consolidation allows waste heat utilization without adding separate, complex heating infrastructure, as the condenser serves both as part of the cooling cycle and the heating source
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 significantly improves temperature stratification within the passenger compartment, allowing for efficient heating of lower areas and cooling of upper areas, thereby enhancing overall heating performance while optimizing energy usage.
Implementation Method 1
a third heat exchanger (22) arranged between the first heat exchanger (21) and the second heat exchanger (20) in the direction of flow of the air flow (14), wherein the third heat exchanger (22) can be operated as a condenser of the refrigerant circuit
Implementation Method 2
a second heat exchanger (20) which is downstream of the first heat exchanger (21) in the direction of flow of the air flow (14) and through which the air flow (14) can flow, has a resistance heating element
Data Source
Figure 1a~4b
Figure 5
Figure 6~7
AI summary
The invention relates to an air conditioning device for a motor vehicle, comprising, arranged in a housing (10), a first heat exchanger (21), through which an air flow (14) can flow and which can be operated as an evaporator of a refrigerant circuit, a second heat exchanger (20, 22) connected downstream of the first heat exchanger in the flow direction of the air flow (14), through which the air flow (14) can flow, and which is provided with a resistance heating element, and further comprising an air guiding flap (30) designed as a bypass flap, by way of which, depending on their position, parts of the air flow (14) can be guided past the second heat exchanger (20, 22).