Vehicle Air Conditioning Apparatus With Segmented Heat Medium Circuits
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Solution Overview
Problem
In vehicles equipped with multiple devices such as electric motors and batteries, achieving distinct target cooling temperatures for these devices using a single cooling water circuit is complex due to differing temperature requirements.
Innovation Solution
A vehicle air conditioning apparatus featuring a refrigerant circuit, a first heat medium circuit, and a second heat medium circuit, with heat exchangers and pumps to manage heat transfer between the refrigerant and heat mediums, allowing for indirect heat exchange to maintain optimal temperatures for each device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If multiple devices with different cooling temperature requirements are connected to one cooling water circuit, then the system structure is simplified, but the control complexity increases to achieve respective target cooling temperatures
Solution Approach 1:
The cooling system is segmented into multiple independent heat medium circuits (first heat medium circuit for battery, second heat medium circuit for motor), each capable of independently controlling the cooling temperature of specific devices. This segmentation allows each circuit to be optimized for its target device's temperature requirements without interfering with others, resolving the control complexity issue while maintaining structural simplicity through modular design.
Solution Approach 2:
The heat medium circuits are designed with multi-functionality, where the first heat medium circuit serves both as a cooling circuit for the battery and as a heat source for the second heat medium circuit. This universal design allows the system to achieve different cooling temperatures for multiple devices while reducing the need for separate independent systems, balancing structural simplicity with temperature control capability.
2Loss of energy
If direct heat exchange between refrigerant and heat medium is used, then heat transfer efficiency is high, but temperature control precision decreases for devices requiring different cooling temperatures
Solution Approach 1:
A heat medium (coolant) is introduced as an intermediary between the refrigerant and the devices requiring cooling. The refrigerant exchanges heat with the heat medium in the heat exchanger, and the heat medium then transports this thermal energy to the battery and motor through separate circuits. This intermediary approach maintains high heat transfer efficiency at the refrigerant-heat medium interface while enabling precise temperature control at the device level through independent circuit regulation.
Solution Approach 2:
Different regions of the cooling system are assigned different thermal characteristics through the use of separate heat medium circuits. The first heat medium circuit is optimized for battery cooling with specific flow rates and heat exchange characteristics, while the second heat medium circuit is optimized for motor cooling. This local quality differentiation allows each device to receive precisely controlled cooling appropriate to its specific temperature requirements while maintaining overall system efficiency.
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 enables easy attainment of respective target cooling temperatures for devices with different requirements without complex controls, ensuring the electric motor and battery are cooled within specific temperature ranges.
Implementation Method 1
a first heat medium heat releasing unit configured to perform a heat exchange between the refrigerant flowing through the refrigerant circuit and the first heat medium flowing through the first heat medium circuit to release the heat from the first heat medium to the refrigerant
Implementation Method 2
a second heat medium heat releasing unit configured to perform a heat exchange between the first heat medium flowing through the first heat medium circuit and the second heat medium flowing through the second heat medium circuit to release the heat from the second heat medium to the first heat medium
Implementation Method 3
a second heat medium heat releasing unit configured to perform a heat exchange between the first heat medium flowing through the first heat medium circuit and the second heat medium flowing through the second heat medium circuit to release the heat from the second heat medium to the first heat medium
Data Source
AI summary
A vehicle air conditioning apparatus includes: a refrigerant circuit that adjusts a temperature or a humidity of air in a vehicle compartment, including a compressor, indoor heat exchangers, an outdoor heat exchanger, and expansion valves; a first heat medium circuit that allows a first heat medium absorbing heat released from a first heat releasing body to flow therethrough; a second heat medium circuit that allows a second heat medium absorbing heat released from a second heat releasing body to flow therethrough; a first heat medium heat releasing unit that performs a heat exchange between the refrigerant and the first heat medium to release the heat from the first heat medium to the refrigerant; and a second heat medium heat releasing unit that performs a heat exchange between the first heat medium and the second heat medium to release the heat from the second heat medium to the first heat medium.