Air Conditioning System Heat Source Switching Control
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Solution Overview
Problem
Conventional air conditioning systems for vehicles do not effectively enhance heating performance by utilizing the heat from cold bodies such as batteries and engines, despite having heat exchangers for different fluids, indicating a need for improved heat management strategies.
Innovation Solution
An air conditioning system incorporating a heat pump, separate liquid-medium circuits, a connection switching device, and a controller to manage heat transfer between a heat source and liquid mediums, allowing for the enhancement of heating performance by switching between different heat exchange paths based on thermal conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a conventional heat pump cycle is used for heating at low outside-air temperature, then the heating operation can be performed, but the refrigerant density becomes too low to exert sufficient compressor performance
Solution Approach 1:
The patent introduces a water heat absorbing and water heating heat pump cycle as an intermediary system. Cooling water from the high-pressure side of the heat pump cycle is circulated through a water-to-water heat exchanger to preheat the refrigerant on the low-pressure side, thereby increasing refrigerant density and compressor performance while maintaining heating capability at low temperatures
2Reliability
If cooling water from the high-pressure side is circulated to the low-pressure side to increase refrigerant density, then compressor performance is improved, but the system complexity increases due to additional circulation paths
Solution Approach 1:
The patent makes the cooling water circulation system multi-functional by enabling it to serve both as a cooling medium for the heat pump cycle and as a heat source for preheating refrigerant. The same water circulation infrastructure is used for both cooling and heating functions, reducing the need for separate dedicated systems and thereby limiting the increase in system complexity
3Adaptability or versatility
If heat exchangers are provided for different fluids (refrigerant, heat medium, air), then heat exchange capability is improved, but the heating performance cannot be further enhanced by utilizing cold bodies such as batteries and engines
Solution Approach 1:
The patent enables the air conditioning system to utilize cold bodies such as batteries and engines as heat sources for the heating operation. The system performs self-service by absorbing heat from these cold bodies through dedicated heat exchangers and incorporating it into the heating cycle, thereby enhancing heating performance without requiring external heating辅助设备
Solution Approach 2:
The patent introduces a cold body heat absorbing circuit as an intermediary system between the cold bodies (batteries, engines) and the heat pump cycle. This circuit includes dedicated heat exchangers that transfer heat from cold bodies to the refrigerant or heat medium, enabling the system to utilize these otherwise wasted heat sources to enhance heating performance
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
The system effectively enhances heating performance by transferring heat from a cold body to the air conditioning target space, improving temperature increase of the conditioned air and preventing frost formation on heat exchangers, thus maintaining efficient operation even at low temperatures.
Implementation Method 1
The refrigerant radiator includes a liquid heater that transfers the heat of the refrigerant to the first liquid medium by performing a heat exchange between the first liquid medium and the refrigerant
Implementation Method 2
The liquid cooler transfers heat of the second liquid medium to the refrigerant by performing a heat exchange between the second liquid medium and the refrigerant
Implementation Method 3
The compressor draws refrigerant flowing out of the liquid cooler, compresses the refrigerant, and discharges the refrigerant
Implementation Method 4
The pressure reducer reduces a pressure of the refrigerant flowing out of the refrigerant radiator and flows the refrigerant to the liquid cooler
Data Source
AI summary
An air conditioning system has a heat pump, a first-liquid-medium circuit in which a first liquid medium circulates, a second-liquid-medium circuit in which a second liquid medium circulates, a heat source, a connection switching device, and a controller. The connection switching device switches between a connection state in which the heat source is connected to the second-liquid-medium circuit and a disconnection state in which the heat source is disconnected from the second-liquid-medium circuit. The controller controls the connection switching device to switch between the connection state and the disconnection state based on a heat-related physical quantity relating to a heat of the first-liquid-medium circuit, a heat-related physical quantity a heat of the second-liquid-medium circuit, a heat-related physical quantity the heat generated by the heat source, or a heat-related physical quantity a heat of the heat pump.