Refrigerant circuit and method of controlling such a circuit
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Solution Overview
Problem
Existing air conditioning systems for motor vehicles require a significant number of valves for heating, cooling, and dehumidification modes, and lack independent control over the refrigerant flow rate in the evaporator and external exchanger during dehumidification, leading to inefficiencies.
Innovation Solution
A refrigerant circuit with a first branch for the interior exchanger, a second branch with a distinct expansion device for the evaporator, and a third branch with a separate expansion device for the external exchanger, allowing independent modulation of the refrigerant flow rate through the use of control valves and a communication mechanism between the branches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single expansion device is used for both the evaporator and outdoor heat exchanger during dehumidification mode, then the device complexity is reduced, but the ability to independently control refrigerant flow rate to each exchanger is lost
Solution Approach 1:
The patent divides the single expansion device function into two separate expansion devices: a first expansion device for the evaporator and a second expansion device for the outdoor heat exchanger. This segmentation allows independent control of refrigerant flow rate to each exchanger, resolving the contradiction by accepting increased device complexity in exchange for superior adaptability and control versatility during dehumidification mode.
2Adaptability or versatility
If multiple valves are added to enable independent control of refrigerant flow in parallel branches, then the adaptability for different operating modes is improved, but the device complexity increases
Solution Approach 1:
The patent designs the refrigerant circuit with components that serve multiple functions across different operating modes. The first and second expansion devices, along with the control valves, are configured to handle heating mode, cooling mode, and multiple dehumidification modes using the same hardware infrastructure. This multi-functionality approach enables high adaptability without proportionally increasing device complexity, as each component is optimized to serve several purposes rather than requiring dedicated components for each mode.
3Ease of operation
If the refrigerant flow rate is not independently adjustable in each branch, then the system is simpler to operate, but the thermal performance during dehumidification is reduced
Solution Approach 1:
The patent incorporates control means that monitor operating conditions and automatically adjust the refrigerant flow rate through the first and second expansion devices. During dehumidification mode, the control system responds to temperature and humidity sensors by modulating the expansion devices to optimize thermal performance. This feedback mechanism maintains high reliability and performance while keeping the operation relatively simple, as the system self-regulates based on sensed conditions.
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 efficient operation in dehumidification modes by matching the refrigerant flow rate to the temperature of each exchanger, optimizing overall circuit efficiency while reducing the number of components and allowing for flexible operation in heating, cooling, and three distinct dehumidification modes.
Implementation Method 1
a compressor (2) arranged to compress a refrigerant fluid circulating in the circuit (1)
Implementation Method 2
an internal heat exchanger (3) arranged to ensure heat exchange between the refrigerant and an interior airflow (4) intended to be sent into the passenger compartment
Implementation Method 3
a first expansion device (15) arranged to reduce the pressure of the refrigerant fluid
Implementation Method 4
an evaporator (16) arranged to cool the interior airflow (4) intended to be sent into the passenger compartment
Implementation Method 5
a second expansion device (27) arranged to reduce the pressure of the refrigerant fluid
Implementation Method 6
an external heat exchanger (28) arranged to ensure heat exchange between the refrigerant and an exterior airflow (44)
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a refrigerant circuit (1) for thermally conditioning a vehicle passenger compartment, comprising a plurality of branches containing at least one exchanger, of which branch a first branch (11) is in series with a second branch (12) and a third branch (13), said second branch (12) being in parallel with said third branch (13), and a means (36) of placing the third branch (13) in communication with the second branch (12), said means being installed between a sector (37) of the third branch (13) which sector is situated downstream of an external exchanger (28) and a portion (38) of the second branch (12) which is situated upstream of a first control member (15).