Vehicle Cabin Thermal Conditioning Control for Outdoor Exchanger Icing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The air conditioning loop in motor vehicles experiences reduced performance due to frosting on the condenser during heating mode, which obstructs the ambient air flow and prevents effective heating of the passenger compartment.
Innovation Solution
A method that involves determining the risk of icing and reducing or eliminating heat exchange at the first exchanger to store calories in a heat transfer fluid, which are then used to defrost the outdoor exchanger, maintaining the thermodynamic cycle's hot point and ensuring proper operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the condenser is used as an evaporator in heating mode to cool ambient air, then the refrigerant picks up heat from ambient air, but frost forms on the condenser obstructing air flow and degrading performance
Solution Approach 1:
The system performs preliminary defrosting action by diverting hot refrigerant to the condenser before frost obstructs air flow, preventing performance degradation. The control unit monitors frost risk and activates defrosting in advance.
Solution Approach 2:
The system converts the harmful frost formation into a beneficial defrosting process by using the refrigerant's heat during defrosting mode to melt frost, thereby maintaining system performance and converting a negative effect into a useful function.
2Reliability
If frost obstructs the ambient air flow through the condenser, then the air conditioning loop performance is greatly degraded, but adding additional components is not desired
Solution Approach 1:
The condenser serves multiple functions: it acts as a heat exchanger during cooling mode, an evaporator during heating mode, and a defrosting chamber during defrosting mode. This multi-functionality eliminates the need for separate defrosting components while maintaining system reliability.
Solution Approach 2:
The system uses its own refrigerant and existing components to perform defrosting, without requiring external heating elements or separate defrosting systems. The refrigerant's heat is utilized to melt frost on the condenser.
3Reliability
If the heat transfer fluid circuit is used to store calories before defrosting, then the outdoor exchanger can be defrosted efficiently, but the first exchanger heat exchange is reduced or eliminated
Solution Approach 1:
The system operates in periodic cycles, alternating between normal heat exchange mode and defrosting mode. During defrosting periods, the first exchanger heat exchange is reduced or eliminated, but this is temporary and followed by restoration of normal operation.
Solution Approach 2:
The system stores calories in the heat transfer fluid circuit before defrosting is needed, preparing the thermal energy in advance to efficiently defrost the outdoor exchanger when required.
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 effectively prevents icing by using the heat transfer fluid circuit for thermal storage, allowing for efficient defrosting of the outdoor exchanger and maintaining the air conditioning loop's performance, even in low temperatures.
Implementation Method 1
the refrigerant fluid picks up heat from the ambient air flow
Implementation Method 2
storing calories consisting of a reduction or elimination of the heat exchange of the first exchanger
Implementation Method 3
the calories stored in the primary circuit are returned to the outdoor exchanger
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a method for controlling a thermal conditioning unit 1 of a vehicle passenger compartment, comprising an air-conditioning circuit 8 through which a refrigerant flows and a primary circuit 25 through which a first heat transfer fluid flows, the air-conditioning circuit 8 comprises at least one compressor 9, a first heat exchanger 10 designed to ensure heat exchange in order to influence the temperature of an interior air flow 3 sent into the passenger compartment and an exterior heat exchanger 13, the primary circuit 25 comprises at least one primary heat exchanger 28 designed to ensure heat exchange between the first heat transfer fluid and the interior air flow 3, said unit comprising a second heat exchanger 24 designed to ensure heat exchange between the refrigerant and the first heat transfer fluid and installed in the air-conditioning circuit 8 downstream of the first heat exchanger 10 in the direction of movement of the refrigerant in the air-conditioning circuit 8, characterized in that: a) a risk of icing of the external heat exchanger 13 is determined, b) if step a) is confirmed, the heat exchange in the first heat exchanger 10 is reduced or suppressed.