Air conditioning assembly with controlled ejector
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Solution Overview
Problem
Existing air conditioning systems using CO2 as a refrigerant are limited in performance at high outside temperatures and pose safety concerns, particularly in heat pump operations.
Innovation Solution
An air conditioning system incorporating a compressor, high-pressure and low-pressure chillers, a liquid separator, and controlled ejectors with adjustable nozzles, allowing for efficient refrigerant management and phase separation, enabling reliable operation under extreme conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If CO2 is used as refrigerant, then environmental friendliness is improved, but performance at high outside temperatures deteriorates
Solution Approach 1:
The ejector nozzle cross-section is made dynamically adjustable through a control mechanism that moves the nozzle wall, allowing the system to adapt the refrigerant flow characteristics to varying operating conditions including high outside temperatures, thereby maintaining optimal performance while using environmentally friendly CO2
Solution Approach 2:
The system changes the physical parameters of the ejector nozzle (cross-sectional area) to optimize refrigerant flow under different temperature conditions, enabling CO2 to maintain high cooling performance across a wide range of outside temperatures while preserving its environmental benefits
2Productivity
If alternative refrigerants like R1234YF are used, then cooling performance is improved, but safety deteriorates due to flammability
Solution Approach 1:
The ejector control mechanism adjusts the nozzle cross-section to optimize refrigerant flow parameters, enabling CO2 to achieve cooling performance comparable to alternative refrigerants while maintaining its non-flammable safety advantage through precise flow management
3Device complexity
If ejector nozzle cross-section is fixed, then device complexity is reduced, but adaptability to varying climatic conditions deteriorates
Solution Approach 1:
The ejector nozzle is designed with a movable wall controlled by an actuator mechanism, transforming the fixed-geometry ejector into a variable-geometry device that can adapt to different climatic conditions while maintaining reasonable structural complexity through integrated control
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 enhances refrigerant efficiency, allowing CO2 to be used reliably across varying climatic conditions, increasing the range of electric vehicles by optimizing refrigerant flow and phase changes, and providing versatile heating and cooling capabilities.
Implementation Method 1
the propellant mass flow is accelerated by the suction mass flow. After passing through the nozzle, the momentum of the propellant mass flow is transferred to the suction mass flow. Both mass flows mix in the process.
Implementation Method 2
In the downstream diffuser of the first ejector, the cross-section increases, reducing the velocity of the resulting total mass flow and increasing the pressure above the level of the suction mass flow.
Implementation Method 3
a liquid separator or economizer... The first ejector is designed as a controlled ejector and has an electric drive (25) for adjusting a cross-section of an annular gap, with which the velocity or volume flow of the propellant mass flow supplied through the propellant mass inlet (22) is adjusted.
Data Source
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AI summary
To create an air conditioning arrangement (10) for heating or cooling a space, in particular a vehicle interior (110), with a compressor (11) for conveying a refrigerant, which can also efficiently utilize the refrigerant CO2 for heat pump applications, it is proposed to arrange a high-pressure chiller (12) for cooling the refrigerant downstream of the compressor (11) and a low-pressure chiller (13) for heating the refrigerant upstream of the compressor (11), wherein a refrigerant exiting the high-pressure chiller (12) can be supplied to a motive mass inlet (22) of a first ejector (21) and a refrigerant exiting the low-pressure chiller (13) can be supplied to a suction mass inlet (23) of the first ejector (21), and wherein an outlet (24) of the first ejector (21) is connected directly or indirectly to a liquid separator (14).