Climate control system with a controlled ejector
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Solution Overview
Problem
Current air conditioning systems using CO2 as a refrigerant face limitations in performance at high outdoor temperatures and safety concerns with alternative refrigerants like R1234YF, which are not environmentally neutral and can be flammable, especially in heat pump modes.
Innovation Solution
A climate control system incorporating a compressor, high-pressure and low-pressure chillers, a liquid separator or economizer, and controlled ejectors, with a variable nozzle cross section to manage refrigerant flow efficiently, allowing reliable operation with CO2 under extreme conditions, and enabling its use in both air conditioning and heat pump modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If CO2 is used as refrigerant in air conditioning systems, then environmental friendliness is improved, but performance at high outdoor temperatures deteriorates
Solution Approach 1:
The ejector nozzle cross-section is made variable through axial displacement of the needle relative to the nozzle, allowing dynamic adjustment of the motive mass flow. This enables the system to adapt to different operating conditions, particularly high outdoor temperatures, while maintaining CO2 as the environmentally friendly refrigerant.
Solution Approach 2:
The invention changes the physical parameters of the refrigerant flow by adjusting the nozzle cross-section area. This parameter change allows optimization of the ejector performance for CO2 at different temperature conditions, resolving the contradiction between environmental friendliness and high-temperature performance.
2Productivity
If alternative refrigerants like R1234YF are used, then cooling performance is improved, but safety deteriorates due to flammability
Solution Approach 1:
The invention achieves the desired cooling performance of alternative refrigerants like R1234YF by optimizing the ejector geometry and control for CO2, rather than switching to flammable refrigerants. The variable nozzle cross-section enables CO2 to deliver comparable cooling performance without compromising safety.
3Productivity
If alternative refrigerants like R1234YF are used, then cooling performance is improved, but environmental neutrality deteriorates
Solution Approach 1:
By making the ejector nozzle cross-section variable, the system can achieve high cooling performance with CO2, matching or exceeding the performance of alternative refrigerants while maintaining environmental neutrality. The dynamic adjustment allows optimal operation across different loading conditions.
4Device complexity
If a fixed nozzle cross section is used in the ejector, then device complexity is reduced, but adaptability to different operating conditions deteriorates
Solution Approach 1:
The ejector nozzle cross-section is made variable through axial displacement of the needle, enabling adaptation to different operating conditions including extreme climatic conditions. This dynamic adjustment capability significantly improves versatility while adding controlled complexity to the ejector structure.
Solution Approach 2:
The variable nozzle cross-section design allows the single ejector to perform multiple functions across different operating conditions, from moderate to extreme temperatures, replacing what would otherwise require multiple fixed-geometry ejectors or complex valve arrangements.
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 the efficiency and reliability of CO2 as a refrigerant, particularly in electric vehicles, by managing pressure surges and pulsations, increasing temperature delta utilization, and providing versatile operation for both cooling and heating applications, thus improving the range and comfort of electric vehicles.
Implementation Method 1
The motive mass flow can thus be accelerated by the suction mass flow in an annular gap between a nozzle and a needle of the ejector. The momentum of the motive mass flow is transferred to the suction mass flow after passing the nozzle.
Implementation Method 2
Both mass flows mix in this case.
Implementation Method 3
The cross section increases in the downstream diffuser of the first ejector, as a result of which the velocity of the resulting total mass flow declines and the pressure increases above the level of the suction mass flow.
Implementation Method 4
the pressure increases above the level of the suction mass flow
Data Source
AI summary
In order to provide climate control system for heating or cooling a space, in particular a vehicle interior, having a compressor for conveying a refrigerant, which can efficiently use the refrigerant CO2 for heat pump applications as well, it is proposed to arrange a high-pressure chiller for cooling the refrigerant downstream of the compressor and a low-pressure chiller for heating the refrigerant upstream of the compressor, wherein a refrigerant exiting from the high-pressure chiller can be supplied to a motive mass inlet of a first ejector and a refrigerant exiting from the low-pressure chiller can be supplied to a suction mass inlet of the first ejector, and wherein an outlet of the first ejector is connected directly or indirectly to a liquid separator.