Simultaneous vapor and liquid injection
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Solution Overview
Problem
Transport climate control systems using A2L refrigerants face challenges in maintaining a desired discharge temperature due to high heat of compression, leading to increased energy consumption and reduced refrigeration capacity, especially when vapor and liquid injection ports are separated, which can result in higher discharge temperatures and reduced sub-cooling capabilities.
Innovation Solution
A system and method for simultaneous vapor and liquid injection control in transport climate control systems, incorporating a compressor with separate vapor and liquid injection ports, a condenser, sub-cooling unit, receiver, and economizer, where a controller adjusts the flow control device to manage the amount of liquid refrigerant injected to maintain the discharge temperature below a threshold, optimizing the compressor's operating envelope and preventing reduced vapor injection mass flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If A2L refrigerants with lower GWP are used, then environmental performance is improved, but discharge temperature increases due to high heat of compression
Solution Approach 1:
The injection system is segmented into separate vapor injection port and liquid injection port, allowing independent control of vapor and liquid refrigerant injection to optimize discharge temperature management for A2L refrigerants
Solution Approach 2:
The system changes the physical state parameter of refrigerant injection by providing both vapor and liquid injection capabilities, adjusting the proportion of liquid to vapor injection to control discharge temperature while using A2L refrigerants
2Temperature
If liquid injection amount is increased to reduce discharge temperature, then discharge temperature control is improved, but vapor injection mass flow is reduced leading to reduced sub-cooling capability
Solution Approach 1:
The controller receives feedback from temperature sensors monitoring discharge temperature and evaporator temperature, dynamically adjusting the liquid and vapor injection amounts to maintain discharge temperature below threshold while preserving sub-cooling capability
Solution Approach 2:
The system dynamically adjusts the proportion of liquid versus vapor injection based on real-time operating conditions, allowing optimal refrigeration capacity and discharge temperature control across varying load conditions
3Use of energy by moving object
If separate vapor and liquid injection ports are used, then energy consumption is reduced relative to refrigeration capacity, but discharge temperature control becomes more challenging
Solution Approach 1:
The compressor is designed with multi-functionality to handle both vapor and liquid refrigerant injection through separate ports, enabling efficient energy consumption across different operating conditions while maintaining manageable system 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
This approach effectively maintains a discharge temperature at or below a desired level, prevents reduction in sub-cooling capability, and achieves a wider compressor operating envelope within mechanical design limits, enhancing refrigeration capacity and energy efficiency.
Implementation Method 1
liquid injection port separated from the vapor injection port... adjust an amount of liquid refrigerant into the liquid injection port to maintain a discharge temperature of the compressor at or below a threshold
Implementation Method 2
prevent reduction of sub-cooling capability of the refrigerant flowing through the evaporator
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
Systems and methods for simultaneous vapor and liquid injection for a transport climate control system are provided. The system includes a compressor (210), a condenser having a condensing unit (220) and a sub-cooling unit (320), a receiver (230), an economizer (330) having a vapor outlet and a liquid outlet, a controller (350), and a flow control device (340). The receiver is disposed downstream of the condensing unit and upstream of the sub-cooling unit. The economizer is disposed downstream of the sub-cooling unit. The compressor includes a suction port (211), a vapor injection port (214) connected to the vapor outlet of the economizer, and a liquid injection port (213) separated from the vapor injection port. The controller is configured to control the flow control device to adjust an amount of liquid refrigerant into the liquid injection port to maintain a discharge temperature of the compressor at or below a threshold.