Dynamically controlled vehicle cooling and heating system operable in multi-compression cycles
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Solution Overview
Problem
Current vehicle heating and cooling systems face challenges with refrigerants like R134a and R1234yf, particularly in low ambient temperatures, and R744 systems experience efficiency drops at high temperatures, necessitating a solution that maintains efficiency across a wide temperature range and is environmentally friendly.
Innovation Solution
A dynamically controlled vehicle heating and cooling system using R744 refrigerant with a compressor that includes dual scrolls operating in parallel or multistage configurations, controlled by a module adjusting compressor power and expansion device pressure drops based on ambient conditions, temperature, and pressure sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If R744 refrigerant is used to achieve environmental friendliness and low GWP, then environmental performance is improved, but cooling efficiency decreases as ambient temperature rises above 40 degrees Celsius
Solution Approach 1:
The compression process is divided into two separate compression stages with an intercooler between them. The first compression stage compresses the refrigerant to an intermediate pressure and temperature, the intercooler cools the refrigerant, and the second compression stage completes the compression to final high pressure. This segmentation allows the system to handle the thermodynamic challenges of R744 at high ambient temperatures more effectively.
Solution Approach 2:
The system dynamically switches between single-compression and dual-compression modes based on ambient temperature conditions. A controller activates the second compressor and intercooler when ambient temperature exceeds a threshold (e.g., 40°C), optimizing performance for different operating conditions. This dynamic adaptation resolves the efficiency drop at high temperatures while maintaining environmental benefits.
2Loss of energy
If traditional refrigerants like R134a are used to achieve adequate cooling performance, then cooling efficiency is maintained, but global warming potential increases with GWP of 1430
Solution Approach 1:
The system changes the refrigerant parameter from traditional high-GWP refrigerants (R134a with GWP 1430) to R744 (carbon dioxide with GWP 1). This parameter change fundamentally improves environmental performance. The dual-compression system with intercooling compensates for R744's thermodynamic limitations, maintaining cooling efficiency despite the refrigerant change.
3Loss of energy
If heat pump technology is used to improve heating efficiency in hybrid and electric vehicles, then heating performance is improved, but system performance suffers from sub-atmospheric pressure operation below -20 degrees Celsius
Solution Approach 1:
The system dynamically adapts its compression strategy based on ambient temperature. Below -20°C, the dual-compression mode with intercooling prevents sub-atmospheric pressure operation issues, while above 40°C, the same dual-compression mode optimizes cooling efficiency. This dynamic operation resolves the reliability issues in cold conditions and efficiency issues in hot conditions.
Solution Approach 2:
The intercooler acts as an intermediary component between the two compression stages. It cools the refrigerant between compressions, enabling the system to operate reliably at sub-atmospheric pressures in cold conditions and efficiently at high ambient temperatures. This intermediary component resolves both the heating and cooling performance issues across different temperature ranges.
4Device complexity
If a single-compression system is used to simplify system structure, then device complexity is reduced, but system performance cannot be optimized across wide temperature ranges from -20 to above 40 degrees Celsius
Solution Approach 1:
The compression system is segmented into two independent compression stages with separate control. Each compressor can be independently activated based on ambient temperature conditions. This segmentation enables the system to optimize performance across wide temperature ranges while maintaining a relatively simple overall structure that can adapt to different conditions.
Solution Approach 2:
The dual-compression system with intercooling serves multiple functions: it optimizes cooling efficiency at high ambient temperatures, prevents sub-atmospheric pressure issues at low temperatures, and can operate in both heating and cooling modes. This multi-functionality resolves the adaptability issue across wide temperature ranges while the modular design keeps complexity manageable.
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 achieves high efficiency and environmental friendliness, improving fuel economy and driving range by optimizing compressor power and expansion device control across varying temperatures, enhancing performance in both cold and warm conditions.
Implementation Method 1
a compressor with dual scrolls operating in parallel or multistage configurations
Implementation Method 2
expansion device pressure drops
Implementation Method 3
temperature and pressure sensors
Implementation Method 4
R744 refrigerant with a compressor
Data Source
AI summary
A vehicle heating and cooling system includes a compressor(s) for compressing a fluid in a cycle including at least two compressions, and a control module for controlling the compressor dependent upon an ambient condition. The module controls a power of the compressor by adjusting a motor speed driving the compressor and/or a pressure drop of the fluid moving through expansion devices. The pressure drop is controlled by changing a size of an opening in the expansion devices. A related method includes compressing a fluid in a first and a second compression cycle, determining an ambient temperature, sensing a temperature of the fluid outlet from a first heat exchanger, sensing a temperature and a pressure of the fluid outlet from a second heat exchanger, calculating a desired power of the compressor based thereon, and adjusting a parameter of the compressor dependent upon the calculated desired power of the compressor.