Compressed Natural Gas Cooling Coil System for Tank Fill Heat Management
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Solution Overview
Problem
Compressed natural gas tanks face inefficiencies during filling due to heat generated from the compression process, leading to incomplete filling and reduced vehicle range, as existing systems require larger and heavier tanks to manage excess heat.
Innovation Solution
A system utilizing a refrigeration unit with a refrigerant coil and bypass valves to cool compressed natural gas by circulating refrigerant through a heat exchanger, where a heat transfer fluid connects the compressed natural gas coil to the refrigerant coil, effectively transferring heat away from the gas during filling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If compressed natural gas is filled into the tank without cooling, then the filling speed is high, but the tank cannot be completely filled to maximum capacity due to heat generation
Solution Approach 1:
The system cools the compressed natural gas before it enters the tank by circulating refrigerant through heat exchangers positioned in the fill line. This preliminary cooling action prevents heat buildup during filling, allowing the tank to be filled to maximum capacity without compromising filling speed.
Solution Approach 2:
A refrigerant circulation system acts as an intermediary between the compressed natural gas and the tank. The refrigerant absorbs heat from the gas during compression through heat exchangers, enabling continuous high-speed filling while maintaining tank capacity through thermal management.
2Reliability
If larger tanks are used to manage excess heat, then the heat management capacity is improved, but the vehicle weight increases
Solution Approach 1:
Instead of using a larger tank to manage heat, the system introduces a refrigerant circulation system as an intermediary. The refrigerant absorbs and removes excess heat through heat exchangers during the filling process, allowing the use of standard-sized tanks while maintaining effective heat management.
Solution Approach 2:
The heat management function is extracted from the tank structure itself and separated into a dedicated refrigeration system. This allows the tank to maintain its optimal size and weight while the separate refrigeration system handles all heat removal requirements during filling.
3Quantity of substance
If the refrigeration system cools the compressed natural gas, then the tank capacity is maximized, but the device complexity increases
Solution Approach 1:
The refrigeration system is designed to serve multiple functions: it cools compressed natural gas during filling, provides cargo space refrigeration, and can operate independently or in conjunction with the vehicle's existing refrigeration system. This multi-functionality justifies the added complexity by delivering multiple benefits from a single system integration.
Solution Approach 2:
The system merges the filling cooling function with the vehicle's existing refrigeration system where possible, sharing components such as the compressor and refrigerant circulation infrastructure. This integration reduces overall system complexity compared to having completely separate systems for filling cooling and cargo refrigeration.
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 allows for efficient cooling of compressed natural gas during filling, maintaining maximum tank capacity and extending the vehicle's range by managing heat effectively, while also being adaptable for use in transport refrigeration systems.
Implementation Method 1
circulating refrigerant through a heat exchanger, where a heat transfer fluid connects the compressed natural gas coil to the refrigerant coil, effectively transferring heat away from the gas during filling
Data Source
Figure 1
Figure 2
AI summary
A system for cooling compressed natural gas comprises a compressed natural gas coil located within a compartment. The compressed natural gas coil has a compressed natural gas inlet and a compressed natural gas outlet. The system also comprises a refrigerant coil located within the compartment. The refrigerant coil has a refrigerant inlet and a refrigerant outlet. The system further comprises a heat transfer fluid located within the compartment. The heat transfer fluid thermally connecting the compressed natural gas coil to the refrigerant coil.