Split-Cycle Engine Cooling with Phase-Change Fluid and Turbine Recovery
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Solution Overview
Problem
Existing cooling systems for split-cycle internal combustion engines are inefficient and do not effectively manage the different thermal requirements of the compression and expansion cylinders, leading to suboptimal thermodynamic efficiency and wasted residual heat recovery.
Innovation Solution
A cooling system using a heat-exchange fluid comprising a phase-change material that changes phase from liquid to vapor within the engine's cooling channels, with a controlled mixture to maintain optimal temperature and recover mechanical energy from the vapor phase, while separately managing the cooling needs of the compression and expansion sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a traditional cooling system with circulating cooling liquid is used for the compression cylinder, then the cooling system structure is simple and easy to manufacture, but the thermodynamic efficiency is reduced and residual heat cannot be effectively recovered
Solution Approach 1:
The patent applies phase transition by using a phase change material that transitions from liquid to gas within the cooling channels of the compression cylinder. This phase change absorbs latent heat effectively, cooling the compressed air while the resulting gas can be directed to drive a turbine or generator, thereby recovering residual heat energy that would otherwise be wasted. The phase transition mechanism simultaneously achieves efficient cooling and energy recovery without requiring complex external heat exchange systems.
Solution Approach 2:
The invention converts the harmful effect of residual heat in the cooling system into a beneficial resource. By introducing a phase change material that absorbs heat during evaporation, the system transforms the waste heat from compression into useful thermal energy that can drive a turbine or generator. This turns the previously wasted thermal energy into a power source, improving overall thermodynamic efficiency while maintaining a relatively simple cooling system structure.
2Temperature
If the compression cylinder walls are cooled to as low a temperature as possible, then the air temperature increase during compression is limited, but the overall thermodynamic efficiency decreases
Solution Approach 1:
The patent uses phase transition of a cooling substance within the compression cylinder walls to maintain optimal cooling temperature. The phase change material absorbs heat at a relatively constant temperature during evaporation, preventing excessive air temperature rise during compression. The resulting gas phase material is then utilized to drive a turbine or generator, converting what would be waste heat into useful work, thereby maintaining thermodynamic efficiency.
Solution Approach 2:
The invention changes the thermal parameters by using a phase change material with specific latent heat properties. Instead of continuously lowering wall temperature through high flow rates of traditional coolant, the system uses the phase change material's constant temperature absorption characteristic during evaporation. This maintains more stable and optimal cooling temperatures while the released thermal energy is captured through phase change and converted to mechanical work, improving overall energy efficiency.
3Use of energy by moving object
If a phase-change material is used in the cooling channels to recover residual heat, then the thermodynamic efficiency is improved, but the device complexity increases
Solution Approach 1:
The patent merges the cooling function and energy recovery function into a single integrated system. The phase change material serves dual purposes: it cools the compression cylinder walls during evaporation and simultaneously provides thermal energy that can drive a turbine or generator. This consolidation eliminates the need for separate cooling and heat recovery systems, achieving improved thermodynamic efficiency without proportionally increasing device complexity.
Solution Approach 2:
The phase change material performs multiple functions within the cooling system: it acts as a cooling agent by absorbing latent heat during phase transition, serves as a heat transfer medium, and becomes a working fluid for driving turbines or generators. This multi-functionality allows the system to achieve both effective cooling and residual heat recovery using a single substance and integrated pathway, avoiding the need for multiple separate systems and reducing overall complexity.
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
Enhances thermodynamic efficiency by optimizing temperature control and recovering residual heat as mechanical energy, reducing energy consumption and improving overall engine performance.
Implementation Method 1
a phase-change material suited to change phase from liquid to vapour while flowing in the cooling channels of the engine itself
Implementation Method 2
this substance evaporates, absorbs heat thanks to the phase change
Implementation Method 3
the walls of the compression cylinder/s can be cooled through convection
Data Source
Figure 1
Figure 2
AI summary
An engine assembly (1) is provided with a split-cycle internal combustion engine (2) having a compression section (3) and an expansion section (4) and with a cooling circuit (41) for circulating a heat-exchange fluid; said fluid has a boiling temperature such that at least a fraction of the fluid changes phase from liquid to vapour flowing through the expansion section (4) of the engine (2), when the latter operates in steady conditions; the circuit (41) comprises a turbine (50) arranged downstream of the engine so as to receive vapour and produce mechanical energy from the expansion of the vapour.