Composition for heat cycle system, and heat cycle system
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Solution Overview
Problem
Current heat cycle systems using hydrofluoroolefin (HFO-1123) face challenges with stability and durability due to self-decomposition under high temperature and pressure conditions, and have a high global warming potential (GWP), necessitating a working fluid with low ozone layer impact and improved stability.
Innovation Solution
A composition comprising trifluoroethylene and difluoromethane with a phosphoric acid ester, where the interaction distance between the working fluid and the ester is optimized, enhancing stability and reducing GWP, while maintaining excellent cycle performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If HFO-1123 is used as a working fluid, then ozone layer protection and low GWP are achieved, but stability and durability deteriorate due to self-decomposition under high temperature and pressure conditions
Solution Approach 1:
A phosphoric acid ester is introduced as an intermediary substance to inhibit the self-decomposition reaction of HFO-1123 under high temperature and pressure conditions. The phosphoric acid ester acts as a stabilizer that mediates between the working fluid and the decomposition reaction, preventing harmful chemical changes while maintaining the low GWP and ozone-layer-friendly properties of HFO-1123
Solution Approach 2:
The chemical composition parameters of the working fluid are changed by adding phosphoric acid ester at specific concentrations (0.01-10 mass%). This parameter change transforms the working fluid from an unstable pure HFO-1123 into a stable mixture that maintains the original environmental benefits while gaining improved durability and resistance to decomposition
2Loss of energy
If HFO-1123 is used as a working fluid, then low GWP is achieved, but cycle performance stability deteriorates under repeated compression and heating conditions
Solution Approach 1:
The phosphoric acid ester serves as a stabilizing intermediary that prevents compositional changes of HFO-1123 during repeated compression and heating cycles. It mediates the thermal and mechanical stresses, preventing the working fluid from undergoing unwanted chemical transformations that would compromise its low GWP properties
Solution Approach 2:
The phosphoric acid ester is pre-added to the working fluid composition before the heat cycle operation begins. This preliminary action ensures that the stabilizer is already in place to prevent decomposition and maintain compositional stability from the start of operation, rather than attempting to address instability after it occurs
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 composition achieves a heat cycle system with reduced ozone layer impact, low GWP, and improved stability and durability, effectively suppressing self-decomposition reactions and maintaining efficient cycle performance.
Implementation Method 1
HFO-1123 may undergo self-decomposition reaction under high temperature and high pressure conditions
Data Source
AI summary
A composition for a heat cycle system having less influence over the ozone layer, a low global warming potential, and excellent stability and durability is provided. A heat cycle system using the composition is also provided. The composition contains a working fluid and a phosphoric acid ester. The working fluid contains trifluoroethylene and difluoromethane. An interaction distance (Ra) between the working fluid and the phosphoric acid ester as determined from the Hansen solubility parameters is at most 15.