Low GWP fluids for high temperature heat pump applications
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Solution Overview
Problem
Existing heat pump systems face challenges with working fluids that have high Ozone Depletion Potential (ODP) and Global Warming Potential (GWP), particularly in middle to high temperature ranges, leading to deteriorated cycle performance and increased accident risks due to excessive discharge pressures and temperatures.
Innovation Solution
The use of a heat transfer composition comprising 85 to 100 wt% trans-HFO-1233zd and 0 to 15 wt% HFC-134a, which achieves a GWP of less than 150, enabling condensing temperatures above 60°C, and provides capacity, efficiency, and glide similar to CFC-114 while reducing environmental impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If chlorofluorocarbon working fluids (CFC-114) are used in heat pumps, then excellent thermal performance in middle to high temperature ranges is achieved, but high Global Warming Potential (GWP) and Ozone Depletion Potential (ODP) result in severe environmental damage
Solution Approach 1:
The patent changes the chemical composition parameters by replacing CFC-114 with a blend of HFO-1233zd (85-95 wt%) and HFC-134a (5-15 wt%), achieving low GWP (<150) while maintaining thermal performance suitable for middle to high temperature heat pump applications
Solution Approach 2:
The patent creates a composite working fluid by blending two different refrigerants (HFO-1233zd and HFC-134a) in specific proportions, combining the low GWP advantage of HFO with the desirable thermodynamic properties of HFC-134a to achieve both environmental compliance and excellent thermal performance
2Object-affected harmful factors
If replacement working fluids (R-22, R-407C, R-410A, R-134a) are used to reduce ODP and GWP, then environmental impact is reduced, but the highest attainable condensing temperature is limited (65°C for R-22/R-407C/R-410A, 73°C for R-134a)
Solution Approach 1:
The patent modifies the working fluid composition to enable operation at condensing temperatures exceeding 100°C,突破ing the temperature limits of conventional low-GWP refrigerants through the specific properties of HFO-1233zd and its blend ratio with HFC-134a
3Temperature
If condensing temperatures exceed the limit of existing working fluids, then middle to high temperature heat pump applications are enabled, but cycle performance deteriorates and risk of accidents increase due to excessive discharge pressures and temperatures
Solution Approach 1:
The patent optimizes the compositional parameters of the working fluid blend to achieve favorable pressure-temperature characteristics, allowing high condensing temperatures (>100°C) to be reached while maintaining discharge pressures and temperatures within safe operational limits, thus preserving cycle performance and system reliability
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 offers a low GWP alternative to CFC-114, maintaining or improving system performance in medium to high temperature heat pumps with reduced environmental impact, suitable for new and retrofit systems without major modifications.
Implementation Method 1
Heat pump systems use a working fluid, i.e., a refrigerant, to facilitate the generation and transfer of heat over the thermodynamic cycle
Implementation Method 2
A heat pump system has a compressor that imparts energy to the low-grade thermal stream
Implementation Method 3
Heat pump systems have been used to upgrade low-grade thermal energy to high-grade thermal energy via a thermodynamic cycle
Implementation Method 4
Heat pump systems use a working fluid, i.e., a refrigerant, to facilitate the generation and transfer of heat
Data Source
AI summary
The present invention relates, in part, to heat transfer compositions, and associated systems and methods, which include a first composition selected from the group consisting of HFO-1233zd, HFC-245fa, and combinations of these; and, optionally, a second composition selected from the group consisting of HFO-1234ze, HFC-134a, and combinations of these.