Refrigerant Charge Control for Matched Temperature Glide Heating
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Solution Overview
Problem
Existing air-conditioning systems using zeotropic refrigerant mixtures face decreased heat exchanging efficiency due to significant differences in temperature glides between refrigerants in different refrigeration cycles, leading to inefficient heat exchange processes.
Innovation Solution
A refrigerant charging method that maintains a predetermined mixing ratio of single refrigerants in the second refrigeration cycle to minimize temperature differences between saturated gas and liquid temperatures, ensuring counterflow heat exchange between first and second refrigerants, thereby enhancing heat exchanging efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If zeotropic refrigerant mixtures with different temperature glides are used in first and second refrigeration cycles, then the refrigeration cycles can operate independently with different refrigerants, but the heat exchanging efficiency decreases due to significant temperature glide differences
Solution Approach 1:
The patent changes the compositional parameters of the zeotropic refrigerant mixtures in both refrigeration cycles so that they have substantially the same temperature glide. This parameter adjustment resolves the contradiction by maintaining adaptability to use different refrigerant formulations while eliminating the temperature glide mismatch that caused energy loss in heat exchange.
Solution Approach 2:
The patent creates homogeneity in the temperature glide characteristic between the two different zeotropic refrigerant mixtures. By designing the mixtures to have matched temperature glides, the system achieves uniform thermal behavior during heat exchange, resolving the efficiency problem while preserving the ability to use different refrigerant compositions.
2Loss of energy
If counterflow heat exchange is implemented between refrigerants in different cycles, then heat exchange efficiency is improved, but temperature glide differences between zeotropic refrigerants still cause efficiency loss
Solution Approach 1:
The patent modifies the compositional parameters of the zeotropic refrigerant mixtures to achieve matched temperature glides. This allows counterflow heat exchange to operate at optimal efficiency by ensuring that both refrigerants experience similar temperature changes during phase change, eliminating the temperature glide difference problem.
3Loss of energy
If refrigerant charging amounts are not optimized, then system operation is simple, but heat exchanging efficiency decreases due to improper temperature differences in the heat exchanger
Solution Approach 1:
The patent performs preliminary optimization of the refrigerant charging amounts during system installation or commissioning. By pre-determining the optimal charge quantities based on the matched temperature glide characteristics, the system achieves high heat exchange efficiency without requiring complex real-time control mechanisms.
Solution Approach 2:
The patent incorporates feedback mechanisms to monitor and adjust refrigerant charging amounts. By measuring temperature differences and heat exchange performance, the system can optimize refrigerant quantities to maintain optimal efficiency while adapting to varying operating conditions.
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 method increases heat exchanging efficiency between refrigerants, resulting in energy savings by optimizing the temperature differences within the heat exchanger, leading to improved operational efficiency of the air-conditioning system.
Implementation Method 1
Heat of the first refrigerant and heat of the second refrigerant are exchanged by the heat exchanger for heating
Implementation Method 2
the first refrigerant which is supplied to the first passage of the heat exchanger for heating and the second refrigerant which is supplied to the second passage form counterflow
Data Source
AI summary
When a first temperature difference is the difference between a saturated gas temperature of a first refrigerant at an inlet side and a saturated liquid temperature of the first refrigerant at an outlet side in a heat exchanger for heating, and when a second temperature difference is the difference between a saturated gas temperature of a second refrigerant at an outlet side and a temperature of the second refrigerant at an inlet side in the heat exchanger for heating, the difference between the first temperature difference and the second temperature difference is held in a predetermined value or less by charging the second refrigerant to the second refrigeration cycle so that a plurality of single refrigerants forming the second refrigerant have a predetermined mixing ratio.