Air conditioner
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Solution Overview
Problem
The reduction of refrigerant charge in air conditioner circuits leads to decreased condensation pressure and temperature, causing a temperature difference reduction between refrigerant and air, which may result in deteriorated air conditioning performance, refrigerant sound generation, and controllability issues with expansion valves due to the gas-liquid two-phase state of refrigerant.
Innovation Solution
An air conditioner design that sets the refrigerant charge between a lower-limit and upper-limit amount, ensuring the refrigerant supercooling degree and quality at specific points in the circuit, allowing for optimal refrigerant flow control and preventing refrigerant sound and controllability issues, while maintaining air conditioning performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the refrigerant charge amount is reduced, then the global warming impact is decreased and safety is improved, but the condensation pressure and temperature decrease causing deterioration of air conditioning capacity
Solution Approach 1:
The patent determines optimal refrigerant charge amounts by establishing specific parameter ranges (supercooling degree and refrigerant quality) at key locations in the refrigerant circuit. By controlling the refrigerant charge to maintain these parameters within defined ranges, the system achieves both reduced refrigerant quantity and maintained air conditioning capacity.
Solution Approach 2:
The patent uses feedback control by measuring actual refrigerant conditions (supercooling degree and refrigerant quality) and adjusting the refrigerant charge amount accordingly. This ensures the refrigerant charge is optimized to prevent global warming while maintaining sufficient condensation capacity for proper air conditioning performance.
2Object-affected harmful factors
If the refrigerant charge amount is reduced, then the global warming impact is decreased, but refrigerant sound is generated due to gas-liquid two-phase state at expansion valve
Solution Approach 1:
The patent prevents refrigerant sound by controlling the refrigerant charge to maintain specific parameter ranges (supercooling degree and refrigerant quality). This ensures refrigerant is properly condensed before reaching the expansion valve, preventing gas-liquid two-phase flow that causes noise, while using the minimum necessary refrigerant amount to reduce global warming impact.
3Object-affected harmful factors
If the refrigerant charge amount is reduced, then the global warming impact is decreased, but the controllability of expansion valve deteriorates
Solution Approach 1:
The patent maintains expansion valve controllability by controlling the refrigerant charge to keep supercooling degree and refrigerant quality within specific ranges. This ensures liquid refrigerant reaches the expansion valve as assumed in the control algorithm, allowing proper adjustment of opening degree to control refrigerant flow rate, while using minimal refrigerant to reduce global warming impact.
4Object-affected harmful factors
If the refrigerant charge amount is reduced, then safety is improved, but the condensation temperature decreases reducing temperature difference with air
Solution Approach 1:
The patent optimizes the refrigerant charge to achieve a specific condensation temperature that maintains sufficient temperature difference with ambient air for effective heat exchange. By controlling parameters like supercooling degree and refrigerant quality, the system uses the minimum safe refrigerant amount while ensuring proper condensation temperature for air conditioning performance.
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 reduced refrigerant charge without compromising air conditioning performance, eliminating refrigerant sound and controllability issues by maintaining appropriate refrigerant flow and condensation capacity within the set charge limits.
Implementation Method 1
an indoor unit having an indoor heat exchanger... exchange heat with the refrigerant inside the condenser
Implementation Method 2
an outdoor heat exchanger... exchange heat with the refrigerant inside the condenser
Implementation Method 3
a condensation pressure in a heat exchanger functioning as a condenser
Implementation Method 4
an expansion valve provided in the outdoor unit, the indoor unit, or the liquid pipe
Implementation Method 5
the controllability of the expansion valve deteriorates when the refrigerant in the gas-liquid two-phase state passes through an expansion valve
Implementation Method 6
drives compressor provided in the outdoor unit such that refrigerant charged in the refrigerant circuit is circulated
Data Source
AI summary
The amount of refrigerant to be charged in a refrigerant circuit of an air conditioner is set to a range defined by a lower-limit charge amount and an upper-limit charge amount. The lower-limit charge amount is a charge amount with which a refrigerant supercooling degree is 0 deg and a refrigerant quality is 0 at a refrigerant outlet side of a supercooling heat exchanger when a cooling operation is performed under an overload condition in which the refrigerant is hardly condensed in an outdoor heat exchanger that functions as a condenser. On the other hand, the upper-limit charge amount is a charge amount with which a refrigerant supercooling degree is 0 deg and a refrigerant quality is 0 at a refrigerant outlet side of the outdoor heat exchanger when the cooling operation is performed under a rated condition.