Air conditioner and control method therefor
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Solution Overview
Problem
Air conditioners using heat pump cycles face decreased heating performance as outdoor temperatures drop, and existing solutions to improve heating efficiency can damage compressors due to liquid back.
Innovation Solution
An air conditioner system with sensors to measure refrigerant temperatures and pressures, and a controller that calculates and controls discharge superheat (DSH) based on compressor frequency and compression coefficient, switching to a two-phase refrigerant injection mode when outdoor temperatures are low to optimize heating performance and prevent compressor damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If refrigerant injection is used to improve heating performance, then heating efficiency increases, but compressor damage due to liquid back occurs
Solution Approach 1:
The patent dynamically adjusts the discharge superheat parameter based on operating conditions (outdoor temperature, compressor frequency, compression ratio) to prevent liquid back while maintaining heating performance. By changing the superheat parameter in real-time, the system resolves the contradiction between heating efficiency and compressor safety.
Solution Approach 2:
The patent implements a feedback control system that continuously monitors operating parameters (outdoor temperature, compressor frequency, compression ratio, discharge temperature) and adjusts the refrigerant injection amount accordingly. This feedback mechanism ensures that heating performance is maximized while preventing compressor damage from liquid back.
2Reliability
If discharge superheat is increased to prevent liquid back, then compressor safety improves, but heating efficiency decreases
Solution Approach 1:
The patent dynamically adjusts the discharge superheat level based on real-time operating conditions rather than using a fixed high superheat value. The system optimizes superheat dynamically to maintain compressor safety while maximizing heating efficiency at different operating points.
Solution Approach 2:
The patent changes the discharge superheat parameter adaptively based on outdoor temperature, compressor frequency, and compression ratio. This parameter optimization resolves the contradiction by finding the optimal superheat level for each operating condition, ensuring both safety and efficiency.
3Reliability
If product-specific reliability tests are performed for each air conditioner model, then compressor safety is ensured, but development time and cost increase
Solution Approach 1:
The patent develops a universal control algorithm based on fundamental thermodynamic parameters (compression ratio, compressor frequency, discharge superheat) that applies across different air conditioner models. This universal approach eliminates the need for extensive product-specific testing while ensuring compressor safety, as the control logic adapts to various models through parameter measurement rather than model-specific calibration.
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
Improves heating performance and efficiency while preventing compressor damage by dynamically controlling the air conditioner based on operating conditions, eliminating the need for product-specific reliability tests and reducing costs.
Implementation Method 1
heat exchange is performed between the outdoor air and the refrigerant, and the heating performance decreases as the outside air temperature decreases
Implementation Method 2
heat exchange is performed between the outdoor air and the refrigerant, and the heating performance decreases as the outside air temperature decreases
Implementation Method 3
a part of the refrigerant passed through the condenser is injected into the compressor to increase the flux of the refrigerant
Data Source
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AI summary
An air conditioner according to an embodiment includes: a compressor configured to compress a refrigerant; an indoor heat exchanger configured to convert a vapor refrigerant into a liquid refrigerant in a heating mode; an outdoor heat exchanger configured to convert a liquid refrigerant into a vapor refrigerant in the heating mode; a main pipe connecting the indoor heat exchanger to the outdoor heat exchanger; an injection pipe branching from the main pipe and connecting to an injection port of the compressor; an injection valve installed on the injection pipe and configured to control a flux of the refrigerant flowing to the injection pipe; and a controller configured to calculate a target discharge superheat (DSH) based on a correlation between a compression coefficient, a compressor frequency, and a DSH that are represented by an operating condition , and control a current DSH based on the target DSH.