Outdoor Heat Exchanger Defrost Sequencing for Stable Heating Resumption
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional air conditioners face issues with resumed heating operations due to extremely low outdoor temperatures, leading to potential blockages in the outdoor heat exchanger and prolonged defrosting times, which can result in ineffective heating and repeated defrosting operations, causing user confusion and inefficiency.
Innovation Solution
An air conditioner with adjustable compressor and fan speeds, temperature detectors, and a heating operation mode that stops heating when the outdoor temperature reaches a predetermined low temperature, initiates defrosting when it rises above a higher specified temperature, and resumes heating after defrosting, ensuring stable heating power resumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the heating operation is immediately resumed after the outdoor temperature increases from extremely low conditions, then the heating operation can continue without interruption, but the outdoor heat exchanger may be blocked by snow or frost deposition and the heating operation does not contribute effectively to heating
Solution Approach 1:
The air conditioner performs a defrosting operation as a preliminary action before resuming the heating operation after the outdoor temperature increases from extremely low conditions. This preliminary defrosting removes snow or frost deposition from the outdoor heat exchanger, ensuring that the subsequent heating operation is effective and not blocked by ice accumulation.
2Reliability
If a defrosting operation is performed immediately after resuming heating operation from extremely low temperature, then frost on the outdoor heat exchanger can be removed, but the user may mistakenly determine that the air conditioner is not operating properly
Solution Approach 1:
The defrosting operation is performed as a preliminary step before resuming heating, which is a standard operational procedure. By implementing this predetermined sequence, the system ensures proper heat exchanger functionality while the control logic manages the transition smoothly to avoid user confusion about system status.
3Loss of time
If the maximum defrosting operating time is set to prevent permanently continued defrosting operation, then the defrosting operation can be limited, but under extremely low outdoor temperature the defrosting may be ended due to expiration of maximum time and heating operation cannot be started for a long period
Solution Approach 1:
The air conditioner dynamically adjusts the maximum defrosting operating time based on the outdoor temperature. When the outdoor temperature is extremely low (e.g., -15°C or lower), the system extends the defrosting time limit to accommodate the slower defrosting process caused by low temperatures, thereby preventing premature termination of defrosting operations and enabling timely resumption of heating.
4Productivity
If the heating operation is continued for a certain time period after resumption to ensure heating contribution, then effective heating can be achieved, but the defrosting operation is delayed and the outdoor heat exchanger remains blocked
Solution Approach 1:
The system performs defrosting as a preliminary action before heating operation to clear the outdoor heat exchanger of snow or frost blocks. This sequence ensures that the heat exchanger is clean and functional before heating begins, maximizing heating efficiency from the start rather than delaying defrosting and risking blocked heat exchange.
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 solution allows for stable continuation of heating operations after resumption from extremely low outdoor temperatures, reducing user confusion and inefficiency by ensuring sufficient heating power and minimizing prolonged defrosting times.
Implementation Method 1
an outdoor heat exchanger
Implementation Method 2
outdoor fan
Implementation Method 3
outdoor heat exchanger
Implementation Method 4
an indoor heat exchanger
Implementation Method 5
indoor fan
Implementation Method 6
indoor heat exchanger
Implementation Method 7
a compressor
Implementation Method 8
heat pump method
Implementation Method 9
a temperature detector for detecting a temperature of the outdoor heat exchanger; and a temperature detector for detecting an outdoor temperature
Data Source
AI summary
The air conditioner 1 includes an outdoor unit 10 and an indoor unit 30. The outdoor unit 10 includes an outdoor heat exchanger 16, a compressor 12, an outdoor fan 15, a temperature detector 23 for detecting a temperature of the outdoor heat exchanger 16, and a temperature detector 27 for detecting an outdoor temperature. The indoor unit 30 includes an indoor heat exchanger 33 and an indoor fan 32. The air conditioner 1 has a heating operation mode: that is, when the outdoor temperature reaches a predetermined first specified temperature or lower during a heating operation, the air conditioner 1 stops the heating operation and goes to standby, and thereafter, when the outdoor temperature reaches a temperature equal to or higher than a predetermined second specified temperature higher than the first specified temperature, the air conditioner 1 executes a defrosting operation and subsequently resumes the heating operation.