Outdoor Fan Defrost Control in Heat Pump Air Conditioners
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Air conditioners face difficulties in melting frost that attaches to outdoor fans and their peripheral members, such as bell mouths and fan guards, even after completing the defrosting operation of outdoor heat exchangers.
Innovation Solution
An air conditioner system that includes a refrigerant circuit, a switching valve, an outdoor fan, and a controller, which directs the refrigerant discharged from the compressor towards the outdoor heat exchanger during defrosting and executes a fan defrosting operation by rotating the outdoor fan to warm the frost-covered areas, while also considering outdoor temperature and compressor operation frequency to enhance defrosting performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the outdoor fan rotates continuously during defrosting operation, then air flow helps melt frost, but energy is wasted and frost may reattach
Solution Approach 1:
The patent applies periodic action by rotating the outdoor fan only during specific time intervals - specifically after the outdoor heat exchanger defrosting is complete and for a predetermined duration to address fan and peripheral member frost. This selective, time-limited operation eliminates unnecessary energy consumption while maintaining effective frost removal where needed.
Solution Approach 2:
The system performs preliminary defrosting of the outdoor heat exchanger first, then uses the already-warmed air from this initial phase to subsequently defrost the fan and peripheral members. This approach leverages the heat already generated, reducing the need for additional energy input while achieving comprehensive defrosting.
2Use of energy by moving object
If the outdoor fan is deactivated during defrosting operation, then energy is saved, but frost on the fan main body and peripheral members cannot be melted
Solution Approach 1:
The patent performs preliminary defrosting of the outdoor heat exchanger while the fan remains deactivated, generating warmed air in advance. Subsequently, the fan is activated only long enough to distribute this pre-generated warm air to the fan and peripheral members, minimizing energy consumption while achieving the necessary defrosting effect.
Solution Approach 2:
The system uses the heat generated during the heat exchanger defrosting phase to subsequently defrost the fan and peripheral members. The warmed air from the first phase serves the dual purpose of completing heat exchanger defrosting and providing thermal energy for fan component defrosting, reducing the need for separate heating operations.
3Object-affected harmful factors
If fan defrosting operation is executed at all outdoor temperatures, then frost is removed, but unnecessary operations are performed when frost does not form
Solution Approach 1:
The patent incorporates feedback mechanisms through temperature sensors that continuously monitor outdoor temperature conditions. The controller uses this real-time temperature data to determine whether frost formation conditions exist, and only activates the fan defrosting operation when temperatures indicate frost risk. This feedback-based control eliminates unnecessary operations during warm conditions while ensuring defrosting occurs when needed.
Solution Approach 2:
The system changes its operational parameters based on outdoor temperature conditions. When the temperature falls below a predetermined threshold where frost formation becomes possible, the fan defrosting operation is activated. When temperatures remain above this threshold, the operation remains inactive. This parameter-based conditional control optimizes the balance between frost removal effectiveness and operational efficiency.
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
Effectively melts frost on outdoor fans and their peripheral members by warming the air with the refrigerant, preventing unnecessary fan defrosting operations and ensuring efficient defrosting performance, even in cold and humid conditions.
Implementation Method 1
air elevates its temperature when passing through the outdoor heat exchanger
Implementation Method 2
the warm air hits the main body of the outdoor fan and its peripheral members by means of rotations of the outdoor fan
Data Source
AI summary
An air conditioner includes a refrigerant circuit, a switching valve, an outdoor fan and a controller. The refrigerant circuit sequentially circulates refrigerant through a compressor, an indoor heat exchanger, a decompression mechanism and an outdoor heat exchanger during a heating operation. The switching valve is connected to the refrigerant circuit to switch a flow direction of the refrigerant discharged from the compressor. The controller executes a defrosting operation control in which the outdoor fan is deactivated and the switching valve directs refrigerant discharged from the compressor towards the outdoor heat exchanger during a defrosting operation. The controller further maintains the switching valve so refrigerant discharged from the compressor is directed towards the outdoor heat exchanger and executes a fan defrosting operation control in which the outdoor fan is rotated for a predetermined period of time after completion of the defrosting operation when a predetermined condition is satisfied.