Bypass Air Conditioning Defrost Control for Stable High Pressure
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In air conditioning devices, the positive cycle defrosting mode struggles to maintain a high pressure level of the refrigerating cycle, leading to reduced power input to the compressor, increased liquid backflow, and a risk of the mode no longer continuing due to a vicious cycle, resulting in insufficient heat for defrosting.
Innovation Solution
The air conditioning device employs a discharge-intake bypass circuit with a superheat valve and adjusts the main valve's opening to maintain a target high pressure level during positive cycle defrosting mode, using the indoor heat exchanger temperature sensor to control the high pressure level and minimize liquid backflow, and optimizes the operation of the outdoor fan to enhance defrosting efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the main valve is opened to nearly a fully open state during positive cycle defrosting mode, then the refrigerant flow is improved, but the high pressure level of the refrigerating cycle cannot rise sufficiently, leading to reduced power input to the compressor and decreased defrosting heat
Solution Approach 1:
The main valve opening degree is dynamically adjusted based on detected high pressure levels. During positive cycle defrosting mode, the control unit increases the main valve opening degree when the high pressure level is lower than a predetermined threshold, and decreases it when the high pressure level reaches or exceeds the threshold. This dynamic adjustment resolves the contradiction by allowing sufficient refrigerant flow while maintaining adequate high pressure levels for compressor power input and defrosting heat.
Solution Approach 2:
The invention changes the operating parameter (main valve opening degree) based on the system state (high pressure level). By monitoring the high pressure level and adjusting the main valve opening degree accordingly, the system optimizes both refrigerant flow and pressure maintenance, preventing the vicious cycle of insufficient pressure leading to reduced compressor power and inadequate defrosting heat.
2Quantity of substance
If the main valve is opened to nearly a fully open state during positive cycle defrosting mode, then the refrigerant circulation is enhanced, but liquid backflow into the compressor increases
Solution Approach 1:
The control unit continuously monitors the high pressure level and uses this feedback to adjust the main valve opening degree. This feedback mechanism ensures that the main valve opening degree is optimized to enhance refrigerant circulation while preventing excessive opening that would cause liquid backflow into the compressor, thereby protecting compressor reliability.
Solution Approach 2:
The main valve opening degree is dynamically controlled based on real-time high pressure level detection. This dynamic control allows the system to enhance refrigerant circulation when needed while automatically reducing the opening degree to prevent liquid backflow, thus resolving the contradiction between refrigerant circulation enhancement and compressor reliability.
3Ease of operation
If the high pressure level decreases due to excessive main valve opening, then the refrigerant flow resistance is reduced, but power input to the compressor decreases and defrosting heat becomes insufficient
Solution Approach 1:
The main valve opening degree is adjusted as a controllable parameter based on the detected high pressure level. When the high pressure level is low, the opening degree is increased to reduce flow resistance. When the high pressure level reaches the threshold, the opening degree is decreased to maintain pressure, ensuring sufficient compressor power input and defrosting heat. This parameter change strategy resolves the contradiction between flow resistance reduction and power maintenance.
Solution Approach 2:
The system dynamically adjusts the main valve opening degree in response to high pressure level changes. This dynamic adjustment allows the system to optimize refrigerant flow resistance while maintaining adequate high pressure levels for sufficient compressor power input and defrosting heat, preventing the vicious cycle described in the contradiction.
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 ensures a consistent high pressure level for effective defrosting, increasing power input to the compressor and maintaining the defrosting mode's operation by adjusting the main valve and superheat valve openings, while also minimizing compressor reliability issues and shortening defrosting time.
Implementation Method 1
a compressor (21)
Implementation Method 2
an indoor heat exchanger (41), ... and an outdoor heat exchanger (23)
Implementation Method 3
a main valve (24), ... a superheat valve (27)
Data Source
AI summary
An air conditioning device includes a main refrigerant circuit and a discharge-intake bypass circuit. The refrigerant circuit is operable in a heating mode and a positive cycle defrosting mode. It is possible for refrigerant to bypass from a discharge side to an intake side of the compressor when the refrigerant circuit is operating in the heating mode. The refrigerant circuit is operable in a positive cycle defrosting mode. When the refrigerant circuit is operating in the positive cycle defrosting mode, a superheat valve of the discharge-intake bypass circuit is opened and the refrigerant is caused to bypass from the discharge side to the intake side of the compressor through the bypass circuit and a defrosting-mode main valve high-pressure control is performed to adjust a valve opening of a main valve so that a high pressure level of a refrigerating cycle in the refrigerant circuit reaches a target high pressure.