Air-Conditioning Bypass Flow Control for Stable Heating During Defrost
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Solution Overview
Problem
Existing air-conditioning apparatuses with parallel heat exchangers face a reduction in heating capacity during defrosting operations due to the redistribution of refrigerant, leading to inefficient heat exchange.
Innovation Solution
An air-conditioning apparatus with a main circuit, flow switching device, pressure reducing device, and parallel heat exchangers, where a controller adjusts the flow control device's opening degree and compressor frequency based on evaporating pressure to maintain refrigerant flow to the indoor heat exchanger during heating-defrosting operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If refrigerant flow is increased to the parallel heat exchanger being defrosted, then defrosting efficiency is improved, but heating capacity of the indoor heat exchanger is reduced
Solution Approach 1:
The flow control device dynamically adjusts the refrigerant flow rate to the defrosting heat exchanger based on real-time operating conditions, allowing the system to optimize between defrosting efficiency and heating capacity maintenance rather than using a fixed flow rate
Solution Approach 2:
The control device receives feedback signals from sensors monitoring refrigerant temperature, pressure, and flow rate, and automatically adjusts the flow control device opening degree to maintain optimal balance between defrosting performance and heating capacity
2Speed
If refrigerant flow rate to the defrosted heat exchanger is increased, then defrosting speed is improved, but heat exchange capacity of the indoor heat exchanger deteriorates
Solution Approach 1:
The system changes the refrigerant flow rate parameter dynamically during defrosting operation, adjusting it based on the accumulated frost amount, outdoor temperature, and heating load requirements to optimize both defrosting speed and heat exchange capacity
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 configuration ensures that the heating capacity is maintained during defrosting by optimizing refrigerant flow, preventing a reduction in indoor heat exchanger performance and ensuring continuous heating.
Implementation Method 1
a flow control device provided to the bypass pipe and configured to adjust a flow rate of the refrigerant flowing through the bypass pipe
Implementation Method 2
a pressure reducing device provided to a parallel pipe connected to the parallel heat exchanger to be defrosted
Implementation Method 3
an evaporating pressure sensor configured to measure an evaporating pressure of the refrigerant
Implementation Method 4
a compressor, a flow switching device, an indoor heat exchanger, a pressure reducing device, and a plurality of parallel heat exchangers connected in parallel with each other are connected by pipes
Implementation Method 5
an outdoor heat exchanger exchanging heat between outdoor air and refrigerant
Data Source
AI summary
An air-conditioning apparatus includes a main circuit in which a compressor, a flow switching device, an indoor heat exchanger, a pressure reducing device, and a plurality of parallel heat exchangers connected in parallel with each other are connected by pipes, a bypass pipe, a flow control device provided to the bypass pipe and configured to adjust a flow rate of refrigerant flowing through the bypass pipe, an evaporating pressure sensor configured to measure an evaporating pressure of the refrigerant, and a controller. The air-conditioning apparatus is configured to operate in a normal heating operation mode and a heating-defrosting operation mode. When an operation associated with the normal heating operation mode is switched to an operation associated with the heating-defrosting operation mode, the controller adjusts an opening degree of the flow control device using the evaporating pressure in the parallel heat exchanger and a driving frequency of the compressor.