Refrigeration cycle device
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Solution Overview
Problem
Air-conditioning apparatuses experience a decrease in heating capacity during simultaneous heating and defrosting operations due to the need for outdoor air to be heated by parallel heat exchangers, leading to increased heat transfer from the defrosting heat exchanger, which reduces overall heating efficiency.
Innovation Solution
The apparatus employs a control system that manages the flow of refrigerant through a defrosting circuit, allowing for selective operation modes such as simultaneous heating and defrosting operations 1 and 2, where refrigerant is distributed to either one or all parallel heat exchangers for defrosting, while maintaining heating capacity by optimizing the operation of heat exchangers and fans.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If outdoor fan operates to receive heat from outdoor air by parallel heat exchangers during simultaneous heating and defrosting, then heating operation can be maintained, but heat transfer from defrosting heat exchanger to outdoor air increases, reducing heating capacity
Solution Approach 1:
The outdoor heat exchanger is divided into multiple parallel heat exchangers, allowing selective operation where one heat exchanger performs defrosting while others perform heating, enabling independent control of heat transfer paths
Solution Approach 2:
The system dynamically switches between different operational modes (simultaneous heating and defrosting with one heat exchanger, simultaneous heating and defrosting with two heat exchangers, or sequential operation) based on outdoor temperature conditions to optimize heating capacity
2Productivity
If simultaneous heating and defrosting operation is performed with one parallel heat exchanger, then heating capacity is maintained better, but system complexity increases due to multiple operation modes
Solution Approach 1:
The control system uses feedback from outdoor temperature sensors to automatically determine the appropriate operational mode, simplifying user interaction while maintaining optimal heating capacity across different temperature conditions
Solution Approach 2:
The system changes operational parameters (number of active heat exchangers, fan speed, refrigerant flow distribution) based on outdoor temperature thresholds to optimize performance without requiring complex manual control
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 approach allows for the suppression of heating capacity decrease during simultaneous heating and defrosting operations by optimizing refrigerant flow and heat exchanger operation, ensuring efficient heating performance even at low outdoor temperatures.
Implementation Method 1
heat from outdoor air be received by the parallel heat exchangers other than the parallel heat exchanger subjected to defrosting
Implementation Method 2
operate as evaporators
Implementation Method 3
The outdoor air sent by the outdoor fan also flows into the parallel heat exchanger subjected to defrosting
Implementation Method 4
an amount of heat transferred from the parallel heat exchanger subjected to defrosting to the outdoor air increases
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A controller switches between and performs a first simultaneous heating and defrosting operation of supplying part of refrigerant discharged from a compressor is supplied to one or some parallel heat exchangers among a plurality of parallel heat exchangers through a defrosting circuit and allowing the other one or more parallel heat exchangers to operate as evaporators, and a second simultaneous heating and defrosting operation of, in one or some heat source units among a plurality of heat source units, supplying the refrigerant discharged from the compressor is supplied to all the plurality of parallel heat exchangers through the defrosting circuit, and in the other one or more heat source units, continuing heating by allowing all the plurality of parallel heat exchangers to operate as evaporators.