Refrigeration device
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Solution Overview
Problem
Conventional refrigeration apparatuses with multiple outdoor units connected in parallel face challenges during defrosting, as excess refrigerant accumulation leads to inefficient defrosting and potential overflow risks, requiring larger accumulators and frequent air-warming operation interruptions.
Innovation Solution
A refrigeration apparatus with a partial defrost mode that reroutes refrigerant flow to include the indoor heat exchanger and non-defrosted outdoor units, allowing refrigerant to flow between all units, suppressing excess refrigerant accumulation and optimizing defrosting efficiency by controlling the indoor expansion valve and compressor operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If defrosting is performed with refrigerant circulated only between outdoor units, then outdoor heat exchangers can be defrosted, but excess refrigerant accumulates in the outdoor heat exchanger and defrosting efficiency decreases
Solution Approach 1:
The refrigerant circuit is segmented into multiple flow paths: one path directs refrigerant to the outdoor heat exchanger for defrosting, while another path directs excess refrigerant to the indoor heat exchanger. This segmentation allows simultaneous defrosting operation and excess refrigerant management, resolving the contradiction between defrosting efficiency and refrigerant accumulation.
Solution Approach 2:
The indoor heat exchanger serves as an intermediary component that receives and processes excess refrigerant from the outdoor heat exchanger. By introducing this intermediary, the system can handle the excess refrigerant without compromising the defrosting process, thereby maintaining defrosting efficiency while preventing refrigerant accumulation.
2Reliability
If accumulator size is increased to suppress liquid refrigerant overflow, then liquid refrigerant overflow is prevented, but device complexity and size increase
Solution Approach 1:
The indoor heat exchanger acts as an intermediary that receives excess refrigerant before it can overflow from the accumulator. This intermediary function allows the use of a smaller accumulator while still preventing liquid refrigerant overflow, thus resolving the contradiction between reliability and device complexity.
Solution Approach 2:
Instead of increasing the accumulator size in one dimension, the system introduces a new dimension by routing refrigerant through the indoor heat exchanger. This dimensional change provides an alternative pathway for excess refrigerant, enabling effective overflow prevention without enlarging the accumulator.
3Quantity of substance
If defrosting is performed frequently to remove excess refrigerant, then refrigerant accumulation is reduced, but air-warming operation interruptions increase
Solution Approach 1:
The system maintains continuous useful action by allowing the indoor heat exchanger to process excess refrigerant during normal operation without requiring separate defrosting cycles. This continuous management of excess refrigerant eliminates the need for frequent air-warming operation interruptions, resolving the contradiction between refrigerant management and operational continuity.
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 effectively manages excess refrigerant, prevents overflow, and reduces the frequency of air-warming operation interruptions during defrosting, enhancing overall defrosting efficiency and system stability.
Implementation Method 1
a flow channel that supplies some of the refrigerant flowing out of the outdoor heat exchangers functioning as condensers to the outdoor heat exchangers functioning as evaporators
Implementation Method 2
outdoor heat exchangers, compressors, and switching valves provided to the respective outdoor units
Implementation Method 3
compressors, and switching valves provided to the respective outdoor units
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Provided is a refrigeration apparatus in which adverse events caused by excess refrigerant can be suppressed even when defrosting is performed with some of a plurality of outdoor units designated as units to be defrosted. An air-conditioning apparatus (100) configured from a parallel connection of a first outdoor unit (10) and a second outdoor unit (20), wherein when a second outdoor heat exchanger (23) of the second outdoor unit (20) is caused to function as an evaporator while a first outdoor heat exchanger (13) of the first outdoor unit (10) is caused to function as a condenser to defrost the first outdoor heat exchanger (13), a refrigerant circuit (3) has a flow channel that supplies some of the refrigerant flowing out of the first outdoor heat exchanger (13) to the second outdoor heat exchanger (23) and a flow channel that supplies the rest of the refrigerant flowing out of the first outdoor heat exchanger (13) to an indoor heat exchanger (62, 66).