Refrigeration apparatus with defrost during heating operation
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Solution Overview
Problem
Conventional refrigeration apparatuses face inefficiencies in heating operations due to frost formation on outdoor heat exchangers, which increases air flow resistance and reduces heating efficiency, and existing defrosting methods do not adequately consider the dryness of the heat exchanger surface or user priorities between heating and defrosting.
Innovation Solution
A refrigeration apparatus with a control unit that differentiates between first and second defrosting start conditions based on the likelihood of frost formation and heating operation load, allowing for continuous heating operation by setting stricter defrosting conditions when the outdoor heat exchanger surface is dry or when the heating load is high.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If defrosting operation is performed frequently to remove frost from outdoor heat exchanger, then heating efficiency is improved, but heating operation continuity is reduced and user comfort deteriorates
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the defrosting start conditions based on multiple parameters including outdoor temperature, humidity, elapsed time since compressor stop, and heat exchanger surface temperature. By changing the threshold values and combination logic of these parameters, the system optimizes the balance between removing frost and maintaining heating continuity, preventing unnecessary defrosting operations that would interrupt heating.
Solution Approach 2:
The patent implements dynamics by making the defrosting control adaptive rather than static. The control unit continuously monitors multiple parameters and adjusts the defrosting decision in real-time based on the current operating conditions. This dynamic approach allows the system to respond to changing environmental conditions and operational states, optimizing heating efficiency while minimizing interruptions to heating operation.
2Duration of action of stationary object
If defrosting operation is delayed to maintain heating continuity, then heating operation continuity is improved, but frost accumulation increases air flow resistance and reduces heating efficiency
Solution Approach 1:
The patent applies preliminary action by performing defrosting operations proactively based on predicted frost accumulation trends rather than waiting for severe frost formation. The control unit monitors parameters such as outdoor temperature, humidity, and elapsed time to anticipate when frost will reach problematic levels, initiating defrosting before it significantly impacts heating efficiency. This prevents both excessive defrosting and allows harmful frost accumulation.
Solution Approach 2:
The patent implements feedback mechanisms by continuously monitoring multiple parameters including outdoor temperature, humidity, elapsed time since compressor stop, and heat exchanger surface temperature. The control unit uses this feedback information to dynamically adjust defrosting timing, ensuring operations are performed only when necessary to maintain heating efficiency while preserving heating continuity. The feedback loop allows real-time optimization of the defrosting schedule.
3Device complexity
If same defrosting start condition is used regardless of outdoor conditions, then control simplicity is maintained, but defrosting efficiency decreases and heating operation is unnecessarily interrupted
Solution Approach 1:
The patent applies segmentation by dividing the defrosting control logic into multiple independent parameter assessments rather than using a single complex condition. The control unit evaluates several separate parameters (outdoor temperature, humidity, elapsed time, heat exchanger temperature) and combines them using logical operations. This segmented approach maintains relative control simplicity while enabling sophisticated, condition-based defrosting decisions that improve efficiency and reduce unnecessary interruptions.
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 enables continuous heating operation while minimizing defrosting, maintaining heating efficiency and preventing air flow resistance increases, thus improving indoor temperature control and user comfort.
Implementation Method 1
a refrigerant circuit and a control unit. The refrigerant circuit includes a compressor, an outdoor heat exchanger, an expansion mechanism, and an indoor heat exchanger connected to each other. The refrigerant circuit is capable of executing at least a heating operation by circulating a refrigerant through the refrigerant circuit.
Implementation Method 2
The control unit is configured to start a defrosting operation when a first defrosting start condition is satisfied in a case where a predetermined premise situation is not established. The control unit is configured to start the defrosting operation when a second defrosting start condition is satisfied in a case where the predetermined premise situation is established. The defrosting operation is an operation for melting frost formed on the outdoor heat exchanger.
Data Source
AI summary
A refrigeration apparatus includes a refrigerant circuit including a compressor, an outdoor heat exchanger, an expansion valve, and an indoor heat exchanger connected to each other, the refrigerant circuit being capable of executing at least a heating operation by circulating a refrigerant through the refrigerant circuit, and a control unit configured to start a defrosting operation for melting frost formed on the outdoor heat exchanger when a first defrosting start condition is satisfied in a case where a predetermined premise situation is not established and start the defrosting operation when a second defrosting start condition stricter than the first defrosting start condition is satisfied in a case where the predetermined premise situation is established. The predetermined premise situation is at least either a situation relating to unlikelihood of formation of frost on the outdoor heat exchanger progressing or a situation where a load of the heating operation is large.