Refrigeration device
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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 operations by setting stricter defrosting conditions when the outdoor heat exchanger surface is dry and the heating load is high, thereby reducing the need for defrosting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a defrosting operation is performed frequently to remove frost from the outdoor heat exchanger, then the air flow resistance is reduced and heating efficiency is improved, but the heating operation is interrupted and user comfort deteriorates
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the defrosting start conditions based on the outdoor heat exchanger surface temperature and environmental parameters. When the surface temperature is high (indicating dry surface), stricter defrosting conditions are applied, allowing heating to continue longer. When surface temperature is low (indicating frost formation), defrosting is triggered earlier. This adaptive parameter adjustment resolves the contradiction by optimizing the balance between maintaining heating continuity and preventing frost-induced efficiency loss.
2Loss of time
If the defrosting start condition is set strictly to maintain heating operation, then heating continuity is improved, but frost accumulates and reduces heating efficiency
Solution Approach 1:
The patent implements dynamics by making the defrosting control system adaptive rather than static. The control unit continuously monitors outdoor heat exchanger surface temperature and environmental conditions, dynamically adjusting the defrosting decision criteria. This allows the system to maintain heating operation under favorable conditions (dry surface, mild temperatures) while automatically triggering defrosting when frost accumulation becomes problematic, thus resolving the contradiction between heating continuity and heating efficiency.
3Device complexity
If defrosting operation is performed based on fixed temperature threshold, then control simplicity is maintained, but defrosting may be executed unnecessarily when surface is dry, reducing heating continuity
Solution Approach 1:
The patent applies parameter changes by incorporating multiple environmental parameters (outdoor temperature, humidity, wind speed) and heat exchanger surface temperature into the defrosting control logic, rather than using a single fixed temperature threshold. This multi-parameter approach maintains reasonable control simplicity while significantly improving the accuracy of defrosting timing, preventing unnecessary defrosting operations when the surface is dry, and thus maintaining heating continuity.
4Productivity
If continuous heating operation is prioritized by setting stricter defrosting conditions, then heating efficiency is improved, but frost formation progresses and may affect system reliability
Solution Approach 1:
The patent implements feedback control by continuously monitoring the outdoor heat exchanger surface temperature and environmental conditions, and using this information to dynamically adjust defrosting decisions. The system provides feedback to the control unit about the actual state of the heat exchanger, enabling intelligent determination of whether defrosting is necessary. This feedback mechanism allows the system to maintain heating efficiency by continuing operation when safe, while ensuring system reliability by triggering defrosting when frost accumulation reaches problematic levels.
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 operations while minimizing defrosting, maintaining heating efficiency and preventing air flow resistance increases, thus improving indoor temperature control and user comfort.
Implementation Method 1
causes an outdoor heat exchanger to function as an evaporator for a refrigerant
Implementation Method 2
function as an evaporator for a refrigerant... by circulating a refrigerant through the refrigerant circuit
Implementation Method 3
causes an indoor heat exchanger to function as a radiator for the refrigerant
Implementation Method 4
The defrosting operation is an operation for melting frost formed on the outdoor heat exchanger
Data Source
Figure 1
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AI summary
Provided is a refrigeration apparatus capable of making a defrosting operation less likely to be executed under the situation where the heating operation is easily continuously executed or it is considered that continuous execution of the heating operation is desired. A refrigeration apparatus includes a refrigerant circuit (6) including a compressor (8), an outdoor heat exchanger (11), an expansion valve (12), and an indoor heat exchanger (32) 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 (9) configured to start a defrosting operation for melting frostformed on the outdoor heat exchanger (11) 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 (11) progressing or a situation where a load of the heating operation is large.