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Solution Overview
Problem
Refrigeration apparatuses using liquid fluid as a heat source face issues with excessive cooling capability leading to dew condensation and freezing at the utilization unit, despite control measures like compressor capacity reduction, and noise generation from refrigerant bypassing.
Innovation Solution
A refrigeration apparatus with a variable capacity compressor, a first heat exchanger for liquid fluid, a second heat exchanger for air, and a controller that directs refrigerant flow through the second heat exchanger as a heat absorber when the compressor capacity is reduced, to manage excessive cooling and prevent dew condensation and freezing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the compressor capacity is reduced to match decreased cooling load at the utilization unit, then the cooling capability is improved to match demand, but the refrigerant temperature excessively decreases causing dew condensation and freezing at the utilization heat exchanger
Solution Approach 1:
The patent introduces a bypass pipe as an intermediary component that allows refrigerant to flow from the discharge side back to the suction side of the compressor. This bypass flow acts as a mediator to control the temperature of refrigerant entering the utilization heat exchanger, preventing it from becoming excessively cold and causing dew condensation or freezing, while still allowing the compressor capacity to be reduced to match cooling load demand.
Solution Approach 2:
The system implements feedback control by monitoring the cooling load at the utilization unit and adjusting the compressor capacity accordingly. When the cooling load decreases, the compressor capacity is reduced to prevent excessive cooling capability. The bypass pipe works in conjunction with this feedback mechanism to ensure that refrigerant temperature remains within safe operating limits, preventing harmful effects while maintaining efficient operation.
2Productivity
If a bypass pipe is used to control refrigerant flow when the heat source unit has excessive cooling capability, then the cooling capability is reduced, but the refrigerant passing through the bypass pipe generates noise
Solution Approach 1:
The patent extracts the noise-generating function from the bypass pipe by introducing a separate flow control valve. The bypass pipe is retained for its essential function of controlling refrigerant flow and preventing excessive cooling capability, but the noise issue is addressed by using a dedicated valve component that can control flow more quietly and efficiently.
Solution Approach 2:
A flow control valve is introduced as an intermediary component between the bypass pipe and the refrigerant flow. This valve acts as a mediator that can precisely control the refrigerant flow through the bypass pipe while minimizing noise generation, separating the flow control function from the noise issue and allowing for more efficient and quieter operation.
3Object-affected harmful factors
If the compressor capacity is continuously reduced to prevent dew condensation, then the refrigerant temperature is controlled, but the cooling capability may still be excessive under certain operation conditions
Solution Approach 1:
The bypass pipe serves as an intermediary mechanism that provides an additional degree of freedom in controlling refrigerant flow. When compressor capacity reduction alone is insufficient to prevent dew condensation or excessive cooling capability, the bypass pipe allows excess refrigerant to be diverted back to the suction side, fine-tuning the cooling output to match actual demand and preventing harmful effects while maintaining optimal cooling capability.
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 efficiently reduces excessive cooling capability, preventing dew condensation and freezing at the utilization unit, while also addressing noise issues and internal temperature control in the refrigeration apparatus.
Implementation Method 1
The first heat exchanger causes heat exchange between the refrigerant and liquid fluid
Implementation Method 2
The second heat exchanger causes heat exchange between the refrigerant and air
Implementation Method 3
The compressor compresses a refrigerant
Data Source
Figure 1
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Figure 3
AI summary
It is provided a refrigeration apparatus that uses liquid fluid as a heat source and is highly reliably configured to reduce the occurrence of dew condensation and freezing at a utilization unit during cooling operation in which a liquid fluid heat exchanger in a heat source unit functions as a radiator. An air conditioner (10) includes a heat source unit (100) having a compressor (110), a first heat exchanger (140) configured to cause heat exchange between a refrigerant and liquid fluid, a second heat exchanger (160) configured to cause heat exchange between the refrigerant and air, and a valve (162) configured to switch to supply or not to supply the second heat exchanger with the refrigerant, a utilization unit (300) constituting a refrigerant circuit (50) along with the heat source unit, and a controller (406) configured to control to operate the compressor and to open or close the valve (162). The controller opens the valve (162) to supply the second heat exchanger with the refrigerant to cause the second heat exchanger to function as a heat absorber when assessing that the refrigerant sent to the utilization unit needs to be decreased in quantity during cooling operation in which the first heat exchanger functions as a radiator.