Liquid-Source Refrigeration Control for Condensation-Free Cooling
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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 due to refrigerant bypassing.
Innovation Solution
Incorporating a second heat exchanger that functions as a heat absorber, controlled by a valve system to regulate refrigerant flow, which reduces excessive cooling by directing refrigerant to the second heat exchanger when necessary, and utilizing a bypass pipe to further adjust refrigerant quantity when the second heat exchanger is already operating as a heat absorber.
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 may excessively decrease causing dew condensation or freezing at the utilization heat exchanger
Solution Approach 1:
A three-way valve is introduced as an intermediary device to regulate refrigerant flow distribution. The valve directs refrigerant to either the utilization heat exchanger or the bypass heat exchanger (or both simultaneously), enabling precise control of refrigerant quantity and temperature before it reaches the utilization unit, thereby preventing excessive cooling and dew condensation while maintaining reliable operation
Solution Approach 2:
The system changes the refrigerant flow parameters (quantity and temperature) by dynamically adjusting the three-way valve position. This allows the refrigerant temperature and flow rate to be optimized in real-time, ensuring that the refrigerant reaches the utilization heat exchanger at appropriate parameters that prevent dew condensation and freezing while matching the cooling load demand
2Productivity
If a bypass pipe is used to reduce refrigerant quantity to the utilization unit, then the cooling capability is improved, but noise is generated by the refrigerant passing through the bypass pipe
Solution Approach 1:
The three-way valve serves as a mediator that directs refrigerant flow through the bypass heat exchanger in a controlled manner. By using the valve to regulate flow rather than relying solely on a simple bypass pipe connection, the system reduces turbulent flow and associated noise while maintaining the ability to control refrigerant quantity to the utilization unit
Solution Approach 2:
The bypass heat exchanger is extracted as a separate functional component from the main refrigeration circuit. This allows refrigerant to be diverted through a dedicated path with proper heat exchange and flow control, reducing noise compared to a direct bypass pipe connection while achieving the desired reduction in refrigerant quantity to the utilization unit
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
Effectively reduces excessive cooling capability, preventing dew condensation and freezing at the utilization unit, while also mitigating noise issues and maintaining a reliable operation by dynamically adjusting refrigerant flow based on operational conditions.
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
AI summary
An air conditioner includes a heat source unit having a compressor, a first heat exchanger configured to cause heat exchange between a refrigerant and liquid fluid, a second heat exchanger configured to cause heat exchange between the refrigerant and air, and a valve configured to switch to supply or not to supply the second heat exchanger with the refrigerant, and a controller configured to control to operate the compressor and to open or close the valve. The controller opens the valve 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.