Refrigeration apparatus, environment forming apparatus, and refrigeration method
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Solution Overview
Problem
Conventional refrigeration apparatuses with bypass flow paths sacrifice refrigeration capacity to excessively protect the compressor, as the constant refrigerant flow through the bypass reduces the flow through the evaporator.
Innovation Solution
A refrigeration apparatus with a bypass flow path that includes a flow rate adjusting valve and a superheating degree control unit, allowing the refrigerant to be suctioned into the compressor without passing through the evaporator, while adjusting the expansion valve and superheating degree according to the refrigeration request degree.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If refrigerant flows through the bypass flow path to cool the compressor, then the compressor discharge pipe temperature is lowered and the compressor is protected, but the refrigeration capacity of the evaporator decreases
Solution Approach 1:
The patent applies dynamics by making the bypass flow path controllable rather than fixed. A flow rate adjusting valve is installed in the bypass flow path to dynamically control the refrigerant flow rate based on operating conditions. This allows the system to adapt between compressor protection mode (when cooling is needed) and refrigeration capacity mode (when cooling is sufficient), resolving the contradiction between reliable compressor operation and evaporator performance
Solution Approach 2:
The patent changes the parameter of refrigerant flow rate in the bypass path from constant to variable. By controlling the flow rate adjusting valve, the system can modify the flow rate parameter according to the compressor discharge pipe temperature and refrigeration demand, thereby balancing compressor protection needs with evaporator refrigeration capacity requirements
2Reliability
If constant flow rate refrigerant flows through the bypass flow path, then the compressor is continuously protected, but the refrigerant flow through the evaporator decreases excessively
Solution Approach 1:
The patent implements feedback control by monitoring the compressor discharge pipe temperature and the refrigerant flow rate, and adjusting the flow rate adjusting valve accordingly. When the discharge pipe temperature is high, the valve opens to increase bypass flow and cool the compressor. When the temperature is acceptable, the valve closes to maximize evaporator refrigeration capacity. This feedback mechanism ensures compressor stability while optimizing refrigeration efficiency
Solution Approach 2:
The system employs periodic adjustment of the bypass flow rate rather than continuous constant flow. The flow rate adjusting valve is controlled to open and close periodically based on temperature conditions, allowing the system to alternate between compressor cooling phases and full refrigeration capacity phases, thus maintaining both reliability and efficiency
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 solution allows for adjustable refrigeration capacity of the evaporator while stably driving the compressor, thereby balancing the protection of the compressor and the refrigeration capacity.
Implementation Method 1
causes a refrigerant liquefied in the condenser to be lowered in temperature by the flow rate adjusting valve
Implementation Method 2
an evaporator... configured to circulate a refrigerant
Data Source
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AI summary
A refrigeration apparatus includes a main circuit that includes a compressor, a condenser, an expansion valve, and an evaporator and circulates a refrigerant, a bypass flow path that includes a flow rate adjusting valve, branches from the main circuit, and causes a refrigerant liquefied in the condenser to be lowered in temperature by the flow rate adjusting valve and to be suctioned into the compressor without passing through the evaporator, an expansion control unit that controls the expansion valve according to a refrigeration request degree, a superheating degree control unit that controls the flow rate adjusting valve so that a degree of superheat with respect to a saturation temperature corresponding to a suction pressure of the compressor becomes a target value, and a changing unit that changes the target value of the degree of superheat.