Air conditioning apparatus
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Solution Overview
Problem
Conventional air conditioning systems face challenges in reliably recovering refrigerant at high outside temperatures, leading to increased discharge temperatures and potential compressor damage, as the pressure reduction during refrigerant recovery operations exacerbates evaporation temperature decreases and superheat increases.
Innovation Solution
The system introduces an intermediate-pressure refrigerant flow to the low-pressure pipe from the compressor, using injection and regulating valves to control the refrigerant recovery process, ensuring stable pressure and evaporation temperatures, and includes a bypass pipe for pressure management during high-load conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If refrigerant recovery operation is performed under high outside temperature conditions, then refrigerant recovery is attempted, but discharge temperature increases excessively causing compressor shutdown before recovery completion
Solution Approach 1:
The patent introduces an intermediate-pressure refrigerant flow path from the compressor discharge side to the suction side, serving as a mediator to reduce discharge temperature. This intermediate flow acts as a cooling medium that mixes with the high-temperature discharged refrigerant, effectively lowering the temperature without requiring additional external cooling systems.
Solution Approach 2:
The patent replaces the conventional mechanical approach of simply pumping down the system with a thermodynamic solution using refrigerant injection. Instead of relying solely on mechanical compression and pressure reduction, the system uses refrigerant phase change and heat exchange principles to actively control discharge temperature, substituting a purely mechanical process with a thermodynamically controlled one.
2Quantity of substance
If pressure reduction is performed during refrigerant recovery, then refrigerant is concentrated, but evaporation temperature decreases and superheat increases leading to higher discharge temperature
Solution Approach 1:
The patent changes the pressure parameter by introducing an intermediate-pressure flow path that maintains a pressure level between the high discharge pressure and low suction pressure. This intermediate pressure state allows the system to concentrate refrigerant while preventing excessive evaporation temperature decrease, as the intermediate pressure acts as a buffer that moderates the pressure reduction effect.
3Temperature
If refrigerant recovery is performed without intermediate-pressure flow, then system complexity is low, but discharge temperature cannot be sufficiently reduced preventing compressor protection
Solution Approach 1:
The patent makes the refrigerant flow control system multi-functional by using the same intermediate-pressure flow path for both refrigerant recovery and discharge temperature control. The flow control mechanism serves dual purposes: concentrating refrigerant in the system and simultaneously managing discharge temperature, thereby reducing the need for separate dedicated systems and minimizing overall complexity.
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 effectively prevents pressure reduction, maintains evaporation temperature, reduces compressor discharge temperature, and ensures reliable refrigerant recovery even at high outside temperatures, preventing compressor shutdown and ensuring efficient refrigerant concentration and liquefaction.
Implementation Method 1
controlling an opening degree of the injection regulating valve... allowing an intermediate-pressure refrigerant to flow to the low-pressure pipe from the compressor
Implementation Method 2
operating the compressor... allowing an intermediate-pressure refrigerant to flow to the low-pressure pipe from the compressor
Implementation Method 3
maintains evaporation temperature... ensures efficient refrigerant concentration and liquefaction
Data Source
Figure 1
Figure 2
Figure 3
AI summary
To provide an air conditioning apparatus capable of reliably performing refrigerant recovery even when the outside temperature is high. An air conditioning apparatus 1 includes an injection pipe 30 connecting an injection port 31 of a compressor 11 and a refrigerant pipe between a first regulating valve 14 and an indoor heat exchanger 21, and an injection regulating valve 32 disposed on the injection pipe 30. A control unit 40 executes a first refrigerant recovery operation including: controlling a four-way valve 12 so that an outdoor heat exchanger 13 serves as a radiator and the indoor heat exchanger 21 serves as an evaporator; operating the compressor 11; fully closing the first regulating valve 14; and controlling the opening degree of the injection regulating valve 32.