Air conditioner device
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Solution Overview
Problem
Air-conditioning systems using refrigerants with low refrigerant density at low pressure face significant challenges due to increased pipe diameter requirements, leading to higher processing costs and difficulties in handling thick pipes, as existing solutions do not adequately address the pressure loss issues associated with these refrigerants.
Innovation Solution
An air-conditioning apparatus that uses HFO1234yf or HFO1234ze as refrigerants, with a supercooling means to reduce the liquid temperature of high-pressure refrigerant to 5 degrees C or less, thereby reducing the refrigerant flow rate and allowing for a narrower low-pressure gas pipe diameter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a refrigerant with low refrigerant density at low pressure (e.g., HFO1234yf) is used, then global warming potential is reduced, but the pipe diameter of the low-pressure gas pipe must be significantly increased
Solution Approach 1:
The invention changes the temperature parameter of the high-pressure liquid refrigerant by implementing supercooling to 5°C or less. This parameter change increases the refrigerant density in the liquid phase, which subsequently allows for reduced pipe diameter in the low-pressure gas line while maintaining the use of environmentally friendly refrigerants with low global warming potential
Solution Approach 2:
The invention performs preliminary supercooling of the high-pressure liquid refrigerant before it reaches the expansion device. By pre-cooling the refrigerant to 5°C or less, the system prepares the refrigerant in an optimal state that enables reduced pipe diameter downstream in the low-pressure gas line
2Loss of energy
If the pipe diameter is increased to reduce pressure loss, then pressure loss is reduced, but processing difficulty and cost significantly increase
Solution Approach 1:
By changing the temperature parameter through supercooling to 5°C or less, the invention increases refrigerant density, which allows maintaining acceptable pressure loss characteristics with significantly reduced pipe diameter, thereby improving ease of manufacture and reducing processing difficulty
3Loss of energy
If the pipe diameter is increased to reduce pressure loss, then pressure loss is reduced, but manufacturing cost significantly increases
Solution Approach 1:
The invention changes the temperature parameter of the high-pressure liquid refrigerant through supercooling to 5°C or less, which increases refrigerant density and enables the use of smaller diameter pipes. This parameter change significantly reduces manufacturing cost while maintaining acceptable pressure loss levels
4Length of stationary object
If supercooling means is added to reduce liquid temperature to 5°C or less, then pipe diameter is reduced, but device complexity increases
Solution Approach 1:
The heat source side heat exchanger performs multiple functions: it acts as both the primary heat exchanger for heating/cooling operations and as the supercooling means for the high-pressure liquid refrigerant. This multi-functionality reduces device complexity by eliminating the need for a separate supercooling component
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
The solution effectively reduces the pipe diameter of low-pressure gas pipes, lowering construction costs, improving handling ease, and enhancing energy efficiency by minimizing pressure loss, while maintaining refrigeration performance.
Implementation Method 1
supercooling means making a liquid temperature of a high-pressure liquid refrigerant sent from the heat source side heat exchanger to the expansion device be 5 degrees C or less in a cooling operation
Implementation Method 2
heat source side heat exchanger
Data Source
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AI summary
Obtained is an air-conditioning apparatus capable of having a thin low-pressure gas pipe even when a refrigerant with a low refrigerant density at low pressure is used. An air-conditioning apparatus includes a refrigerant circuit 10 connecting a compressor 1, a heat source side heat exchanger 3, expansion devices 20, and use side heat exchangers 21 with pipes and circulating a refrigerant whose density in a saturated refrigerant gas at 0 degrees C is 35 to 65% of the density of an R410A refrigerant, and supercooling means (supercooling heat exchanger 4, expansion device 5, and bypass 7) making a liquid temperature sent from the heat source side heat exchanger 3 to the expansion devices 20 be 5 degrees C or less in a cooling operation.