Air conditioning apparatus
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In air conditioning systems with multiple indoor units connected to an outdoor unit via refrigerant pipes, accurately charging the refrigerant circuit with the prescribed quantity is challenging, especially at low outdoor temperatures, due to varying ease of refrigerant accumulation across indoor heat exchangers, leading to potential overcharging or undercharging.
Innovation Solution
The system employs a control component that performs a combination of heating and cooling refrigerant charging operations, starting with a heating refrigerant charging operation to prevent indoor temperature drops and then switching to a cooling operation to ensure the circuit is charged with the prescribed quantity, using conditions such as refrigerant state, subcooling, and temperature differences to determine charging completion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the determination of refrigerant charging completion is performed on the basis of state quantities of all indoor heat exchangers functioning as radiators, then the refrigerant charging operation can be completed, but the refrigerant circuit may become overcharged because refrigerant accumulates at different rates in different indoor heat exchangers
Solution Approach 1:
The patent divides the determination of refrigerant charging completion into two separate determinations: first determining whether refrigerant has accumulated in any indoor heat exchanger (first determination), and then determining whether the refrigerant circuit is charged with the prescribed quantity (second determination). This segmentation allows the system to handle the varying accumulation rates of different indoor heat exchangers by treating them as separate conditions rather than requiring simultaneous evaluation of all heat exchangers.
Solution Approach 2:
The patent performs the first determination (whether refrigerant has accumulated in any indoor heat exchanger) before performing the second determination (whether the refrigerant circuit is charged with the prescribed quantity). This preliminary action ensures that the system acknowledges refrigerant accumulation in at least one indoor heat exchanger before proceeding to verify overall charging completion, preventing premature termination that could lead to undercharging or overcharging.
2Temperature
If the refrigerant circuit is switched to the heating cycle state for refrigerant charging, then indoor temperatures are maintained, but it becomes difficult to determine charging completion accurately due to multiple indoor heat exchangers with different accumulation characteristics
Solution Approach 1:
The patent segments the detection task by first checking whether refrigerant has accumulated in any indoor heat exchanger (without requiring identification of which specific heat exchanger), and then separately determining overall charging completion. This segmentation simplifies the detection process in heating mode by not requiring the system to evaluate all indoor heat exchangers simultaneously, thus reducing the difficulty of detection while maintaining indoor temperatures.
Solution Approach 2:
Instead of determining whether all indoor heat exchangers have accumulated refrigerant (the conventional approach), the patent inverts the logic by first determining whether any indoor heat exchanger has accumulated refrigerant. This inversion simplifies the detection process in heating cycle mode, where refrigerant accumulation patterns are unpredictable across multiple heat exchangers, making the inverted approach more practical for maintaining indoor temperatures while achieving accurate charging.
3Quantity of substance
If the refrigerant circuit is switched to the cooling cycle state for refrigerant charging, then the refrigerant circuit can be charged with the prescribed quantity, but indoor temperatures are excessively lowered
Solution Approach 1:
The patent performs a preliminary determination (first determination) to check whether refrigerant has accumulated in any indoor heat exchanger before proceeding with the cooling refrigerant charging operation. This preliminary action allows the system to verify that refrigerant distribution has reached an acceptable state before completing the charging process, thereby preventing excessive indoor temperature lowering while ensuring proper refrigerant charging.
Solution Approach 2:
The patent uses feedback from the first determination (whether refrigerant has accumulated in any indoor heat exchanger) to control the timing and completion of the cooling refrigerant charging operation. This feedback mechanism allows the system to monitor refrigerant distribution in real-time and adjust the charging process accordingly, preventing excessive indoor temperature lowering while achieving the prescribed refrigerant charge quantity.
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 approach prevents excessive indoor temperature lowering and ensures accurate refrigerant charging, balancing accumulation differences across indoor heat exchangers, thereby maintaining the refrigerant circuit's optimal charge even at low outdoor temperatures.
Implementation Method 1
a refrigerant circuit 10 that is switchable to a cooling cycle state, which causes the outdoor heat exchanger 24 to function as a radiator of the refrigerant and causes the indoor heat exchangers 52a and 52b to function as evaporators of the refrigerant, and a heating cycle state, which causes the outdoor heat exchanger 24 to function as an evaporator of the refrigerant and causes the indoor heat exchangers 52a and 52b to function as radiators of the refrigerant
Implementation Method 2
an outdoor unit 2 having an outdoor heat exchanger 24 and plural indoor units 5a and 5b having indoor heat exchangers 52a and 52b
Data Source
AI summary
When charging a refrigerant circuit with refrigerant, a control component starts a heating refrigerant charging operation that is performed by switching the refrigerant circuit to a heating cycle state and performs the heating refrigerant charging operation until a predetermined heating refrigerant charging completion condition is met. Thereafter, the control component switches to a cooling refrigerant charging operation that is performed by switching the refrigerant circuit to a cooling cycle state and performs the cooling refrigerant charging operation until a refrigerant charging completion condition where the refrigerant circuit is charged with a prescribed quantity of the refrigerant is met.