Compressor Oil Temperature Sensing for Accurate Refrigerant Charge
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Solution Overview
Problem
Existing methods for judging the adequacy of refrigerant quantity in air conditioner circuits are inefficient due to high calculation loads and inaccuracies caused by temperature distributions in refrigerant oil, making it difficult to determine the correct refrigerant quantity dissolved in the oil reservoir.
Innovation Solution
An air conditioner system that divides the refrigerant circuit into portions, calculates the refrigerant quantity using operation state quantities including ambient temperature, refrigerant temperature, and pressure, and incorporates an oil temperature detecting means to accurately determine the dissolved refrigerant quantity, thereby improving judgment accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If simulation of refrigeration cycle characteristics is performed to judge refrigerant quantity, then judgment accuracy is improved, but calculation time becomes excessively long and calculation might be impossible with low-cost devices
Solution Approach 1:
The patent segments the complex refrigeration cycle simulation into simplified calculation sections. Instead of performing full-cycle simulation, the invention divides the calculation into manageable parts using relational expressions between refrigerant quantity in each portion and operation state quantities, thereby reducing computational complexity while maintaining adequate judgment accuracy.
Solution Approach 2:
The patent changes the calculation parameters from complex simulation variables to simplified operational parameters. By using relational expressions based on easily measurable operation state quantities (such as temperatures, pressures, and flow rates) rather than full thermodynamic simulation parameters, the calculation becomes feasible for low-cost microcomputers while still providing useful refrigerant quantity judgment.
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 system enables high-accuracy judgment of refrigerant adequacy with reduced calculation load by accounting for temperature distributions in the refrigerant oil, ensuring precise refrigerant quantity determination.
Implementation Method 1
the quantity of refrigerant dissolved in the refrigerating machine oil, in particular, the quantity of refrigerant dissolved in the refrigerating machine oil accumulated in an oil reservoir in a compressor
Implementation Method 2
the refrigerating machine oil accumulated in the oil reservoir in the compressor is influenced by the temperature of the refrigerant in contact with the refrigerating machine oil and by the temperature of a wall surface of a compressor casing which forms the oil reservoir
Implementation Method 3
a temperature distribution in the refrigerating machine oil is generated, and the temperature of the refrigerating machine oil is varied
Data Source
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AI summary
With the present invention, the quantity of the refrigerant dissolved in the refrigerating machine oil in a compressor can be correctly determined and the adequacy of the refrigerant quantity in a refrigerant circuit to be judged with high accuracy. An air conditioner (1) includes a refrigerant circuit (10), a refrigerant quantity calculating means, and a refrigerant quantity judging means. The refrigerant circuit (10) is configured by the interconnection of a compressor (21), an outdoor heat exchanger (23), an indoor expansion valve (41, 51), and an indoor heat exchanger (42, 52). The refrigerant quantity calculating means calculates the refrigerant quantity in the refrigerant circuit (10) taking into account a dissolved refrigerant quantity (Mqo) that is the quantity of refrigerant dissolved in the refrigerating machine oil in the compressor, based on an operation state quantity of constituent equipment or refrigerant flowing in the refrigerant circuit (10). The refrigerant quantity judging means judges the adequacy of the refrigerant quantity in the refrigerant circuit (10) based on the refrigerant quantity calculated by the refrigerant quantity calculating means. In addition, the refrigerant quantity calculating means calculates the dissolved refrigerant quantity (Mqo) based on operation state quantities that include at least the ambient temperature outside the compressor (21).