Air-conditioning device
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Solution Overview
Problem
Conventional air conditioning apparatuses face challenges in accurately detecting saturation temperature during low refrigerant circulation, leading to liquid pooling and subcooling control issues, especially when the thermistor is mounted at a lower portion of the indoor heat exchanger, which can result in incorrect pressure readings and increased costs due to the need for pressure sensors.
Innovation Solution
The air conditioning apparatus positions a temperature sensor above the height-wise center of the indoor heat exchanger or distributor body, ensuring it detects the saturation temperature accurately even at low refrigerant circulation, eliminating the need for a pressure sensor and reducing liquid pooling by mounting it on the gas-side end of refrigerant paths, thus avoiding detection failures during subcooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the temperature sensor is mounted in the lower portion of the indoor heat exchanger, then the harness length is reduced and maintenance is easier, but liquid pooling occurs at the sensor position causing inaccurate saturation temperature detection
Solution Approach 1:
The patent changes the mounting position of the temperature sensor from the lower portion to the upper portion of the indoor heat exchanger, utilizing the vertical dimension to avoid liquid pooling while maintaining detection accuracy. This dimensional change allows the sensor to be positioned above the liquid level in the heat exchanger.
Solution Approach 2:
The patent proactively positions the temperature sensor above the liquid level to prevent liquid pooling from affecting the measurement. By anticipating the liquid pooling issue and designing the sensor position to be above the liquid level, the system prevents measurement errors before they occur.
2Measurement precision
If a pressure sensor is added to convert pressure values to saturation temperature, then accurate saturation temperature can be detected even with liquid pooling, but product cost increases
Solution Approach 1:
The patent extracts the temperature sensor from the lower portion where liquid pooling occurs and relocates it to the upper portion above the liquid level. This extraction of the sensor from the problematic liquid pooling zone eliminates the need for additional pressure sensors while maintaining accurate saturation temperature detection.
Solution Approach 2:
The patent uses the existing temperature sensor (thermistor) in a repositioned location rather than adding a more expensive pressure sensor. This approach uses a simpler, cheaper component (the relocated temperature sensor) to achieve the same measurement accuracy without increasing device complexity or cost.
3Use of energy by moving object
If the circulation amount of refrigerant is reduced for low load operation, then energy efficiency is improved, but liquid pooling occurs causing subcooling control to fail
Solution Approach 1:
The patent utilizes the vertical dimension by positioning the temperature sensor above the liquid level in the heat exchanger. This allows the system to operate at low circulation amounts for energy efficiency while the sensor remains in a position where liquid pooling does not interfere with saturation temperature detection, maintaining subcooling control reliability.
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 allows for accurate saturation temperature detection, preventing subcooling control hindrances and eliminating the need for pressure sensors, enhancing operational efficiency and reducing costs while maintaining accurate temperature readings.
Implementation Method 1
a temperature sensor configured to detect a saturation temperature of refrigerant flowing through the indoor heat exchanger
Implementation Method 2
a distributor including a distributor body positioned in the neighborhood of a refrigerant outlet of the indoor heat exchanger and a plurality of distribution pipes branching from the distributor body and each connected to one of a plurality of refrigerant paths
Data Source
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AI summary
An object of the present invention is to provide an air conditioning apparatus allowing an indoor heat exchanger to function as a radiator for refrigerant to perform a heating operation and enabling detection of an accurate saturation temperature even if liquid pooling occurs in an operational state with circulation amounts in a low range. Even when the compressor (12) operates at a lower number of compressor rotations to output a minimum heating capacity to reduce a circulation amount of refrigerant, since liquid pooling does not occur above a height-wise center of the indoor heat exchanger (32) or the distributor body (81a), the air conditioning apparatus (10) enables the refrigerant temperature sensor (183) mounted at the above described region to detect an accurate saturation temperature. Consequently, the likelihood of hindrance of subcooling control is removed, so that the control of opening of an electric valve in the conventional manner needs not to be performed only for the removal of liquid pooling. Of course, no pressure sensor is needed.