Heat Pump Charge Diagnostics Using Air Temperature Sensing
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Solution Overview
Problem
Existing heat-pump systems face challenges in accurately determining and maintaining optimal refrigerant charge levels, which affects their efficiency and operation, as current methods lack precise diagnostics for fluid charge conditions.
Innovation Solution
A method and system that utilize sensors to measure air and refrigerant temperatures, with a processor determining the working-fluid charge condition based on temperature differences and comparisons to predetermined values, and a cloud-based processing device for remote diagnostics and alerts, enabling efficient monitoring and fault detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional refrigerant charge monitoring methods are used, then system operation continues without interruption, but measurement precision of refrigerant charge conditions deteriorates
Solution Approach 1:
The patent uses air temperature as an intermediary parameter to indirectly measure refrigerant charge conditions. Temperature sensors measure air temperatures at different locations (return air, supply air, heat exchanger surfaces), and these temperature differences serve as mediators to diagnose refrigerant charge status without directly measuring refrigerant properties.
Solution Approach 2:
The patent replaces direct mechanical or chemical refrigerant measurement methods with thermal field-based temperature sensing. Instead of using complex refrigerant analysis equipment, the system uses temperature sensors and thermal imaging to detect charge conditions through the thermal effects of refrigerant flow and heat exchange.
2Measurement precision
If multiple temperature sensors and cloud-based processing are implemented, then measurement precision of refrigerant charge conditions improves, but device complexity increases
Solution Approach 1:
The system implements feedback by continuously monitoring temperature differences and comparing them against predetermined thresholds or expected ranges. The processor receives temperature data from multiple sensors, analyzes the differences, and provides diagnostic feedback about refrigerant charge conditions, enabling continuous optimization and adjustment.
Solution Approach 2:
The temperature sensors serve multiple functions: they monitor air temperatures for HVAC control, measure heat exchanger surface temperatures for efficiency optimization, and provide diagnostic data for refrigerant charge detection. This multi-functionality reduces the need for separate dedicated sensors and simplifies the overall system architecture.
3Productivity
If real-time temperature monitoring and cloud processing are used, then productivity of system maintenance improves, but loss of time for data transmission and processing increases
Solution Approach 1:
The system performs preliminary local processing of temperature data using the onboard processor, which compares temperature differences against predetermined values and generates preliminary diagnostics. This preliminary action filters and prepares data before cloud transmission, reducing the amount of data that needs to be transmitted and enabling faster initial responses without waiting for cloud processing.
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 solution allows for precise determination of refrigerant charge conditions, improving the efficiency and operation of heat-pump systems by identifying undercharge, overcharge, or flow restriction issues, and providing real-time alerts and guidance for technicians to adjust fluid levels, thereby optimizing system performance.
Implementation Method 1
The return-air temperature sensor may be adapted to measure a first air temperature of air upstream of the indoor heat exchanger
Implementation Method 2
The supply-air temperature sensor may be adapted to measure a second air temperature of air downstream of the indoor heat exchanger
Implementation Method 3
The processor may be in communication with the working-fluid temperature sensor and may be programmed to determine the working-fluid-charge condition of the heat-pump system based on the working-fluid temperature
Implementation Method 4
an indoor heat exchanger, an outdoor heat exchanger, a compressor circulating a working fluid between the indoor and outdoor heat exchangers
Data Source
AI summary
A heat-pump circuit may include an indoor heat exchanger, an outdoor heat exchanger, a compressor adapted to circulate a working fluid between the indoor and outdoor heat exchangers, and an expansion device disposed between the indoor and outdoor heat exchangers. A monitor for the heat-pump system may include a return-air temperature sensor, a supply-air temperature sensor, and a processor. The return-air temperature sensor may be adapted to measure a first air temperature of air upstream of the indoor heat exchanger. The supply-air temperature sensor may be adapted to measure a second air temperature of air downstream of the indoor heat exchanger. The processor may be in communication with the return-air temperature sensor and the supply-air temperature sensor. The processor may be programmed to determine a working-fluid-charge condition of the heat-pump system based on the first and second air temperatures.