Heat pump type heat source apparatus
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional refrigeration apparatuses face issues with detecting the dropout of discharge temperature sensors due to mechanical detachment and temperature rise effects, leading to potential compressor failure and complex cycle configurations.
Innovation Solution
A heat pump type heat source apparatus that utilizes existing temperature sensors to detect the dropout of discharge temperature sensors by comparing the discharge temperature with the temperature of heat-exchanged refrigerant after a predetermined waiting time from compressor startup, ensuring accurate detection without the need for additional pressure sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pressure sensor is used to detect discharge pressure, then the discharge pressure can be monitored, but the system becomes more expensive and complex with poor manufacturability
Solution Approach 1:
The patent replaces the mechanical pressure sensor with a thermal field-based detection system. By measuring discharge temperature and comparing it with the saturation temperature corresponding to the discharge pressure, the system indirectly monitors pressure without requiring direct mechanical contact sensors in the refrigeration cycle.
Solution Approach 2:
The patent introduces temperature as an intermediary parameter to indirectly measure pressure. Instead of directly measuring pressure with a sensor in the high-pressure zone, the system measures temperature (which is easier and safer) and uses the known relationship between temperature and pressure in the refrigeration cycle to infer pressure conditions.
2Measurement precision
If a discharge temperature sensor is attached to the discharge pipe, then the discharge temperature can be detected, but the sensor may fall off due to vibration and disturbance
Solution Approach 1:
The patent uses the temperature difference between the discharge temperature sensor reading and the saturation temperature (calculated from discharge pressure) as an intermediary indicator. This temperature difference serves as a proxy to detect sensor dropout without requiring the sensor to remain physically attached to the discharge pipe.
Solution Approach 2:
The system continuously monitors the temperature difference and uses this feedback to detect abnormal conditions. When the temperature difference falls outside the expected range, the system identifies sensor dropout and takes appropriate action, creating a closed-loop detection mechanism.
3Reliability
If the discharge temperature sensor falls off, then the detection becomes unreliable, but the sensor reading may still rise due to compressor temperature rise causing false negatives
Solution Approach 1:
The patent uses the temperature difference (discharge temperature minus saturation temperature) as an intermediary metric rather than relying on absolute temperature readings. This difference remains meaningful even when the sensor has detached, because it reflects the thermal relationship between the compressor discharge and the refrigerant state, enabling reliable dropout detection despite compromised absolute temperature measurement.
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 reliably detects sensor dropouts, preventing compressor failures and simplifying the system configuration by using existing sensors, thereby enhancing the apparatus's reliability and manufacturability.
Implementation Method 1
a discharge temperature sensor configured to detect a discharge temperature
Implementation Method 2
a first-heat-exchanger outlet-side temperature sensor configured to detect a temperature of heat-exchanged refrigerant
Implementation Method 3
a first heat exchanger in the refrigeration cycle, a heat-medium flow passage connected to the first heat exchanger as a flow passage of a heat medium circulating between the first heat exchanger and a utilization-side device
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A heat pump type heat source apparatus includes a refrigeration cycle provided with a compressor, a first heat exchanger, an expansion device and a second heat exchanger, a heat-medium flow passage connected to the first heat exchanger as a flow passage of a heat medium circulating between the first heat exchanger and a utilization-side device, a discharge temperature sensor provided in piping on a discharge side of the compressor and detects a discharge temperature, a first-heat-exchanger outlet-side temperature sensor configured to detect a temperature of a heat-exchanged refrigerant flowing out of the first heat exchanger, and a controller configured to stop the compressor when a difference obtained by subtracting the temperature of a heat-exchanged refrigerant from the discharge temperature is smaller than a predetermined temperature value after elapse of a predetermined waiting time from start-up of the compressor.