Heat pump hydronic heater
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Solution Overview
Problem
In separate type heat pump hydronic heaters, the variable length of pipes connecting the indoor and outdoor units makes it difficult to precisely determine the temperature range, leading to erroneous refrigerant leakage detection.
Innovation Solution
Incorporating discharge pressure detecting means and discharge superheat degree detecting means, along with a control device that stops the compressor if the discharge pressure is below set thresholds or if the superheat degree is excessively high after a predetermined time, allowing for accurate refrigerant leakage detection regardless of pipe length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the heat pump hydronic heater uses variable length pipes to connect indoor and outdoor units, then installation flexibility is improved, but refrigerant leakage detection accuracy deteriorates
Solution Approach 1:
The patent applies parameter changes by using multiple discharge pressure thresholds (first set pressure and second set pressure) instead of a single threshold. The control device compares the discharge pressure against these multiple thresholds to determine refrigerant leakage, which resolves the contradiction by making the detection system adaptable to different pipe lengths while maintaining detection accuracy. The first threshold handles normal operation variations, while the second threshold provides a safety margin for longer pipe installations.
Solution Approach 2:
The patent implements feedback control by continuously monitoring the discharge pressure and superheat degree, comparing them against set thresholds, and adjusting the compressor operation accordingly. The control device uses this feedback loop to stop the compressor when refrigerant leakage is detected, regardless of pipe length variations. This feedback mechanism ensures accurate leakage detection while accommodating installation flexibility.
2Productivity
If the compressor operates with insufficient refrigerant, then cooling or heating performance is maintained, but compressor durability deteriorates
Solution Approach 1:
The control device continuously monitors discharge pressure and superheat degree, comparing them against predetermined thresholds. When the discharge pressure falls below the second set pressure or when both pressure and superheat degree indicate refrigerant insufficiency, the control device stops the compressor operation. This feedback control prevents compressor damage from operating with insufficient refrigerant while minimizing impact on productivity.
Solution Approach 2:
The patent applies preliminary anti-action by detecting refrigerant insufficiency conditions before they cause severe compressor damage. The control device monitors discharge pressure and superheat degree continuously and stops the compressor proactively when thresholds are breached, preventing the harmful effects of operating with insufficient refrigerant before they can occur.
3Device complexity
If a single pressure threshold is used for refrigerant leakage detection, then detection simplicity is improved, but detection accuracy under varying pipe lengths deteriorates
Solution Approach 1:
The patent uses multiple discharge pressure thresholds (first set pressure and second set pressure) instead of a single threshold to account for variations in pipe length and installation conditions. The first threshold is used for normal operation monitoring, while the second threshold provides a safety margin for longer pipe installations. This multi-parameter approach maintains detection accuracy across different installation scenarios without significantly increasing system complexity.
Solution Approach 2:
The patent adds another dimension to the detection system by incorporating both discharge pressure and discharge superheat degree measurements. Instead of relying solely on pressure thresholds, the control device evaluates both parameters simultaneously, creating a two-dimensional detection approach that improves accuracy while maintaining reasonable system complexity.
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 enables reliable refrigerant leakage detection, enhancing the usability of heat pump hydronic heaters and preventing compressor damage by ensuring the compressor does not operate with insufficient refrigerant, thus improving durability and user notification of abnormalities.
Implementation Method 1
a compressor which compresses a refrigerant
Implementation Method 2
a water-refrigerant heat exchanger which heat-exchanges between the refrigerant and water
Implementation Method 3
a decompressor which decompresses the refrigerant
Implementation Method 4
an outdoor heat exchanger which heat-exchanges between the refrigerant and air
Implementation Method 5
discharge pressure detecting means which detects a pressure of the refrigerant discharged from the compressor
Implementation Method 6
discharge superheat degree detecting means which detects a superheat degree of the refrigerant discharged from the compressor
Data Source
Figure 1
Figure 2
Figure 3
AI summary
In a heat pump hydronic heater of the present invention, the control device 11a stops operation of the compressor 1 if the discharge pressure detected by the discharge pressure detecting means 1b is lower than a first set pressure and a discharge superheat degree detected by the discharge superheat degree detecting means is equal to or higher than a predetermined value when predetermined time is elapsed after the compressor 1 is started, or if the discharge pressure detected by the discharge pressure detecting means 1b is lower than a second set pressure which is set lower than the first set pressure. Therefore, it is possible to enhance usability without erroneously detecting leakage of a refrigerant.