Indirect Hot Water Circuit Clog Detection Using Tank Temperature
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Solution Overview
Problem
Existing methods for detecting clogging in hot water apparatuses, particularly in indirect-heating systems, are costly and prone to false detection or delayed detection, as they require additional devices like flow sensors and pressure sensors, and can incorrectly identify clogging due to thermal expansion or reduced heating capability.
Innovation Solution
A hot water apparatus that uses fluid and tank temperature sensors to detect clogging in the secondary water circuit, eliminating the need for extra devices and reducing false detection by comparing fluid temperature above a threshold with tank temperature below another threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If flow-rate measuring devices such as flow switches or flow sensors are used to measure the flow rate of water, then clogging detection accuracy is improved, but the cost of the hot water apparatus increases
Solution Approach 1:
The system uses the heat source's own heating function and existing temperature sensors to detect clogging, rather than adding separate measurement devices. The heat source heats water in the water circuit, and the controller monitors temperature changes that indicate clogging conditions
Solution Approach 2:
The patent replaces mechanical flow measurement devices with a thermal-based detection method. Instead of using flow sensors or pressure sensors, the system uses temperature measurement and heating capability assessment to infer clogging conditions in the water circuit
2Measurement precision
If pressure measuring devices such as pressure switches or pressure sensors are used to measure water pressure, then clogging detection accuracy is improved, but the cost of the hot water apparatus increases
Solution Approach 1:
The system uses the heat source's own heating function and existing temperature sensors to detect clogging, rather than adding separate measurement devices. The heat source heats water in the water circuit, and the controller monitors temperature changes that indicate clogging conditions
Solution Approach 2:
The patent replaces mechanical pressure measurement devices with a thermal-based detection method. Instead of using pressure sensors, the system uses temperature measurement and heating capability assessment to infer clogging conditions
3Reliability
If the detection threshold is set loosely to avoid false detection due to thermal expansion, then false detection is reduced, but clogging detection is delayed
Solution Approach 1:
The controller continuously monitors the relationship between the heat source's heating capability and the actual temperature change in the water circuit. When the heating capability exceeds a predetermined threshold, the system adjusts operation to maintain accurate detection timing, preventing both false detections and delays
Solution Approach 2:
The detection threshold and operation timing are dynamically adjusted based on the heat source's heating capability. When heating capability is high, the system can detect clogging more quickly; when heating capability is low (near target temperature), the system adjusts to avoid false detections
4Device complexity
If heating capability is measured to detect clogging, then device complexity is reduced, but false detection occurs when temperature approaches target water temperature
Solution Approach 1:
The detection threshold and operation timing are dynamically adjusted based on the heat source's heating capability. When heating capability is high, the system can detect clogging more quickly; when heating capability is low (near target temperature), the system adjusts to avoid false detections
Solution Approach 2:
The controller continuously monitors the relationship between the heat source's heating capability and the actual temperature change in the water circuit. When the heating capability exceeds a predetermined threshold, the system adjusts operation to maintain accurate detection timing, preventing both false detections and delays
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 allows for accurate detection of clogging without additional costly sensors, reducing the likelihood of false positives and energy wastage by utilizing existing temperature sensors, thereby saving costs and improving detection efficiency.
Implementation Method 1
a water circuit, connected to the fluid circuit via a heat exchanger, in which water circulates
Data Source
AI summary
An indirect-heating hot water apparatus is designed to correctly detect clogging in a secondary water circuit at low costs. A hot water apparatus is provided with: a primary water circuit in which water heated by absorbing heat from a refrigerant at a heat exchanger circulates; a secondary water circuit connected to the primary water circuit via a heat exchanger, in which water circulates; and a tank connected to the secondary water circuit, in which the water circulating in the secondary water circuit is stored. The hot water apparatus detects the temperature of the water circulating in the primary water circuit and the temperature of the water stored in the tank. When the temperature of the water circulating in the primary water circuit is at or above a first threshold and the temperature of the water stored in the tank is at or below a second threshold, the hot water apparatus issues a notification indicating that the secondary water circuit is clogged.