Tankless Water Heater Air Bubble Detection via Downstream Flow Sensing
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Solution Overview
Problem
Existing tankless water heaters face challenges in reliably detecting air bubbles within the fluid channel, as air can originate from both the cold water supply and be generated during the heating process, leading to overheating and potential damage, especially when multiple heat elements are involved.
Innovation Solution
A tankless water heater design with a flow sensor arranged downstream of the heat element arrangement, capable of detecting air bubbles using a single flow sensor and an electronic controller that adapts heating power based on flow signal changes, along with temperature sensors for efficient control and a throttle valve to manage flow rate, ensuring reliable air bubble detection and preventing overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the flow sensor is arranged upstream of the heat element arrangement, then air bubbles from the cold water supply can be detected, but air bubbles generated during the heating process cannot be detected, leading to overheating of downstream heat elements
Solution Approach 1:
The flow sensor is inverted from its conventional upstream position to a downstream position relative to the heat element arrangement. This inversion allows the sensor to detect air bubbles that are generated during the heating process, which were previously undetectable. The downstream placement enables the sensor to monitor the fluid after it has passed through the heating zone, thereby detecting air bubbles that form due to heating without requiring additional upstream sensors.
2Reliability
If two distinct flow meters are arranged upstream and downstream of the heat element arrangement, then air bubbles from any origin can be detected, but the system complexity and cost increase
Solution Approach 1:
The single flow sensor arranged downstream of the heat element arrangement serves multiple detection functions: it detects air bubbles from the cold water supply, air bubbles generated during heating, and provides flow rate measurement for control purposes. This multi-functional placement eliminates the need for separate upstream and downstream sensors, reducing system complexity while maintaining comprehensive air bubble detection capability.
Solution Approach 2:
The invention merges the functions of multiple flow sensors into a single downstream flow sensor. By combining air bubble detection from various sources and flow rate measurement into one sensor position, the system achieves comprehensive monitoring without requiring multiple distinct sensors, thereby reducing complexity and cost.
3Productivity
If heating power is continuously provided to the heat element arrangement, then efficient water heating is achieved, but overheating occurs when air bubbles are present in the fluid channel
Solution Approach 1:
The electronic controller continuously monitors the flow signal from the downstream flow sensor and uses this feedback to detect air bubbles. When air bubbles are detected through characteristic changes in the flow signal, the controller automatically adapts the heating power provided to the heat element arrangement, reducing or stopping heating to prevent overheating damage while maintaining efficient operation during normal conditions.
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 effective detection and prevention of overheating by accurately identifying air bubbles from any origin, reducing system complexity and ensuring safe operation by stopping heating when air bubbles are present, thus protecting the tankless water heater from damage.
Implementation Method 1
a flow sensor being arranged at or within the fluid channel downstream the heat element arrangement, wherein the electronic controller is configured to detect the presence of air bubbles within the fluid channel based on a change of a flow signal provided by the flow sensor
Implementation Method 2
a heat element arrangement, arranged at or within at least a section of the fluid channel for transferring heat to fluid present within the fluid channel
Data Source
AI summary
A water heater including an inflow terminal for connecting a tankless water heater to a cold water supply and an outflow terminal for connecting the tankless water heater to a tap. A fluid channel proves a fluid connection from the inflow terminal to the outflow terminal. A heat element arrangement is arranged at or within at least a section of the fluid channel for transferring heat to fluid present within the fluid channel. An electronic controller is configured to control a heating power provided to the heat element arrangement. A flow sensor is arranged at or within the fluid channel downstream the heat element arrangement. The electronic controller is further configured to detect the presence of air bubbles within the fluid channel based on a change of a flow signal provided by the flow sensor and to adapt the heating power provided to the heat element arrangement in reaction to the determination of air bubbles.