Sanitary Hot Water Circulator Speed Control Against Stagnation
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Solution Overview
Problem
Existing domestic hot water circulator regulation methods are complex and fail to consistently maintain a satisfactory temperature variation in the hot water circuit, leading to potential stagnation and hygiene issues, while also being inefficient in energy consumption.
Innovation Solution
A method that dynamically regulates the speed of the circulator based on domestic hot water temperature and flow rate thresholds, ensuring a minimum flow rate to prevent stagnation and maintaining a desired temperature, using temperature and flow sensors to adjust the motor speed accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the flow rate in the domestic hot water installation is increased to reduce temperature variation, then the temperature consistency is improved, but the energy consumption by the circulator increases
Solution Approach 1:
The circulator operates according to different hydraulic curves based on operational conditions. The system dynamically switches between a first hydraulic curve (higher flow rate) when temperature variation needs reduction and a second hydraulic curve (lower flow rate) when energy consumption needs limitation, making the flow rate adjustable rather than fixed
Solution Approach 2:
The system changes the operational parameters of the circulator by selecting different hydraulic curves. The flow rate and pressure characteristics are modified according to the chosen curve, allowing optimization of temperature consistency versus energy consumption based on real-time conditions
2Ease of operation
If a fixed hydraulic curve is selected for the circulator, then the adjustment process is simplified, but the temperature variation cannot be maintained satisfactory in all situations
Solution Approach 1:
The system uses temperature sensors to monitor the actual temperature variation in the circuit and flow meters to measure flow rate. This feedback information is used to automatically select the appropriate hydraulic curve, eliminating the need for manual adjustment while ensuring satisfactory temperature maintenance in all situations
Solution Approach 2:
The circulator system automatically selects and adjusts its own operational parameters based on sensor feedback. The control system autonomously determines which hydraulic curve to use based on current temperature and flow conditions, making the system self-regulating without requiring installer intervention
3Use of energy by moving object
If the circulator flow rate is reduced to limit energy consumption, then the energy efficiency is improved, but the risk of water stagnation and hygiene issues increases
Solution Approach 1:
The system dynamically adjusts the flow rate by selecting appropriate hydraulic curves. When stagnation risk is detected or conditions require higher flow, the system switches to a curve ensuring minimum flow rate. When temperature consistency is the priority and flow can be higher, it selects the corresponding curve, making the flow rate adaptive rather than static
Solution Approach 2:
Flow meters provide feedback on the actual flow rate in the circuit. The control system uses this information to ensure that when a hydraulic curve is selected, the resulting flow rate remains above the minimum threshold required to prevent stagnation, automatically adjusting operations to maintain hygiene standards
Data Source
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Figure 3
AI summary
The method involves choosing a threshold value of minimal flow (Qmin) of domestic hot water and determining a flow (Q) of domestic hot water. A temperature threshold (Tmin) of domestic hot water is adjusted. Temperature (T) of the domestic hot water is measured, and rotation speed of the motor is modified according to the minimal flow threshold, determined flow, temperature threshold and the measured temperature. The speed is increased when the determined flow is lower than the minimal flow threshold or when the measured temperature is lower than the temperature threshold. Independent claims are also included for the following: (1) a domestic hot water circulator (2) a domestic hot water facility.