Hot Water Recirculation Flow-Switch Control to Reduce Energy Waste
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Solution Overview
Problem
Traditional hot water recirculating systems are energy inefficient and stressful on plumbing, as they continuously circulate hot water even when not in use, and often require complex user interfaces or timers that are difficult to adjust.
Innovation Solution
A recirculating flow controller coupled with a flow switch and pump that activates the recirculation pump only when hot water is needed, allowing users to initiate circulation by briefly turning on any hot water faucet, with the pump operating for a programmed duration to deliver hot water to targeted fixtures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the recirculation pump operates continuously to provide hot water on demand, then hot water availability is improved, but energy consumption and plumbing stress increase
Solution Approach 1:
The recirculation pump operates periodically rather than continuously, being activated only when a flow switch detects water flow through the water heater. The controller runs the pump for a predetermined duration to circulate hot water through the system, then deactivates it until the next activation signal, thereby reducing energy consumption while maintaining hot water availability when needed.
2Use of energy by moving object
If a timer is used to control recirculation pump operation, then energy efficiency is improved, but device complexity and user adjustment difficulty increase
Solution Approach 1:
The system uses a flow switch that automatically detects when water is flowing through the water heater and triggers pump activation without requiring user programming or complex timer settings. The controller simply responds to the flow switch signal by running the pump for a predetermined time, eliminating the need for users to adjust timer parameters while maintaining energy efficiency.
3Reliability
If the recirculation pump runs for longer duration to reach distant fixtures, then hot water delivery reliability is improved, but energy consumption and water waste increase
Solution Approach 1:
The controller runs the recirculation pump for a predetermined duration that is sufficient to push hot water through the plumbing system to all fixtures, even if this exceeds the minimum time needed for some locations. This ensures reliable hot water delivery to the most distant fixtures while limiting the total run time to a fixed value that prevents excessive water waste, accepting that the pump may run slightly longer than strictly necessary in some cases.
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 provides hot water on demand without unnecessary energy consumption or plumbing stress, simplifying user interaction and installation by leveraging existing infrastructure and eliminating the need for dedicated buttons or smartphone applications.
Implementation Method 1
a flow switch operably coupled to a hot water line and configured to change state to indicate water flow in the hot water line
Implementation Method 2
a recirculation pump configured to circulate water through a return line to a water heater
Data Source
AI summary
The present disclosure provides for a recirculating flow controller that is operably coupled to a flow switch and to a recirculation pump. The recirculating flow controller determines that hot water has begun to flow by way of the connection with the flow switch. In response, the recirculating flow controller activates the recirculation pump to circulate hot water from a water heater. The recirculating flow controller can activate the recirculation pump for a predetermined duration. The flow switch can be configured to sense flow in a hot water line connected to a water heater. The flow switch can be activated by turning on any hot water faucet connected to the water heater.