Electronic Mixing Valve for Low Flow Water Tempering
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Solution Overview
Problem
Existing water tempering systems in high-rise buildings face challenges during periods of low usage, where anti-scalding mixing valves require minimum flow rates for accurate mixing, leading to potential scalding risks and increased maintenance due to calcium build-up and malfunctioning valves.
Innovation Solution
A water tempering system incorporating a mixing tank, a variable frequency drive pump, and an electrically operated valve, controlled by a system that adjusts flow rates based on temperature data to ensure consistent tempering of hot water, even at reduced flow rates, using a recirculation line to maintain water flow and prevent scalding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a recirculation pump is used during low usage periods, then water flow is maintained through the system, but the flow rate is lower than the minimum required for accurate mixing in anti-scalding valves
Solution Approach 1:
The patent replaces the mechanical anti-scalding mixing valve with an electronic mixing valve that uses electronic control systems and sensors to regulate water mixing. This electronic system can accurately control mixing at lower flow rates by using electronic signals and control algorithms rather than relying solely on mechanical flow-dependent mechanisms.
Solution Approach 2:
The patent changes the operating parameters of the mixing system by introducing electronic control that can adjust mixing ratios dynamically based on actual flow conditions. The electronic mixing valve can adapt to varying flow rates by modifying valve positioning and control signals, maintaining mixing accuracy across a wider range of flow conditions including low recirculation flows.
2Loss of energy
If the pump rate of the recirculation pump is reduced for energy saving, then energy consumption decreases, but accurate mixing and tempering cannot be ensured
Solution Approach 1:
The electronic mixing valve with electronic control replaces the mechanical mixing valve, enabling accurate tempering control at lower flow rates. The electronic system can precisely regulate the mixing ratio using control algorithms and sensor feedback, maintaining tempering accuracy even when recirculation pump rates are reduced for energy conservation.
Solution Approach 2:
The patent incorporates control systems with sensors that provide feedback on actual water temperatures and flow conditions. This feedback mechanism allows the electronic mixing valve to continuously adjust its operation to maintain accurate tempering, compensating for variations in recirculation flow rates and ensuring reliable temperature control regardless of pump speed.
3Reliability
If typical anti-scalding mixing valves are used, then tempering control is provided, but calcium build-up causes valve failure and increased maintenance requirements
Solution Approach 1:
The patent replaces mechanical anti-scalding mixing valves with electronic mixing valves that have fewer moving mechanical parts susceptible to calcium build-up. The electronic control system uses solenoids and electronic actuators rather than complex mechanical valve mechanisms, reducing the surfaces where calcium can accumulate and causing valve failure.
Solution Approach 2:
The electronic mixing valve changes the operational parameters by using electromagnetic control instead of purely mechanical operation. This reduces the mechanical wear and calcium deposition issues associated with traditional mechanical valves, as the control elements are not subject to the same erosion and build-up problems.
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
The system effectively maintains safe water temperatures and reduces maintenance needs by ensuring accurate mixing and preventing scalding, even during low usage periods, through adaptive flow control and recirculation, enhancing the reliability and cost-effectiveness of water tempering systems.
Implementation Method 1
a mixing tank having a first inlet for receiving fluid from a first water supply line at a first temperature, a second inlet for receiving fluid from a second water supply line, and a first outlet for discharging fluid from the mixing tank and delivering the fluid via a third water supply line at a predetermined second temperature
Data Source
AI summary
A water tempering system comprising a mixing tank located downstream from the main hot water storage tank, the mixing tank receiving a supply of hot water at a first temperature and a supply of cold water, the hot water and cold water supplies mixing within the mixing tank to provide a source of tempered hot water at a reduced, second temperature that is discharged from the mixing tank for distribution and use within an overall system. The amount of cold water directed to the mixing tank is controlled by a variable frequency drive pump which can adjust depending on system demands to ensure that sufficient cold water is directed to the mixing tank to ensure adequate mixing occurs to bring the temperature of the hot water to the second reduced temperature even during periods of low demand.