Flow-Through Water Heater Assembly for Calcification and Thermal Mixing
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Solution Overview
Problem
Current water heating systems in aircraft lavatories and galleys face inefficiencies due to calcification and thermal stratification, leading to increased power consumption and frequent replacement of heating elements, as well as sanitary issues from biofilm and bacterial growth.
Innovation Solution
A water heater design featuring a flow-through heating element located in the lower portion of the water tank, which recirculates water to promote thermal mixing and efficient heating, using a thermostatic mixing valve to regulate temperature and prevent scalding, while minimizing surface heating area and reducing biofilm growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a tank contains two or more electrical heating elements immersed in water, then water is heated to high temperature, but calcification and mineral deposits form on the heating elements
Solution Approach 1:
The heating element is extracted from the water-filled tank environment and placed in a dry, sealed housing. Only the heating portion contacts water through a controlled interface, while the electrical components remain isolated from water, preventing calcification on electrical parts.
Solution Approach 2:
A sealed housing acts as an intermediary barrier between the heating element and the water tank environment. The housing protects the heating element from direct water contact and calcification while still allowing heat transfer to the water through the housing walls.
2Temperature
If heating elements are immersed in water, then water heating is achieved, but thermal stratification occurs and power consumption increases
Solution Approach 1:
The heating element pre-heats water before it enters the main tank, creating a temperature gradient that promotes natural convection and thermal mixing. This preliminary heating action reduces thermal stratification and improves overall heating efficiency.
Solution Approach 2:
The system uses natural convection currents created by the heating element to promote water circulation and thermal mixing without requiring external pumps or mechanical agitation, reducing energy consumption while maintaining effective heat distribution.
3Temperature
If heating elements operate in water, then water is heated, but biofilm and bacterial growth occur causing sanitary issues
Solution Approach 1:
The heating element is taken out of the water-filled environment and placed in a sealed housing, creating a barrier that prevents biofilm formation on electrical components and reduces bacterial growth areas, improving sanitary conditions.
4Temperature
If mineral deposits form on heating elements, then heating continues, but thermal conductivity decreases and additional power is required
Solution Approach 1:
The heating element is extracted from direct water contact and placed in a sealed housing, preventing mineral deposits from forming on the heating surfaces. This maintains optimal thermal conductivity and prevents the need for additional power to compensate for deposit buildup.
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 solution enhances thermal efficiency, reduces power consumption, extends the life of heating elements, and maintains sanitary conditions by uniformly heating water, preventing bacterial growth, and ensuring safe temperature delivery.
Implementation Method 1
a flow-through heating element... heats water as volumes of water are passed through an interior of the heating element
Implementation Method 2
The deposits are poor thermal conductors and hence, overtime, additional power is required to heat the water
Implementation Method 3
a recirculation line that transports water from the water tank to the input end of the heating element
Implementation Method 4
heats water as volumes of water are passed through an interior of the heating element... recirculates water to promote thermal mixing
Data Source
AI summary
A water heater system includes a water tank and a flow-through heating assembly. The water tank contains heated water. The flow-through heating assembly may extend into the water tank and heats water as water is passed through an interior channel of the flow-through heating assembly. In one embodiment, the flow through heater assembly is a thermosiphonic heater having a hollow body and a heating element extending therein such that an annular recess is defined between an interior surface of the hollow body and the external surface of the heating element.