Hot Water Tank Stratification Using Multi-Height Diffuser Inlets

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Solution Overview

Problem

Existing systems for filling hot water tanks with multiple strata of different temperatures struggle to achieve effective stratification and control over water layers, leading to inefficient energy use and turbulence.

Innovation Solution

A system comprising a tank with multiple inlets and outlets connected to a heat exchanger and heating circuit, allowing for precise control over water layer volumes and temperatures, and using diffusers to minimize turbulence and maintain stratification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by stationary object

If water is introduced into the tank to create multiple temperature strata, then thermal energy storage capacity is improved, but turbulence occurs causing mixing of different temperature layers

Engineering Contradiction:
Improvethermal energy storage capacityVSAvoidstratification stability
Core Design Contradiction:
Use of energy by stationary objectVSStability of the object's composition

Solution Approach 1:

A diffuser is introduced as an intermediary device at the water inlet to mediate between the incoming water flow and the stratified layers. The diffuser disperses the incoming water into multiple smaller streams, reducing the kinetic energy and turbulence that would otherwise cause mixing. This allows water to be added to maintain stratification without compromising layer stability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system changes the flow parameters of incoming water by using a diffuser to reduce flow velocity and distribute flow evenly. This parameter change (from high velocity concentrated flow to low velocity distributed flow) prevents turbulence and maintains the stability of temperature stratification while still allowing water to be added to the tank.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If multiple inlets and outlets are provided at different heights, then control over water layers is improved, but device complexity increases

Engineering Contradiction:
Improvecontrol over water layersVSAvoidnumber of inlets and outlets
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The tank is segmented into multiple zones with dedicated inlets and outlets at different heights, allowing independent control of each temperature layer. This segmentation enables precise control over water addition and removal from specific layers, improving operational control despite the increased number of connection points.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system adds vertical dimensionality to the control mechanism by positioning inlets and outlets at different heights corresponding to different temperature layers. This spatial arrangement in the vertical dimension provides intuitive control - water enters and exits at the appropriate temperature level without requiring complex mechanical actuators or valves.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Stability of the object's composition

If cold water is introduced at the bottom and hot water at the top, then stratification is maintained, but flow turbulence can carry cold water upward or hot water downward

Engineering Contradiction:
Improvetemperature layer separationVSAvoidcross-contamination of temperature layers
Core Design Contradiction:
Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

Diffusers are positioned at the inlets as intermediary devices that dissipate the momentum of incoming water before it reaches the stratified layers. By converting the concentrated high-velocity flow into dispersed low-velocity flow, the diffuser prevents the harmful injector effect that would carry water from one temperature layer into another.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system converts the potentially harmful high-velocity incoming flow into a beneficial dispersed flow pattern. The diffuser transforms the harmful injector effect into a gentle distribution of water that respects the density stratification, allowing cold water to settle at the bottom and hot water to remain at the top without mutual contamination.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 achieves superior stratification and control over water layers, enhancing energy efficiency and maintaining stratification by minimizing turbulence and optimizing heating cycles.

Implementation Method 1

a heat exchanger (12) equipped with an inlet configured to receive water in the tank (2) and an outlet configured to supply said water to the tank

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

a heating circuit configured to provide a fluid connection between the outlet of the heat exchanger (12) and either the first inlet (7) or the second inlet (5)

Methodology Applied
Scientific EffectThermal circulation: Convection

Implementation Method 3

stratification is understood as the occurrence and maintenance of adjacent, vertically distributed masses of water of different temperature and density

Methodology Applied
Scientific EffectDensity stratification: Density Gradient

Implementation Method 4

a cold water layer (13) at the bottom, a medium temperature water layer (14) in the middle and a hot water layer (15) at the top

Methodology Applied
Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Data Source

PatentEP4130582B1A system and method for achieving stratification in a hot water tank
Publication Date: 2025.04.30 DAIKIN EURO
  • EP4130582B1 patent drawingFigure 1
  • EP4130582B1 patent drawingFigure 2
  • EP4130582B1 patent drawingFigure 3

AI summary

A tank-type system suitable for receiving, storing and supplying water, said system comprising a water tank, a heat exchanger and a heating circuit configured to permit different types of heating cycles. Said heating cycles being further governed by a method which permits the extraction of water from said tank, heating said water and subsequent injection of said heated water into said tank through different inlets. Said inlets being equipped with radial injection diffusion devices located at different heights within the tank. The system in combination with said method permit a superior stratification inside the water tank, said stratification being carried out in a highly controlled and efficient manner.