Vertical heat recovery system

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Solution Overview

Problem

Existing drain heat exchangers are inefficient in recovering heat from drain water due to limited surface area and susceptibility to contamination, leading to energy waste and potential health hazards from bacterial growth.

Innovation Solution

A vertical heat recovery system with a corrugated internal pipe and turbulators to enhance heat transfer, combined with a leak detection system and air break to prevent contamination, ensuring efficient heat transfer and safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a plain copper tube is used for heat transfer, then the system is simple to manufacture, but the heat transfer efficiency is limited due to insufficient surface area

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidheat transfer efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The internal pipe is designed with corrugated geometry featuring axial waves and helical corrugations that create curved surfaces. This curvature increases the effective heat transfer surface area and promotes turbulent flow patterns, thereby improving heat transfer efficiency while maintaining a relatively simple manufacturing process for the corrugated structure

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Ease of manufacture

If the internal pipe surface is smooth, then the pipe is easy to manufacture, but bacterial growth and contamination occur more easily

Engineering Contradiction:
Improvepipe manufacturing easeVSAvoidbacterial contamination
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The corrugated surface with axial waves and helical patterns creates a non-smooth topology that disrupts bacterial adhesion and promotes self-cleaning through turbulent flow. The curved corrugations prevent stagnant zones where bacteria could accumulate, reducing contamination risk while remaining manufacturable

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Stability of the object's composition

If the drain water flow is laminar, then the flow is stable, but heat transfer efficiency is reduced

Engineering Contradiction:
Improveflow stabilityVSAvoidheat transfer efficiency
Core Design Contradiction:
Stability of the object's compositionVSProductivity

Solution Approach 1:

The corrugated internal pipe surface with axial waves and helical corrugations forces the drain water flow into turbulent patterns. The curved corrugations create flow separation and reattachment zones that enhance mixing and heat transfer efficiency while maintaining overall flow stability through the structured geometry

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The system utilizes the hydraulic properties of flowing water to generate turbulence through the corrugated surface. The interaction between the water flow and the corrugated geometry creates natural turbulence without requiring additional mechanical components, improving heat transfer while maintaining flow stability

Inventive Principle:
Principle #29Pneumatics and hydraulics

4Area of stationary object

If a vertical heat exchanger is installed, then space is saved compared to horizontal systems, but the system height may exceed construction limitations

Engineering Contradiction:
Improvefloor space usageVSAvoidsystem height
Core Design Contradiction:
Area of stationary objectVSLength of stationary object

Solution Approach 1:

The internal corrugated pipe is nested within the external pipe, creating a compact heat exchanger assembly. This nested configuration maximizes heat transfer surface area within a constrained vertical envelope, reducing the overall system height while maintaining effective heat recovery functionality

Inventive Principle:
Principle #7Nested doll (Nesting)

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 recovers up to 70% of heat from drain water, maintaining efficiency and preventing contamination, thus reducing energy consumption and environmental impact.

Implementation Method 1

A specifically engineered heat exchanger transfers heat energy from the waste hot shower water to the incoming fresh water supply

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

the internal pipe (3) comprises a corrugated geometry... at least one turbulator (6) arranged on the external surface of the internal pipe (3)

Methodology Applied
Scientific EffectTurbulence: Turbulence

Implementation Method 3

a leaked water channel (LW) arranged between the first drain water passage (4) and the external pipe (2) or arranged between the second drain water passage (5) and the external pipe (2)

Methodology Applied
Scientific EffectPressure differential: Pressure Gradient

Data Source

PatentEP4426988B1Vertical heat recovery system
Publication Date: 2026.02.25 ZYPHO SA
  • EP4426988B1 patent drawingFigure 1A~1C
  • EP4426988B1 patent drawingFigure 2
  • EP4426988B1 patent drawingFigure 3A~3B

AI summary

The present invention relates to a vertical heat recovery system (1) for drains suitable for the recovering heat from drain water to mains water. The vertical heat recovery system (1) comprises an external pipe (2), an internal pipe (3) arranged inside the external pipe (2), wherein the internal pipe (3) comprises at least one wall and has a corrugated geometry to increase the heat transfer area. The system (1) further comprises at least one turbulator (6) configured to optimize the turbulence regime flow conditions of mains water, thus substantially improving the heat recovery from drain water.