Pressureless Heat Accumulator With Partitioned Tank Stratification

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Solution Overview

Problem

Existing district heating systems face challenges with pressurized hot water accumulator tanks, which are costly, require frequent and expensive inspections, and pose safety risks due to pressure differentials, necessitating a safer and less expensive alternative for storing water at temperatures above 100 °C.

Innovation Solution

A pressureless accumulator design featuring a tank divided into compartments by a partition wall with conduits for fluid communication, incorporating insulating materials to prevent heat loss and turbulence, and featuring strategically placed inlets and outlets to manage heat transfer and expansion efficiently.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If pressurized hot water accumulator tanks are used, then heat storage capacity is improved, but safety risks and inspection costs increase due to pressure differentials

Engineering Contradiction:
Improveheat storage capacityVSAvoidsafety
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The accumulator tank is divided into multiple compartments by partition walls, with each compartment capable of storing hot water independently. This segmentation allows the system to maintain heat storage capacity while operating at atmospheric pressure in each compartment, eliminating pressure-related safety risks

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Partition walls with holes act as intermediaries between compartments, allowing controlled fluid communication while maintaining atmospheric pressure in each section. The holes enable heat transfer and fluid exchange without creating pressure differentials that would compromise safety

Inventive Principle:
Principle #24Intermediary (Mediator)

2Quantity of substance

If pressurized hot water accumulator tanks are used, then heat storage capacity is improved, but manufacturing and inspection costs increase

Engineering Contradiction:
Improveheat storage capacityVSAvoidmanufacturing cost
Core Design Contradiction:
Quantity of substanceVSEase of manufacture

Solution Approach 1:

The tank is segmented into multiple atmospheric-pressure compartments using partition walls with holes. This approach allows manufacturing simpler, thinner-walled tanks compared to pressurized vessels, reducing material costs and manufacturing complexity while maintaining equivalent heat storage capacity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The partition walls with holes provide a cost-effective solution that eliminates the need for expensive pressure-containing structures. The simple design reduces both initial manufacturing costs and ongoing inspection maintenance costs

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Stability of the object's composition

If partition walls without holes are used, then stratification is improved, but heat transfer between compartments is reduced

Engineering Contradiction:
ImprovestratificationVSAvoidheat transfer efficiency
Core Design Contradiction:
Stability of the object's compositionVSLoss of energy

Solution Approach 1:

The partition walls feature localized holes positioned at specific heights to enable heat transfer between compartments while preserving thermal stratification. The holes are strategically placed to allow convection currents to develop, facilitating heat exchange without complete mixing of temperature layers

Inventive Principle:
Principle #3Local quality

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 pressureless accumulator effectively stores water at temperatures above 100 °C, reducing design, manufacturing, and maintenance costs while ensuring safety and efficiency in heat management, eliminating the need for periodic inspections and minimizing turbulence.

Implementation Method 1

a thin and stable partition layer is maintained between the hot water layer and the cold water layer

Methodology Applied
Scientific EffectStratification: Density Gradient

Implementation Method 2

the least possible turbulence will occur in the water volume of the accumulator tank

Methodology Applied
Scientific EffectTurbulence reduction: Turbulence

Implementation Method 3

The tank further comprises a thermal insulation layer arranged outside the tank wall

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 4

to prevent the ingress of oxygen

Methodology Applied
Scientific EffectVapor pressure: Vapour Pressure

Data Source

PatentEP2698584B1Pressureless accumulator for district heating systems
Publication Date: 2015.10.21 HEDBACK TORE J
  • EP2698584B1 patent drawingFigure 1
  • EP2698584B1 patent drawingFigure 2
  • EP2698584B1 patent drawingFigure 3

AI summary

The present invention relates to a pressureless accumulator (1) for district heating systems, comprising a tank (2) connected to at least one heat emitting system and at least one heat absorbing system. The tank (2) comprises a lid (46), a bottom section (4) and a top section (6). The bottom section (4) comprises at least one first bottom inlet/outlet (24). The tank (2) further comprises a partition wall (8) arranged between the bottom section (4) and the top section (6) for the purpose of dividing the tank in a first compartment (10) arranged above the partition wall (8) and a second compartment (12) arranged beneath the partition wall (8). The first compartment (10) and the second compartment (12) are in fluid communication with each other by at least one conduit (38). The first compartment (10) comprises a first heat transfer medium (14) and the second compartment (12) comprises a second heat transfer medium (16). The second compartment (12) further comprises a first top inlet/outlet (22) arranged in the top of the second compartment (12).