Solar Hot-Water Overheating Protection Circuit With Steam Mixing

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Solution Overview

Problem

Existing systems for producing domestic hot water using solar thermal collectors face inefficiencies due to the use of heat transfer fluids with anti-freeze additives, require specific storage tanks, and struggle with overheating and slow water temperature stratification, leading to increased costs and environmental impact.

Innovation Solution

A system with direct water circulation from solar collectors to the hot water tank, incorporating a stratification chamber and a protection circuit against overheating, which eliminates the need for a primary and secondary circuit design, uses the same water in interconnected circuits, and includes a protection mechanism to manage steam and prevent overheating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a heat transfer fluid with anti-freeze additive is used in the primary circuit, then protection against ice formation is improved, but heat transfer efficiency deteriorates and the fluid circulates with greater difficulty

Engineering Contradiction:
Improveprotection against ice formationVSAvoidheat transfer efficiency
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent extracts the anti-freeze additive from the heat transfer fluid, using only water in the primary circuit. This eliminates the viscosity and heat capacity problems caused by additives while maintaining freeze protection through system design (drainage capability and insulation).

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the physical-chemical parameters of the heat transfer fluid by using pure water instead of glycol-based solutions, thereby improving thermal conductivity and reducing viscosity while accepting the need for alternative freeze protection methods.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a heat exchanger is used between primary and secondary circuits, then thermal isolation is improved, but heat transfer speed deteriorates and installation complexity increases

Engineering Contradiction:
Improvethermal isolationVSAvoidheat transfer speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent merges the primary and secondary circuits by allowing the same water to circulate in both, eliminating the heat exchanger component. This direct contact between solar-heated water and storage tank water dramatically accelerates heat transfer while reducing system complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent uses the water itself as the intermediary medium that directly transfers heat from solar collectors to the storage tank, eliminating the need for a separate heat exchanger component while maintaining thermal transfer function.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Loss of energy

If the exchanger is placed at the bottom of the tank to optimize heat exchange, then heat transfer efficiency is improved, but water temperature stratification deteriorates and hot water availability slows

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidhot water availability time
Core Design Contradiction:
Loss of energyVSLoss of time

Solution Approach 1:

The patent inverts the conventional approach by allowing hot water to rise naturally to the top of the tank through direct injection, rather than forcing cold water up from the bottom. This utilizes natural convection to achieve both heat transfer and stratification simultaneously.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The system uses natural convection currents to automatically achieve water stratification without mechanical intervention. Hot water naturally rises to the top where it is most needed, while cooler water sinks to the bottom for reheating, creating a self-organizing thermal structure.

Inventive Principle:
Principle #25Self-service

4Reliability

If a primary and secondary circuit design is used, then fluid separation is improved, but system complexity and cost increase

Engineering Contradiction:
Improvefluid separationVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the primary and secondary circuits into a single integrated system where the same water serves both as the solar collector fluid and the storage tank fluid, eliminating the heat exchanger and reducing system complexity while maintaining functional separation through operational control.

Inventive Principle:
Principle #5Merging (Combining)

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

This solution enhances heat transfer efficiency, reduces the need for anti-freeze additives, allows for the use of existing hot water tanks, and effectively manages overheating, resulting in a more cost-effective, efficient, and environmentally friendly hot water production system.

Implementation Method 1

at least one solar thermal water collector

Methodology Applied
Scientific EffectSolar energy conversion: Solar Energy

Implementation Method 2

supply said tank with hot water

Methodology Applied
Scientific EffectThermal energy transfer: Heating

Implementation Method 3

protection mechanism to manage steam and prevent overheating

Methodology Applied
Scientific EffectPhase change (water to steam): Evaporation

Implementation Method 4

protection circuit against the effects of overheating

Methodology Applied
Scientific EffectPressure relief: Depressurisation

Data Source

PatentEP2947393B1Circuit for protection against the effects of overheating in a hot-water production system, and corresponding hot-water production system
Publication Date: 2018.03.07 THOMERE FINANCE
  • EP2947393B1 patent drawingFigure 1
  • EP2947393B1 patent drawingFigure 2~3

AI summary

The invention relates to a protection circuit against the effects of overheating in a hot water production system connected to a water network, said system comprising at least one solar collector, said protection circuit comprising: - an inlet pipe (60) of superheated water from the solar collectors (1), - a valve (61) opening under the effect of pressure allowing the opening of the inlet pipe (60) of superheated water in case of overpressure, - an inlet pipe (62) of water from said water network, before passing through the solar collectors (1), - a thermostatic element (63) controlling the opening of a valve (64) opening the inlet pipe of water (62) from the water network under the effect of temperature. - a mixing chamber (65) of steam from superheated water and water from the network, connecting the superheated water inlet duct (60) and the water inlet duct (62) from the water network.