Solar Hot Water Tank Stratification Using a Thermostatic Chamber
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Solution Overview
Problem
Existing domestic hot water production systems using solar thermal collectors face inefficiencies due to the use of heat transfer fluids with anti-freeze additives, require separate primary and secondary circuits, and often necessitate specific storage tanks, leading to increased costs and environmental impact.
Innovation Solution
A system that connects solar thermal collectors directly to a domestic hot water tank using an intermediate chamber with four ducts for efficient heat transfer, eliminating the need for anti-freeze fluids and separate circuits, and allowing for integration with existing tanks, utilizing thermosiphon for natural water circulation and stratification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a heat transfer fluid with anti-freeze additive is used in the primary circuit, then the system can operate in freezing conditions, but the heat capacity of the installation is reduced and efficiency decreases
Solution Approach 1:
The invention extracts and eliminates the anti-freeze additive from the heat transfer fluid, using pure water instead. This resolves the contradiction by removing the substance that reduces heat capacity while maintaining the ability to operate in freezing conditions through alternative means (system design, insulation, circulation controls).
Solution Approach 2:
The invention changes the chemical composition parameter of the heat transfer fluid from a glycol-water mixture to pure water, thereby improving heat capacity and thermal efficiency while addressing freezing protection through operational parameters rather than chemical additives.
2Reliability
If a heat exchanger is used to separate primary and secondary circuits, then fluid isolation is achieved, but the device complexity increases and costs rise
Solution Approach 1:
The invention merges the primary and secondary circuits into a single integrated circuit, eliminating the need for a separate heat exchanger. The solar collectors directly heat the domestic water in the storage tank, simplifying the system structure while maintaining functional separation through operational control rather than physical isolation.
Solution Approach 2:
The heat transfer fluid in the primary circuit serves multiple functions: it circulates through the solar collectors to absorb solar energy and directly heats the domestic water in the storage tank. This multi-functional approach eliminates the need for separate heat exchanger equipment while achieving the desired thermal transfer.
3Loss of energy
If exchangers are placed in the lower part of the storage tank for optimized heat exchange, then maximum efficiency is achieved, but the heating time increases due to stratification
Solution Approach 1:
The invention inverts the conventional approach by placing the heat input at the top of the storage tank rather than at the bottom. The solar collectors inject hot water directly into the upper zone of the tank, reversing the traditional thermosiphon flow pattern and enabling faster heating by directly heating the upper water layers where hot water is most needed.
Solution Approach 2:
The invention introduces an intermediate chamber or injection system that mediates between the solar collectors and the storage tank, allowing direct injection of heated water into the upper zone. This intermediary mechanism enables controlled hot water injection that bypasses the slow stratification process while maintaining efficient heat transfer.
4Productivity
If a solar storage tank is added or existing tank replaced, then hot water production capability is improved, but installation costs increase significantly
Solution Approach 1:
The invention makes the existing storage tank serve dual functions: it stores domestic water and simultaneously acts as the heat transfer medium for solar heating. The tank's existing structure is utilized for solar thermal processing, eliminating the need for specialized solar storage tanks and reducing installation costs while maintaining improved hot water production capability.
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 configuration enhances heat transfer efficiency, reduces costs, and allows for faster production of hot water at higher temperatures, eliminating the need for specialized tanks and anti-freeze fluids, while maintaining system integrity and safety.
Implementation Method 1
at least one solar thermal water collector
Implementation Method 2
intermediate means connected on the one hand to said solar collector(s) and, on the other hand, to said hot water tank so as to supply said tank with hot water
Implementation Method 3
utilizing thermosiphon for natural water circulation and stratification
Implementation Method 4
The tank water temperature rises while remaining very uniform in the enclosure. Such a phenomenon is relatively slow, and it therefore takes hours of heating before obtaining a sufficient water temperature
Data Source
Figure 1
Figure 2
Figure 3~9
AI summary
The invention relates to a system for producing hot water, including: at least one solar collector (1) for water heating; at least one hot water tank (2); an intermediate means connected to said solar collectors (1) and to said hot water tank (2) so as to supply said tank with hot water, the intermediate means including a chamber (3) defining a space (300) placing at least four pipes in communication, i.e.: a first pipe (30) for discharging water into the hot water tank and connected to the top portion of said chamber; a second pipe (31) for taking in water and connected to the bottom portion of said chamber; a third pipe (32) for taking in water from the collector(s) and connected to an intermediate intake area located between the top and bottom portions; a fourth pipe (33) for discharging water toward the solar collector(s) and placing the bottom portion and the intermediate intake area in communication, characterised in that said pipe comprises a mechanical stratification means including a thermostatic valve (3010) placed on the outlet of the first pipe (30).