Heat exchanger element
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Solution Overview
Problem
Classic circulation systems for hot water supply in heating systems mix the temperature layers in buffer tanks, reducing storage efficiency and increasing energy losses, while also failing to meet strict drinking water requirements.
Innovation Solution
A heat exchanger element with a layered tube structure that stratifies return circulation water within the buffer storage tank, maintaining temperature gradients and preventing mixing, allowing for efficient heat transfer and compliance with drinking water regulations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a classic circulation system is used for hot water supply, then hot water can be provided rapidly at the tap, but the return water mixes with the buffer tank layers, reducing storage efficiency and increasing energy losses
Solution Approach 1:
The heat exchanger is divided into multiple heating sections (first heating section, second heating section, etc.) arranged at different heights within the buffer tank. Each section heats the circulation water at a specific temperature level, preventing mixing while maintaining thermal stratification. The segmentation allows the system to provide hot water rapidly while preserving the buffer tank's energy storage efficiency.
Solution Approach 2:
The heat exchanger acts as an intermediary device between the buffer tank and the circulation system. It transfers heat from the buffer tank water to the circulation water without allowing direct mixing. The heat exchanger sections are positioned to extract heat from different temperature layers, maintaining the stratification while enabling hot water supply.
2Device complexity
If the buffer tank is used for both heating storage and hot water circulation, then system complexity is reduced, but the temperature gradients are destroyed and storage efficiency decreases
Solution Approach 1:
Different sections of the heat exchanger are positioned at different locations within the buffer tank to interact with different temperature layers. The first heating section is positioned to access warmer water layers, while the second heating section accesses cooler layers. This local differentiation allows the system to maintain temperature gradients while using a single integrated buffer tank for both heating storage and hot water circulation.
3Loss of energy
If a larger buffer tank volume is used to maintain temperature gradients during circulation, then storage efficiency is improved, but system cost and space requirements increase
Solution Approach 1:
The heat exchanger sections are pre-positioned within the buffer tank to access specific temperature layers before circulation begins or during operation. This preliminary arrangement ensures that heat is efficiently extracted from appropriate layers without requiring excessive tank volume. The system is designed to maintain temperature gradients through the strategic placement of heating sections rather than relying on large volume alone.
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 ensures rapid hot water provision without compromising the buffer tank's usability, reduces energy losses, and allows for efficient operation of local heating networks, even with small volume buffer tanks and large temperature spreads, enabling longer network shutdowns during summer months.
Implementation Method 1
a heat exchanger element (1) for forming a first material space (4) of a heat exchanger (30) for indirect heat transfer
Implementation Method 2
stratification means that due to the natural density differences, the water is stratified in such a way that the warmest water with the lowest density is at the top and the coldest water with the highest density is at the bottom
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a heat exchanger element (1) and a heat exchanger (30) with such a heat exchanger element (1), as well as a method for operating a heat exchanger (30). Furthermore, the invention relates to a heat storage tank (2), a system (10) for hot water preparation with such a heat storage tank (2), and a method for hot water preparation with such a system (10). Finally, the invention also relates to a district heating system in which such a heat storage tank (2) serves as a heating buffer storage tank. In general, the invention describes a novel circulation system for hot water systems (10), particularly in conjunction with fresh water stations. A particular innovation in this context is the combination of a stratified tube (13) with a heat exchanger tube (11).