Underground Brine Buffer Storage for District Heat Loss Reduction
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Solution Overview
Problem
Conventional heat storage devices are expensive to construct and require significant space due to high heat losses, making them inefficient for storing large amounts of excess thermal energy, especially in district heating systems where seasonal fluctuations and limited fuel sources pose challenges.
Innovation Solution
An underground buffer storage device filled with brine as a heat storage medium, utilizing a primary and secondary circuit with heat exchangers, where the surrounding rock acts as thermal insulation, reducing heat losses and allowing for efficient transfer of excess heat to and from the storage medium, with the secondary circuit connected to heat consumers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If large storage tanks are used to store larger amounts of excess thermal energy, then the storage capacity is improved, but the construction cost and space requirements increase significantly
Solution Approach 1:
The invention transitions from surface-level storage tanks to underground storage, utilizing the third dimension (depth) for storage capacity. The storage tank is installed underground, allowing large volumes to be utilized without increasing surface footprint, thus resolving the contradiction between storage capacity and space requirements.
Solution Approach 2:
The surrounding ground soil automatically provides thermal insulation without requiring additional artificial insulation layers. The earth itself serves as the insulating medium, eliminating the need for expensive insulation materials and reducing construction costs while maintaining thermal efficiency.
2Quantity of substance
If large storage tanks are used to store larger amounts of excess thermal energy, then the storage capacity is improved, but the construction cost increases due to expensive insulation requirements
Solution Approach 1:
The ground soil automatically provides thermal insulation without requiring additional artificial insulation layers. The earth itself serves as the insulating medium, eliminating the need for expensive insulation materials and reducing construction costs while maintaining thermal efficiency.
Solution Approach 2:
The invention converts the naturally occurring heat loss to the surrounding environment into a beneficial automatic insulation effect. The temperature difference between the stored hot water and the surrounding soil creates a natural thermal gradient that the system exploits through the underground placement, turning what would normally be a disadvantage (heat loss) into an advantage (free insulation).
3Loss of energy
If thermal insulation is applied to reduce heat losses, then the heat loss is reduced, but the construction cost increases due to insulation material and thermal bridge prevention
Solution Approach 1:
The ground soil automatically provides thermal insulation without requiring additional artificial insulation layers. The earth itself serves as the insulating medium, eliminating the need for expensive insulation materials and reducing construction costs while maintaining thermal efficiency.
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 significantly reduces heat losses, minimizes space requirements, and allows for cost-effective storage and retrieval of excess heat, enabling efficient heating, hot water supply, and air conditioning while maintaining ecological safety by using existing underground cavities and brine as a heat storage medium.
Implementation Method 1
a first heat exchanger in the primary circuit through which the first heat transfer medium flows being set up to transfer excess heat fed into the primary circuit from the first heat transfer medium to the brine in the underground storage tank
Implementation Method 2
a second heat exchanger in the secondary circuit, through which the second heat transfer medium flows, is set up to at least partially transfer the excess heat stored in the brine in the underground storage tank
Implementation Method 3
In the case of such an underground storage tank, the surrounding rock or soil serves as thermal insulation. Heat losses from the storage container can thus be reduced particularly efficiently.
Data Source
Figure 1
AI summary
The invention relates to a buffer storage device (1) comprising an underground storage tank (3) filled with brine (5) as a heat storage medium, a primary circuit (10) filled with a first heat transfer medium (11, 12), and a secondary circuit (20) filled with a second heat transfer medium (21, 22), wherein a first heat exchanger (W1) in the primary circuit (10), through which the first heat transfer medium (11, 12) flows, is configured to transfer excess heat fed into the primary circuit (10) from the first heat transfer medium (11, 12) to the brine (5) in the underground storage tank (3), and a second heat exchanger (W2) in the secondary circuit (20), through which the second heat transfer medium (21, 22) flows, is configured to transfer, if necessary, at least some of the excess heat stored in the brine (5) in the underground storage tank (3) to the second heat transfer medium (21, 22). 22) to transfer,wherein the secondary circuit (20) is coupled to at least one heat consumer. Furthermore, a method for buffer storage of excess heat in a heat storage medium is specified.