Assembly and method for controlling the loading of buffer storage for a district heating consumer and district heating distribution station
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Solution Overview
Problem
Existing district heating buffer storage tank control systems fail to efficiently manage temperature gradients, leading to prolonged heat penetration delays and excessive temperature fluctuations, especially in stratified tanks, due to limited temperature sensing and binary loading control.
Innovation Solution
Incorporating additional temperature sensors between the flow and return connections in the buffer storage tank to provide a more comprehensive temperature reading, allowing for earlier intervention in loading control and enabling continuous, stepless variation of loading rates to mitigate temperature fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional temperature sensors are installed between flow and return connections, then temperature control precision is improved, but device complexity increases
Solution Approach 1:
The buffer storage tank is divided into multiple vertical zones, each monitored by dedicated temperature sensors. The sensor arrangement includes a first sensor near the flow connection, a second sensor near the return connection, and at least one additional sensor positioned between them, creating segmented temperature monitoring zones that independently track thermal conditions throughout the tank volume.
Solution Approach 2:
The temperature monitoring system transitions from two-dimensional (flow and return connections only) to three-dimensional coverage by adding vertical positioning of sensors at different heights within the tank. This spatial dimensionality change enables comprehensive monitoring of temperature gradients from top to bottom, capturing the full thermal profile of the stratified storage system.
2Ease of operation
If binary loading control (on/off) is used, then control simplicity is improved, but temperature fluctuation stability deteriorates
Solution Approach 1:
The loading control system transitions from static binary (on/off) to dynamic continuous control by modulating the loading pump's rotational speed. The controller adjusts the pump speed proportionally to the temperature difference between the buffer tank and supply network, enabling smooth, stepless variation of loading rates that continuously adapts to changing thermal conditions and prevents temperature oscillations.
Solution Approach 2:
The control system implements closed-loop feedback by continuously comparing the temperature measured by the additional sensor with the supply network temperature and using this temperature difference to dynamically adjust the loading pump speed. This feedback mechanism ensures the loading rate automatically responds to real-time thermal conditions, maintaining optimal buffer tank temperature and preventing excessive fluctuations.
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 approach allows for more precise control of the loading process, reducing temperature gradients and preventing excessive return temperatures, thereby optimizing the operation of district heating networks by ensuring smoother heat distribution and reducing energy waste.
Implementation Method 1
a first temperature sensor, which is designed to detect a first temperature of the heat transfer medium at the flow connection and a second temperature sensor, which is designed to detect a second temperature of the heat transfer medium at the return connection
Implementation Method 2
The 'hot' heat transfer medium is discharged back in the direction of the heat transfer point or the supply network via a return connection
Implementation Method 3
Stratified storage tanks have the property that the mixing of the heat transfer medium in the storage tank is kept as low as possible. Thus, there is a significant temperature gradient in the vertical direction between the top layer, where the hot heat transfer medium is supplied, and the bottom layer, from where the cooled heat transfer medium is discharged
Data Source
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AI summary
District heating transfer station and arrangement for controlling the charging of a stratified buffer storage tank for a district heating customer side, wherein the stratified buffer storage tank has a supply connection for supplying a heat transfer medium and a return connection for returning the heat transfer medium, comprising: a first temperature sensor configured to detect a first temperature of the heat transfer medium at the supply connection, a second temperature sensor configured to detect a second temperature of the heat transfer medium at the return connection, wherein the control of the charging of the stratified buffer storage tank is based on the detected first temperature and the detected second temperature, wherein at least one further temperature sensor is provided, which is configured to detect at least one further temperature of the heat transfer medium in the stratified buffer storage tank between the supply connection and the return connection.and which also incorporates at least one other temperature in the stratified buffer storage into the control of the charging process.