District Heating Load Control Using Building Thermal Mass
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Solution Overview
Problem
District heating systems face challenges in optimizing energy usage due to stochastic variations in consumer demand, leading to overcapacity and high costs, as existing methods rely on oversized components and peak load boilers, with largest energy flows occurring during specific times, necessitating efficient power distribution and control.
Innovation Solution
A district heating system with a central unit and local substations equipped with monitoring and control computers uses intelligent software agents to dynamically manage energy consumption by identifying suitable buildings for power reduction, allowing for fair and optimal distribution of power reductions based on thermal mass and comfort levels, enabling continuous monitoring and adaptive energy output without compromising service quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the capacity of the district heating net is increased to fulfil extreme demands, then the system can meet peak loads, but the power consumption and costs increase
Solution Approach 1:
The system dynamically adjusts the capacity of individual substations based on real-time conditions. Instead of maintaining fixed oversized capacity, each substation can temporarily reduce its power intake when conditions permit, allowing the network to adapt its total capacity dynamically rather than relying on permanent overcapacity
Solution Approach 2:
The system performs preliminary heating of buildings before peak demand periods by increasing power intake when conditions are favorable. This stores thermal energy in the buildings' thermal mass, allowing them to maintain comfortable temperatures during peak periods without requiring continuous high power input across the entire network
2Use of energy by moving object
If power reduction is applied to reduce overall consumption, then costs decrease, but the comfort level of buildings may be reduced
Solution Approach 1:
The system applies power reductions locally and selectively to specific substations and buildings rather than uniformly across the entire network. Each substation's power intake is adjusted independently based on its specific conditions, allowing the system to reduce total consumption while maintaining comfort in buildings where power reduction would be detrimental
Solution Approach 2:
The system continuously monitors temperature conditions and comfort levels in buildings, using this feedback to adjust power reductions in real-time. If a building approaches uncomfortable temperature levels, the system reduces or eliminates power reductions to that substation, ensuring comfort is maintained while still achieving overall consumption reduction
3Ease of operation
If separate power control is applied to each substation, then individual control is achieved, but optimal distribution and fairness cannot be realized
Solution Approach 1:
The system merges the control of individual substations into a coordinated network-level control system. While each substation retains local monitoring and control capabilities, they are integrated into a broader optimization framework that considers the entire network's conditions, enabling both individual control and optimal distribution
4Use of energy by moving object
If larger power reductions are applied during peak flows, then consumption reduction is maximized, but temperature impact increases
Solution Approach 1:
The system performs preliminary heating before peak demand periods by increasing power intake when conditions are favorable, storing thermal energy in building thermal mass. This allows the system to maintain temperature stability during peak periods without requiring continuous high power input
Solution Approach 2:
The system applies power reductions periodically and intermittently rather than continuously, adjusting power intake in cycles that align with building thermal response characteristics. This periodic adjustment maximizes consumption reduction while allowing buildings to maintain stable temperatures through their thermal inertia
Data Source
Figure 1~3
AI summary
The present invention concerns a method of optimizing the power usage of district heating systems. A district heating system has a central unit (1), such as a power plant or an intake from a larger system, and a number of local units (2), normally different buildings. The local units (2) pick up heat from water delivered by the central unit (1), by means of heat exchangers (9, 10). The present system has means for monitoring and control of the central unit (1) and the local units (2). The data picked up by the means for monitoring and control are used for the optimizing of the power usage. The power outtake of the district heating system is regulated by reduced flow into one selected local unit (2) during a short time period.