District Heating Thermal Inertia Scheduling for Wind Power Absorption
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Solution Overview
Problem
The challenge is to enhance wind power absorption in combined heat and power systems by optimizing the operational flexibility of district heating networks and buildings, considering thermal inertia, to reduce wind power abandonment and improve overall system economics.
Innovation Solution
An integrated energy system operational optimization method is developed, which includes establishing district heating network and building models to account for transmission delay and thermal storage capacity, and solving an optimization model to schedule gas turbine and gas boiler outputs, as well as electricity purchasing from the grid and wind power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the combined heat and power unit operates in a mode of thermal load following to supply heat load, then the heat supply reliability is improved, but the power output flexibility deteriorates and wind power absorption is limited
Solution Approach 1:
The patent applies preliminary action by utilizing the thermal inertia of buildings and transmission delay of district heating networks in advance to store thermal energy during periods of high wind power generation and low heat demand, then releasing this stored energy during periods of low wind power generation. This allows the CHP unit to deviate from strict thermal load following mode while ensuring heat supply reliability, thereby improving power output flexibility and wind power absorption capability.
2Productivity
If the CHP unit increases power output to absorb more wind power, then the wind power absorption rate is improved, but the heat supply capability deteriorates
Solution Approach 1:
The patent introduces thermal energy storage in buildings and the district heating network as intermediary elements between the CHP unit and the heat consumers. These intermediaries can store excess heat when the CHP unit operates at high power output, and release stored heat when power output is reduced to absorb wind power, thus decoupling the direct coupling between heat and power output and enabling higher wind power absorption rates while maintaining heat supply capability.
3Use of energy by moving object
If the heat load is supplied by centralized CHP units, then the heat supply efficiency is improved, but the system operational flexibility deteriorates and wind power abandonment increases
Solution Approach 1:
The patent applies dynamics by transforming the static thermal load following operation mode into a dynamic operation mode that exploits the time-varying thermal inertia of buildings and transmission delay of the district heating network. The system dynamically adjusts CHP unit output based on predicted wind power generation and thermal storage status, enabling operational flexibility while maintaining high heat supply efficiency through centralized CHP units.
4Reliability
If the CHP unit operates to meet peak heat demand, then the heat demand satisfaction is improved, but the power output exceeds demand during low heat demand periods causing wind abandonment
Solution Approach 1:
The patent applies self-service by enabling the district heating system and buildings to serve themselves as thermal energy storage facilities. During periods of low heat demand and high wind power generation, the system automatically stores excess heat in buildings and the district heating network. During periods of high heat demand, the stored heat is automatically released, reducing the need for CHP unit operation and enabling wind power absorption without compromising heat demand satisfaction.
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 significantly improves wind power absorption rates and system economic performance by adjusting heat load distribution and balancing heat supply and demand over a longer timescale, reducing wind power abandonment and operational costs.
Implementation Method 1
utilize the thermal storage capacity of buildings to change heat load temporal distribution
Implementation Method 2
establishing a building model considering thermal storage capacity
Data Source
AI summary
Disclosed is an integrated energy system operational optimization method considering thermal inertia of district heating networks and buildings, comprising the following steps. Step 10: respectively establish a district heating network model considering transmission delay and heat loss and a building model considering thermal storage capacity. Step 20: establish an integrated energy system optimization model consisting of a combined cooling, heat and power system model, the district heating network model and the building model. Step 30: solve the integrated energy system optimization model to obtain an optimal scheduling plan, control outputs of a gas turbine and a gas boiler per hour according to the optimal scheduling plan, and purchase electricity from a power grid and a wind power. According to the method, both the district heating network and buildings are included in a scheduling scope, so that the load adjustment with multiple degrees of freedom can be achieved.