Research On The Simplification Of Building Thermal Model In Heating Accident

By 2017,the central heating area has reached 8.31 billion m~2 including heating systems with more than100 million m~2.There are many components in large-scale heating systems which can lead to high frequency of heating accidents and large scope of impact.With the improvement of residents'living standards,the requirements for heating quality are gradually improved and the tolerance for heating accidents is reduced.Thus,the research on heating reliability is more focused on reflecting the response of heating buildings to accidents.However,the 1-order thermal model is more severely distorted,and high-order thermal models are too complex for large-scale heating systems.Therefore,this paper aims to reduce the order of the heating building thermal model building and improve the calculation efficiency.According to the thermal characteristics of the building,a physical model of building heat transfer was established.Based on the Lumped parameter method,the heat transfer model of the envelope,the radiators model and the heat balance model of the indoor air were established.And the state space model was used to construct the state space model of the heating building.An energy-efficient building in Changchun was chosen as a case study in this work to build a high-order thermal model with each room of the building as a space-unit.The thermal model is used to simulate the dynamic thermal characteristics under accident conditions.After that,this whole building is considered as a spatial unit by reducing the order of the high-order thermal model and 8-order thermal model and 2-order thermal model were established.By comparing the simulated data of the typical room with the measured temperature data,the accuracy of the high-order model was verified in the time domain.The 8-order and 2-order models'simulated indoor temperature's rationality in the time domain was also proved though analysis.The Bode diagram of the high-order thermal model,the 8-order thermal model and the 2-order thermal model were drawn using the heat of indoor air as the state space and the outdoor temperature as the excitation.The rationality of the reduced-order models was verified by analyzing the frequency characteristics of the model in low frequency.It is verified by experiments that the 8-order model and the 2-order model both have high precision,which can accurately reflect the indoor temperature variation of the heating building under accident conditions.However,compared with the 8-order thermal model,the 2-order thermal model has smaller computational complexity.Therefore,it is more suitable for accident simulation study for large-scale heating systems.