Simulation for Heating System Indirectly Connected to the Secondary Heating System
Author(s): WANG Hongwei, LIU Zhichao, HAO Hong, School of Municipal and Environmental Engineering, Shenyang Jianzhu University
Pages: 516-523
Year: 2015 Issue: 3
Journal: Journal of Shenyang Jianzhu University(Natural Science)
Keyword: thermal hysteresis; mathematical model; simulation; load forecasting; demand heating;
Abstract: The aim of this paper is to study the large thermal hysteresis of district heating systems,so as to provide some theoretical supports for demand heating. Taking a residential district in Shenyang as the research object,based on the principle of heat transferring and the lawof conservation of mass and energy,a mathematical model for the secondary network of indirectly connected district heating system was built and temperature responses were simulated and dynamical characters were also observed using M ATLAB / Simulink. It is found that at the time of 15 h,the outdoor temperature rapidly increases form- 16. 8 ℃ to- 5 ℃. The indoor temperature reaches stability about in 4 hours. The return water temperature of the heat exchanger is in stability about in 5. 5hours and the supply water temperature reaches stability about in 6. 5 h. The supplying heat exceeds 500 k W. Conclusion is that the district heating system has a large thermal hysteresis. It can-not adjust heating load according to the outdoor temperature. In order to achieve heat requirements of users,it requires timely and accurately forecast load for heating system to guide adjustment of heating system,so as to realize demand heating.
Pages: 516-523
Year: 2015 Issue: 3
Journal: Journal of Shenyang Jianzhu University(Natural Science)
Keyword: thermal hysteresis; mathematical model; simulation; load forecasting; demand heating;
Abstract: The aim of this paper is to study the large thermal hysteresis of district heating systems,so as to provide some theoretical supports for demand heating. Taking a residential district in Shenyang as the research object,based on the principle of heat transferring and the lawof conservation of mass and energy,a mathematical model for the secondary network of indirectly connected district heating system was built and temperature responses were simulated and dynamical characters were also observed using M ATLAB / Simulink. It is found that at the time of 15 h,the outdoor temperature rapidly increases form- 16. 8 ℃ to- 5 ℃. The indoor temperature reaches stability about in 4 hours. The return water temperature of the heat exchanger is in stability about in 5. 5hours and the supply water temperature reaches stability about in 6. 5 h. The supplying heat exceeds 500 k W. Conclusion is that the district heating system has a large thermal hysteresis. It can-not adjust heating load according to the outdoor temperature. In order to achieve heat requirements of users,it requires timely and accurately forecast load for heating system to guide adjustment of heating system,so as to realize demand heating.
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