Study On Operation Control Strategy Of Heating System In University Campuses In Severe Cold Area

With the proposal of the national "carbon peak and carbon neutrality" strategy,there are higher requirements for energy conservation and emission reduction.For colleges and universities in severe cold regions,the energy consumption of the heating system accounts for a large proportion of the energy consumption of the campus.Adjusting the operation of the heating system is of great significance for improving the operation quality of the heating system and energy conservation and emission reduction.This paper aims at the heating system of university campuses in severe cold areas,takes Harbin as a representative city,and based on the TRNSYS numerical simulation software,establishes a simulation model of the heating system of university campuses in severe cold areas.By analyzing the indoor temperature changes of different buildings in various control strategies,this paper analyzes and studies the optimization of the operation control strategies of the heating system of university campuses.Firstly,for the secondary network heating system,according to the heat balance equation of the heating station,the secondary network and the various parts of the heat building,as well as the logic and energy transitive relation relationship between the various components and variables of the actual system,each module in TRNSYS software is connected and debugged,and a complete simulation model of the heating system of university campuses in severe cold areas is established.The dynamic load changes of university buildings during the heating period are simulated,and the load rate and frequency distribution of hourly load and daily average load are analyzed.The results shows that the frequency of load rates between 60% and 90% is relatively high,and the daily average load distribution can basically reflect the hourly load distribution.Secondly,according to the outdoor temperature and building load,six typical days are selected in the heating period,and the indoor temperature changes of the buildings in the heating system under different water supply and different supply and return water temperature difference and variable flow regulation strategies are analyzed on each typical day.The results shows that under the selected operation strategy,the indoor temperature fluctuation of the heating buildings is small and the heating effect is good.This paper studies the startup and shutdown control of public buildings in the heating system at night.Based on the selection of different water supply temperatures,this paper analyzes the indoor temperature changes under different startup and shutdown times on different typical days,determines the optimal startup and shutdown time of the system on each typical day,and optimizes the strategy by increasing the water supply temperature in the preheating stage to make the indoor temperature of the building more consistent with the set requirements during use.Finally,the influence of the change of thermal inertia index of the building envelope on the operation strategy of the heating system is analyzed.In engineering applications,the appropriate preheating and shutdown time should be determined based on the actual thermal storage performance of the building.On the basis of the optimal operation and regulation strategies of each typical day,a case study is conducted on the heating system of the university campus.According to the outdoor daily average temperature and building load,three different heating schemes are set for time-sharing and zoning control and regulation based on the water supply temperature and the start and stop time.The total heating capacity of each scheme in the heating period is analyzed.By comparison,the energy saving rates of Scheme II and Scheme I are17.1% and 34.8%,respectively.The calculation of standard coal conversion and emission reduction for the heating capacity of each scheme shows that the coal savings of Scheme II and Scheme III are 85.8t and 174.3t respectively,which can reduce CO2 emissions of 204.8t and419.5t compared to Scheme I.The research results provide a reference for optimizing the operation control strategy of the heating system of university campuses in severe cold regions.