Study On Influence Of Thermal Inertia Of Central Heating System On Peak Regulation Performance Of Heating Units

At present,the three north areas of the long winter heating time,heating load demand is big,cogeneration units as heat source of centralized heat-supply system is an important lifeline protection of the normal life of three north areas demand,so the research on the central heating system is more sophisticated,heating pipelines as the most important part of the central heating system,pipe size,and number of user groups,To some extent,it serves as the energy storage equipment of the central heating system,and does not need additional investment to guarantee the heating quality and thermal comfort of users.Therefore,the study on the thermal inertia of the central heating system can break the strong thermoelectric coupling characteristics of the cogeneration unit to a certain extent.In this paper,the effect of thermal inertia of heating system on peak regulation performance of heating unit is studied.In the aspect of system modeling,according to the operation characteristics of cogeneration units,the electrothermal operation characteristic equation of cogeneration units is established.Based on the thermodynamic principle and Kirchhoffs law,the hydraulic and thermal model of heating pipe network is established by graph theory method.Based on the thermal conductivity characteristics of the building,the indoor temperature change model on the user side is established,and the energy transfer model of heat-source-pipe network-building is also established.To study the thermal inertia of centralized heat-supply system,this paper takes the indoor temperature of heating network export parameters and construction side as the research object,its dynamic characteristic is studied,for heating pipe network,through the simulation model and the actual operation data,the results showed that the main factors influencing the outlet temperature of the pipe network is section length and the fluid velocity,time lag and section is proportional to the length,Is inversely proportional to the flow velocity,and when the inlet temperature changes,the outlet temperature change trend is basically the same.For buildings,the influence of increasing and decreasing water supply temperature on indoor temperature during heating period is mainly studied.The results show that the heat storage capacity of the envelope will significantly affect the indoor temperature change.The lower the water supply temperature is,the indoor temperature change will be affected by both the outdoor temperature and the envelope.In order to study the influence of thermal inertia of heating system on peak regulation performance of heating units,the combined operation model of cogeneration unit,pure condensing thermal power unit and Wind power unit is proposed in this paper.Under the premise of ensuring the indoor temperature at 16～20℃,the strong coupling characteristics of cogeneration unit are broken by the thermal inertia of central heating system.By comparing the system model under the traditional heat-determined power mode with the operation model considering the thermal inertia of the heating system,the results show that considering the thermal inertia of the district heating system can significantly improve the peak regulation performance of the heating unit,and the latter consumes 30%more wind power than the former in terms of wind power consumption during the typical daily operation.