District Heating System Adjustment Theoretical Based on Heat Users’ Real Load

With the passage of time and enhanced insulation in buildings, nonnegligible change may occur in the existing buildings’ thermal performance. Under this circumstance, the original heating system will not guarantee the heat users’ demand. Therefore, it is necessary to re-calibrate the thermal characteristics of the building, based on which the users’ supply and return water temperature should be determined. In this paper, a model to solve the heat users’ real heat load was established based on energy balance equation, considering that the building’s heat load was uncertain. A correction coefficient β was introduced to illustrate the relationship between the design heat load and the real heat load. A demonstration project in Harbin was tested during the period from January 27, 2011 to February 25, 2011 with the application of this adjustment method to verify the validity of this model. The results showed that the users’ actual room temperature deviated from the design room temperature seriously before the adjustment method used and this deviation was reduced after this method used.