A MODIFIED HOURLY LOAD ESTIMATION METHOD APPLIED TO THE OPTIMAL SIZING OF CHP SYSTEMS

The efficiency of combined generation of heat and power (CHP) is significantly affected by the load profiles, because it mainly depends on the amount of the cogenerated heat that is actually used. Therefore, the knowledge of the load profile for heat on hourly basis plays a leading role in the assessment of this kind of systems. In this paper the hourly load estimation procedure (h-LEP), to estimate the building space heating load profile on the hourly basis by the monthly consumption, is modified to better fit the actual load. To validate the proposed procedure, based on a multivariate regression approach, the restored hourly load profiles of a nine storey building for hospital use is compared with the hourly profile obtained by TRNSYS simulation tool. The results point out that the estimation procedure allows to restore the building hourly space heating load profile satisfactorily, ranging the coefficient of multiple determination R2 between 0.69 and 0.94. With the aim to provide a suitable tool for optimizing the performances of the building CHP systems, the estimation procedure is then applied to the evaluation of the useful fraction of the cogenerated heat. In the considered case study, the inverse procedure allows to evaluate the useful fraction of the cogenerated heat with an average accuracy of ± 1.5%.