Evaluation on energy saving of CTHP circulating system

Abstract Based on EHR, index PEHR was performed to evaluate energy-saving of different heat-ing systems. The PEHR formulas were obtained for the boiler district heating system, cogen-eration district heating system and the CTHP heating system. Numerical calculation and anal-ysis were carried out, the results show the PEHR value increases with the total pipeline length and the CTHP system has the minimum PEHR value as the total length of the pipeline under the same conditions, the lower limit COP value of the heat pump increase with the increase of value a and the smaller length of the CTHP system may be easier to realize energy saving.