In this study, the impact of load demands on the energy-saving characteristics of the systems was analyzed, and the mathematical model was derived for the relationship between the load supply and demands under different capacity design modes and operation strategies, and the influence of the key parameters (load demands, load rate, matching degree) on system integration and operation characteristics in different energy use scenarios was quantitative analyzed to elucidate the inherent mechanism of energy saving characteristics. Furthermore, the impact of energy-matching degree and system efficiency on the energy saving rate (ESR) was discussed, and based on the load demands, an universal system boundary of the ESR was constructed. Based on this, the coupling mechanism between the system and users from a global perspective was reconstructed, and an collaborative integrated method based on centralized energy supply systems, CCHP systems, and load demands was proposed to expand the energy-saving boundary under all operating conditions. Finally, a case analysis and method verification were conducted using typical summer days at Beijing hotel as an example. The results show that this method universally characterizes the coupling matching relationship and energy-saving characteristics. Through collaborative integration, the ESR increase of 5% can be achieved.