To develop an operating strategy under unconventional conditions for the triple-sleeve energy exchanger (TRESE) based energy storage heat pump system, and to validate stability and reliability at heat exchangers switchover moment for an operating system, a series of unconventional experiments were carried out by using a 2HP prototype. Experimental results indicated that cooling COP of TRESE assisted air source heat pump was 2.8-2.4,7% higher than that of an air source heat pump alone, when ambient temperature was 38-43 ℃. Its heating COP with solar energy assisted could be 2.8 while ambient temperature was -17--10 ℃, 65% higher than that of an air source heat pump alone. On the other hand, switchover of heat exchangers triggered slight fluctuation of operation parameters for operating prototype, while the duration for restoration of stability was less than 420 s, which verified the reliability of the prototype.