In order to study the energy consumption law of water-loop heat pump system under nonstandard conditions

the circulating water was selected as the research foundation and on the basis of the circulating water energy equations

the system energy consumption equations were built by using a linear transfer function method. The theoretical results show that the change law is nonlinear between the system energy consumption and load rate

and it will more remarkable in winter; because the effect of load rate on the energy consumption

with the circulating water energy changing

the change law of system energy consumption will appear a distortion characteristic

which significantly affect system energy saving. In order to determine the range and lasting time of distortion condition point

an engineering was selected in Tianjin as the experiment object

and the test data was analyzed by energy gap method of circulating water. The experimental results show that for this building

the distortion condition point is in the range of 4~5 level

and its lasting time is less 10% of the total run time; the capacity of auxiliary heat source is reasonable with 55% of building heat load.