and 74 3 have the cop characteristic for every cooling water inlet temperature has been described however for example the heat source apparatus control devices 74 1 74 2 and 74 3 may have the cop characteristic for every outside air temperature in addition for example in the cop characteristic shown in fig5 because each of the cooling water inlet temperatures is set discretely the cop characteristic may not exist for some of the cooling water inlet temperatures in this case an interpolating process etc may be performed to obtain the cop characteristic that corresponds to the present cooling water inlet temperature by calculation thereby setting the appropriate operating region in addition in this embodiment each of the heat source apparatus control devices 74 1 74 2 and 74 3 extracts the cop characteristic that corresponds to the cooling water inlet temperature at various times from the cop map obtains the appropriate operating region from this cop characteristic and sends it to the number of units control device 100 however instead of this each of the heat source apparatus control devices 74 1 74 2 and 74 3 may send the cop map itself or the cop characteristic that corresponds to the cooling water inlet temperature at various times to the number of units control device 100 in this case the number of units control device 100 sets the appropriate operating region in each of the heat source apparatuses 11 12 and 13 in addition each of the heat source apparatuses 11 12 and 13 may have a cop map in which the amount of heat output has been.