JPS6433457A - Controller for air conditioner - Google Patents

Abstract

PURPOSE:To prevent dew condensation at an outlet port and in its vicinity by detecting the temperature of indoor air and restricting the set value of the maximum rotational speed of a variable speed compressor to a predetermined value or below when the temperature of the indoor air is not lower than a predetermined value. CONSTITUTION:An enthalpy arithmetic means 25 calculates the enthalpy of indoor air according to the results detected by a room temperature sensor 20 and a humidity sensor 21, and according to the calculated result thus obtained, a maximum output frequency decision means 27 determines the maximum rotational speed of a compressor 10, namely, the maximum output frequency Fm of an invertor device 18, for forming no dew condensation. An operation frequency decision means 28 compares the output frequency Fd corresponding to room temperatures, which is calculated by an output frequency arithmetic means 24 corresponding to room temperatures, with the maximum output frequency Fm. In case of Fd<=Fm, the compressor 10 is driven according to a frequency of Fr=Fd, and in case of Fd>Fm, the compressor 10 is driven according to the maximum output frequency Fm as the output frequency Fr. Therefore, while the temperature difference DELTAT between the compressor and an indoor heat exchanger 11, which functions as an evaporator, is controlled, the operation of the compressor 10 can be continued at the maximum rotational speed which is possible under the condition that no dew condensation is formed.