Air conditioner
An air conditioner including an outdoor unit; at least one indoor unit configured to cool and heat an indoor space while repeating operation (Thermo-ON) and operation stop (Thermo-OFF); a sensor unit configured to measure a temperature and humidity of each indoor space in which the at least one indoor unit is located; and a controller. The controller calculates a sensible heat load and a latent heat load of each indoor space, based on a time when the operation stop occurs, a time when the operation starts again after the operation stop occurs, and temperature and humidity information of each indoor space, derives target sensible heat and target latent heat based on the calculated sensible heat load and latent heat load, and derives a target refrigerant temperature and an air volume of the at least one indoor unit based on the target sensible heat and the target latent heat.
1 . An air conditioner, comprising:
an outdoor unit;
at least one indoor unit configured to cool and heat an indoor space while repeating operation (Thermo-ON) and operation stop (Thermo-OFF);
a sensor unit configured to measure a temperature and humidity of each indoor space where the at least one indoor unit is located; and
a controller, wherein the controller calculates a sensible heat load and a latent heat load of each indoor space, based on a time when the operation stop occurs, a time when the operation starts again after the operation stop occurs, and temperature and humidity information of each indoor space, derives a target sensible heat and a target latent heat based on the calculated sensible heat load and latent heat load, and derives a target refrigerant temperature and an air volume of the at least one indoor unit based on the target sensible heat and the target latent heat, wherein the sensor unit measures a first indoor temperature and a first indoor humidity at a first time when the operation stop of the at least one indoor unit occurs, and measures a second indoor temperature and a second indoor humidity at a second time when the operation starts again after the first time, wherein the controller derives a temperature change rate of each indoor space during an operation stop time using the first time, the second time, the first indoor temperature, and the second indoor temperature, and calculates the sensible heat load of each indoor space based on the temperature change rate and a volume of each indoor space, and derives an enthalpy change rate of each indoor space during the operation stop time by using the first time, the second time, the first indoor humidity, and the second indoor humidity, and calculates the latent heat load of each indoor space, based on the enthalpy change rate, the volume of each indoor space, and the sensible heat load.
2 . The air conditioner of claim 1 , wherein the controller sets the target sensible heat to be larger by a preset ratio in comparison with the sensible heat load, and the controller sets the target latent heat to be larger by a preset ratio in comparison with the latent heat load.
3 . The air conditioner of claim 1 , wherein the controller determines an operation mode, and when the operation mode is a cooling mode, if the latent heat load is 0, derives the air volume of the at least one indoor unit based on the target sensible heat and a target supply air temperature of the at least one indoor unit, and if the latent heat load is a positive number, derives the air volume of the at least one indoor unit based on the target latent heat.
4 . The air conditioner of claim 3 , wherein when the operation mode is a heating mode, the controller derives the air volume of the at least one indoor unit based on the target sensible heat and the target supply air temperature of the at least one indoor unit.
5 . The air conditioner of claim 4 , wherein when the at least one indoor unit comprises a single indoor unit the controller determines the target refrigerant temperature based on the target sensible heat.
6 . The air conditioner of claim 1 , wherein the controller derives a number of rotations of an outdoor fan that maximizes a coefficient of performance (COP).
7 . The air conditioner of claim 6 , wherein the coefficient of performance is a value obtained by dividing a heating/cooling capacity by a total power consumption, wherein the total power consumption is a value obtained by adding power consumptions of a compressor, an indoor fan, and the outdoor fan, and wherein the number of rotations of the outdoor fan is derived from a number of rotations satisfying a condition in which a change rate of the total power consumption due to a change in the number of rotations of the outdoor fan is zero.
8 . The air conditioner of claim 7 , wherein the controller determines an operation mode, and when the operation mode is a cooling mode, calculates an effective heat capacity, calculates a discharge temperature change according to a condensation temperature change, and derives the number of rotations of the outdoor fan by applying the calculated effective heat capacity and the calculated discharge temperature change according to the condensation temperature change to the condition in which the change rate of the total power consumption due to the change in the number of rotations of the outdoor fan is zero.
9 . The air conditioner of claim 7 , wherein the controller determines an operation mode, and when the operation mode is a heating mode, calculates a dew point temperature, and if the calculated dew point temperature is higher than a heat exchanger temperature, determines the number of rotations of the outdoor fan as a maximum number of rotations, and if the calculated dew point temperature is lower than the heat exchanger temperature, calculates an effective heat capacity, and calculates a discharge temperature change rate according to an evaporation temperature change, and derives the number of rotations of the outdoor fan by applying the calculated effective heat capacity and the calculated discharge temperature change rate according to the evaporation temperature change to the condition in which the change rate of the total power consumption due to the number of rotations of the outdoor fan is zero.
10 . The air conditioner of claim 8 , wherein the effective heat capacity is a change rate of a difference between discharge enthalpy and suction enthalpy according to the condensation temperature change or the evaporation temperature change.
11 . The air conditioner of claim 4 , wherein when the at least one indoor unit comprises a plurality of indoor units the target refrigerant temperature is determined further based on a number of the plurality of indoor units, a ratio of rated cooling/heating capacity of each of the plurality of indoor units, a sensible heat exchange effectiveness, an air mass flow of each indoor unit, and an indoor temperature.