Heat pump system and control method thereof

Abstract

A heat pump system which executes cooling and heating operations of an A2A indoor unit and cooling and heating operations and a hot water operation of an A2W indoor unit in a time division multiplexing (TDM) method, and a control method thereof. Further, the heat pump system solves shortage of a refrigerant during a heating operation of the A2A indoor unit or the A2W indoor unit when the TDM method is used. Therefore, the heat pump system includes a control unit to alternately operate the A2A indoor unit or the A2W indoor unit, upon judging that a simultaneous operating condition of the A2A indoor unit or the A2W indoor unit is satisfied. The heat pump system further includes a refrigerant distribution unit to circulate a refrigerant selectively to the A2A indoor unit or the A2W indoor unit.

1 . A heat pump system comprising:
 an outdoor unit including an outdoor air heat exchanger;   at least one first indoor unit including an indoor air heat exchanger;   at least one second indoor unit including an indoor water-refrigerant heat exchanger;   a refrigerant circulation pipe unit connected to the outdoor unit, the at least one first indoor unit, and the at least one second indoor unit to circulate a refrigerant; and   a control unit to control the at least one first indoor unit and the at least one second indoor unit so as to be alternately operated, upon judging that a simultaneous operating condition of the at least one first indoor unit and the at least one second indoor unit is satisfied.   
     
     
         2 . The heat pump system according to  claim 1 , wherein a capacity of the at least one first indoor unit and a capacity of the at least one second indoor unit are equal to a capacity of the outdoor unit. 
     
     
         3 . The heat pump system according to  claim 1 , wherein the sum total of a capacity of the at least one first indoor unit and a capacity of the at least one second indoor unit is in the range of 50-130% of a capacity of the outdoor unit. 
     
     
         4 . The heat pump system according to  claim 1 , wherein the outdoor unit further includes a variable capacity compressor having a variable capacity. 
     
     
         5 . The heat pump system according to  claim 4 , wherein the control unit controls the outdoor unit such that an output of the outdoor unit is not automatically varied but the outdoor unit is operated according to the maximum capacity of the operating one of the at least one first indoor unit and the at least one second indoor unit. 
     
     
         6 . The heat pump system according to  claim 1 , further comprising:
 a water circulation pipe unit to circulate water having exchanged heat with the refrigerant in the at least one second indoor unit;   a hot water tank connected to the water circulation pipe unit;   a first sub heater to heat the water circulation pipe unit; and   a second sub heater to heat the hot water tank,   wherein the control unit executes a heating operation or a hot water operation of the at least one second indoor unit using at least one of the first sub heater and the second sub heater and controls the outdoor unit so as to execute a cooling operation of the at least one first indoor unit, if the heating operation or the hot water operation of the at least one second indoor unit is requested during the cooling operation of the at least one first indoor unit.   
     
     
         7 . The heat pump system according to  claim 1 , further comprising an input unit, through which an operation mode of the at least one first indoor unit and the at least one second indoor unit is input,
 wherein the control unit controls the at least one first indoor unit and the at least one second indoor unit so as to be alternately operated under the condition that the operation of the at least one first indoor unit or the at least one second indoor unit is limited to a cooling mode or a heating mode according to the cooling mode or the heating mode input through the input unit.   
     
     
         8 . The heat pump system according to  claim 1 , further comprising an input unit, through which an operation mode of the at least one first indoor unit and the at least one second indoor unit is input,
 wherein the control unit controls the at least one first indoor unit and the at least one second indoor unit so as to be operated in a hot water operation mode only, if the hot water operation mode is input through the input unit.   
     
     
         9 . The heat pump system according to  claim 8 , wherein, if the at least one first indoor unit is operating when the hot water operation mode is input through the input unit, the control unit operates the at least one first indoor unit in a rapid cooling mode or a rapid heating mode to enable the at least one first indoor unit to reach a target temperature and then controls the at least one first indoor unit and the at least one second indoor unit so as to be operated in the hot water operation mode only. 
     
     
         10 . The heat pump system according to  claim 9 , wherein the control unit stops the operation in the hot water operation mode, if a signal to stop the hot water operation mode is input through the input unit or water in a hot water tank reaches a hot water set temperature. 
     
     
         11 . The heat pump system according to  claim 1 , wherein the control unit simultaneously operates the at least one first indoor unit and the at least one second indoor unit, upon judging that the sum total of a capacity required by the at least one first indoor unit and a capacity required by the at least one second indoor unit is less than a capacity of the outdoor unit. 
     
     
         12 . The heat pump system according to  claim 1 , wherein the control unit preferentially operates any one of the at least one first indoor unit and the at least one second indoor unit, upon judging that a simultaneous operating condition of the at least one first indoor unit and the at least one second indoor unit is satisfied. 
     
     
         13 . The heat pump system according to  claim 12 , wherein the control unit preferentially operates the at least one first indoor unit, upon judging that the simultaneous operating condition of the at least one first indoor unit and the at least one second indoor unit is satisfied. 
     
     
         14 . The heat pump system according to  claim 13 , wherein the control unit changes the operation of the at least one first indoor unit into the operation of the at least one second indoor unit, upon judging that the at least one first indoor unit reaches a first target temperature during the preferential operation of the at least one first indoor unit or the at least one first indoor unit is operated for a first set time. 
     
     
         15 . The heat pump system according to  claim 14 , wherein the control unit stops the operation of the at least one second indoor unit, upon judging that the at least one second indoor unit reaches a second target temperature during the operation of the at least one second indoor unit or the at least one second indoor unit is operated for a second set time. 
     
     
         16 . The heat pump system according to  claim 15 , wherein the control unit lowers the first target temperature by a reference value, if the first target temperature and the second target temperature are equal, the at least one second indoor unit is not operated, and the number of on/off of the operation of the at least one first indoor unit reaches a designated number. 
     
     
         17 . A control method of a heat pump system, which has an outdoor unit including an outdoor air heat exchanger, at least one first indoor unit including an indoor air heat exchanger, at least one second indoor unit including an indoor water-refrigerant heat exchanger, and a water circulation pipe unit connected to the outdoor unit, the at least one first indoor unit, and the at least one second indoor unit to circulate a refrigerant, comprising:
 alternately operating the at least one first indoor unit and the at least one second indoor unit, upon judging that a simultaneous operating condition of the at least one first indoor unit and the at least one second indoor unit is satisfied.   
     
     
         18 . The control method according to  claim 17 , wherein any one of the at least one first indoor unit and the at least two indoor unit is preferentially operated, upon judging that the simultaneous operating condition of the at least one first indoor unit and the at least one second indoor unit is satisfied. 
     
     
         19 . The control method according to  claim 18 , wherein the at least one first indoor unit is preferentially operated, upon judging that the simultaneous operating condition of the at least one first indoor unit and the at least one second indoor unit is satisfied. 
     
     
         20 . A heat pump system comprising:
 at least one first indoor unit including an indoor air heat exchanger and a first expander;   at least one second indoor unit including an indoor water-refrigerant heat exchanger and a second expander;   an outdoor unit including an outdoor air heat exchanger, a compressor, and a third expander;   a refrigerant circulation pipe unit connected to the at least one first indoor unit, the at least one second indoor unit, and the outdoor unit to circulate a refrigerant;   a refrigerant distribution unit to circulate the refrigerant selectively to the at least one first indoor unit and the at least one second indoor unit; and   a control unit controlling the at least one first indoor unit and the at least one second indoor unit so as to be alternately operated, upon judging that a simultaneous operating condition of the at least one first indoor unit and the at least one second indoor unit is satisfied.   
     
     
         21 . The heat pump system according to  claim 20 , wherein the refrigerant distribution unit includes a four-way valve. 
     
     
         22 . The heat pump system according to  claim 21 , wherein the refrigerant distribution unit further includes check valves. 
     
     
         23 . The heat pump system according to  claim 20 , wherein the refrigerant distribution unit includes a three-way valve. 
     
     
         24 . The heat pump system according to  claim 20 , wherein the control unit executes a preliminary heating operation by driving the compressor, under the condition that the expander of one of the at least one first indoor unit and the at least one second indoor unit, a heating operation of which is executed, is closed and the expander of the other one of the at least one first indoor unit and the at least one second indoor unit is opened, before the heating operation of the one of the at least one first indoor unit and the at least one second indoor unit is executed. 
     
     
         25 . A control method of a heat pump system, which has at least one first indoor unit including an indoor air heat exchanger and a first expander, at least one second indoor unit including an indoor water-refrigerant heat exchanger and a second expander, an outdoor unit including an outdoor air heat exchanger, a compressor, and a third expander, a refrigerant circulation pipe unit connected to the at least one first indoor unit, the at least one second indoor unit, and the outdoor unit to circulate a refrigerant, and a refrigerant distribution unit to circulate the refrigerant selectively to the at least one first indoor unit and the at least one second indoor unit, comprising:
 executing a preliminary heating operation by driving the compressor, under the condition that the expander of one of the at least one first indoor unit and the at least one second indoor unit, a heating operation of which is executed, is closed and the expander of the other one of the at least one first indoor unit and the at least one second indoor unit is opened, before the heating operation of the one of the at least one first indoor unit and the at least one second indoor unit is executed.