Heat source system

Abstract

A heat source system includes a plurality of heat source units provided in parallel, a plurality of pumps provided in parallel, a collective pipe that collects flow paths between the plurality of heat source units and the plurality of pumps into one, and a control unit. The control unit determines a requested flow rate, based on at least a minimum required flow rate set for each heat source unit and an operation state of each heat source unit, determines a current water supply amount or a maximum water supply amount, based on a flow rate set for each pump and an operation state of each pump, makes a comparison between the requested flow rate and the current water supply amount or the maximum water supply amount, and controls operation of the plurality of heat source units or the plurality of pumps according to a result of the comparison.

1 . A heat source system comprising:
 a plurality of heat source units provided in parallel with each other;   a plurality of pumps provided in parallel with each other;   a collective pipe arranged to collect flow paths between the plurality of heat source units and the plurality of pumps into one; and   controller processing hardware that is configured by execution of computer readable instructions to control operation of the plurality of heat source units and the plurality of pumps, wherein   the controller processing hardware is configured to:   determine a requested flow rate, based on at least minimum required flow rates set for the plurality of heat source units and operation states of the plurality of heat source units;   determine a current water supply amount or a maximum water supply amount, based on flow rates set for the plurality of pumps and operation states of the plurality of pumps; and   make a comparison between the requested flow rate and the current water supply amount or the maximum water supply amount, and control the operation of the plurality of heat source units or the plurality of pumps according to a result of the comparison.   
     
     
         2 . The heat source system according to  claim 1 , wherein
 at least either the plurality of heat source units or the plurality of pumps are configured to have a plurality of different capacities.   
     
     
         3 . The heat source system according to  claim 1 , wherein
 the controller processing hardware is further configured to increase or decrease the number of operating heat source units among the plurality of heat source units or the number of operating pumps among the plurality of pumps.   
     
     
         4 . The heat source system according to  claim 1 , wherein
 the controller processing hardware is configured to determine the requested flow rate, based on the operation states of the plurality of heat source units and flow rates obtained by multiplying the minimum required flow rates by a coefficient considering a flow rate variation in respective pipes connected to the plurality of heat source units.   
     
     
         5 . The heat source system according to  claim 1 , wherein
 the controller processing hardware is configured to make a comparison between the requested flow rate and the current water supply amount, and, when the requested flow rate is larger, select a pump whose operation is to be started from among the plurality of pumps so that the current water supply amount satisfies the requested flow rate and a change in the current water supply amount is minimum.   
     
     
         6 . The heat source system according to  claim 1 , wherein
 the controller processing hardware is configured to calculate a post-decrease water supply amount from the current water supply amount, based on information on a pump scheduled to stop operation among the plurality of pumps, make a comparison between the post-decrease water supply amount and the requested flow rate, and permit or prohibit stopping of operation of the pump according to a result of the comparison.   
     
     
         7 . The heat source system according to  claim 1 , wherein
 at least one of the plurality of pumps is a VFD pump, and   the controller processing hardware is configured to update a VFD command value for the VFD pump that is operating, based on a difference between the requested flow rate and the current water supply amount.   
     
     
         8 . The heat source system according to  claim 7 , wherein
 the controller processing hardware is further configured to:   determine a VFD command value of the VFD pump, based on a difference between a pressure of a pipe connected to the VFD pump and a set value of the pressure;   determine the current water supply amount by multiplying a flow rate set for the VFD pump that is operating by a rotation rate;   make a comparison between the requested flow rate and the current water supply amount, and calculate a lower limit value of the VFD command value so as to compensate for the difference between the requested flow rate and the current water supply amount when the requested flow rate is larger; and   update the VFD command value with the lower limit value when the lower limit value is larger than the VFD command value.   
     
     
         9 . The heat source system according to  claim 1 , wherein
 the controller processing hardware is configured to make a comparison between the requested flow rate and the maximum water supply amount, and, when the requested flow rate is larger, select a heat source unit whose operation is to be stopped from among the plurality of heat source units so that the maximum water supply amount satisfies the requested flow rate.   
     
     
         10 . The heat source system according to  claim 9 , wherein
 the controller processing hardware is configured to:   make a comparison between the requested flow rate and the maximum water supply amount, and selectively perform first control and second control when the requested flow rate is larger;   in the first control, select a heat source unit whose operation is to be stopped from among the plurality of heat source units so that the maximum water supply amount satisfies the requested flow rate; and   in the second control, select a heat source unit whose operation is to be stopped from among the plurality of heat source units so that the maximum water supply amount satisfies the requested flow rate and a change in the requested flow rate is minimum.   
     
     
         11 . The heat source system according to  claim 1 , wherein
 the controller processing hardware is configured to calculate a post-increase requested flow rate from the requested flow rate, based on information on a heat source unit scheduled to start operation among the plurality of heat source units, make a comparison between the post-increase requested flow rate and the maximum water supply amount, and permit or prohibit a start of operation of the heat source unit according to a result of the comparison.   
     
     
         12 . The beat source system according to  claim 1 , wherein
 the controller processing hardware is configured to make a comparison between the requested flow rate and the maximum water supply amount, and, when the requested flow rate is larger, limit a capacity of an operating heat source unit among the plurality of heat source units.   
     
     
         13 . The heat source system according to  claim 1 , wherein
 the controller processing hardware is configured to:   make a comparison between the requested flow rate and the maximum water supply amount, and selectively perform third control and fourth control when the requested flow rate is larger;   in the third control, select a heat source unit whose operation is to be stopped from among the plurality of heat source units so that the maximum water supply amount satisfies the requested flow rate; and   in the fourth control, limit a capacity of an operating heat source unit among the plurality of heat source units.   
     
     
         14 . The heat source system according to  claim 13 , wherein
 the controller processing hardware is configured to perform the fourth control when the requested flow rate is larger than the maximum water supply amount.   
     
     
         15 . The heat source system according to  claim 13 , wherein
 the controller processing hardware is configured to perform the third control when the requested flow rate is larger than the maximum water supply amount and the capacity of the operating heat source unit among the plurality of heat source units is lower than a predetermined lower limit value.   
     
     
         16 . The heat source system according to  claim 13 , wherein
 the controller processing hardware is configured to:   selectively perform fifth control and sixth control as the third control when the requested flow rate is larger than the maximum water supply amount and the capacity of the operating heat source unit among the plurality of heat source units is lower than a predetermined lower limit value;   in the fifth control, select a heat source unit whose operation is to be stopped from among the plurality of heat source units so that the maximum water supply amount satisfies the requested flow rate; and   in the sixth control, select a heat source unit whose operation is to be stopped from among the plurality of heat source units so that the maximum water supply amount satisfies the requested flow rate and a change in the requested flow rate is minimum.