JP7506487B2 - Heat source device control device - Google Patents

Description

The present invention relates to a control device for a heat source machine that controls the operation of multiple outdoor units provided in the heat source machine.

In a heat source machine equipped with multiple outdoor units, a technique is known in which when the load is less than 100%, only some of the outdoor units are selectively put into operation, and the operation order is rotated each time the operation time of each outdoor unit reaches a predetermined time, thereby equalizing the operation time of the multiple outdoor units (see, for example, Patent Document 1).

Japanese Patent Application Laid-Open No. 10-281577

By rotating the operating time according to the operating time of the outdoor unit as described above, it is possible to equalize the cumulative operating time of each outdoor unit. However, the inventors of the present application realized that, for example, the operating efficiency of each outdoor unit is affected by operating conditions such as various environmental conditions, and that equalizing the operating times does not necessarily improve the operating efficiency of each outdoor unit or the overall operating efficiency.

In view of the above, the present invention aims to improve the operating efficiency of heat source machines.

In order to achieve the above object, the present invention provides
A control device for a heat source machine having a plurality of outdoor units arranged adjacent to each other and capable of variably setting a load factor,
The heat source machine is characterized in that, when the load of the entire machine is operated at partial load, the load rate of each outdoor unit is set so that the load rate of some outdoor units differs from that of other outdoor units.

This allows some outdoor units to operate at a high COP, improving the operating efficiency of the entire heat source unit.

The present invention can improve the operating efficiency of the heat source machine.

1 is an explanatory diagram showing a schematic configuration of an air conditioning system including a heat source unit. 4 is a graph showing an example of the relationship between the load factor and the COP of an outdoor unit. 10 is a graph showing an example of COP according to settings of the load factor of the outdoor unit.

(General configuration of the air conditioning system)
An air conditioning system including a heat source unit includes an outdoor unit module 110 including a plurality of outdoor units 111 such as air-cooled heat pumps, as shown in FIG. 1. The outdoor units 111 supply cold water and hot water to a secondary air conditioner 141 via a supply water pipe 121 and an inverter pump 131, respectively, and recover the cold water and hot water via a return water pipe 151. A free bypass circuit 161 is provided between the supply water pipe 121 and the return water pipe 151 to balance the flow rate of cold water and hot water flowing to the heat source unit side and the load side, and an expansion tank 174 is provided in the return water pipe 151. In addition, temperature sensors 171 and 172 and a flow rate sensor 173 are provided in the supply water pipe 121 and the return water pipe 151, and the operation load is calculated.

In addition, each outdoor unit is equipped with a temperature sensor (not shown) that detects the temperature of the cold water at the cold water outlet connected to the supply water pipe 121, and the load rate can be controlled by adjusting the temperature of the cold water at the cold water outlet to a predetermined set temperature.

The outdoor unit module 110 is controlled in operation by, for example, a module controller 211. Specifically, the module controller 211 determines the load factor (the ratio of cooling capacity to rated capacity) based on the water temperature and flow rate detected by, for example, the temperature sensors 171 and 172 and the flow rate sensor 173, and sets and controls the temperature of the cold water at the cold water outlet of the outdoor unit 111 so that the outlet temperature of the outdoor unit module 110 becomes the set temperature. Here, the set temperature of the cold water is made different for each outdoor unit 111 (or for each specified group), so that each outdoor unit can be operated at a different load factor. More specifically, for example, the set temperature and load factor of each outdoor unit 111 are controlled based on a predetermined pattern according to the load factor of the entire heat source machine and the outdoor air temperature, in response to an instruction from the central heat source controller 212.

(Example of Control of Load Rate of Each Outdoor Unit Module 110)
The COP of the outdoor unit module 110, for example, during cooling operation, changes depending on the outdoor temperature and load factor as shown in Figure 2, and generally becomes higher as the outdoor temperature is lower and within a specified range where the load factor is smaller than 100%.

The outdoor units 111 constituting the outdoor unit module 110 are each, for example, composed of four unit devices connected in a predetermined direction, and the outdoor unit module 110 is composed of ten outdoor units 111 arranged adjacent to each other in a direction perpendicular to the predetermined direction. Furthermore, the outdoor unit module 110 as described above is installed, for example, on the roof of a building, and is often arranged surrounded by a building partially built on the roof or a wall. For this reason, depending on the outside temperature, wind direction, wind speed, etc., heat accumulation may occur, and the operating conditions such as the flow of surrounding air may differ in each outdoor unit 111, resulting in a decrease or variation in COP. In particular, when adjacent outdoor units 111 are in operation at the same time, the flow rate of outside air flowing into each outdoor unit 111 may decrease, or the air discharged from the outdoor unit 111 may hit the building or the surrounding wall and become a downward flow, resulting in the intake of air with a higher temperature than the outside air, which tends to increase the temperature of the actually inhaled outside air.

For this reason, if the load factor of the entire heat source device is 80%, and all outdoor units 111 (unit numbers 1 to 10) are operated at a load factor of 80%, the COP of the outdoor units 111 near the center of the ten outdoor units 111 may decrease, as shown by the dashed line in FIG. 3 as operation pattern 1. Therefore, if the outdoor units 111 with unit numbers 4 and 7, which are located near the center of the series of ten outdoor units 111 and spaced apart from each other, are operated at a load factor of 40% and the other outdoor units at a load factor of 90%, even if the load factor of the entire heat source device is the same 80%, the COP of the outdoor units 111 with unit numbers 4 and 7 will increase by about 25%, for example from 3.2 to 3.3 in operation pattern 1 to 4.0 to 4.1 in operation pattern 2, due to the smaller load factors.

Moreover, the COP of the outdoor units 111 with unit numbers 3, 5, 6, and 8 adjacent to the outdoor units 111 with unit numbers 4 and 7 also increases. This is thought to be because the load factor of the outdoor units 111 with unit numbers 4 and 7 is reduced, reducing the amount of outdoor air drawn into these units, which in turn increases the amount of outdoor air drawn into the other outdoor units 111 and reduces their temperature.

On the other hand, for example, the COP of outdoor units 111 with unit numbers 1, 2, 9, and 10 has slightly decreased, but this is thought to be largely due to the load factor being increased from 80% to 90%. However, the increase in COP caused by operating other outdoor units 111 in a load factor range of, for example, 30 to 50% is greater than the decrease in COP caused by slightly increasing the load factor in such a high load factor range, so the average COP of the entire heat source equipment can be increased by approximately 5 to 6%, for example from 3.4 to 3.6.

The above-mentioned effect of increasing COP can be easily achieved by setting the load rate of each outdoor unit 111, for example, when the load rate of the entire heat source equipment is 60% or more and the outdoor air temperature is 30°C or more in cooling operation or 5°C or less in heating operation.

The load rate can be set as described above, specifically, by setting the temperature of the cold water at the cold water outlet of each outdoor unit 111. That is, for example, if the cold water inlet temperature of the outdoor unit module 110 is 17°C and the cold water outlet temperature is 7°C when the load rate is 100%, then if the load is 80%, the cold water inlet temperature will be 15°C. Therefore, the outdoor units 111 with unit numbers 4 and 7 can be operated at a load rate of 40% by setting the cold water outlet temperature to 11°C, while the other outdoor units 111 can be operated at a load rate of 90% by setting the cold water outlet temperature to 6°C.

(Other matters)
The setting of the load rate of each outdoor unit 111 as described above is not limited to being controlled based on a preset set temperature or load rate pattern, but may be performed by, for example, calculating the COP of each outdoor unit 111 based on operation information such as load, and preferentially operating, for example, multiple outdoor units 111 with a small COP at a small load rate. Such control can be performed, for example, by using a separately provided PLC to calculate the COP of each outdoor unit 111 based on operation information, outdoor temperature, load heat amount, etc., and having the module controller 211 set the load rate via a central heat source controller. In addition, multiple outdoor units whose load rate is set smaller than the other outdoor units may be selected based on a unit with a large defrost occurrence time ratio (time during which the unit is defrosting/operation time) during heating operation in winter.

In addition, commands indicating the load rate and chilled water outlet temperature to be set for each outdoor unit 111 may be sent from the remote monitoring center to the module controller 211 via the Internet and the central heat source controller 212, etc., and the module controller 211 may control the load rate and the like of each outdoor unit 111 in response to the commands.

As described above, by controlling the load rate to be different for each outdoor unit 111 or each group thereof, the operating efficiency of the heat source unit can be easily improved.

REFERENCE SIGNS LIST 110 Outdoor unit module 111 Outdoor unit 121 Supply water piping 131 Inverter pump 141 Air conditioner 151 Return water piping 161 Free bypass circuit 171, 172 Temperature sensor 173 Flow rate sensor 174 Expansion tank 211 Module controller 212 Central heat source controller

Claims (1)

A control device for a heat source machine having a plurality of outdoor units arranged adjacent to each other and capable of variably setting a load factor,
When the load of the entire heat source device is operated at a partial load, the load factor of some of the outdoor units is set to be large and the load factor of the other outdoor units is set to be small, and at least one combination of an outdoor unit with a large load factor and an outdoor unit with a small load factor adjacent to each other is present ,
A control device for a heat source machine, characterized in that, when the load of the entire heat source machine is operated at partial load, the load rate of each outdoor unit is set so that the load rate of some outdoor units differs from that of other outdoor units, and one or more outdoor units with a high load rate are arranged between outdoor units with low load rates, thereby increasing the amount of outside air drawn into the outdoor units with a high load rate .

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