JP2760293B2 - How to control the number of fluid heaters - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to the installation of a plurality of fluid heaters such as a hot water boiler, a heat medium boiler, a heat exchanger, an absorption refrigerator and the like. The present invention relates to a number control method for automatically controlling the number of operating units.

[0002]

2. Description of the Related Art As is well known, a hot water boiler multi-can installation system in which a plurality of hot water boilers are installed in parallel, and the number of operating hot water boilers is automatically controlled according to the load situation. It has been implemented. This hot water boiler multi-can installation system can operate each hot water boiler with high efficiency compared to installing one large-capacity hot water boiler. It has the advantage of excellent responsiveness to fluctuations.

[0003]

However, in the above multi-can installation system, when the start and stop of each hot water boiler are synchronized, a vibration phenomenon occurs in the hot water temperature, and the hot water temperature is not stabilized, and the hot water boiler is not stable. However, there is a problem that the number of times of starting and stopping the hot water boiler becomes excessive and the life of each attached device is shortened.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and suppresses synchronization of starting and stopping of a fluid heater in a multi-can installation system of a fluid heater such as a hot water boiler. It is another object of the present invention to reduce the fluctuation range of the supply temperature of the fluid. That is, according to the present invention, a plurality of fluid heaters are installed in parallel, these fluid heaters and a load are connected by a fluid supply path and a fluid return path, and the number of operating the fluid heaters is set in a predetermined priority order. According to the number control method according to the load condition, the number of operation permitted is determined according to the load condition, and an operation permission signal is output to the fluid heater by the operation permitted number, fluid heater which receives this operation permission signal, the heating of the fluid when the fluid temperature T has reached the set temperature T _B is stopped, when the fluid temperature T is lowered by Darensharu value [Delta] T _B content than the set temperature T _B Heating of the fluid is started, and the differential value ΔT _B of the fluid heater having the higher priority is set to be larger than the differential value ΔT _B of the fluid heater having the lower priority.

[0005]

[Action] The present invention, by setting the differential value [Delta] T _B of high priority fluid heater greater than the differential value [Delta] T _B of the lower priority fluid heater, and start-stop of the high priority fluid heater The start and stop of the fluid heaters of lower priority are not synchronized, and the supply temperature of the fluid supplied to the load through the fluid supply path is stabilized.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below. In FIG. 1, a plurality of fluid heaters 1 are installed in parallel, and these fluid heaters 1 and a load 2 are connected by a fluid supply path 3 and a fluid return path 4.
Are controlled in accordance with the status of the load 2. As the fluid heater 1, a hot water boiler, a heat medium boiler, a heat exchanger, an absorption refrigerator, or the like is applied. A circulation pump 5 is inserted in the fluid return path 4.
This circulation pump 5 may be inserted into the fluid supply path 3. The fluid supply path 3 is provided with a first temperature detector 6 for detecting a supply temperature To of the fluid. The fluid return path 4 is provided with a second temperature detector 7 for detecting a return temperature Ti of the fluid. Based on signals from these temperature detectors, the number of operating fluid heaters 1 is controlled according to a control procedure preset by the control device 8. Priorities are set in the fluid heater 1 in advance, respectively.
The operation of each fluid heater 1 is controlled according to this priority. The priority is set so that rotation is performed appropriately so that the operation time of each fluid heater is averaged.

With respect to the above configuration, an example of a specific number control method will be described. First, at the time of initial startup of the system, the number N of operation permitted fluid heaters 1 is calculated according to the following equation, and an operation permission signal is output to the fluid heater 1 by the number N of operation permission. N = M × (To _SET− Ti) / (T _B −Ti) M: Total number of fluid heaters 1 To _SET : Set temperature of fluid in fluid supply path 3 Ti: Return temperature of fluid in fluid return path 4 T _B : Set temperature of the fluid heater 1 As the operation permitted number N, a value rounded down to the decimal point is used. ON-OF of the fluid heater 1 which received the operation permission signal
F follows the set value set for each fluid heater 1. That is,
The heating of the fluid is stopped when the internal fluid temperature T reaches the set temperature T _B, and the heating of the fluid is started when the fluid temperature T falls below the set temperature T _B by the differential value ΔT _B.

Next, based on the supply temperature To of the fluid in the fluid supply path 3, when the supply temperature To is within a preset range, the current permitted number of operation is maintained, and the supply temperature To is set in advance. When the temperature falls below the range, the number of permitted units is increased by one, and when the supply temperature To exceeds the preset range, the number of permitted units is reduced by one. The determination of the increase or decrease in the number of operating units is performed at predetermined time intervals (for example, every 10 seconds). The above-mentioned preset range is:
The set temperature the To _SET of the fluid in the fluid supply channel 3 and the upper limit value, .DELTA.Tw (e.g., about 5 from the set temperature the To _SET
(° C) is the lower limit. When the value of the supply temperature To is within ΔTw, by maintaining the current permitted number of units, it is possible to prevent the fluid heater 1 from being uselessly started and stopped, and to stabilize the supply temperature To.

As the supply temperature To of the fluid in the above-described fluid supply path 3, the value measured by the first temperature detector 6 may be used. The average value To 'of the outlet temperature of the fluid at the outlet of the machine 1 may be obtained by the following equation, and the value may be used. That is, the N number of the fluid heater undergoing operation permission signal is out fluid heated to a set temperature T _B, the fluid returned through the fluid return path 4 return from the remaining M-N base Since the fluid flows out of the fluid heater 1 at the temperature Ti, the average value To 'can be obtained from the following equation. To '= {N × T _B + (M−N) × Ti} / M

[0010] As shown in FIG. 2, but the set temperature T _B of the fluid heating device 1 is set to substantially the same (e.g., 95
° C), and the differential value ΔT _B is set to a different value according to the priority order. In the embodiment shown in FIG.
Fluid heaters are installed, and up to the fourth highest priority fluid heater, the differential value ΔT _B is set to be large in descending order of priority (for example, the first priority is 10).
° C, the second priority is 8 ° C, the third priority is 6 ° C, the fourth priority is 4 ° C), and the differential values ΔT of the fifth and sixth priority fluid heaters thereafter _B is set to be substantially the same as the differential value ΔT _B of the fluid heater having the fourth highest priority. Of course, the differential values ΔT _B of all the fluid heaters may be made different in descending order of priority, or only the differential value ΔT _B of the fluid heater of the first priority may be set to a larger value.

As described above, when the differential value ΔT _B of the fluid heater 1 having a higher priority is set to be larger than the differential value ΔT _B of the fluid heater 1 having a lower priority, the start and stop of the fluid heater having a higher priority are performed. The start and stop of the fluid heaters having the lower priority are not synchronized, and the supply temperature of the fluid supplied to the load 2 through the fluid supply path 3 does not cause the vibration phenomenon. Therefore, the fluctuation range of the supply temperature can be reduced, and a fluid having a stable temperature can be supplied. This is particularly effective when the load is small.

[0012]

The present invention has the above configuration,
By setting the differential value of the high-priority fluid heater to be larger than the differential value of the low-priority fluid heater, the start and stop of the high-priority fluid heater and the low-priority fluid heater are started and stopped. Synchronization can be suppressed, and the occurrence of a vibration phenomenon in the supply temperature of the fluid can be effectively prevented. Therefore, a fluid having a stable temperature can be supplied to the load through the fluid supply path. Further, the number of times of starting and stopping of the entire system, particularly the number of times of starting and stopping of the high-priority fluid heater having a high operation rate is reduced, the fluctuation range of the supply temperature is reduced, and the life of each attached device is significantly extended.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an example of setting a differential value according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fluid heater 2 Load 3 Fluid supply path 4 Fluid return path 5 Circulation pump 6 1st temperature detector 7 2nd temperature detector 8 Control device

Claims (3)

(57) [Claims] 1. A plurality of fluid heaters 1 are installed in parallel, these fluid heaters 1 and a load 2 are connected by a fluid supply path 3 and a fluid return path 4, and the number of operating the fluid heaters 1 is reduced. This is a number control method for controlling according to the status of the load 2 in accordance with a preset priority, and determining the number of operation-permitted units according to the status of the load 2, and controlling the fluid heater 1 by the number of operation-permitted units. to output the operation permission signal, the fluid heating apparatus 1 which has received the operation permission signal, the heating of the fluid when the fluid temperature T has reached the set temperature T _B is stopped, the fluid temperature T is higher than the set temperature T _B characterized in that the heating of the fluid begins when lowered by Darensharu value [Delta] T _B content was set differential value [Delta] T _B of high priority fluid heating device 1 larger than the differential value [Delta] T _B of the lower priority fluid heating apparatus 1 Toss Units control method for a fluid heater. 2. The method for controlling the number of fluid heaters according to claim 1, wherein the differential value Δ
The T _B, the number control method for a fluid heater, characterized in that sequentially larger than the higher priority. 3. The method of controlling the number of fluid heaters according to claim 1, wherein the differential value Δ
A method for controlling the number of fluid heaters, wherein T _B is set to be larger by a predetermined number than the one with the highest priority and in descending order of the priority, and the remaining ones are set substantially the same.