JPS5952733B2 - How to control the number of air conditioning heat sources in operation - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling the number of operating air conditioning heat sources, and more particularly to a control method for connecting a plurality of heat source devices in parallel and controlling the number of operating heat source devices in accordance with the air conditioning load.

Conventionally, in air conditioners that connect multiple heat source devices such as refrigerators, boilers, or absorption type water chillers/heaters in parallel and supply medium to the air conditioner, there is a A temperature detector is installed, and the heat output of each heat source device is controlled in stages according to the detected temperature value.

In such a conventional technique, stable control can be performed when the heat capacity is relatively large, but the response delay becomes large. Furthermore, if the heat source device has a long start-up time, the number of times the heat output is switched during low load is increased, which not only makes stable operation impossible but also reduces the overall thermal efficiency. An object of the present invention is to provide a control method that solves the above-mentioned technical problems by operating an optimal number of heat source devices according to the air conditioning load.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a system diagram of an embodiment of the present invention. Heat source equipment Al, A2, etc., such as absorption type water chiller/heater, arranged in parallel with multiple units.
...Ai and the air conditioner 1 are connected via an outgoing pipe 2 and a return pipe 3 to form a closed circuit. Each heat source machine Al, A
2. The medium, such as water, heated or cooled by Ai circulates through the closed circuit, and in the air conditioner 1, heating or cooling is achieved by radiating heat or cooling. Temperature detectors B1, B2, ...Bi are installed at each outlet or inlet of each heat source machine Al, A2, ...Ai.
are provided respectively, and these temperature detectors B1,
B2,...The detected value of Bi is for each heat source machine A1, A2
,...Controllers C1 and C individually corresponding to Ai
2, . . . are respectively input to Ci. Each controller C1, C2,...Ci has a temperature sensor B1,
B2, ...... Each heat source device A1 according to the detected value of Bi
, A2, . . . control the heat output of Ai. In addition,
The control positions of each heat source device A1, A2, . . . Ai are set to the same or close values, for example 10
It is controlled in two stages: 0% and 50%. In this way, the heat output of each heat source device A1, A2, . Change. Moreover, the operation and stop of each heat source device A1, A2, . . . Ai is controlled by the control means 4. Furthermore, the control means 4 also has a function of controlling the heat output of each heat source device A1, A2, . . . Ai to be constant. As shown in FIGS. 2 and 3, this control means 4 controls the heat output of each heat source device A1, A2, . The heat source devices A1, A2, etc. in period T2 are detected respectively.
- Calculates the average heat output Ha of the entire Ai, and selects operation and stop of each heat source device A1, A2, . . . Ai in the next cycle T2 based on the average heat output Ha. Note that the period T2 may be a preset constant time, or each heat source device A], A2,...
...Period in which the heat output of Ai changes, for example, Fig. 2 3
As shown, the heat output of heat source device A1 is 100% → 50% →
The period may vary by 100%. During the period T2, the heat output of each heat source device A1, A2, . . . Ai is detected n times, and each heat source device A1, A2, .
The number of times the heat output of Ai is 100% is m1, m2, ・
....mi, the ratio E of the time during which the heat output of all i heat source devices is 100% during the period T2 is
is expressed by the following equation (1).

Further, the ratio E'' at which the heat output of the entire heat source device is 50% is expressed by the following equation (2).

Here, mth, m2'', . . . mi'' respectively indicate the number of times that the heat output of each heat source device A1, A2, . . . Ai is 50%.

In this way, the ratio E of each thermal output to the period T2,
After determining E'', the average heat output H in period T2 can be obtained by calculating according to equation (3).
After determining the average heat output H of the entire heat source device in period T2 as described above, the average heat output H in the next period T2 is estimated based on the average heat output H, and based on the estimation result, heat source device A1 , A2, . . . , the transfer and stop of Ai are selected.

Referring to FIG. 4, if the average heat output from time t2 to time t3 is H0, and the average heat output from the previous time t1 to time t2 is H1, then the average heat output from time t2 to time t3 is H1. The average heat output H2 in the next cycle is
It is predicted as shown in FIG. 4 and is expressed by equation (4). Note that although the actual average heat output does not change linearly as described above, it can substantially be sufficiently controlled by the predicted value shown in equation (4).

The control means 4 stores in advance the average thermal output and the number of operating units, and the number of heat source units A1, A2, . . . Ai to be operated is determined based on the predicted average thermal output value H2. selected.

For example, if j units are selected to operate in the next cycle T2 from time t3 to time t4, (1-j) heat source units A are stopped in that cycle T2.
In addition, the heat output of the remaining j heat source devices A is controlled in a stepwise manner by the function of each individually provided controller C.
Note that the control means 4 controls the rate of change in the average thermal output, that is, (
H2-HO)/T2 and the number of operating units are stored in correspondence, and the number of heat source units A1 between time t3 and t4 is
, A2, . . . A3 may be controlled.

Next, for ease of explanation, we will introduce two heat source machines A1 and A2.
Control of the number of operating units when they are connected in parallel will be explained with reference to FIG.

FIG. 5 1 shows the operating state of the heat source device A1, and FIG. 5 2 shows the operating state of the heat source device A2. The operation and stop of the heat source machines A1 and A2 are controlled according to the predicted average heat output value H2 in the period T2 of the two heat source machines A] and A2, and
The heat output of one of the heat source devices, for example A2, is controlled to be constant.

For example, if the average predicted heat output value H2 is HX% (HX>50
), each heat source device A1, A2 is operated at 50% or 100% heat output by the action of the controllers C1, C2 as shown by diagonal lines. Further, when the average predicted heat output value H2 is less than HX% and greater than or equal to HY% (HY50), one heat source device A2 is controlled to have a constant heat output of 50%. In this case, the heat output of the other heat source device A1 is controlled by the function of the controller C], and therefore the heat source device A1 is operated at 100% heat output for a relatively long time. Therefore, the number of times the thermal output of the heat source device A1 is switched during low load is reduced, and the thermal efficiency is improved accordingly. When the predicted average heat output value H2 further decreases to less than HY%, one heat source machine A2 is stopped and the remaining heat source machine A
Operation using only 1 is performed. In this case, the time for low thermal output operation with poor thermal efficiency is reduced and the time for high thermal output operation is increased, so that the overall thermal efficiency is improved. In addition, in the above-mentioned embodiment, a case was described in which control was performed at two positions of heat output of 50% and 100%, but each heat source device A1
, A2, . . . Ai may be controlled at two or more positions.

As described above, according to the present invention, the average heat output in a predetermined period of time or a period in which the heat output of the heat source device changes is calculated, and the average heat output in the next certain period or period is estimated and predicted. The number of operating units is selected based on the average heat output.

Therefore, the number of operating heat source devices is controlled as quickly as possible according to the air conditioning load, and the number of times the heat output is switched during low loads is reduced, and the overall thermal efficiency is improved accordingly.

[Brief explanation of drawings]

Fig. 1 is a system diagram of an embodiment of the present invention, Fig. 2 is a diagram showing the operating status of each heat source device A], A2, ... Ai, and Fig. 3 is a diagram showing the heat output detection evening timing. FIG. 4 is a flowchart for explaining the prediction of the average heat output, and FIG. 5 is a diagram for explaining the operating state of the two heat source machines A1 and A2.

Claims (1)

[Claims] 1. A closed circuit is constructed by connecting a plurality of heat source devices arranged in parallel and each having a function of controlling heat output stepwise according to the medium temperature at the outlet or inlet. In a method for controlling the number of operating air conditioning heat sources, which is configured so that the heat output control device of each heat source device can be read individually, the control means for controlling the operation and stop of each heat source device is set in a predetermined manner. During a certain period of time or within a cycle in which the heat output of the heat source devices changes, the average heat output of all heat source devices is calculated using the control positions resulting from stepwise control of the heat output of multiple heat source devices according to the medium temperature. is calculated, and the average heat output in the next fixed time or cycle is estimated by comparing the heat output with the average heat output in the previous fixed time or cycle, and the heat output or the heat output is calculated. 1. A method for controlling the number of operating air conditioning heat sources, characterized in that the number of operating units for the next certain time or period is selected based on the number of operating units determined and set in accordance with the rate of change of the number of operating units. 2. The air conditioner according to claim 1, wherein the control means has a function of controlling the operation and stopping of each heat source device, as well as a function of controlling the heat output of the operating heat source device to a constant value. Method for controlling the number of operating heat sources.