JPH043832A - Heat accumulating amount calculating method - Google Patents

Abstract

PURPOSE:To eliminate useless operation of a heat source device by a method wherein a heat accumulating amount in a heat accumulating tank is determined based on a difference between a tank water temperature and a predicted return water temperature from a heat emitter and a tank water amount. CONSTITUTION:A thermal load amount Qi at an n-step before a present time is predicted, a thermal load factor Xi being a ratio between a predicted thermal load amount Qi and a plan maximum thermal load amount Qpeak is determined, and an allowable water feed temperature TC to an air conditioner is decided. After, through comparison of a tank water temperature TST with an allowable feed water temperature TC, it is conformed that the tank water temperature TST exceeds the allowable feed water temperature TC, a difference DELTAT between the tank water temperature TST and a predicted temperature TSR of return water from an air conditioner is determined by using a thermal load factor Xi. A heat accumulating amount QST in a heat accumulating tank is calculated by multiplying DELTAT and a tank water amount FST in a heat accumulating tank. This method provides an accurate effective quantity of heat and performs use less operation of a heat source device.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a heat storage amount calculation method for calculating the heat storage amount in a heat storage tank.

[Conventional technology]

Building air conditioning systems equipped with heat storage tanks are becoming more common. Since thermal energy can be stored, adopting a heat storage tank in an air conditioning system can contribute to the effective use of energy.

FIG. 6 shows a schematic configuration example around the heat storage tank.

In the figure, 1 is a heat pump as a heat source device, 2
3 is an air conditioner as a heat radiator, and 3 is a heat storage tank using water as a medium. The heat storage tank 3 is the first heat storage tank 3 to the 100th heat storage tank 3-
1°. and a heat storage tank 3-1~3°. There is a partitioned passageway.
4-99.

That is, the hot water from the heat storage tank 3-1oo is heated by the heat pump 1 and then discharged to the heat storage tank 3-1, and the hot water from the heat storage tank 3-2 to 3-7. After that, the heat storage tank 3-1°. It led to
Heat is stored by circulating through this route. On the other hand, after the hot water from the heat storage tank 3-5 is radiated by the air conditioner 2, it is heated to the heat storage tank 3-3°. and is discharged to the heat storage tank 3-7. ~ 3-2 to the heat storage tank, and by circulating through this route, heating is performed. Therefore, the heat storage tank 3-1 side is a high temperature tank, and the heat storage tank 3-5°. The side will be a low temperature chamber.

FIG. 7 is a diagram in which the horizontal axis represents the tank order of the heat storage tanks 3-2 to 3-10°, and the vertical axis represents the tank water temperature.

In this figure, if the heat storage tank lower limit temperature TL is determined, the heat storage tank lower limit temperature TL, each type of heat storage type heat tank water temperature TST (J), the tank water amount FST (J) of each heat storage tank, and the specific heat α are calculated as follows (1
)2, the total amount of heat stored in the heat storage tank 3 can be calculated.

Σ(TST (J) TL)XFST (J) It becomes possible to efficiently carry out nighttime heat storage operation during the time zone, and compensatory heat storage operation that makes up for the insufficient amount of nighttime heat storage during the day.

[Problem to be solved by the invention]

However, according to such a method of calculating the amount of heat storage, there is no clear regulation regarding the lower limit temperature TL of the heat storage tank, and the lower limit temperature TL of the heat storage tank is set to a high value within a range that does not cause any trouble.

For this reason, a problem has arisen in that the effective heat storage amount is underestimated, and the heat pump 1 is operated in vain.

[Means to solve the problem]

The present invention was proposed to solve such problems, and it predicts the heat load amount n steps ahead from the current time, and calculates the heat load that is the ratio of the predicted heat load amount and the design maximum heat load amount. After determining the allowable water supply temperature to the heat radiator and confirming that the temperature of the water in the heat storage tank is within the limit range of this allowable water supply temperature, The difference ΔT from the expected return water temperature is calculated based on the heat load rate, and this ΔT
The amount of heat stored in the heat storage tank is calculated based on the amount of water in the tank and the amount of water in the tank.

[Effect]

Therefore, according to the present invention, based on ΔT (the difference between the tank water temperature located within the limit range of allowable water supply temperature and the expected return water temperature that may be located outside the limit range of allowable water supply temperature) and the tank water amount,
The amount of heat storage is required.

〔Example〕

Hereinafter, the heat storage amount calculation method according to the present invention will be explained in detail.

First, in the present invention, in order to predict the time load (heat load) in a building, the literature: Box & Jenkins CBox & Jenkins: Ti
me 5eries Analysis--forca
sting controlHoIden-dayc1
The ARMA (autoregressive moving average) model described in this article is adopted, and the ARIMA model formula which adds periodicity and trend characteristics to this ARMA model is used. In other words, the following formula has periodicity and trend characteristics. ARIMA model with trend characteristics (2) However, A: two autoregressive parameters, B8: moving average parameter, x(t): predicted load for I step ahead, x(
t-1): Actual load at current time, x(t-z): Actual load one step before, e(t-+): Actual load at current time predicted one step before.

The following equation (3) is the above equation (2) when p=25. q
=25, and the autoregressive parameter A1 and moving average parameter B1 are A + = 0.7980. A
z ~A 23-〇, 0000. A,,--1,
0000, At5=0.7980. Bl=-0,30
90,Bz ~B2. =O, 0OOOO, B2. =-0,
A when set as 6399, B, , = 0.1977
This is an RTMA model formula.

x(t) 0.7980x(t,+) X(t-Z
4) 0.7980X(t-25)=e(t) 0
．． 3090e(t-+) 0.6399e(t-za
)+0.1977e (t-zs) (3) However, in the above formula, et=Q, autoregressive parameter A, and moving average parameter B.

is calculated based on actual load data for the past 10 days.

Next, specific time load prediction using this ARIMA model formula will be explained. Now, in Fig. 2, assuming that the current time is 22:00 on Thursday, the hourly actual load data from the current time until 24 hours ago is substituted into the ARIMA model equation (formula (3) above). Ru. That is, the actual load data at the current time is substituted by The predicted load x(t) for one hour ahead (23:00) is determined. Next, hourly actual load data from 23:00 predicted load x(t) until 23 hours ago is substituted into the ARIMA model equation in the same manner. In other words, the predicted load x(t) at 23:00 is substituted as x(t+), the actual load data 22 hours ago is substituted as x(t - z4), and the actual load data 23 hours ago is substituted as X(t - zs). and the predicted load x(t) for 2 hours ahead (24 hours)
is found. Thereafter, by repeating this process, the predicted load up to 22:00 on Friday is sequentially determined, and the basic pattern at the current time is created as shown by the dotted chain line in the figure. This operation is repeated every time the current time advances by one hour, and therefore the basic pattern is updated each time the current time advances by one hour.

If the current time is 22:00 on Friday, the autoregressive parameter A and the moving average parameter B in the ARIMA model equation up to that point.

A new estimate is made. That is, the actual load data from 22:00 on Thursday to 22:00 on Friday is replaced with the final actual load data for the past 10 days, and using this actual load data for the past 10 days, the autoregressive parameters A, And the moving average parameter B1 is newly estimated.

FIG. 1 is a flowchart showing a control operation in the air conditioning system shown in FIG. 6, to which an embodiment of the heat storage amount calculation method according to the present invention is applied.

Now, in Figure 2, the current time is Thursday at 22:00,
It is assumed that the predicted heat loads until 22:00 on Friday have been sequentially determined and a basic pattern has been created. In this case, first in step 101, the predicted heat load amount for one hour ahead, that is, the predicted heat load amount Q1 at 23:00 is obtained. Then, it is confirmed that ■ is 24 or less (I≦24) (step 102), and the process proceeds to step 103. here,
(2) is determined such that 23:00 is 1.24:00 and 2:10 is 3 for the predicted time of the predicted heat load amount obtained in step 101. In step 103, the predicted heat load amount Q
The heat load factor X1 is obtained by dividing , by the maximum heat load amount Q□. Here, the maximum heat load Q p a k
is determined as the rated value (design maximum heat load) of the amount of heat load that the heat pump 1 can exert in one hour, and is set to 290 Mcal/H in this example. After determining the heat load factor X1 in step 103, this heat load factor
1 to find the allowable water supply temperature TC to the air conditioner 2 from the characteristic table TBI shown in FIG. Characteristic table T
In BI, the relationship between the heat load factor X8 and the allowable water supply temperature TC is determined in advance based on experience or the like. In addition, at the same time as deriving the allowable water supply temperature TC from this characteristic table TBI, the allowable water supply temperature T to the air conditioner 2 is calculated from the memory table TB2 shown in FIG. 3 using the predicted time of the predicted heat load amount Q.
Find C. In the storage table TB2, the relationship between the predicted time and the allowable water supply temperature TC is predetermined based on experience or the like. Then, the allowable water supply temperature TC derived from the characteristic table TBI is compared with the allowable water supply temperature TC derived from the memory table TB2, and the higher allowable water supply temperature TC is selected and set as the allowable water supply temperature TC(1). Moreover,
Proceed to step 104.

In step 104, assuming that the heat storage tank rank J is 1, J≧1
After confirming whether the value is 00 or not, the process proceeds to step 105. In step 105, for the first heat storage tank, the tank water temperature TST (1) is compared with the allowable water supply temperature TC (1). Then, in step 105, it is confirmed that the tank water temperature TST(1) is higher than the allowable water supply temperature TC(1) (TST(1)≧TC(1)), that is, the allowable water supply temperature TC( After confirming that the tank water temperature TST (1) is within the limit range of 1), the process proceeds to step 106. In step 106, the heat load factor
Using, from the characteristic table TB3 shown in Fig. 4, the tank water temperature TST (1) and the expected return water temperature T from the air conditioner 2
Find the difference ΔT(1) from SR(1). Then, the process proceeds to step 107, where ΔT(1) is multiplied by the tank water amount FST (1) in the heat storage tank 3-1 to calculate the heat storage amount QST (1) in the heat storage tank 3-1.

Now, considering the calculated heat storage amount QST (1), the allowable water supply temperature TC (1) is the heat load factor X,
Alternatively, it is clearly determined based on the predicted time (23:00). In addition, the tank water temperature TST(1) located within the limit range of the allowable water supply temperature TC(1) and the allowable water supply temperature TC(1)
The difference ΔT(1) between the expected return water temperature TSR(1) which may be located outside the limit area is calculated, and the difference between this ΔT(1) and the tank water volume FS
The heat storage amount (1) is calculated by multiplying by T(1).

Therefore, as can be seen by replacing the allowable water supply temperature TC(1) with the heat storage tank lower limit temperature T mentioned in the prior art, it is clear that within ΔT(1), the temperature outside the limit range of the allowable water supply temperature TC(1) is The heat storage amount corresponding to the located portion is added to the effective heat storage amount, contributing to an increase in the calculated effective heat storage amount.

Then, the process proceeds to step 108, where the new predicted heat load amount Q1 is obtained by subtracting the heat storage amount QST (1) from the predicted heat load amount Q, and the heat storage tank rank J is increased by 1 (step 1).
09), the predicted heat load amount Q10 value is checked (step 110). Here, if the predicted heat load amount Q+ is ≧O, it is determined that the predicted heat load amount Q obtained in step 101 cannot be covered only by the heat storage amount QST (1) in the heat storage tank 3-1. , return to step 104, and step 1051
The amount of heat storage QST (2) in the heat storage tanks 3 to 2 is calculated through step 06, and the heat storage tank ranking is moved up in the same manner until the predicted heat load lid Q1 in step 110 becomes O or less, and the above operation is performed. repeat.

When the predicted heat load amount Q1 at step 110 becomes 0 or less, I, which indicates the predicted time, is increased by 1 (step 111).
, returns to step 101 and obtains the predicted heat load amount Q2 two hours ahead of the current time, that is, at 24 o'clock. Then, in step 103 after passing through step 102, the predicted heat load amount Q2 is divided by the maximum heat load amount Q p e a k to obtain the heat load factor X2. After determining the heat load factor x 2 in step 103, the allowable water supply temperature TC is determined from the characteristic table TBI using this heat load factor TC and the lower allowable water supply temperature T
After selecting C and setting it as the allowable water supply temperature TC(2), the process proceeds to step 104. Here, the heat storage tank rank J at step 104 has been moved up to a heat storage tank rank N that can cover the predicted heat load amount Q1. Therefore, in step 105 after passing through step 104, the tank water temperature TST (N) and the allowable water supply temperature TC (2) are compared for the heat storage tank 3-H, and the tank water temperature TST (N) is determined to be the allowable water supply temperature TC. (
2) After confirming that it is higher than Step 7, step 106
Proceed to. In step 106, the difference ΔT (N) between the tank water temperature TST (N) and the expected return water temperature TSR (N) is determined from the characteristic table TB3 using the heat load factor X2.

Then, the process proceeds to step 107, where ΔT (N) is multiplied by the tank water amount FST (N) in the heat storage tank 3-N, and
Calculate the heat storage IQsT (N) at −N. Then, the process proceeds to step 108, and from the predicted heat load amount Q2, the heat storage amount QS is calculated.
T (N) is subtracted to obtain a new predicted heat load amount Q2, the heat storage tank rank J is increased by 1 (step 109), and the value of the predicted heat load amount Q2 is checked (step 110).
. Here, if the predicted heat load amount Q, is ≧0, it is determined that the predicted heat load tQ2 obtained in step 101 cannot be covered only by the heat storage amount QST (N) in the heat storage tank 3□,
Returning to step 104, the process goes through steps 105 and 106, and the heat storage tank 3. . Calculate the amount of heat storage QST (N+1) at step 110, and calculate the predicted heat load amount QST (N+1) at step 110 in the same manner.
The heat storage tank rank is moved up and the above-mentioned operation is repeated until 2 becomes O or less.

When the predicted heat load amount Q2 at step 110 becomes 0 or less, I, which indicates the predicted time, is increased by 1 (step 111).
, returns to step 101, obtains the predicted heat load amount Q3 for three hours ahead of the current time, that is, 1 o'clock, and repeats the above-mentioned operation in the same manner until ■ exceeds 24 in step 102.

In step 102, when I exceeds 24, that is, when it is determined that the heat storage tank 3 can cover the predicted heat load amount Q for 1 hour ahead to the predicted heat load amount Q24 for 244 hours ahead, the heat pump 1 is in operation. If so, the operation is stopped (step 112) and the predicted
The relationship between iQ, ~Qza and the possible heat storage tank ranks is displayed as a heat storage potential screen. Figure 5 shows
This is an example of a heat storage potential screen when the current time is 15:00 and the heat radiation completion time is 22:00. In the figure, the solid line shows the tank water temperature TST (J), the - dotted line shows the allowable water supply temperature TC (i), the two-dot chain line shows the return water temperature TSR (J) as an expected value, and the horizontal axis shows the heat storage tank rank. It shows. According to the heat storage potential screen shown here, the predicted heat load amount QI8 at 16:00 in divided areas 1 to 3 on the screen is from heat storage tanks 3- to 3-1. The predicted heat load QI9 at 17:00 is covered by the heat storage amount from the heat storage tank 3-16 to 3-3°. It is possible to visually grasp the relationship between the load amount and the ranking of heat storage tanks that can cover it.

In addition, in step 105 shown in FIG. It is determined that it is not possible to obtain a sufficient temperature difference from the return water temperature, and the operation of heat pump 1 is permitted (step 114). In other words, if heat pump 1 is not in operation, it is assumed to be operated. , displays the heat storage potential screen until the tank water temperature TST (J) reaches the allowable water supply temperature TC (i) or less (Step 11
3). Furthermore, in step 104 shown in FIG.
If the heat storage tank rank J exceeds 100 (J≧100), the current heat storage tank 3-1 to 3-1°. It is determined that the amount of heat stored at 10:00 cannot cover the predicted heat load until 10:00 p.m., and the operation of heat pump 1 is permitted (step 114).
, a heat storage potential screen up to the predicted time that can be met is displayed (step 113).

〔Effect of the invention〕

As is clear from the above explanation, according to the heat storage amount calculation method according to the present invention, ΔT (the difference between the tank water temperature that is within the limit range of allowable water supply temperature and the expected return water temperature that may be located outside the limit range of allowable water supply temperature) Since the heat storage amount is calculated based on the difference ΔT) and the tank water volume, the heat storage amount corresponding to the portion of ΔT that is outside the limit range of the allowable water supply temperature is added to the effective heat storage amount, and the calculated effective heat storage amount is Based on this calculated accurate effective heat storage amount, it becomes possible to operate the heat source equipment without waste.

[Brief explanation of the drawing]

Fig. 1 is a flowchart showing the control operation in an air conditioning system using an embodiment of the heat storage amount calculation method according to the present invention, and Fig. 2 explains specific hourly load prediction using ARIMA model 2. Figure 3 shows the characteristic table TBI and memory table TB2 for determining the allowable water supply temperature.
Figure 4 shows the difference ΔT between the tank water temperature and the expected return water temperature.
Figure 5 is a diagram showing an example of the heat storage potential screen when the current time is 15:00 and the heat radiation completion time is 22:00. Figure 6 is a schematic diagram of the area around the heat storage tank. FIG. 7 is a diagram showing a typical configuration example, with the horizontal axis representing the heat storage tank rank and the tank water temperature along the vertical axis. 1... Heat pump, 2... Air conditioner, 3゜3-, ~
3-+o. ...heat storage tank, TBI, TB3...characteristic table, TB2...memory table.

Claims (1)

[Claims] After predicting the amount of heat load n steps ahead from the current time, finding the heat load factor which is the ratio of this predicted amount of heat load to the maximum design heat load, and determining the allowable water supply temperature to the heat radiator, After confirming that the tank water temperature of the heat storage tank is within the limit range of this allowable water supply temperature, the difference ΔT between this tank water temperature and the expected return water temperature from the heat radiator is determined based on the heat load rate. A method for calculating the amount of heat storage, characterized in that the amount of heat stored in the heat storage tank is calculated based on ΔT and the amount of water in the tank.