JPH0942740A - Operation controller for heat storage air conditioner system and operation controlling method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the waste residue of heat storage and to take out a suitable amount of heat storage by calculating an estimated radiation possible amount by considering the radiating characteristics of a heat storage tank, comparing it with the predicted air conditioning load previously stored, and selecting the optimum operation mode of a heat storage air conditioner system based on it. SOLUTION: A radiation possible amount calculator 35 calculates radiation possible amount from the residual storage amount, brine exit temperature and temperature in tank by considering the radiation characteristics of an ice thermal storage tank stored in an ice thermal storage tank radiation characteristic memory 34. On the other hand, a thermal load predicting unit 32 predicts the thermal load based on weather conditions and past storage data. A predicted air conditioning load calculator 33 calculates predicted air conditioning load from the present time to next heat storage starting time based on the result of the unit 32. An operation mode judging unit 37 compares the calculated radiation possible amount with the predicted air conditioning load, and selects the optimum operation mode from the modes stored in an operation mode memory 36.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operation control device for a heat storage air conditioning system used for air conditioning of buildings.

[0002]

2. Description of the Related Art In recent years, a thermal storage air conditioning system has been developed in which heat is stored using latent heat or sensible heat in a thermal storage tank using inexpensive nighttime electric power, and air conditioning operation is performed using the amount of heat stored during the day. . In this case, in order to obtain a sufficient energy saving effect, it is necessary to completely use up the heat stored the night before on the next day. As an example of the technique for controlling the heat radiation from the heat storage tank, there is the technique disclosed in Japanese Patent Laid-Open No. 63-251743. This is because in an ice heat storage air conditioning system having a plurality of operation patterns with different heat dissipation rates, the amount of heat storage measured during operation of the air conditioner is constantly compared with the preset amount of predicted heat storage, and when there is a load change. In this system, the excess heat storage amount can be used up by automatically switching the operation mode so as to follow the fluctuation.

[0003]

By the way, in the heat storage tank, as shown in FIG. 5, the amount of heat released per unit time (the amount of heat that can be released) when the outlet temperature is constant varies depending on the amount of stored heat. Therefore, if the heat radiation control is performed by considering only the outlet temperature of the heat storage tank while keeping the heat radiation characteristics constant, proper heat radiation control cannot be performed.Therefore, when the air conditioning load is small during the heat source unit priority mode operation, There is a risk that the stored heat will be wasted at the end. Therefore, the present invention provides more detailed control of the heat storage air conditioning system,
The purpose is to properly extract the amount of stored heat so that the stored heat does not remain in vain.

[0004]

In order to achieve the above object, the invention according to claim 1 is a heat storage air conditioning system having a heat storage tank and a heat source device, and the heat source device is operated at night to store heat.
In the operation control device of the heat storage air conditioning system having a control device that controls the heat storage air conditioning system so as to perform air conditioning by consuming this heat storage in the daytime, the control device estimates the heat radiation considering the heat radiation characteristics of the heat storage tank. An operation control device for a heat storage air-conditioning system, which calculates a possible amount, compares it with a predicted air-conditioning load, and automatically selects an optimum operation mode of the heat storage air-conditioning system based on this.

Such control can be started at any time after the air conditioning operation is started, but it is desirable to perform it immediately after the operation is started in order to perform more detailed control. The time interval is also arbitrary, but from 30 minutes
Once an hour is sufficient. The invention according to claim 2 is
The operation control device of the heat storage air conditioning system according to claim 1, wherein the heat radiation characteristic is a characteristic that depends on a residual heat storage amount of the heat storage tank.

According to a third aspect of the present invention, at least two operation modes are provided: a heat dissipation priority mode in which heat dissipation operation is preferentially performed over the heat source machine, and a heat source machine priority mode in which heat dissipation machine is preferentially operated over heat dissipation operation. It is an operation control device of the heat storage air conditioning system according to claim 1 or 2 characterized by the above. The invention according to claim 4 is the operation control device for a heat storage air-conditioning system according to any one of claims 1 to 3, characterized in that the above-mentioned comparison determination is repeatedly performed. The invention according to claim 5 is the operation control device for a heat storage air conditioning system according to any one of claims 1 to 4, wherein the comparison determination is performed after a certain set time.
The set time is appropriately selected according to the condition of the facility where the air conditioning is performed, and for example, the closing time when the cooling load is significantly reduced is adopted.

According to a sixth aspect of the present invention, the heat storage air conditioning system is controlled so that the heat source device is operated at night to store heat in the heat storage tank and the heat storage air conditioning system is controlled to consume the heat storage during the daytime to perform air conditioning. In the control method, the estimated heat dissipation possible amount is calculated in consideration of the heat dissipation characteristics of the heat storage tank, and this is compared with the predicted air conditioning load stored in advance, and the optimum operation mode of the heat storage air conditioning system is selected based on this. It is an operation control method of a heat storage air conditioning system characterized by having a process.

[0008]

According to the present invention, the estimated heat radiation amount is calculated by taking into consideration the heat radiation characteristic of the heat storage tank, which depends on, for example, the remaining heat storage amount, and this is compared with the predicted air conditioning load. Since the optimum operation mode is automatically selected, more detailed operation control is performed in consideration of the heat radiation characteristics of the heat storage tank.

Therefore, for example, even when the cooling load suddenly decreases after the end of work hours in an office or the like, the amount of heat that can be radiated per unit time (the amount of heat that can be radiated) calculated from the current remaining storage amount taking into account the heat radiation characteristics of the heat storage tank. ) And the cooling load for one hour from the current time calculated from the heat load prediction (predicted cooling load), and if it is determined that the current remaining storage amount can cover the cooling load for the next one hour, The mode is automatically switched to the heat dissipation priority mode to prevent wasteful accumulation of heat.

[0010]

1 shows an ice heat storage air conditioning system S according to an embodiment of the present invention. The configuration of this system is roughly divided into brine system and water system. The brine system mainly includes a heat storage tank 1, a main heat source device (refrigerator) 2, a brine pump 3 for circulating brine in the main heat source device, and heat radiation brine pumps 4, 5 for performing heat radiation operation from the heat storage tank. It is composed of a three-way valve 6 for adjusting the temperature. The water system is composed of auxiliary heat source devices (coolers) 7 and 8 and cold water pumps 9 and 10 for circulating water in the auxiliary heat source devices.
A water-brine heat exchanger 1 for exchanging heat between water and brine during heat dissipation operation and chasing operation of the main heat source machine.
1, 12 and secondary side heat exchange pumps 13 and 14 for circulating water in the water-brine heat exchanger.

FIG. 2 shows the configuration of the control device of the ice heat storage air conditioning system S, which includes a personal computer 21 for storing and calculating various data, and a detecting device 22,
It consists of 23.

This ice heat storage tank 1 is called an internal melting type, and as shown in FIG. 3, during storage of heat, a cold brine 2 is placed in a tube 25 surrounded by water 24 in the heat exchangers 11 and 12.
6 flows to generate ice 27 on the outer surface of the tube 25, and when heat is dissipated, warm brine 26
The ice 27 on the outer surface of the tube 25 is melted by flowing the water. The ice heat storage tank 1 is provided with a remaining amount detecting device 22 and a temperature detecting device 23 for detecting the current remaining amount, and these output terminals are connected to the personal computer 21.

The personal computer 21 has a start time storage unit 3 for storing the control start time input from the keyboard unit 30.
1. A heat load predicting unit 32 that predicts a heat load based on meteorological conditions and past accumulated data, and a predictive air conditioning load calculating unit 33 that calculates a predicted air conditioning load per unit time based on the result of the heat load predicting unit 32. An ice heat storage tank heat radiation characteristic storage unit 34 that stores the heat radiation characteristic of the ice heat storage tank, a heat radiation possible amount calculation unit 35 that calculates the heat radiation amount per unit time from the remaining storage amount and the heat radiation characteristic of the ice heat storage tank, and a plurality of operation modes Is provided with an operation mode storage unit 36 for storing, and an operation mode determination unit 37 for determining the operation mode based on the comparison judgment of the heat radiation possible amount and the predicted air conditioning load. In this embodiment, the operation mode stored in the operation mode storage unit 36 is, as shown in FIG. 4, an ice heat dissipation priority mode in which ice heat dissipation is preferentially operated over a refrigerator and a refrigerator is prioritized over ice heat dissipation. There is a refrigerator priority mode to operate in.

A feature of the present invention is to use the heat radiation characteristics of the heat storage tank stored in the ice heat radiation tank heat radiation characteristic storage unit 34 when performing heat radiation control. Below, a method of calculating the heat radiation possible amount per unit time in consideration of the heat radiation characteristics will be described. The heat exchange amount [Q] of the ice heat storage tank is expressed by the following equation. Where, U: heat transfer rate (kcal / m ² · h ·
℃) A: Heat transfer area (outer surface area) of the heat exchanger in the ice storage tank
(M ² ) ΔT: Logarithmic mean temperature difference (° C) T ₀ : Temperature in tank (° C) T ₁ : Brine inlet temperature (° C) T ₂ : Brine outlet temperature (° C) where A is the outer diameter of the tube and From the length again, T ₀ ,
T ₁ and T ₂ can be easily obtained from the resistance temperature detector. Therefore, the heat exchange rate U can be calculated to calculate the amount of heat exchanged in the ice storage tank, that is, the amount of heat that can be dissipated.

Next, a method of calculating the heat transmission rate U will be described. The heat transmission rate U is generally expressed by the following equation. α _i : Heat transfer coefficient (kcal / m ² · h ・) in the pipe (brine side)
℃) α ₀ : Outer pipe (water side) heat transfer coefficient (kcal / m ² · h · ° C) D _i : Tube inner diameter (m) D ₀ : Tube outer diameter (m) R _t : Heat transfer tube resistance (kcal / m ² · h · ° C) R _s : Scale coefficient (kcal / m ² · h · ° C) where D _i , D ₀ , R _t , and R _s are constants, and α _i has a small change within the use range. There is a constant. Therefore, if α ₀ can be calculated, the heat transmission rate U of the ice heat storage tank can be calculated.

Next, a method for calculating the outside (water side) heat transfer coefficient α ₀ will be described. There is natural convection heat transfer between the ice and the tube surface, but water having an extreme value in specific gravity at 4 ° C. is natural convection in the vicinity, which is very special. Therefore, it is generally difficult to determine the extra-tube (water side) heat transfer coefficient α ₀ , but the present invention adopts the following method.

The external heat transfer coefficient α ₀ is generally related to the surface area of the tube tube wall, the heat flux, the brine temperature, and the temperature distribution around the tube tube. Here, the maximum ice heat storage amount (full storage amount) Q ₀ is used as a reference, and the ice heat storage rate P _f is defined as a ratio with the heat storage amount (remaining storage amount) Q _r (P _f = Q _r / Q ₀ ). This ice heat storage rate P _f is used instead of the distance between the tube wall and the ice. Therefore, the heat transfer coefficient α ₀ is represented by a function of P _f , T ₁ −T ₀ , and T ₂ −T ₀ as shown in the following empirical formula. α ₀ = f (P _f , T ₁ −T ₀ , T ₂ −T ₀ ) Thus, the heat transfer coefficient α ₀ is calculated by the residual amount Q _r and the temperature T in the tank.
Since it is a function of ₀ , the brine inlet temperature T ₁ , and the brine outlet temperature T ₂ , it is possible to calculate the exchange heat amount of ice storage, that is, the heat radiable amount, by calculating the above-mentioned four parameters. Thereby, the graph as shown in FIG. 5 is calculated.

Next, with reference to the control flow chart shown in FIG. 6, the operation of the operation control device of the ice storage type air conditioning system will be described. The control start time is input in advance from the keyboard unit 30 and stored in the control start time storage unit 31 (step 1). The control start time may be the same as the operation start time, or may be a time when the cooling load sharply decreases, such as in the evening (for example, 18:00, which is the end time of the business office or office). The control start time is the same unless it is updated.

The control start time is determined (step 2), the remaining amount detecting device 22 detects the current remaining amount from the heat storage tank water level signal from the ice heat storage air conditioning system S (step 3), and the temperature is detected. The brine inlet / outlet temperature and the bath temperature are calculated by the device 23 (step 4). Heat dissipation possible amount calculation part 3
5, in consideration of the heat radiation characteristic of the ice heat storage tank 1 stored in the ice heat storage tank heat radiation characteristic storage unit 34 from the above-mentioned residual storage amount, the inlet / outlet temperature of the brine 26, and the tank temperature, that is, Based on this, the heat radiation possible amount is calculated (step 5).

On the other hand, the heat load predicting unit 32 predicts the heat load based on the meteorological condition and past accumulated data, and the predictive air conditioning load calculating unit 33 calculates the next time from the current time based on the result of the heat load predicting unit 32. The predicted air conditioning load up to the heat storage start time is calculated (step 6). Then, the operation mode determination unit 37 compares the heat radiation possible amount (a) calculated above with the predicted air conditioning load (b) (step 7) to determine the operation mode stored in the operation mode storage unit 36. The optimum operation mode is selected from the above (steps 8 and 9). That is, if (a)> (b), the ice heat radiation priority mode is selected. If (a) <(b), the refrigerator priority mode is selected. The selected operation mode is output to the ice storage air conditioning system 1. The above control is performed at regular time intervals from the control start time to the heat storage start time.

FIG. 7 illustrates the effect of the present invention. If the control according to the present invention is not performed, as shown in FIG. 9, the refrigerator is preferentially operated even when the load suddenly disappears, and the heat storage amount remains. On the other hand, when the control according to the present invention is performed, as shown in FIG. 7, heat storage can be appropriately taken out by switching the operation mode according to the load fluctuation. As a simpler control method, FIG.
The case where time is set as the control start time is shown.

The air conditioning system to which the present invention is applied is not limited to an ice heat storage air conditioning system, but one that utilizes latent heat from a heat storage medium that solidifies at or above 0 ° C., or sensible heat such as cold water heat storage or hot water heat storage. It can be applied to any heat storage air conditioning system such as the one used.

[0023]

EFFECTS OF THE INVENTION According to the present invention, in addition to the conditions such as residual storage amount, brine inlet / outlet temperature, tank temperature, etc., the heat dissipation amount calculated in consideration of the heat dissipation characteristics of the heat storage tank and the heat load prediction By comparing the estimated expected air-conditioning load and automatically switching to an appropriate operation mode, the amount of heat storage is extracted appropriately, so the ice storage air-conditioning system is controlled more finely and air conditioning that effectively utilizes heat storage. The system can be constructed and the running cost of the air conditioning equipment can be greatly reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing an overall configuration of a heat storage system according to an embodiment of the present invention.

FIG. 2 is a block diagram showing the overall configuration of a heat storage system controller according to an embodiment of the present invention.

FIG. 3 is a sectional view showing a structure of a main part of an ice heat storage tank.

FIG. 4 is a graph showing an operation mode in the operation control device according to the embodiment of the present invention.

FIG. 5 is a graph showing a relationship between a heat storage amount and a heat dissipation possible amount.

FIG. 6 is a flow chart of control of the operation control device.

FIG. 7 is a graph showing effects of the operation control device according to the present invention.

FIG. 8 is a graph showing effects of the operation control device according to the present invention.

FIG. 9 is a graph showing an effect of a conventional operation control device.

[Explanation of symbols]

 S Ice heat storage air conditioning system 1 Heat storage tank 23 Control device (personal computer) 33 Predictive air conditioning load unit 35 Heat dissipation possible amount calculation unit 37 Operation mode determination unit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasushi Osawa 1-33, Roppongi, Minato-ku, Tokyo Inside NTT FACILITIES INC. (72) Inventor Noboru Makita 11 Asahi-cho, Haneda, Ota-ku, Tokyo No. 1 in EBARA CORPORATION (72) Inventor Mitsuteru Furuya 11-1 Haneda Asahi-cho, Ota-ku, Tokyo Inside EBARA CORPORATION

Claims (6)

[Claims] 1. A heat storage air conditioning system having a heat storage tank and a heat source device, and a control for controlling the heat storage air conditioning system such that the heat source device is operated at night to store heat, and this heat storage is consumed during the daytime to perform air conditioning. In the operation control device of the heat storage air conditioning system having a device, the control device calculates the estimated heat dissipation possible amount in consideration of the heat dissipation characteristics of the heat storage tank, and compares this with a pre-stored predicted air conditioning load, An operation control device for a heat storage air conditioning system, which automatically selects an optimum operation mode of the heat storage air conditioning system based on the above. 2. The operation control device for a heat storage air conditioning system according to claim 1, wherein the heat radiation characteristic is a characteristic that depends on a residual heat storage amount of the heat storage tank. 3. The operation mode has at least two of a heat dissipation priority mode in which heat dissipation operation is prioritized over heat source equipment, and a heat source equipment priority mode in which heat dissipation equipment is operated preferentially over heat dissipation operation. Item 3. An operation control device for a heat storage air conditioning system according to item 1 or 2. 4. The operation control device for a heat storage air conditioning system according to claim 1, wherein the comparison and judgment are repeated. 5. The operation control device for a heat storage air conditioning system according to claim 1, wherein the comparison judgment is performed after a certain set time. 6. A heat storage air conditioning system operation control method for controlling a heat storage air conditioning system such that a heat source device is operated at night to store heat in the heat storage tank and this heat storage is consumed during the daytime to perform air conditioning. Calculate the estimated heat dissipation possible considering the heat dissipation characteristics,
An operation control method for a heat storage air conditioning system, comprising a step of comparing this with a predicted air conditioning load stored in advance and selecting an optimum operation mode of the heat storage air conditioning system based on this.