JPH03170735A - Controlling method for ice heat storage air-conditioning system - Google Patents

Abstract

PURPOSE:To reduce the running cost by a method wherein a heat medium is cooled or heated at night by using a night discount power and subjected to heat exchange, a load is estimated from an average outside-air temperature at the time of cooling so as to make ice in an optimum quantity and thereby the residual quantity of ice in a heat storage tank is made to be zero at the end of a cooling operation. CONSTITUTION:A heat storage tank 28 accommodating water inside is provided and the water is iced by using a freezer 19 which is operated at night by a night discount power, while air cooling is conducted in daytime by utilizing the cooling by the ice. An average value of outside-air temperatures in the prescribed time zones of the past several days is determined and substituted for a prescribed function so as to determined an aimed quantity of ice. The prescribed function is obtained by measuring a plurality of data on the average value of outdoor-air temperatures and on executed values of a load of use of the day and set so that it contains a set of measuring points, and thereby the residual quantity of ice in a heat storage tank 28 is made to be zero at the time of the end of a cooling operation. According to this method, it is possible to use effectively the ice in the heat storage tank and thereby to reduce the running cost.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control system for an ice heat storage air conditioning system that stores ice heat using nighttime electricity.

Prior Art> As a conventional control method for a thermal storage air conditioning system that stores heat in a thermal storage tank by using low-cost nighttime electricity, for example, Japanese Patent Publication No. 17312/1983 is known. . This calculates the heat storage amount using the operating time (heat storage amount) of the heat source equipment, the difference between the outside temperature and the reference temperature over the past few days, and the residual heat amount in the heat storage tank over the past few days. It was something. In this case, the heat storage tank stores cold water or hot water.

<Problems to be Solved by the Invention> In other words, conventional control technology of this type is not of the type that calculates the amount of ice made. Therefore, when this method is applied to ice heat storage, it is difficult to accurately measure the amount of remaining water, so calculation of the amount of heat storage depends largely on the amount of remaining water. Ice thermal storage systems have larger errors. Similarly, if the amount of remaining ice is controlled to 0, the prediction error of the amount of heat storage increases. Therefore, this method reduces the amount of remaining ice to 0.
I can't control it properly. In addition, since standard values are used, it is difficult to set the standard values, and the standard values change depending on the air conditioning conditions and the installation conditions of the heat storage system, and depending on the setting of the standard values, the error in the calculated values is large, making it less versatile. It is something.

? In addition, since heat storage is concentrated at a specified time (night),
When an air heat source is used, there are drawbacks such as the inability to obtain a predetermined amount of heat storage depending on the outside air conditions (■).

In view of the above-mentioned circumstances, the present invention provides control of an ice heat storage air conditioning system that solves the above problem by determining the target ice production amount by determining the average outside air over the past few mouths from the day before the air conditioning day. It is intended to provide a method.

<Means for Solving the Problems> The present invention has a heat storage tank that stores water inside, makes water ice using a refrigerator operated on nighttime electricity at night, and cools the ice during the day. In an ice storage air conditioning system that performs air conditioning by This is what I did.

Function> The above control method calculates the average value of the outside air temperature in a specified special open zone over the past few days, substitutes the average value into a predetermined function to obtain the target ice production amount, and calculates the target ice production amount using the predetermined function. measures multiple data of the average value of outside air temperature and the actual value of usage load for that day, and sets it to include the set of flFJ fixed points,
The amount of ice remaining in the heat storage tank is reduced to zero at the end of cooling operation.

Embodiments> Hereinafter, embodiments of the present invention will be described based on the drawings.

Figure 1 shows an ice storage air conditioning system, one of which has a refrigerant compressor, a heat source side heat exchanger, a pressure reduction device, and a user side heat exchanger.
This is an air-cooled refrigerator equipped with a four-way valve, and a solenoid valve 2 is installed in the brine piping 20 that supplies the cooled or heated prine (antifreeze) led from the refrigerator 19, and an electromagnetic valve is installed in the prine piping 21 that branches at the front. A valve 3 is provided, and a heat exchanger 25 with a capacity of 2 g for heat storage is connected to the tip side of the solenoid valve 3, and a refrigerator 19 is connected to the brine piping 23 at the tip via a brine pump 17 to form a return circulation path. Furthermore, the brine pipe 22 at the tip of the electromagnetic valve 2 is led to the heat exchanger 24 of the brine/water heat exchanger 26, and further to the brine pipe 23.
It becomes connected to. This heat storage tank 28 is configured to freeze the water inside by flowing low-temperature brine into the heat exchanger 25, or to heat the water inside by flowing high-temperature brine.

Further, a water amount detector 8, a water level detector 9, and a temperature detector 12 are attached to the heat storage tank 28 to detect the amount of ice. A three-way switching valve 13 is connected to a water pipe 30 led out from this heat storage tank 28, a load 32 is provided to one side of the three-way switching valve 13 via a cold/hot water pump 29, and the water pipe 33 is connected to the brine. / The water heat exchanger 26 is connected to the heat exchanger 27, and the heat exchanger 27 returns to the heat storage tank 28 via water pipes 34 and 35, while the water pipe 3 branched from the water pipe 34
6 is connected to the three-way switching valve 13. 6 is water pipe 3
A temperature detector provided at 4 issues a signal when the water temperature falls below a set temperature to prevent freezing and viscosity in the water pipe 34.

5 is a temperature sensor for the water pipe 33, 7 is a water supply valve, 16 is an expansion tank provided in the brine pipe 23, 4 is a temperature sensor provided in the brine pipe 22, and 18 is an outside air temperature detector that detects the outside air temperature. It is a vessel.

Next, to explain this effect, in the cooling mode, the I
: Heat storage standard (IIL (target ice making amount determination standard water level control), ■
：Heat storage operation, ■＝Thawing, follow-up, ■Two preliminary heat storage processes.

First, based on the operating time shown in FIG. 2A, the heat storage tf'
As a precaution, the water level in the heat storage TFF 28 is controlled to a reference value, and the amount of ice made is calculated. After this, heat storage operation begins. This is achieved by closing the electromagnetic valve 2 of the brine pipe 20 led from the air-cooled refrigerator 19, opening the electromagnetic valve 3 on the branch road side and turning on the brine pump 17, resulting in heat storage operation. However, the hot and cold water pump 29 is turned off. In this case, the water amount detector 8
When the detected amount of ice production reaches the value calculated in the heat storage preparation, the operation of the brine bomb 17 and the refrigeration unit 819 is stopped.

Here, when performing the cooling operation of the load 32, the brine pump 17 and one refrigerator are turned off to perform the ice-thawing process.
FF, turn on the two cold and hot water pumps, and turn on the three-way switching valve 13.
is automatic. At this time, when the temperature detected by the temperature detector 5 exceeds the set temperature, the solenoid valve 2 is opened and the solenoid valve 3 is opened.
Close the refrigerator and turn on one refrigerator and brine bomb 17.

In this case, 1 is the start time of the cooling operation, which is set arbitrarily by the user. t2 is the end time of thawing (the time when the amount of remaining water in the heat storage tank becomes O). That is, when the cooling operation ends, the amount of water remaining in the heat storage tank 28 is set to zero. In this case, if the amount of ice made was set to a small amount, and the remaining water level was O during the time period between 12:00 and 15:00 when the cooling capacity was needed the most, it was determined only by the capacity of the refrigerator. This results in cooling operation, and the original purpose of storing heat cannot be achieved. Therefore, it is necessary to obtain in advance an amount of ice that is commensurate with the amount of cooling used.

t, is the period n5 during which the cooling operation ends, and is arbitrarily set by the user. In addition, in the chasing process from t2 to t3,
The solenoid valve 2 is closed, the solenoid valve 3 is opened, the 3-way switching valve 13 is set to automatic, the cold/hot water pump 29 is turned on, and when the temperature inside the heat storage tank 28 detected by the temperature detector 12 exceeds the set value, the refrigerator is turned off. 19. Turn on the brine bomb 17.

In the subsequent preliminary heat storage step, the temperature detected by the temperature detector 12 is controlled to be equal to or lower than the set value.

In setting this target ice production amount, ① Find the average value of the outside air temperature during a predetermined time period over the past few days.

(2) Substituting the average value into a predetermined function to obtain the target ice production amount. (2) The predetermined function is a function that is set to include a set of measurement points obtained by measuring a plurality of data of the average value of outside air temperature and the actual measurement value of the usage load on that day.

For example, the graph shown in FIG. 3 is a distribution for multiple outlets when the relationship between the average value of outside air temperature during the air conditioning time period of a certain air conditioning load and the magnitude of the load at that outlet is actually measured.

A is the characteristic of the function for determining the target ice production amount.

B is the heat storage ffi (cold heat) of the entire heat storage tank, the latent heat of the ice + the sensible heat of the water (0 to 7°C).A' part is the state where the ice production amount in the heat storage tank is 100%.

Therefore, if the ice production amount is set based on the characteristics of A, no ice will remain in the heat storage cylinder (the actual ill load is larger than the load based on the characteristics of A).

The characteristic of this A is the average outside temperature T. Expressed as a function of , it becomes the following formula.

The minimum ice production amount is -40% (corresponding outside air temperature is TL°C).

'rosTt-ice making iG-40 [%]TLkuT. ≦
T1I → Ice production amount G (U (To +TL) - βl
(To Tt.)+γ1g [%) α, β. γ is a constant, g is the remaining water amount To<T. ) 1 ice making ffiG-100 [%] Here, it is virtually impossible to calculate the amount of water to be used on the day from the average value of the outside air temperature of the day, so we calculate the amount of water to be used on that day from the average value of the outside air temperature of several days in the past. I will do it.

The operating time is from 8:00 to 18:00, and the outside air temperature is measured every hour (10 points per day).

The average of the measurement points (30 measurement points) during the past three mouths is the predicted outside temperature T for the next mouth. shall be.

Note that prediction of outside air temperature is not limited to this method; factors such as the average outside air temperature of the relevant month in the previous year or a predetermined constant may be taken into account, or a predetermined function may be used instead of simply an average value. good.

In addition, in the heating mode, l: heat storage preparation (basic water level control), ■: heat storage operation, ■: skeleton heat storage operation, rV:
It goes through the process of Jlli' heat and V2 preliminary heat storage.

Based on the operating time shown in FIG. 2B, first, the water level in the heat storage tank 28 is controlled to a reference value for heat storage and preparation. In the subsequent heat storage operation, the solenoid valve 2 is closed, the solenoid valve 3 is opened, and the cold/hot water cylinder 29 is turned on or'p. The brine bomb 17 is turned on and the refrigerator 19 is heated until the temperature TI in the heat storage tank 28 detected by the temperature detector 12 reaches 52°C. Furthermore, when the outside air temperature 1 hour before the heating operation start time 1+ (set arbitrarily by the user) is equal to or higher than the set value, the framework heat storage operation of ■ is omitted and the heat storage operation mode is maintained up to 11. . If the outside temperature is below the set value, open the solenoid valve 2, close the solenoid valve 3, set the three-way switching valve l3 in the closing direction, turn on the cold/hot water pump 29, turn on the refrigerator 19, and turn on the brine pump 17. shall be. This heat storage operation heats the heating chamber in advance to improve the start-up at the start of the heating operation. Or'p brine bomb 17 to reduce fever
1 Turn off the refrigerator 19, turn on the cold/hot water bomb 29
Heating operation is performed from the fan coil with the three-way switching valve 13 set to automatic. At this time, when the temperature detected by the temperature detector 12 becomes lower than the set temperature, the solenoid valve 2 is closed, the solenoid valve 3 is opened, and the refrigerator 19 and the brine bomb 17 are turned on. After that, the solenoid valve 2 is closed for preliminary heat storage, the solenoid valve 3 is opened, the cold/hot water pump 29 is turned off, and when the detected value of the temperature detector 12 is 38°C or less, one refrigerator is turned on, and the brine bomb 17 is turned on.
Turn on.

Effects of the Invention> As described above, the control method for the ice storage air conditioning system of the present invention cools or heats the heat medium at night using nighttime electricity, exchanges heat therewith, and reduces the load from the average outside temperature during cooling. By predicting and making the optimal amount of ice, and setting the amount of water remaining in the heat storage tank to 0 at the end of cooling operation, the ice in the heat storage tank can be used effectively, preventing ice from remaining and increasing efficiency. Good ice making and ice thawing operation is possible. Therefore, it has the effect of reducing initial costs and reducing running costs due to heat storage using nighttime electricity.

[BRIEF DESCRIPTION OF THE DRAWINGS] The drawings show an embodiment of the present invention, and FIG. 1 is a schematic diagram of an ice storage air conditioning system, FIG. 2A is an explanatory diagram showing the operating time of the cooling mode, and FIG. 2B is an explanatory diagram showing the operating time of the heating mode, and FIG. 3 is a characteristic diagram of a function for determining the target ice making amount. 2... Solenoid valve, 3... Solenoid valve, 5... Temperature detector, 8... Water amount detector, 9... Water level detector, 13...
・3-way switching valve, 17...Brine pump, 18...
Outside air d degree detector, 19... air-cooled refrigerator, 24,.・
Heat exchanger, 25... Heat exchanger, 26... Brine/
water heat exchanger, 27... heat exchanger, 28... heat storage tank,
29...Cold/hot water cylinder, 32...Load. Patent application

Claims (1)

[Claims] 1. In an ice thermal storage air conditioning system that has a thermal storage tank that stores water inside, uses a refrigerator operated on nighttime electricity to make water into ice at night, and performs air conditioning by cooling the ice during the day.
A control method for an ice storage air conditioning system characterized in that the target ice production amount is set by determining the average outside air over the past several days from the day before the air conditioning day, and determining the next day's target ice production amount using a correlation equation between the outside air and the load.