KR20000060877A - Optimal operation control method by predicated building load algorithm for ice storage system - Google Patents

Abstract

PURPOSE: A method for controlling optimum operation of an ice storage thermal system by building load estimation algorithm is provided to improve the work following performance with relation to a change of real building loads for reducing operation time, thereby reducing power consumption and improving dynamic characteristics with relation to a rapid load change. CONSTITUTION: A method for controlling optimum operation of an ice storage thermal system by building load estimation algorithm includes the steps of estimating a real building load by measuring a temperature of brine recovered water at a heat exchanger when load cooling(S101), performing a sole operation of a heat accumulating tub if the estimated building load is below a predetermined limit (about 40%) of a maximum load(S102,S103), and performing a parallel operation if the estimated building load is higher than the predetermined limit, wherein a freezer and the heat accumulator are operated in parallel if the building load is in a predetermined limit (40%-70%)(S104,S105), and two freezer and the heat accumulator are operated in parallel if the building load is higher than the predetermined limit (over 70%)(S106,S107).

Description

OPTIMAL OPERATION CONTROL METHOD BY PREDICATED BUILDING LOAD ALGORITHM FOR ICE STORAGE SYSTEM}

The present invention relates to the optimal operation control method of the ice storage system by the building load prediction algorithm to reduce the operating cost by selecting the optimal operation method in the cooling heat storage system, and to maintain a comfortable room by improving the load followability In particular, the present invention relates to an optimal operation control method for an ice heat storage system by a building load prediction algorithm that can predict an indoor load by comparing a return temperature on the heat exchanger side and thus optimally operate a heat storage tank and a freezer.

Ice heat storage system is one of the air conditioning and refrigeration technology developed since the first energy shock in 1970.

The ice heat storage system uses the active power remaining at night to freeze the ice in the heat storage tank, and thaw the ice during the daytime residence to handle indoor cooling loads.

The ice storage system consists of a refrigerator, a heat storage tank, a heat exchanger, and a cooling tower.

In general, this system is a time-scheduled operation, which consists of a single storage tank operation, a refrigeration operation alone, and a parallel operation of the storage tank and the refrigerator.

However, in the automatic mode rather than the manual mode in which the user can select a driving method, the criteria for selecting each driving method are ambiguous, and each operation method is not properly selected, and unnecessary energy is wasted. This results in failure to meet the requirements.

Therefore, in the present invention, in order to solve this problem, by installing a temperature sensor downstream of the three-way valve on the heat exchanger side, by monitoring the return temperature of the heat chain brine, the indoor load is predicted, and by operating the heat storage tank and the freezer according to the load, it is unnecessary. We have developed an optimal operation control method that can maintain a more comfortable interior by saving energy and improving the followability to rapid building load changes.

Such an invention will be described later.

FIG. 1 is a circuit diagram of a typical ice heat storage system. As shown in FIG. 1, the refrigerant outlet of the first heat exchanger 40 is connected to the refrigerant inlet of the first refrigerator 10 through a three-way valve 3V1. It is connected to the refrigerant inlet of the second refrigerator 20 via a three-way valve (3V2) to the refrigerant outlet of the two heat exchangers 50, and two ways to the refrigerant outlets of the first and second refrigerators 10 and 20. It is connected to the refrigerant inlet of the heat storage tank 30 through the valve (2V1) and at the same time connected to the input side of the brine pump (BP) through the two-way valve (2V2), the first and second coolers (10, 20) Another coolant of the first and second coolers 10 and 20 by sequentially passing through the first and second cooling towers CT1 and CT2 and the coolant pump CWP1 and CWP2, respectively, at the outlet of the refrigerant. The inlet, and the output side of the brine pump (BP) is connected to another inlet of the three-way valve (3V1) (3V2) and to the refrigerant inlet of the first, second heat exchanger (40) (50) Connect and configure.

Looking at the prior art configured as described above is as follows.

First, only the three-way valve (3V1) (3V2) and the two-way valve (2V2) is on, and the two-way valve (2V1) is off.

When a low temperature voltage refrigerant is supplied to the refrigerant inlets of the first and second heat exchangers 40 and 50, the surrounding heat is taken away and evaporated so that cool air is sent to the load side.

The evaporated refrigerant is supplied to the first and second refrigerators 10 and 20 through the three-way valve 3V1 and 3V2.

Then, the first and second refrigerators 10 and 20 cool the refrigerant by the cooling water circulated by the first and second cooling towers CWP1 and CWP2 to supply the two-way valve 2V2.

At this time, the brine pump BP performs a pumping operation to supply the refrigerant passing through the two-way valve 2V2 to the refrigerant inlets of the first and second heat exchangers 40 and 50.

The load is cooled by this operation.

In addition, only the three-way valve (3V1) (3V2) and the two-way valve (2V1) are on, and the two-way valve (2V2) is turned off during the heat storage tank alone operation and the single operation.

When a low temperature voltage refrigerant is supplied to the refrigerant inlets of the first and second heat exchangers 40 and 50, the surrounding heat is taken away and evaporated so that cool air is sent to the load side.

The refrigerant evaporated above passes through the three-way valve (3V1) (3V2), the first and second refrigerators 10 and 20, and the two-way valve (2V1) in order to be supplied to the heat storage tank (30).

Then, the heat storage tank 30 is responsible for cooling the indoor load by freezing the ice using the refrigerant or thawing the frozen ice.

When the ice is frozen in the above, the brine pump (BP) is supplied to the other inlet of the three-way valve (3V1) (3V2) the refrigerant discharged from the heat storage tank (30).

When the supplied refrigerant is again supplied to the heat storage tank 30 through the first and second refrigerators 10 and 20 and the two-way valve 2V1, the ice is frozen by the same operation as described above.

During thawing, the brine pump BP supplies the cooled refrigerant to the refrigerant inlets of the first and second heat exchangers 40 and 50 while the heat storage tank 30 melts the ice therein.

Then, the air on the load side is deprived of heat by the refrigerant, and thus the cooled air is cooled as it is supplied to the load side.

The refrigerant, which is deprived of heat and becomes high temperature and high pressure, is again supplied to the heat storage tank 30 through the three-way valve (3V1) (3V2), the first and second refrigerators 10 and 20, and the two-way valve (2V1). Repeat the same operation as above.

In addition, the parallel operation of the heat storage tank and the freezer controls the on / off operation of the two-way valve 2V1 (2V2) to operate the heat storage tank and the refrigerator alternately.

In addition, a temperature sensor for sensing the temperature of the coolant or the sub-line at the refrigerant inlet and the refrigerant outlet of the refrigerator, the refrigerant inlet of the heat exchanger, the refrigerant inlet and the refrigerant outlet of the heat storage tank is respectively installed.

The overall operation control of the ice heat storage system operated in the same manner as described above will be described with reference to FIG. 2, and the heat exchanger inlet brine temperature Ti is measured during operation of the ice heat storage system and compared with a preset temperature Tset.

As a result, when the heat exchanger inlet brine temperature Ti is higher than the set temperature Tset, the refrigerator is turned on, and when the heat exchanger inlet brine temperature Ti is lower than the set temperature Tset, the heat storage tank is turned on. Let's do it.

This operation corresponds to the parallel operation of the refrigerator and the heat storage tank.

The operation is performed until a system error occurs and stops when an error occurs.

However, in the prior art as described above, the freezer priority method has a low energy saving effect because the freezer is operated for 24 hours, and the load that the freezer is responsible for, especially when the load is low, cannot thaw all of the regenerated ice. In some cases, if the load is large, the peak load may not be satisfied, and thus the refrigerator needs to be overdriven. And the storage tank priority method is to defrost a certain amount of ice during the ice making time and to thaw the storage tank uniformly according to the thawing time, and to operate the refrigerator simultaneously according to the time schedule, and this method is not controlled according to the load change. In a large time, the load is not removed only by the operation of the heat storage tank alone. That is, there is a problem that can not properly control the load of the room because the trackability to the load is poor.

Therefore, the present invention for solving the above problems is to estimate the actual building load by measuring the return temperature of the heat exchanger side brine, and to optimize the ice heat storage system by the building load prediction algorithm to properly operate each system accordingly. An operation control method is provided.

Another object of the present invention is to perform the operation of the heat storage tank alone when the predicted building load is below a certain degree (approximately 40%) of the maximum load, and to perform parallel operation when it is above a certain degree (approximately 40% or more) to reduce unnecessary energy consumption. The present invention provides an optimal operation control method for an ice storage system by using a building load prediction algorithm.

It is another object of the present invention to provide an optimal operation control method for an ice storage system by a building load prediction algorithm to improve the dynamic characteristics against sudden load fluctuation so as to keep the room more comfortable.

1 is a circuit diagram of a typical ice heat storage system.

2 is a flowchart illustrating an operation control method of an ice heat storage system according to a conventional load.

3 is a flowchart illustrating an optimal operation control method for an ice storage system according to the present invention building load prediction algorithm.

***** Explanation of symbols for the main parts of the drawing *****

10,20: refrigerator 30: heat storage tank

40,50: heat exchanger BP: brine pump

CT: Cooling Tower CWP: Coolant Pump

2V1,2V2: 2 way valve 3V1,3V2: 3 way valve

The present invention for achieving the above object is a first step of predicting the actual building load by measuring the brine return temperature of the heat exchanger side during load cooling, and if the building load predicted in the first step is less than a certain degree of the maximum load And a third step of performing parallel operation if the building load predicted in the first step and the building load predicted in the first step are greater than or equal to a certain degree of maximum load.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 3 is a flowchart illustrating an optimal operation control method of an ice heat storage system using a building load prediction algorithm according to an embodiment of the present invention. As shown in FIG. 3, a method for predicting an actual building load by measuring a brine return temperature at a heat exchanger side during load cooling is shown. Step 1 and the second step (S102-S103) of performing the heat storage tank alone when the building load predicted in the first step is 40% or less of the maximum load, and the building load predicted in the first step is 40 of the maximum load. If it is within% -70%, the third step (S104-S105) performs parallel operation with one heat storage tank and a freezer, and if the building load predicted in the first step is 70% or more of the maximum load, the parallel operation with a heat storage tank and two freezers is performed. The fourth step (S106-S107) is performed, and the fifth step (S108-S109) for turning off the freezer, cooling tower, cooling water pump, and brine pump when an error occurs in the system.

When described in detail with respect to the operation and effect of the present invention made of each step as follows.

When the ice heat storage system as shown in FIG. 1 is driven, when the sea ice mode is started in the heat storage tank priority method, CPI not shown operates the brine pump (BP), and heat exchanges through a temperature sensor installed between the freezer and the three-way valve. Measure the return temperature (TO) of the brine passing through the group 40 or (50).

Thus, the building load is predicted as the return temperature (TO) of the brine (S101).

Determine whether the estimated building load corresponds to 40% or less of the maximum load (design load) (S102), 40% to 70% (S104), or 70% or more (S106). do.

If the predicted building load corresponds to 40% or less of the maximum load, the storage tank is operated alone.

In order to operate the heat storage tank 30 alone, the two-way valve 2V1 is turned on and the two-way valve 2V2 is turned off as described in the related art.

If the building load predicted in step S101 falls between 40% and 70% of the maximum load, the building load and the refrigerator are used to operate in parallel. (S105)

In addition, if the building load predicted in the step S101 is 70% or more of the maximum load, the load is a large case, so that the refrigerator is operated in parallel by using both the heat storage tank and the two refrigerators to prevent excessive operation of the refrigerator.

As described above, the building load is predicted and the operation of the ice storage system is controlled accordingly.

As described in detail above, following the actual load change of the building is improved to reduce the unnecessary operating time by reducing the surplus operation time, as well as to improve the dynamic characteristics of the sudden load change to keep the room more comfortable One effect is to make it work.

Claims (2)

The first step of predicting the actual building load by measuring the brine return temperature on the heat exchanger side during load cooling, and if the building load predicted in the first step is below a certain degree (about 40%) of the maximum load, the operation of the storage tank alone is performed. And a third step of performing a parallel operation if the building load predicted in the first step is equal to or greater than a certain degree of the maximum load. The method of claim 1, wherein the third step is a first process of parallel operation of a refrigerator and a heat storage tank when the building load is within a certain range (40% -70%), and the building load is greater than a certain level (70%). In this case, the optimum operation control method of the ice storage system by building load prediction algorithm, characterized in that the second step of parallel operation of the two refrigerators and the heat storage tank.