KR100545040B1 - Method and apparatus of cooling system using ice slurry as second coolant - Google Patents

Abstract

The present invention relates to a cooling system and a control method for directly transporting an ice slurry made through an ice slurry type refrigerating system to a heat exchanger in a cooling apparatus and utilizing the secondary refrigerant, and more particularly, an ice making machine for producing an ice slurry. A heat storage tank for storing the ice slurry with stirring; A space formed inside or outside of the heat storage tank to store only water or an aqueous solution of ice slurry; A supply pipe for supplying ice slurries from the heat storage tank to individual cooling devices; At least one distribution pipe connected to the supply pipe and at least one heat exchanger in the cooling device; A first pump for supplying an ice slurry in the heat storage tank to a cooling device through a supply pipe; A second pump for supplying a liquid in a space formed to store only water or an aqueous solution as a liquid to a supply pipe; A third pump for supplying a liquid in a space formed to store only water or an aqueous solution as the liquid to the ice maker; An opening and closing valve installed at the distribution pipe to control the supply of ice slurries to the heat exchanger in the cooling device; A fourth pump installed in the distribution pipe and supplying the ice slurry to the heat exchanger in the cooling device while operating in conjunction with the open / close valve; A temperature sensor provided to measure a temperature inside the cooling device; It is installed in the distribution pipe of the cooling system and consists of a pressure gauge for detecting the pressure in the distribution pipe or the heat exchanger, and features the structure and control method of the cooling system having both the advantages of the direct cooling type and the indirect cooling method. .

Ice Slurry, Direct Transport, Heat Exchanger, Storage Tank, Bulkhead

Description

Cooling system using ice slurry as secondary refrigerant and its control method {Method and apparatus of cooling system using ice slurry as second coolant}             

Figure 1a is a schematic diagram showing a refrigerant direct cooling system according to the prior art,

Figure 1b is a schematic diagram showing an indirect cooling system according to the prior art,

Figure 2a is a schematic diagram showing a cooling system having a partition installed inside the heat storage tank of the cooling system according to the present invention,

Figure 2b is a schematic diagram showing a cooling system in which a separate reservoir is installed outside the heat storage tank of the cooling system according to the present invention,

Figure 3 is a graph showing the pressure drop test value according to the ice particle ratio (IPF, Ice Packing Factor) of the ice slurry in the cooling system according to the present invention,

Figure 4 is a graph showing the heat transfer coefficient experimental value according to the ice slurry flow rate and ice particle ratio (IPF, Ice Packing Factor) in the cooling system according to the present invention.

<Description of the symbols for the main parts of the drawings>

(10): cold heat source equipment (11): cooling device

(12): evaporator (13): expansion valve

(14): refrigerant supply pipe (15): refrigerant ring water pipe

(16): cooling fan (17): pump for cold water piping

(18): Temperature sensor

(20): secondary refrigerant storage tank (21): secondary refrigerant supply pump

(22): secondary refrigerant supply piping (23): secondary refrigerant return piping

(24): secondary refrigerant opening and closing valve (25): secondary refrigerant pump

(26): secondary refrigerant heat exchanger (27): distribution pipe

(101): ice slurry heat storage tank 102: ice maker

103: stirrer 104: partition wall

(105): reservoir (106): ice slurry supply piping

(107): ice slurry return piping (108): first pump

(109): second pump 110: third pump

120: ice slurry heat exchanger 121: opening and closing valve

(122): fourth pump 123: pressure gauge

124: electric heater

The present invention relates to a cooling system using the ice slurry as a secondary refrigerant, and a control method thereof. In particular, an ice slurry containing small ice particles in water or an aqueous solution has a large amount of cold heat transportation per unit flow rate, and even after cold heat is transferred. The present invention relates to a cooling system and a control method using the same as a secondary refrigerant of a heat exchanger in a cooling apparatus by using a feature of having almost no change and having excellent heat transfer characteristics.

In general, a cooling system is connected to a cold heat source device that produces cold heat to form a cooling system, which is used for cooling and dehumidifying buildings and factories by cooling liquids such as water, or cooling food or other objects for long-term fresh storage. It is a device that can be widely used in cooling systems, low-temperature warehouses, showcases, etc. of various industrial processes, and is largely classified into a refrigerant direct cooling type and an indirect cooling method.

FIG. 1A is a schematic diagram of a conventional refrigerant direct expansion cooling system, comprising a cold heat source device 10 for producing cold heat and one or more cooling devices 11, connected by refrigerant pipes 14 and 15 therebetween. do.

The cooling device 11 has an evaporator 12, which is a heat exchanger through which refrigerant flows, and is connected to the refrigerant pipe 14 through an expansion valve 13, and control of the temperature sensor 18 installed in the cooling device. When cooling is necessary because the temperature is higher than the set temperature by comparing the set value with the set temperature, open the expansion valve 13 to supply the refrigerant to the evaporator 12, which is a heat exchanger in the cooling system, and at the same time circulate the cold air generated by the evaporator if necessary. Cooling is performed by supplying a cooling fan 16 or supplying a liquid, such as water, to the cold water pipe pump 17, and when the temperature measured by the temperature sensor 18 is lower than or equal to a set value, cooling is no longer required. The expansion valve 13 is closed to block the refrigerant from entering the evaporator so that no further cooling is performed.

Figure 1b is a schematic diagram of a conventional general indirect cooling system, a cold heat source device 10 for producing cold heat to cool the secondary refrigerant, such as brine, and a heat storage tank 20 for storing the cooled secondary refrigerant or one or It consists of more than one cooling device (11), between the heat storage tank and the cooling device is connected to the secondary refrigerant pipes (22, 23) and the distribution pipe (27), the secondary refrigerant by each of the secondary refrigerant supply pump (21) It is supplied to the distribution pipe.

The cooling device 11 has a heat exchanger (26) through which the secondary refrigerant flows, and is connected to the secondary refrigerant supply pipe (22) by a distribution pipe (27). 24) and the secondary refrigerant pump 25 is driven in conjunction with the opening and closing sides, and the control is compared with the temperature value and the set temperature value of the temperature sensor 18 installed in the cooling device above the set temperature to require cooling In this case, the opening and closing valve 24 is opened to operate the secondary refrigerant pump 25 to supply the secondary refrigerant to the heat exchanger 26 in the cooling device, and at the same time a cooling fan for circulating the cold air generated in the heat exchanger if necessary. Cooling is carried out by driving (16) or by supplying a liquid such as water to the cold water pipe pump (17), and when the temperature measured by the temperature sensor (18) is lower than the set value and no further cooling is required, the secondary refrigerant is used. By stopping the pump 25 and closing the open / close valve 24, the secondary refrigerant It prevents the inflow to the heat exchanger 26, each device is made not to perform any further cooling.

However, the conventional refrigerant direct cooling system as described above has excellent cooling capability because it uses the latent heat of evaporation of the refrigerant, but it is difficult to control the cooling capacity, and the ability to cope with load fluctuation is low, and the operation and stopping of the cold heat source equipment are frequent. The lifespan of a cold heat source device is shortened and energy consumption is high.A high pressure refrigerant pipe is required between the cold heat source device and the cooling device to require high airtightness. It is also difficult to distribute cold, and in particular, CFC system or HCFC system refrigerant is used in all pipes and heat exchangers as well as the cold heat source equipment, which has a disadvantage of causing serious problems in ozone layer destruction or global warming in case of leakage.

In addition, the conventional indirect cooling system as described above, it is possible to transport the secondary refrigerant through the general pipe, and when connecting a plurality of cooling devices it is easy to distribute the secondary refrigerant to each cooling device, CFC system or HCFC system Is not used in pipes and heat exchangers, but the cooling capacity is extremely low due to heat transport and heat transfer by sensible heat, and a large amount of secondary refrigerant transport is required for sufficient cooling heat transfer. The pipe size is large, the temperature difference at the inlet and outlet of the heat exchanger is large, so that uniform cooling is difficult, and thus the use is limited.

An object of the present invention for solving the above problems is to store and stir the ice slurries produced from the ice maker in the heat storage tank, by supplying the ice slurries stored in the heat storage tank to the heat exchanger inside each cooling device through a pump installed in the pipe. The present invention provides a cooling system using a ice slurry to perform cooling in a cooling apparatus as a secondary refrigerant, and a control method thereof.

The present invention to achieve the object as described above and to perform the problem for eliminating the conventional defects, an ice making machine for producing an ice slurry in which small ice particles are mixed with water or an aqueous solution in a cooling system; A heat storage tank for storing the ice slurry with stirring; Storage means configured to store only water or an aqueous solution of ice slurry in or inside the heat storage tank; A supply pipe for supplying ice slurries from the heat storage tank to individual cooling devices; At least one distribution pipe connected to the supply pipe and at least one heat exchanger in the cooling device; A first pump for supplying an ice slurry in the heat storage tank to a cooling device; A second pump for supplying a liquid of a storage means formed to store only water or an aqueous solution as a liquid to a supply pipe; A third pump for supplying the liquid of the storage means formed to store only the water or the aqueous solution as the liquid to the ice maker; An opening and closing valve installed in the distribution pipe to control an ice slurry supply to a heat exchanger in a cooling device; A fourth pump installed in the distribution pipe and supplying the ice slurry to the heat exchanger in the cooling device while operating in conjunction with the open / close valve; A temperature sensor provided to set a temperature in the cooling device; It is installed in the distribution tube of the cooling device, characterized in that consisting of a pressure gauge for detecting the pressure in the heat exchanger.

Ice slurry is a solid-liquid two-phase fluid in which small ice particles are mixed in water or an aqueous solution. The ice slurry has a large amount of cold heat transportation and has excellent thawing ability, and thus can be utilized as a secondary refrigerant of various cooling systems. In particular, ice slurry has very advantageous characteristics in heat exchanger design and application because there is almost no temperature change after heat exchange as long as ice particles remain.

Heat exchangers using ice sludge as a secondary refrigerant have a large amount of cold heat transportation and excellent thawing characteristics, making it easy to control the cooling capacity while maintaining excellent cooling capacity, which is an advantage of the conventional refrigerant cooling system. It has the advantage of excellent response ability. In addition, in the case of a refrigeration type direct cooling system using a plurality of cooling devices connected to a single cold source device, it is difficult to distribute the refrigerant. When the ice slurry is used as a secondary refrigerant, it is also easy to distribute and cool. General piping can be used up to the heat exchanger inlet of the device, which has the advantage of easy maintenance. That is, the cooling system utilizing the ice slurry as the secondary refrigerant is a cooling system having all the advantages of the conventional refrigerant direct cooling system and the indirect cooling system.

Hereinafter, the configuration and the operation of the embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Figure 2a is a schematic diagram showing a cooling system in which a partition is installed inside the heat storage tank of the cooling system according to the present invention, Figure 2b is a schematic diagram showing a cooling system having a separate reservoir installed outside the heat storage tank of the cooling system according to the present invention. To explain this, using the cold heat source device 10 and the ice maker 102 to produce ice sludge mixed with small ice particles (tens of several tens of micrometers to several mm) from water or an aqueous solution and stored in the heat storage tank 101, and stored in the heat storage tank 101 Operate the installed stirrer 103 to agitate the ice slurry, and supply the ice slurry to the distribution pipe 27 having the individual cooling device 11 through the first pump 108 and the ice slurry supply pipe 106. In the condition that cooling of each cooling device is required, the ice slurry is supplied to the heat exchanger 120 inside the cooling device by the opening / closing side 121 and the fourth pump 122 installed in the distribution pipe 27 to cool the necessary cooling. After performing, and farewell to storage tank 101 via a back-exchange pipe 107.

At this time, by the partition 104 in the heat storage tank 101 or a separate storage tank 105 installed in the outside to maintain a space in which only liquid exists, the liquid water or an aqueous solution in which there is almost no ice particles in the space. Is present, and the liquid here is supplied to the supply pipe 106 through the second pump 109 to adjust the ratio of ice particles in the ice slurry supplied to the cooling device, and the ice slurry through the supply pipe After the transportation is completed, only the second pump 109 is operated for a suitable time to remove the ice slurry containing the ice particles in the supply pipe 106 to prevent the airtight from clogging due to the aggregation of ice particles, ice When the slurry is iced, the third pump 110 is operated so that only liquid water or an aqueous solution in the space flows into the ice maker 102, whereby ice particles are transferred to the ice maker 102. It is to solve the instability of ice making that can occur when entering.

Figure 3 shows the change in the pressure drop generated inside the pipe according to the IPF change of the ice slurry, Figure 4 is an experimental value showing the heat transfer coefficient change in the heat exchanger in the cooling apparatus according to the flow rate and the IPF change of the ice slurry, this It can be seen that the heat transfer increases as the ice slurry flow rate and IPF increase, but if the IPF is too high, the pressure drop increases, which increases the pump power and may cause pipe closure.

2A and 2B, the agitator 103 installed in the heat storage tank 101 is installed at the lower end to stir the ice slurry in the heat storage tank while preventing the agitation of the ice particles suspended in the upper surface of the water layer. Since the ice particles suspended on the upper surface are easily changed into a solid ice mass, since it is easy to cause the pipe sealing when it is transported through the supply pipe 106, it is not stirred using the stirrer 103 to the cooling device 11. It is preferable to transfer the cold heat and to melt or stir using water or an aqueous solution returned to the heat storage tank 101 through the return pipe 107.

One or more distribution pipes 27 are connected to the supply pipe 106, and an opening and closing valve 121 and a fourth pump 122 are installed in each distribution pipe 27 to connect with the heat exchanger 120 in the cooling device. Do it. An electric heater 124 is installed in the distribution pipe so that ice particles are agglomerated in the distribution pipe and the pipe is sealed, and an electric heater 124 is installed in the vicinity of the heat exchanger 120 to defrost if necessary. Do it.

In the condition that ice slurries must be circulated in the internal heat exchanger 120 for cooling in the cooling device 11, the opening / closing side 121 of the distribution pipe 27 connected to the heat exchanger 120 is opened and at the same time or a slight time difference. The fourth pump 122 is operated to circulate the ice slurry to the heat exchanger 120 inside the cooling device. In addition, in order to stop the cooling of the ice slurry, which is the secondary refrigerant, in order to stop the cooling, the fourth pump 122 is stopped and the opening and closing valve 121 is closed to improve the cooling efficiency of the cooling device. will be.

In general, since the cooling fan 16 installed outside the heat exchanger 120 in the cooling device or the pump 17 of the cold water pipe always operates, it is stagnant in the heat exchanger 120 in the cooling device even after the circulation of the ice slurry is stopped. By melting all of the ice particles of the ice slurries there may be prevented from sealing the pipe by the ice particles stopped inside the heat exchanger 120, otherwise the cooling fan 16 or cold water after the ice slurry circulation is stopped. After the pump 17 of the pipe is further operated for an appropriate time, the pump 17 is stopped to control the melting of all the ice particles in the ice slurry inside the heat exchanger 120.

Whether the pipe is sealed in the distribution pipe 27 or the heat exchanger 120 during ice ice transportation is detected using a pressure gauge 123 installed in the distribution pipe, and when the pressure rises above the normal state, the pipe is closed. , If the pipe sealing by the ice particles is detected by operating the electric heater 124 to dissolve the ice inside the distribution pipe or heat exchanger can be eliminated pipe sealing. The electric heater 124 may also be utilized in the defrosting process of the heat exchanger.

The temperature sensor 18 mounted inside the cooling device 11 is connected to a control device based on the set temperature to control the opening / closing side 121 and the fourth pump 122 installed in the distribution pipe 27.

The present invention is not limited to the above-described specific preferred embodiments, and various modifications can be made by any person having ordinary skill in the art without departing from the gist of the present invention claimed in the claims. Of course, such changes will fall within the scope of the claims.

The cooling system using the present invention ice slurry as a secondary refrigerant as described above uses a feature that a large amount of cold heat transportation of the ice slurry is excellent and the thawing characteristics, while maintaining the excellent cooling ability of the conventional refrigerant direct expansion cooling system while cooling It is easy to control the capability and excellent ability to cope with load fluctuations.

Refrigerant direct cooling system using a plurality of cooling devices connected to a single cold heat source equipment is difficult to distribute the refrigerant, when using the ice slurry of the present invention as a secondary refrigerant is easy to distribute, cooling Since the general pipe can be used to the heat exchanger inlet of the device, the maintenance is also easy, and thus the cooling system of the present invention utilizing the ice slurry as the secondary refrigerant has advantages of the conventional refrigerant direct cooling system and the indirect cooling system. It is a useful invention having all of them is an invention that is expected to be greatly used in industry.

Claims (7)

In a cooling system, An ice maker for producing an ice slurry in which solid ice particles and liquid water or an aqueous solution are mixed; A heat storage tank for storing the ice slurry with stirring; Storage means configured to store only water or an aqueous solution of ice slurry in or inside the heat storage tank; A supply pipe for supplying ice slurries from the heat storage tank to individual cooling devices; At least one distribution pipe connected to the supply pipe and at least one heat exchanger in the cooling device; A first pump for supplying an ice slurry in the heat storage tank to a cooling device; A second pump for supplying the liquid of the storage means to the supply pipe; A third pump for supplying the liquid of the storage means to the ice maker; An opening and closing valve installed in the distribution pipe to control an ice slurry supply to a heat exchanger in a cooling device; A fourth pump installed in the distribution pipe and supplying the ice slurry to the heat exchanger in the cooling device while operating in conjunction with the opening / closing valve; A temperature sensor provided to measure a temperature inside the cooling device; A cooling system using ice sludge as a secondary refrigerant, characterized in that it is installed in a distribution pipe of a cooling device and consists of a pressure gauge for detecting pressure in a distribution pipe or a heat exchanger. The method of claim 1, Cooling system using the ice sludge as a secondary refrigerant, characterized in that the means for storing only water or an aqueous solution of the ice slurry in the heat storage tank is a partition wall installed in the heat storage tank. The method of claim 1, Cooling system using the ice slurry as a secondary refrigerant, characterized in that the means for storing only water or an aqueous solution of the ice slurry in the heat storage tank is a separate storage tank installed outside the heat storage tank. The method of claim 1, Cooling using the ice slurry as a secondary refrigerant, characterized in that it further comprises an electric heater installed at the distribution pipe or heat exchanger inlet for supplying the ice slurry to the heat exchanger in each cooling device, and defrosting the ice particles when necessary. system. In the control method of the cooling system, An ice maker for producing an ice slurry in which solid ice particles and liquid water or an aqueous solution are mixed; A heat storage tank for storing the ice slurry with stirring; Storage means configured to store only water or an aqueous solution of ice slurry in or inside the heat storage tank; A supply pipe for supplying ice slurries from the heat storage tank to individual cooling devices; At least one distribution pipe connected to the supply pipe and at least one heat exchanger in the cooling device; A first pump for supplying an ice slurry in the heat storage tank to a cooling device; A second pump for supplying the liquid of the storage means to the supply pipe; A third pump for supplying the liquid of the storage means to the ice maker; An opening and closing valve installed in the distribution pipe to control an ice slurry supply to a heat exchanger in a cooling device; A fourth pump installed in the distribution pipe and supplying the ice slurry to the heat exchanger in the cooling device while operating in conjunction with the open / close valve; A temperature sensor provided to measure a temperature inside the cooling device; After having a cooling system installed in the distribution pipe of the cooling device and using the ice slurry made of a pressure gauge for detecting the pressure in the distribution pipe or the heat exchanger as the secondary refrigerant, When the temperature of the cooling device is higher than the set temperature and needs to be cooled, the opening and closing valve of the distribution pipe connected to the heat exchanger in the cooling device opens, and at the same time or with a slight time difference, the fourth pump operates to transfer the ice slurry to the heat exchanger in the cooling device. Circulating; And stopping the supply of the ice slurry to the heat exchanger by stopping the operation of the fourth pump and closing the opening / closing valve when the condition of the cooling device being no longer required while the ice slurry is being cooled by the secondary refrigerant. A control method of a cooling system using the ice slurry as a secondary refrigerant. The method of claim 5, Operating a first pump for transporting ice slurries through a supply pipe in a heat storage tank in a condition that a plurality of coolers are present and ice slurries are supplied to at least one of the coolers and cooling is to proceed; In a condition that cooling is not required in all the cooling devices, the first pump is stopped and the second pump is operated to supply only liquid to the supply pipe, further comprising the step of removing ice sludge present in the supply pipe. A control method of a cooling system using ice slurry as a secondary refrigerant. The method of claim 5, The pressure gauge installed in the distribution pipe of the cooling system detects the sealing of the pipe in the distribution pipe or the heat exchanger.If the pressure in the distribution pipe rises due to the sealing of the pipe due to the aggregation of ice particles, the operation of the fourth pump is stopped. And operating the electric heater installed in the heat exchanger to melt the ice in the distribution pipe or the heat exchanger.

Images