HIGH-EFFICIENCY EXTRA-LARGE COOLING CAPACITY SERIES CHILLER IN ENERGY STATION

Abstract

A high-efficiency extra-large cooling capacity series water-cooled chiller in an energy station, comprising at least two evaporators, a condenser, a chilled water main pipe and a cooling water main pipe, all the evaporators form an evaporator series set in a series connection form, both ends of the evaporator series set are connected to the chilled water main pipe, and each evaporator is provided with a refrigerant channel for connecting the condenser. According to the present invention, the evaporators are set in series combination. When the load is very low, one compressor operates at a high load or at full load, that is, the compressor continuously operates in a high efficiency zone, which avoids multiple compressors operating in an inefficient zone, and high total power.

Description

This application claims priority to Chinese Patent Application Ser. No. CN 201810500187X filed on May 23, 2018.

TECHNICAL FIELD

The present invention relates to a water-cooled chiller, and more particularly, to a high-efficiency extra-large cooling capacity series water-cooled chiller in an energy station using a multistage pipe embedded evaporator.

BACKGROUND

Present water-cooled chillers, compressors, evaporators, condensers and expansion valves are compactly assembled together. When multiple chillers are used in parallel, chilled water with higher temperature flew back at the tail end of the chiller will enter each parallel chiller along branches of chilled water return main pipes. After being cooled, the chilled water will be incorporated to the chilled water main supply pipes through each chilled water supply branch, and then supplied to the tail end. This type of chiller takes up a lot of space because of the connection of multiple branches and the reasonable installation space required by the chiller itself.

The chiller operates at high load rates with high efficiency and operates at low and medium loads with low efficiency. When the tail end load is small, that is, the cooling demand is small, but the chilled water flow demand is large because the cooling area is large, a single chiller can operate in the high efficiency zone when the existing chiller is used in the case that the number of operating chillers is small. The total power is lower, but due to the limitation of the pipe diameter of the evaporator, the flow of the chilled water delivered is small, such that there is insufficient chilled water flow at the tail end, and the cooling effect is poor in some areas. If the number of operating chillers is large, the chilled water delivered can meet the tail end demand, but a single chiller operates in a low-load, low-efficiency zone, which has a high total power. Because the chillers are selected according to the highest cooling load, the chillers operate under the above-mentioned low-load conditions in most of the time, and the energy consumption of a cold water host is high.

In order to ensure the safe operation of the chiller, no matter the chiller operates in high or low and medium loads, the chilled water pump must continue to provide a basic fixed head consumption for the chiller, generally no less than 80 kPa, resulting in high energy consumption of the chilled water pump.

The designed chilled water supply and return temperature difference of the existing chiller is generally 5 to 8□. When the actual temperature difference is higher or lower than the design value during operation, the efficiency of the chiller will decrease. In addition, the existing chillers cannot achieve a given chilled water return temperature by adjusting the chilled water supply temperature (6 to 12□) in a wide range. Therefore, for the project which requires frequently changed temperature difference at the tail end and can keep comfortable at a fixed return temperature, the existing chiller cannot provide the cooling capacity continuously, efficiently and effectively.

SUMMARY

Object of the present invention: in order to overcome the deficiencies in the prior art, a high-efficiency extra-large cooling capacity series water-cooled chiller in an energy station with high operating efficiency and small energy consumption and using a multistage pipe embedded evaporator is provided.

Technical solutions: in order to achieve the above object, the present invention provides a high-efficiency extra-large cooling capacity series water-cooled chiller in an energy station comprising at least two evaporators, a condenser, a chilled water main pipe and a cooling water main pipe. All the evaporators form an evaporator series set in a series connection form, both ends of the evaporator series set are connected to the chilled water main pipe, and each evaporator is provided with a refrigerant channel for connecting the condenser, the refrigerant channel is divided into two parts comprising a refrigerant supply channel and a refrigerant return channel, the refrigerant supply channel and the refrigerant return channel are respectively provided with a relief valve and the compressor, the evaporator is internally provided with a temperature sensor for collecting a temperature of chilled water leaving the evaporator, and the temperature sensor is connected to the corresponding compressor.

The design principle of the present invention is as follows: the evaporators are arranged in series combination, and each evaporator can reduce the temperature of the chilled water by about 3 degrees at the rated flow rate and the full load of the compressor. When the load is very low, one compressor operates at a high load or at full load, that is, the compressor continuously operates in a high efficiency zone, which avoids multiple compressors being operated in an inefficient zone, and high total power, so that the energy consumption of the chiller is greatly saved. Moreover, because the series structure is adopted, one evaporator operation can provide the same chilled water flow as that of three evaporator operation, which can meet the chilled water flow demand at the tail end.

Further, the evaporator series set is embedded in the chilled water main pipe.

Further, an evaporating shell pass of the evaporator serves as a refrigerant channel, and the evaporator is internally provided with a plurality of evaporating tube passes as chilled water channels. The evaporating tube pass is a single-pass structure, a water pressure drop of each evaporator is 6 to 8 kPa, and the water pressure drop is 18 to 24 kPa if three evaporators are connected in series, which is obviously smaller than a water pressure drop (50 to 100 kPa) of an evaporator of the current chiller, so that an energy consumption of a chilled water pump can be reduced.

Further, the condenser is embedded in the cooling water main pipe, a condensing shell pass of the condenser serves as a refrigerant channel and the condenser is internally provided with a plurality of condensing tube passes as cooling water channels, such that both the refrigerant and the cooling water have respectively independent channels and will not contact and interfere with each other. The refrigerant flows between the separate evaporators and the overall condenser. No matter how many evaporators are operating, the refrigerant can maximize the heat exchange area in the condenser and improve the operating efficiency of each compressor.

Further, a total length of the refrigerant channel is no more than 200 meters, and a length of the refrigerant channel should not be too long, which may affect the using effect of the refrigerant.

Further, the condenser is placed on the ground, and the evaporator is suspended above the condenser. The evaporator does not occupy the floor space, which can reduce an area of a central air-conditioning room.

Further, the evaporator and the chilled water main pipe are connected by a reduction nipple, so that the evaporators of different pipe diameters can be perfectly jointed with the chilled water main pipe.

Further, a total cross-sectional area of the condensing tube passes is no less than a cross-sectional area of the chilled water main pipe, and a total cross-sectional area of the condensing tube passes is no less than a cross-sectional area of the cooling water main pipe, thus reducing the resistance for the chilled water and the cooling to flow in and out of the evaporator and the condenser respectively, and making the chilled water and the cooling water flow in and out more smoothly.

Beneficial effects: compared with the prior art, the present invention has the following advantages.

1. The evaporators are set in series combination. When the load is very low, one compressor operates at a high load or at full load, that is, the compressor continuously operates in a high efficiency zone, which avoids multiple compressors being operated in an inefficient zone, and high total power, so that the energy consumption of the chiller is greatly saved.

2. Both the tube passes and the shell passes are single-pass structures, so that the chilled water and the cooling water do not require a return stroke. Compared with the original return structure, the flow resistance of the chilled water and the cooling water is reduced, thereby reducing the energy consumption.

3. Because of the series structure, one evaporator operation can provide the same chilled water flow as that of multiple evaporator operation, which can meet the chilled water flow demand at the tail end, so that each compressor can meet the chilled water demand at the tail end on the basis of keeping high efficiency operating, which not only guarantees the cooling effect, but also greatly saves the energy consumption and reduces the operating costs, thus being very suitable for large-area centralized cooling.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a structural schematic diagram of the present invention;

FIG. 2 is a sectional drawing of an evaporator;

FIG. 3 is a sectional drawing of a condenser;

FIG. 4 is a structural schematic diagram of a chiller in a second embodiment; and

FIG. 5 is a partial schematic diagram of a flow direction of cooling water.

DETAILED DESCRIPTION

The invention will be further clarified with reference to the accompanying drawings and specific embodiments. It should be appreciated that these embodiments are intended to illustrate the invention and not to limit the scope of the invention. Modifications of equivalent forms to the invention made by those skilled in the art after reading the invention all fall within the scope defined by the appended claims of the application.

First Embodiment

As shown in FIG. 1 to FIG. 3, the present invention provides a high-efficiency extra-large cooling capacity series water-cooled chiller in an energy station comprising three evaporators 1, a condenser 3, a chilled water main pipe 21 and a cooling water main pipe 31. The three evaporators 1 are embedded in the chilled water main pipe 21, each evaporator 1 is provided with a refrigerant channel 5 for connecting the condenser 3, each refrigerant channel 5 is divided into two parts comprising a refrigerant supply channel 51 and a refrigerant return channel 52, the refrigerant supply channel 51 and the refrigerant return channel 52 are respectively provided with a relief valve 4 and the compressor 2, the evaporator 1 is internally provided with a temperature sensor 10 for collecting a temperature of chilled water leaving the evaporator 1, and the temperature sensor 10 is connected to the corresponding compressor 2. The evaporator 1 adopts a structure of a full liquid evaporator, an evaporating shell pass 11 of the evaporator 1 serves as a refrigerant channel, and the evaporator 1 is internally provided with a plurality of evaporating tube passes 12 as chilled water channels, and the condenser 3 is embedded in the cooling water main pipe 31. The condenser 3 adopts a structure of a full liquid condenser, a condensing shell pass 32 of the condenser 3 serves as a refrigerant channel, and the condenser 3 is internally provided with a plurality of condensing tube passes 33 as cooling water channels, and a total length of the refrigerant channel 5 is 100 meters. The condenser 3 is placed on the ground and the evaporator 1 is suspended above the condenser 3. Both the evaporator 1 and the chilled water main pipe 21, and the condenser 3 and the cooling water main pipe 31 are connected by a reduction nipple. A total cross-sectional area of the evaporating tube passes 12 is no less than a cross-sectional area of the chilled water main pipe 21, and a total cross-sectional area of the condensing tube passes 33 is no less than a cross-sectional area of the cooling water main pipe 31.

Second Embodiment

A target temperature value of a chilled water supply temperature of the chiller was preset. As shown in FIGS. 2 and 4, three evaporators 1 were respectively recorded as an evaporator a, an evaporator b and an evaporator c, and chilled water return water 6 entered an evaporating tube pass 12 of the evaporator a through a chilled water main pipe 21, a refrigerant was located in an evaporating shell pass 11 of the evaporator a, and the refrigerant exchanged heat with the chilled water return water 6 in the evaporating tube pass 12 to become a gaseous state, the temperature of the chilled water return water 6 dropped, a relief valve 4a was opened, the gaseous refrigerant entered a refrigerant supply channel 51a, and then flowed into a condenser 3. The gaseous refrigerant flew in a condensing shell pass 32 of the condenser 3, and the gaseous refrigerant was turned into a liquid state by the compression of a compressor 2a and returned to the evaporator a through a refrigerant circuit channel 52a. The process was circulated in this way.

Therefore, when the compressor 2a and the condenser 3 were operating, the refrigerant flew between the evaporator 1 and the entire condenser 3, completing the process of transferring heat from the evaporator 1 to the condenser 3, and the temperature of the chilled water dropped. A temperature sensor 10a collected a temperature value of the chilled water leaving the evaporator a as the operation basis for a compressor 2b. When the temperature value collected by the temperature sensor 10a was higher than the preset target temperature value, the temperature sensor 10a sent a start instruction to the compressor 2b.

The chilled water return water 6 entered the evaporator b, a relief valve 4b was in an opened state. The gaseous refrigerant entered a refrigerant supply channel 51b, and then flew into the condenser 3. The gaseous refrigerant flew in the condensing shell pass 32 of the condenser 3, and the gaseous refrigerant was turned into a liquid state by the compression of a compressor 2b and returned to the evaporator b through a refrigerant return channel 52b. The process was circulated in this way.

Therefore, when the compressor 2b and the condenser 3 were operating, the refrigerant flew between the evaporator 1 and the entire condenser 3, completing the process of transferring heat from the evaporator 1 to the condenser 3, and the temperature of the chilled water dropped again. A temperature sensor 10b collected a temperature value of the chilled water leaving the evaporator b as the operation basis for a compressor 2c. When the temperature value collected by the temperature sensor 10b was higher than the preset target temperature value, the temperature sensor 10b sent a start instruction to the compressor 2c.

The chilled water return water 6 entered the evaporator c, a relief valve 4c was in an opened state. The gaseous refrigerant entered a refrigerant supply channel 51c, and then flew into the condenser 3. The gaseous refrigerant flew in the condensing shell pass 32 of the condenser 3, and the gaseous refrigerant was turned into a liquid state by a compressor 2c and returned to the evaporator c through a refrigerant return channel 52c. When the compressor 2c and the condenser 3 were operating, the refrigerant flew between the evaporator 1 and the entire condenser 3, completing the process of transferring heat from the evaporator 1 to the condenser 3, and the temperature of the chilled water dropped again. A temperature sensor 10c collected a temperature value of the chilled water leaving the evaporator c, and the chilled water was outputted through the chilled water main pipe 21 as chilled water supply water 7.

Third Embodiment

A target temperature value of a chilled water supply temperature of the chiller was preset. As shown in FIGS. 2 and 4, three evaporators 1 were respectively recorded as an evaporator a, an evaporator b and an evaporator c, and chilled water return water 6 entered an evaporating tube pass 12 of the evaporator a through a chilled water main pipe 21, a refrigerant was located in an evaporating shell pass 11 of the evaporator a, and the refrigerant exchanged heat with the chilled water return water 6 in the evaporating tube pass 12 to become a gaseous state, the temperature of the chilled water return water 6 dropped, a relief valve 4a was in opened state, the gaseous refrigerant entered a refrigerant supply channel 51a, and then flowed into a condenser 3. The gaseous refrigerant flew in a condensing shell pass 32 of the condenser 3, and the gaseous refrigerant was turned into a liquid state by a compressor 2a and returned to the evaporator a through a refrigerant return channel 52a. When the compressor 2a and the condenser 3 were operating, the refrigerant flew between the evaporator 1 and the entire condenser 3, completing the process of transferring heat from the evaporator 1 to the condenser 3, and the temperature of the chilled water dropped. A temperature sensor 10a collected a temperature value of the chilled water leaving the evaporator a as the operation basis for a compressor 2b; when the temperature value collected by the temperature sensor 10a was lower than the preset target temperature value, a relief valve 4b, a relief valve 4c, the compressor 2b and a compressor 2c were all in a closed and stopped state, which did not cool the chilled water return water 6. The chilled water return water 6 passed through the evaporator b and the evaporator c in sequence, and was finally outputted through the chilled water main pipe 21 as chilled water supply water 7.

Fourth Embodiment

As shown in FIG. 1 and FIG. 5, a condenser 3 was connected to a cooling water main pipe 31, and was powered by a cooling pump. Cooling water return water 8 cooled by a cooling tower entered the condenser 3 to cool the condenser 3, and take away the heat of the condenser 3. Cooling water effluent 9 flew to the cooling tower 91, and the process was circulated in this way.

It can be known from the second embodiment and the second embodiment that no matter how many compressors 2 are compressor, each compressor 2 can maintain full load operation, avoiding the compressor 2 in a low load operating state. The operating efficiency of the chiller is very efficient, and the energy consumption is reduced.

Claims

1. A high-efficiency extra-large cooling capacity series chiller in an energy station, comprising at least two evaporators (1), a condenser (3), a chilled water main pipe (21) and a cooling water main pipe (31), wherein all the evaporators (1) form an evaporator series set in a series connection form, both ends of the evaporator series set are connected to the chilled water main pipe (21), and each evaporator (1) is provided with a refrigerant channel (5) for connecting the condenser (3), the refrigerant channel (5) is divided into two parts comprising a refrigerant supply channel (51) and a refrigerant return channel (52), the refrigerant supply channel (51) and the refrigerant return channel (52) are respectively provided with a relief valve (4) and the compressor (2), the evaporator (1) is internally provided with a temperature sensor (10) for collecting a temperature of chilled water leaving the evaporator (1), and the temperature sensor (10) is connected to the corresponding compressor (2).

2. The high-efficiency extra-large cooling capacity series water-cooled chiller in an energy station according to claim 1, wherein the evaporator series set is embedded in the chilled water main pipe (21).

3. The high-efficiency extra-large cooling capacity series chiller in an energy station according to claim 1, wherein an evaporating shell pass (11) of the evaporator (1) serves as a refrigerant channel, and the evaporator (1) is internally provided with a plurality of evaporating tube passes (12) as chilled water channels.

4. The high-efficiency extra-large cooling capacity series chiller in an energy station according to claim 1, wherein the condenser (3) is embedded in the cooling water main pipe (31), a condensing shell pass (32) of the condenser (3) serves as a refrigerant channel, and the condenser (3) is internally provided with a plurality of condensing tube passes (33) as cooling water channels.

5. The high-efficiency extra-large cooling capacity series chiller in an energy station according to claim 1, wherein a total length of the refrigerant channel (5) is no more than 200 meters.

6. The high-efficiency extra-large cooling capacity series chiller in an energy station according to claim 1, wherein the condenser (3) is placed on the ground and the evaporator (1) is suspended above the condenser (3).

7. The high-efficiency extra-large cooling capacity series chiller in an energy station according to claim 1, wherein the evaporator (1) and the chilled water main pipe (21) are connected by a reduction nipple.

8. The high-efficiency extra-large cooling capacity series chiller in an energy station according to claim 3, wherein a total cross-sectional area of the evaporating tube passes (12) is no less than a cross-sectional area of the chilled water main pipe (21).

9. The high-efficiency extra-large cooling capacity series chiller in an energy station according to claim 4, wherein a total cross-sectional area of the condensing tube passes (33) is no less than a cross-sectional area of the cooling water main pipe (31).

10. The high-efficiency extra-large cooling capacity series chiller in an energy station according to claim 2, wherein the condenser (3) is placed on the ground and the evaporator (1) is suspended above the condenser (3).

11. The high-efficiency extra-large cooling capacity series chiller in an energy station according to claim 3, wherein the condenser (3) is placed on the ground and the evaporator (1) is suspended above the condenser (3).

12. The high-efficiency extra-large cooling capacity series chiller in an energy station according to claim 4, wherein the condenser (3) is placed on the ground and the evaporator (1) is suspended above the condenser (3).

13. The high-efficiency extra-large cooling capacity series chiller in an energy station according to claim 5, wherein the condenser (3) is placed on the ground and the evaporator (1) is suspended above the condenser (3).