CN1299084C - Double temperature cold water unit for air conditioning system - Google Patents

Abstract

The utility model relates to a dual-temperature cold water/cooler air unit used in an air-conditioning system, which belongs to the technical field of refrigeration and air-conditioning equipment. It is a two-stage compressor consisting of a low-pressure stage compressor and a high-pressure stage compressor, a condenser, a liquid receiver, a high-pressure stage throttle valve, an intercooler, a low-pressure stage throttle valve, and a low-temperature evaporator/evaporative air cooling evaporator, high temperature evaporator and evaporating pressure regulating valve. Its structural feature is that the interior of the high-temperature evaporator is a coil heat exchanger with a medium-temperature cold water channel, which is set in the liquid refrigerant of the intercooler to produce medium-temperature cold water. The non-evaporated liquid refrigerant in the intercooler enters the low-temperature evaporator/evaporative air cooler through the low-pressure throttling valve to produce low-temperature cold water or cold air. The invention can not only provide low-temperature cold water or cold air at about 7°C, but also provide medium-temperature cold water at about 18°C, and can conveniently provide dual-temperature cold sources for the air-conditioning system of "cold radiation ceiling + independent fresh air system". Compared with the prior art, the present invention has the advantages of high energy-efficiency ratio, simple and convenient construction, and easy popularization and popularization.

Description

A dual-temperature cold water/cooler unit for air-conditioning systems

technical field

The invention belongs to the technical field of refrigeration and air-conditioning equipment, in particular to a dual-temperature cold water/cooling air unit used in an air-conditioning system.

Background technique

Traditional air-conditioning systems, such as all-air systems, control indoor heat, humidity, and air quality through ventilation. The cold coil dehumidification method needs to treat the air below its dew point temperature, so a cold source with a lower temperature is required to meet the dehumidification requirements; for the indoor sensible heat load, a higher temperature cold source can meet its requirements. However, in the actual application process, since the system often uses a single cooling source to meet the indoor heat and humidity requirements at the same time, resulting in a mismatch in energy utilization and large irreversible losses in energy transfer. Moreover, the large air supply volume causes thermal comfort problems of the human body such as the feeling of blowing. In order to use energy reasonably and effectively, it is necessary to separate the control of indoor thermal environment, humid environment and air quality. The radiant cooling air-conditioning system works in the "dry working condition" environment, that is, as long as the surface temperature of the radiant panel is controlled above the indoor dew point temperature, the indoor thermal environment control, humidity environment, and air quality control can be controlled. Separately, the radiative cooling system is responsible for removing the indoor sensible heat load and undertaking the task of maintaining the indoor temperature within a comfortable range, while the ventilation system is responsible for the delivery of required fresh air, indoor humidity adjustment, and the dilution and emission of pollutants. This independent control strategy makes it possible for the air-conditioning system to optimize the processing of heat, humidity, and fresh air respectively. It is of great significance to the energy saving of the indoor environment control of the building, and it makes the human body feel more comfortable.

In the existing technology, the air conditioning form of "cold radiant ceiling + independent fresh air system (Dedicated Outdoor Air Systems)" has attracted more and more attention from the industry. This type of system uses medium-temperature cold water at about 18°C in the cold radiant ceiling to take away the indoor sensible heat load, and uses low-temperature cold water at about 7°C in the independent fresh air system to take away the full heat load and indoor latent heat load of the fresh air. Not only can the energy consumption of the air conditioning system be reduced, but also a very comfortable indoor environment can be provided. However, the chillers used in air-conditioning systems in the prior art can only provide a cold source with a single water temperature, and are all developed with the goal of producing 7°C low-temperature cold water. The structure of the existing water chillers adopts the form of a two-stage compression cycle with incomplete cooling in the middle, which is composed of a low-pressure stage compressor, a high-pressure stage compressor, a condenser, a high-pressure liquid receiver, a high-pressure stage throttle valve, an intercooler, and a low-pressure stage. The throttle valve and the low temperature evaporator constitute the cold water production system, as shown in Figure 1. Obtain cold water at a low temperature of about 7°C through a low-temperature evaporator. Since there is no efficient water chiller that provides medium-temperature cold water at around 18°C, two methods are usually used in projects to obtain medium-temperature cold water at around 18°C. One method is to use groundwater as a cooling source. If the temperature of the groundwater is low, mix the groundwater with the cold radiation ceiling water and then send it to the cold radiation ceiling to ensure that the surface temperature of the ceiling is higher than the dew point temperature of the indoor air. The problem with this method is that it is difficult to popularize due to the limitation of groundwater sources. Another method is to first send the low-temperature cold water of about 7°C produced by the chiller to the independent fresh air system to process the fresh air, and then mix the heated cold water with the effluent of the cold radiant ceiling, and then send it to the cold radiant ceiling. The problem with this method is that the chiller needs to produce cold water at a low temperature of about 7°C, the evaporation temperature is low, and it needs to provide cooling capacity to eliminate all heat and humidity loads. Therefore, the energy efficiency of the unit is low, and the engineering construction is difficult. big.

Contents of the invention

In order to solve the above-mentioned technical problems in the prior art, the object of the present invention is to provide a dual-temperature cold water/cooler unit suitable for the air conditioning system of "cold radiant ceiling + independent fresh air system". It can not only provide low-temperature cold water or cold air at about 7°C, but also provide medium-temperature cold water at about 18°C, and has high energy efficiency ratio, simple construction, and easy popularization and promotion.

In order to realize the above-mentioned purpose of the invention, the technical solution of the present invention is realized in the following manner:

A dual-temperature cold water/cooler unit for air-conditioning systems, which is composed of a low-pressure stage compressor and a high-pressure stage compressor, a two-stage compressor, a condenser, a liquid receiver, a high-pressure stage throttle valve, an intercooler, Low-pressure stage throttle valve, low-temperature evaporator/evaporative air cooler and high-temperature evaporator. Its structural feature is that a high-temperature evaporator is arranged in the intercooler, and the high-temperature evaporator is immersed in a medium-temperature liquid refrigerant throttled by a high-pressure throttling valve. The high-temperature evaporator passes through medium-temperature cold water, and the gaseous refrigerant evaporated by being heated by the medium-temperature cold water enters the exhaust pipe of the low-pressure stage compressor through the set evaporation pressure regulating valve, mixes with the exhaust gas of the low-pressure stage compressor, and then enters the high-pressure stage compressor . The non-evaporated liquid refrigerant in the intercooler enters the low-temperature evaporator/evaporative air cooler through the low-pressure stage throttle valve, and the low-temperature evaporator/evaporative air cooler passes through low-temperature cold water or cold air. The vaporized gaseous refrigerant heated by low-temperature cold water or cold wind enters the suction pipe of the low-pressure stage compressor, and the high-pressure and high-temperature gaseous refrigerant compressed by the high-pressure stage compressor enters the condenser. The refrigerant that is condensed into a high-pressure liquid is stored in the liquid receiver, and then enters the intercooler after being throttled by the high-pressure stage throttle valve. Realize the use of high-temperature evaporators to produce medium-temperature cold water, and use low-temperature evaporators/evaporative air coolers to produce low-temperature cold water or cold air.

According to the above technical solution, the high temperature evaporator is a cooling coil heat exchanger.

According to the above technical solution, the high-pressure throttling valve is a float type expansion valve placed in the intercooler to control the liquid level in the intercooler and adjust the heat exchange of the medium-temperature cold water.

According to the above technical solution, both the low-pressure stage compressor and the high-pressure stage compressor are centrifugal refrigeration compressors.

According to the above technical solution, the two-stage compressor composed of the low-pressure stage compressor and the high-pressure stage compressor is a single-unit two-stage compressor.

According to the above technical solution, the two-stage compressor composed of the low-pressure stage compressor and the high-pressure stage compressor is a centrifugal, screw, and scroll type quasi-two-stage compressor with continuous compression characteristics with intermediate air supply. The air outlet of the evaporating pressure regulating valve is directly connected with the intermediate air supply port of the quasi-two-stage compressor.

Due to the adoption of the above-mentioned structure, the dual-temperature cold water/cooler air unit of the present invention can not only provide low-temperature cold water or cold air at about 7°C, but also provide medium-temperature cold water at about 18°C. Its production will promote the vigorous development of the "cold radiant ceiling + independent fresh air system" air-conditioning system to improve people's quality of life and reduce the waste of electricity and groundwater resources. Compared with the prior art, the invention has the advantages of high energy-efficiency ratio, simple construction, easy popularization and popularization, and obvious economic and social benefits.

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

Description of drawings

Fig. 1 is the structural schematic diagram of prior art water chiller;

Fig. 2 is a structural schematic diagram of Embodiment 1 of the present invention;

Fig. 3 is the structural schematic diagram of the second embodiment of the present invention;

Fig. 4 is the structural schematic diagram of the third embodiment of the present invention;

Fig. 5 is a structural principle diagram of Embodiment 4 of the present invention.

Detailed ways

Embodiment one:

As shown in Figure 2, a dual-temperature chiller with independent high- and low-pressure compressors is used. The dual-temperature chiller is a two-stage compression refrigeration cycle with two-stage throttling and incomplete cooling in the middle. It consists of a low-pressure stage compressor 1 and a high-pressure stage compressor 2. A two-stage compressor, a condenser 3, a liquid receiver 4, and a high-pressure stage Throttle valve 5, intercooler 6, low pressure stage throttle valve 7, low temperature evaporator 8, high temperature evaporator 9 and evaporation pressure regulating valve 11 constitute. Wherein the high temperature evaporator 9 is a cooling coil heat exchanger, which is arranged inside the intercooler 6 . When the unit is running, the high-temperature evaporator 9 is immersed in the medium-temperature liquid refrigerant throttled by the high-pressure stage throttle valve 5, and medium-temperature cold water passes through the interior of the high-temperature evaporator 9. The gaseous refrigerant evaporated after being heated by the medium-temperature cold water enters the exhaust pipe of the low-pressure compressor 1 through the evaporation pressure regulating valve 11, mixes with the exhaust gas of the low-pressure compressor 1, and then enters the high-pressure compressor 2. The unevaporated liquid refrigerant in the intercooler 6 enters the low-temperature evaporator 8 through the low-pressure stage throttle valve 7, absorbs the heat of the low-temperature cold water on the other side of the low-temperature evaporator 8 and evaporates, and the evaporated gaseous refrigerant enters the low-pressure stage compressor 1 is compressed and discharged into its discharge pipe, mixed with the gaseous refrigerant returning from the intercooler 6 into the high-pressure stage compressor 2. The high-pressure, high-temperature gaseous refrigerant compressed by the high-pressure compressor 2 enters the condenser 3, and the gaseous refrigerant is condensed into a high-pressure liquid refrigerant through the cooling circuit formed by the cooling water inlet 12 and the cooling water outlet 13, and then stored in the storage tank. In the liquid tank 4, it is throttled by the high-pressure throttle valve 5 and enters the intercooler 6.

The chilled water unit of above-mentioned cycle will enter the water in the high-temperature evaporator 9 by medium temperature cold water inlet 14 and cool to about 18 ℃, deliver to cold radiation ceiling by medium temperature cold water outlet 15 again. And enter the low-temperature evaporator 8 by the low-temperature cold water inlet 16 and make the low-temperature cold water of about 7 ℃, send in the heat exchange equipment of independent fresh air system through the low-temperature cold water outlet 17.

In order to ensure that the high-temperature evaporator 9 is immersed in the liquid refrigerant in the intercooler 6, the high-pressure stage throttle valve 5 is placed in the intercooler 6 with a ball float expansion valve, and the liquid level in the intercooler 6 is controlled by the ball float valve. , to adjust the heat exchange of cold water at medium temperature.

In order to stabilize the intermediate temperature and/or intermediate pressure of the refrigerant in the intercooler 6 after throttling by the high-pressure throttling valve 5 , the evaporating pressure regulating valve 11 is provided to ensure the stability of the working conditions.

Embodiment two:

As shown in Fig. 3, in the above embodiment, the difference is that the two-stage compressor composed of the low-pressure compressor 1 and the high-pressure compressor 2 is a single two-stage compressor 18, which can simplify the structure of the chiller. The outlet pipe of the evaporating pressure regulating valve 11 is connected to the connecting pipeline between the exhaust pipe of the low-pressure compressor 1 and the suction pipe of the high-pressure compressor 2 . Others are identical with embodiment one.

Example 3:

As shown in Figure 4, in the first embodiment above, the difference is that the two-stage compressor composed of the low-pressure stage compressor 1 and the high-pressure stage compressor 2 adopts a centrifugal, screw, The scroll type quasi-two-stage compressor 19 with continuous compression characteristics can further simplify the unit structure, and the outlet pipe of the evaporating pressure regulating valve 11 is directly connected to the intermediate gas supply port of the quasi-two-stage compressor 19 . Others are identical with embodiment one.

Embodiment four:

As shown in Figure 5, a medium-temperature cold water + low-temperature cooling air unit with independent high- and low-pressure compressors is used. The difference is that the low-temperature evaporator 8 of the unit in Embodiment 1 is a direct evaporative air cooler, that is, the high-temperature evaporator 9 is used to produce medium-temperature cold water, and the evaporative air cooler 8 is used to produce low-temperature cold air. The low-temperature cold air is sent to the heat exchange equipment of the independent fresh air system. Others are identical with embodiment one.

Claims (6)

1, a kind of double-temperature refrigerator water/cold wind unit that is used for air-conditioning system, the double-stage compressor that it is made up of low-pressure stage compressor (1) and hiigh pressure stage compressor (2), condenser (3), reservoir (4), hiigh pressure stage choke valve (5), intercooler (6), low-pressure stage choke valve (7), cryogenic vaporizer/vaporation-type aerial cooler (8) and high-temperature evaporator (9) constitute, it is characterized in that, high-temperature evaporator (9) is set in the described intercooler (6), high-temperature evaporator (9) is immersed in the middle temperature liquid refrigerant after hiigh pressure stage choke valve (5) throttling, high-temperature evaporator (9) is inner by middle temperature cold water, by in the heating of warm cold water and evaporation gaseous refrigerant through set evaporating pressure regulating valve (11) enter low-pressure stage compressor (1) blast pipe and with enter hiigh pressure stage compressor (2) after the exhaust of low-pressure stage compressor (1) mixes, the liquid refrigerant that is not evaporated in the intercooler (6) enters cryogenic vaporizer/vaporation-type aerial cooler (8) through low-pressure stage choke valve (7), cryogenic vaporizer/vaporation-type aerial cooler (8) is inner by low-temperature cold water or cold wind, by the heating of low-temperature cold water or cold wind and the gaseous refrigerant of evaporation enters the air intake duct of low-pressure stage compressor (1), high pressure after hiigh pressure stage compressor (2) compression, the high-temperature gas cold-producing medium enters in the condenser (3), the cold-producing medium that is condensed into high-pressure liquid is stored in the reservoir (4), enters intercooler (6) after hiigh pressure stage choke valve (5) throttling; Warm cold water during realization is produced with high-temperature evaporator (9) is produced low-temperature cold water or cold wind with cryogenic vaporizer/vaporation-type aerial cooler (8).

2, according to the described double-temperature refrigerator water of claim 1/cold wind unit, it is characterized in that described high-temperature evaporator (9) is the cooling coil heat exchanger.

3, according to claim 1 or 2 described double-temperature refrigerator water/cold wind units, it is characterized in that, described hiigh pressure stage choke valve (5) is for placing the float-ball type expansion valve of intercooler (6), with the heat exchange amount of warm cold water in the liquid level in the control intercooler (6), the adjusting.

According to the described double-temperature refrigerator water of claim 3/cold wind unit, it is characterized in that 4, described low-pressure stage compressor (1) and hiigh pressure stage compressor (2) all adopt centrifugal refigerating compressor.

According to the described double-temperature refrigerator water of claim 3/cold wind unit, it is characterized in that 5, the double-stage compressor that described low-pressure stage compressor (1) and hiigh pressure stage compressor (2) are formed is single machine two-stage compressor (18).

6, according to the described double-temperature refrigerator water of claim 3/cold wind unit, it is characterized in that, the double-stage compressor that described low-pressure stage compressor (1) and hiigh pressure stage compressor (2) are formed is centrifugal, the screw of tonifying Qi in the middle of the band, the accurate double-stage compressor (19) with continuous compressive features of vortex, and the gas outlet of described evaporating pressure regulating valve (11) directly is connected with the middle gas supplementing opening of accurate double-stage compressor (19).

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