RU2375222C1 - Passenger railway car air conditioner - Google Patents

Abstract

FIELD: railroad transport. ^ SUBSTANCE: air conditioner represents an integral independent unity mounted under roof of passenger car and comprises tight heat-insulated housing (1) with air inlet and outlet. Housing (1) is separated by web (2) into two compartments. First compartment accommodates refrigerating compressor (3), two axial fans (4), and air condensers (5). Web (2) has openings with valves (6) arranged between outside air inlet and air condensers (5). Second compartment accommodates supply fan (7) and outside air valves (8), air filters (9), air coolers (10), water and electric calorifers (11, 12) arranged along outside airflow. First compartment incorporates additionally parallel feed evaporator coolers (13) fitted in first compartment ahead of air condensers (5). Second compartment houses recuperative heat exchangers (14) mounted ahead of air filters (9), between outside air inlet and opening in web (2). Housing bottom accommodates condensate collector (15) and water pump (17). ^ EFFECT: higher efficiency. ^ 2 dwg

Description

The invention relates to equipment for railway transport, providing comfortable conditions for passengers in cars, in particular to installations for air conditioning.

Known installation of air conditioning (VHF), made in the form of a monoblock placed in the roof space of the car, and which are automatically adjustable compression refrigeration machines [1].

The disadvantage of such VHFs with compression refrigeration machines is their high energy consumption. For example, at a rated cooling capacity of 20–28 kW, the total energy consumption is 15–20 kW.

Indirectly-evaporative type air conditioning units are deprived of this drawback, based on the effect of air cooling during its humidification [2]. These units, placed partly under the carriage, partly under its roof, have much lower power consumption, determined only by the fan used to blow air, and with a cooling capacity of 20 kW it is 3-5 kW. The disadvantage of such air conditioning units is the impossibility of stable operation with nominal cooling capacity in regions with a relative outdoor humidity of more than 40%, typical of most regions of the Russian Federation.,

The closest technical solution to the claimed object of the invention, adopted as a prototype, is the installation of air conditioning for passenger cars, made in the form of a single autonomous unit, placed in the roof space of a railway carriage, and containing a sealed heat-insulated casing with windows for air inlet and outlet, and the casing divided by a partition into two compartments, one of which has fans, a refrigeration compressor and air condensers, and the other has a supply The fan, external air valves, and electric water heaters. At least one axial fan is installed in the compartment where the refrigeration compressor and air condensers are located, while in the said partition dividing the heat-insulated casing into two compartments, windows for the passage of external air are made in the sections between the windows for external air inlet and the condensers with adjustable valves installed in them. Axial fans are made with DC valve motors [3].

The main disadvantage of this installation is its high energy consumption, which at high outdoor temperatures, in particular at temperatures above 35 ° C, is approximately 20 kW with a cooling capacity of 28 kW.

The aim of the present invention is to provide such a design for an air conditioning installation of passenger cars, which would ensure high efficiency of the VHF workflow with all the required and actually existing summer air temperature range.

This goal is achieved by the fact that in the inventive installation of air conditioning of passenger cars, made in the form of a single autonomous unit, placed in the roof space of a railway car, containing a heat-insulated casing with windows for air inlet and outlet, divided by a partition into two compartments with refrigeration equipment machines, in the first of which a compressor is installed, at least two axial fans and condensers, while in the partition, in areas between the window for the windows of the external air inlet and condensers are made with valves installed in them, and at least one supply fan is installed in the second compartment, and the external air valves, air filters, air coolers, water heaters are arranged sequentially in relation to the air entering the installation and electric heaters, according to the invention, in the VHF compartment, where the refrigeration compressor and air condensers are located, in addition to the condensers in the direction of travel Direct-flow evaporative air cooling devices are installed in the air, and in the VHF compartment, where the air supplied to the car is processed, a regenerative heat exchanger is placed between the window for external air inlet and the window in the partition, a condensate collector and a water pump are installed in the bottom of the case.

The invention is illustrated by a description with reference to the drawings, where:

Figure 1 - layout diagram of the implementation of the compression-evaporative installation of air conditioning.

Figure 2 - schematic pneumohydraulic diagram of the processing of air in an air conditioning installation.

The air conditioning installation of passenger cars is made in the form of a single autonomous unit, located in the roof space of a railway car, containing a heat-insulated casing 1 with windows for air inlet and outlet, divided by a partition 2 into two compartments with the equipment of a refrigeration machine. A compressor 3, at least two axial fans 4, condensers 5 are installed in the first compartment. In this case, windows with installed valves 6 are made in the partition 2 in the sections up to the condensers 5. Supply fans 7 are installed in the second compartment, and they are symmetrical with respect to them the external air valves 8, air filters 9, air coolers 10, water heaters 11 and electric heaters 12 are arranged sequentially in the direction of the air entering the air unit. According to the invention, in the VHF compartment where the refrigerator is located compressor and air condensers, additionally, direct-flow evaporative cooling devices 13 are installed in front of the condensers in the direction of the air flow, and regenerative heat exchangers 14 are installed in the second compartment up to the air filters 9, a condensate collector 15 is made in the bottom of the body with the possibility of water supply from the water supply system through the valve 16 and water pump 17.

Various constructive solutions of direct-flow evaporative cooling devices and regenerative heat exchangers are possible. Direct-flow evaporative cooling devices 13 can be made in the form of combs with nozzles; a casing filled with hygroscopic material, irrigated with water, etc. Recuperative type heat exchangers 14 can be made in the form of plate or fin heat exchangers with cross or countercurrent air flow: the main one supplied to the carriage and the auxiliary one that has passed direct-through evaporative cooling devices 13. Direct-flow evaporative cooling devices and regenerative type heat exchangers form the first outdoor air cooling circuit .

The work of the proposed VHF is carried out in the following modes:

- air cooling;

- ventilation;

- air heating (in heat pump mode or with

electric and / or water heaters).

When operating in cooling mode, a chiller and ventilation equipment are involved in the installation. Air cooling is as follows. When the chiller is turned on under the action of the vacuum created by the supply fan 7, recirculated air from the car and outside air enter the air conditioning unit through the windows in the casing wall, the flow rate of which can be controlled using the valves of the outdoor air 8. The flows of recirculated and outdoor air are mixed, pass through the air filters 9, then, cooling in the air cooler 10, the air is pumped using the supply fan 7 into the car through the window for the exit annogo fresh air.

The difference of the claimed VHF is that the external air, before mixing with the recirculation air, passes through the heat exchanger of the regenerative type 14 and is pre-cooled in it, with the part of the auxiliary air stream previously passed through the direct-flow evaporative cooling device 13 and cooled to it to the temperature of the wet thermometer. Another part of this cooled auxiliary stream is supplied to the condensers 5 and increases the efficiency of the chiller by reducing the condensing pressure of the refrigerant, reducing its energy consumption.

The operation of VHF in this mode is clearly illustrated by the circuit in figure 2. The fan 4 takes the air flow from the medium and directs it to the direct-flow evaporative cooling device 13, where it is moistened to saturation and cooled to the temperature of the “wet thermometer”. Then, using valve 6, it is divided into two streams. One is used to cool the condenser 5 and is discharged into the atmosphere, the second passes through a regenerative heat exchanger type 14 and is also discharged into the atmosphere. In this case, the temperature and condensation pressure of the refrigerant will decrease, which will lead to a decrease in the degree of compression of the refrigerant in the compressor and a decrease in the power consumption of VHF [4, 5]. The fan 7 provides the movement of external air through a heat exchanger of the regenerative type 14 in countercurrent or cross-flow with a cooled auxiliary stream, the external air is cooled, while maintaining the original moisture content, and sent for subsequent cooling to the evaporator 10 of the compression refrigeration machine, and then to the air-conditioned object with the required temperature . Thermodynamic analysis of the operation of such a combined compression-evaporative VHF shows that its power consumption does not exceed 7 ÷ 10 kW, i.e. under comparable conditions, it turns out to be twice as efficient as pure compression in energy consumption. [four; 5]

For further analysis, we turn to a specific example. We assume that the outside air has a temperature of t _n = 40 ° C, a moisture content of d _n = 13.7 g / kg, a relative humidity of φ _n = 30% and a specific enthalpy i _n = 75 kJ / kg. In compartment cars at a selected outdoor temperature, it is considered to be a comfortable temperature t _at = 26 ° C. In order to maintain it, the central air conditioner must remove heat flux up to 8 kW from the car. For this, the air conditioner must continuously pump fresh air into the car, the flow rate G _{x of} which will depend on its temperature t _x . We assume that the temperature at the entrance to the car is maintained equal to t _x = 12 ° C. At this temperature, air has a density

ρ ≅ 1.2 kg / m ³ , moisture content d _x = 8 g / kg and specific enthalpy i _x = 31 kJ / kg. The specific enthalpy of air in the car at a temperature t _in = 26 ° C and a moisture content of d _in = 8 g / kg is i _in = 50 kJ / kg, therefore, SCR should provide an air flow rate of at least

G _x ≅ 0.4 m ³ / s = 1440 m ³ / h. Therefore, at a relative humidity of outdoor air φ _n = 30%, according to the id-diagram, a typical air conditioner is required to provide cooling capacity Q _x = 21.2 kW, consuming electricity of at least 15 kW.

Combined SCR must have the same cooling capacity (Q _x = 21.2 kW). However, part of it will be generated by the regenerative heat exchanger RT. According to the id-diagram, in RT, the outside air is able to cool to the temperature of the "wet thermometer" t _mt , which in this case is close to 25 ° C. We assume that the cooled air enters the evaporator of the air conditioner with a temperature of 27 ° C, while maintaining the original moisture content d _n = 13.7 g / kg, i.e. having a relative humidity φ _t = 63% and a specific enthalpy i _t = 63 kJ / kg. Therefore, the desired cooling capacity of the heat exchanger RT is

Q _RT = 5.8 kW, and the missing part of the total cooling capacity should provide a compression air conditioner. We have Q ₀ = (Q _x - Q _RT ) = 15.4 kW.

To evaluate the energy consumption of a compression air conditioner, you should know its refrigeration coefficient k _x . As experience shows, it substantially depends on the temperature of the air cooling the condenser CD. If we assume that air with a temperature of 40 ° C is used to cool the condenser (as in a typical compression SCR), then the refrigeration coefficient is close to k _x ≅ 1.5. In this case, the air conditioner will consume electricity with a power of W = Q ₀ / k _x = 10.2 kW. But physically this means that in the combined SCR, all the outside air cooled by the regenerative heat exchanger is supplied only to the evaporator. Whereas in the considered block diagram, humidified air having the temperature of the “wet thermometer”, i.e. with a temperature of 27 ° C, which is 13 K lower than the temperature of the outside air. Therefore, even at t _n = 40 ° C, the refrigeration coefficient of the air conditioner due to lowering the condensate temperature can reach values of k _d ≅ 3. PCHM will consume energy with the power W = Q ₀ / k _x = 5.1 kW, and the total energy consumption of the combined SCR ( taking into account additional fan power) will not exceed 7 kW.

An important result was obtained - the combined SCR under equal external conditions (in the example close to the limiting) turned out to be almost two times more economical than a typical compression SCR.

When operating in ventilation mode, the chiller, water heaters 11, electric heaters 12, once-through evaporative cooling devices 13 and fans 4 are turned off and only supply fans 7, outdoor air valves 8 are used to ensure air exchange in the car.

When operating in air heating mode, water heaters 11 and electric heaters 12 can be activated. Adjustable air exchange is ensured by external air valves 8. Air is forced into the car using a supply fan 7, as described above.

In the heat pump mode, the unit provides heating of the supply air during operation of the refrigeration machine. The flows of the refrigerant are reversed, and hot steam will be introduced into the air coolers 10. The air passing through the air cooler is heated by removing heat from the condensing vapor of the refrigerant.

Information sources

1. Ventilation systems and air conditioning installations. Wagons. / Ed. L.D. Kuzmina. - M. Mechanical Engineering, 1978.

2. Markman M.D., Nazartsev A.A. / Features of the development and equipping of KSKV passenger cars of increased comfort. / Ventilation, air conditioning and heating systems in passenger cars. Collection of reports of a scientific and practical seminar. Ed. prof. S.E.Burovogo .:

SPbGUNiPT, BTKiO CJSC, BSK LLC. - SPb. 2001 year

3. Patent No.RU 2223880 C1. Air conditioning installation of a passenger railroad car. / Emelyanov A.L., Garanov S.A.

4. Kurylev ES, Gerasimov N.A. Refrigeration units:

A textbook for university students enrolled in the specialty "Refrigeration and compressor machines and installations." - 3rd ed., Revised. and add. - L .: Engineering, Leningrad. Department, 1980 .-- 662 p., ill.

5. Refrigerators: A textbook for students of technical colleges of the specialty "Technics and Physics of Low Temperatures". / A.V. Baranenko, N.N. Bukharin, V.I. Pekarev, L.S. Timofeevsky; Under the total. ed. L.S. Timofeevsky. - SPb .: Polytechnic, 2006. - 944 p.: Ill.

Claims (1)

The air conditioning installation of a passenger railway carriage, made in the form of a single autonomous unit installed in the roof space of a railway carriage, containing a sealed heat-insulated casing with windows for air inlet and outlet, the casing being divided by a partition into two compartments, the first one has a refrigeration compressor, at least , two axial fans, air condensers, while in the partition on the sections between the window for external air inlet and the air condenser The windows are made with valves installed in them, and in the second compartment at least one supply fan and outdoor air valves, air filters, air coolers, water and electric heaters located along the direction of the outdoor air are installed, characterized in that in the first compartment straight-through evaporative cooling devices are additionally installed in front of the air condensers in the direction of the air flow, and in the second compartment in front of the air filters between the window for external air inlet and A recuperative type heat exchangers are placed in a window in the partition, and a condensate collector and a water pump are installed in the bottom of the installation case.

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