KR100378533B1 - An expansion device for turbo-chillers - Google Patents

Abstract

The present invention corresponds to the freezing capacity of the freezer by reducing the enthalpy of the refrigerant flowing into the evaporator by increasing the kinetic energy at the outlet by using a supersonic nozzle as an expansion mechanism for expanding the liquid refrigerant condensed in the condenser of the turbo freezer and sending it to the evaporator. It relates to an expansion mechanism that can further obtain the latent heat of evaporation of the refrigerant per unit flow rate.

The present invention is an expansion mechanism for expanding the liquid refrigerant condensed in the condenser of the turbo refrigerator to send to the evaporator,

Characterized in that one or a plurality of supersonic nozzles for increasing the kinetic energy of the refrigerant on the end of the refrigerant pipe connecting the condenser and the evaporator.

Description

An expansion device for turbo-chillers

The present invention relates to an expansion mechanism for use in a turbo-cooler, and in particular, to expand the liquid refrigerant condensed in the condenser of the turbo-cooler and to send it to the evaporator. It relates to an expansion mechanism that can further obtain the latent heat of evaporation of the refrigerant per unit flow rate corresponding to the freezing capacity of the refrigerator by reducing the enthalpy of.

1 is a block diagram of a typical single stage turbo compressor. The refrigerant gas evaporated in the evaporator 2 is compressed by the turbo compressor 3 to be a gas of high temperature and high pressure and is sent to the condenser 4. The refrigerant gas is condensed in the condenser 4 to become a liquid phase, and the liquid refrigerant is added at the bottom of the condenser 4 to expand in the orifice 1 and temperature and pressure drop occur. The expanded refrigerant flows into the evaporator in a mixture of liquid and gaseous phases.

Conventionally, an orifice (or valve) throttling device having a simple structure as an expansion mechanism has been used, or an isentropic expansion mechanism such as a turbine has been used. It is an expansion mechanism that is simple in structure and easy to design, and is widely used in turbo chillers.

However, since the enthalpy value before and after expansion is the same, the latent heat of evaporation of the refrigerant in the evaporator is smaller than that of the turbine type expansion mechanism. Turbine-type expansion mechanism is advantageous in terms of efficiency because the enthalpy of the refrigerant flowing into the evaporator is low by expanding the refrigerant through isotropic process to obtain more heat of evaporation than isotropic expansion and recovering turbine days. The design is difficult and the device is additionally disadvantageous economically.

Therefore, the present invention is to solve the above problems of the prior art, by expanding the kinetic energy at the outlet by using a supersonic nozzle as an expansion mechanism for expanding the liquid refrigerant condensed in the condenser of the turbo freezer to send to the evaporator is introduced into the evaporator It is an object of the present invention to provide an expansion mechanism capable of further obtaining a latent heat of evaporation of a refrigerant per unit flow rate corresponding to a freezing capacity of a refrigerator by reducing the enthalpy of refrigerant.

Specific means of the present invention for achieving the above object,

An expansion mechanism that expands the liquid refrigerant condensed in the condenser of the turbo refrigerator and sends it to the evaporator.

Characterized in that one or a plurality of supersonic nozzles for increasing the kinetic energy of the refrigerant on the end of the refrigerant pipe connecting the condenser and the evaporator.

1 is a configuration diagram of a turbo chiller using a conventional expansion mechanism,

2 is a configuration diagram of a turbo chiller using the expansion mechanism of the present invention,

3 is a configuration diagram of a turbocooler combining the expansion mechanism and the conventional expansion mechanism of the present invention,

4 is a refrigeration cycle diagram of a turbo chiller using the expansion mechanism of the present invention.

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

1: expansion valve 2: evaporator

3: turbo compressor 4: condenser

5: supersonic nozzle

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

The configuration of the present invention is as shown in FIG. As in FIG. 1, FIG. 2 is a configuration diagram of a turbo chiller, and includes an evaporator 2, a turbo compressor 3, and a condenser 4, and an expansion mechanism uses a supersonic nozzle 5.

At this time, the state of the refrigerant at the inlet of the supersonic nozzle 5 becomes a form of an ideal flow in which the liquid refrigerant and the gas are mixed due to the normal cycle piping loss. Assuming that the refrigerant gas and the liquid are uniformly mixed at the inlet of the supersonic nozzle 5, the speed of sound at the inlet is determined by temperature and dryness. Since the velocity of the refrigerant injected from the outlet of the supersonic nozzle 5 to the evaporator 2 is high, the enthalpy value decreases, so that latent heat of evaporation can be obtained. However, since the refrigerant liquid may be scattered in the evaporator 2, the evaporator 2 It is preferable to install in the transverse direction in terms of).

It is assumed that the speed of the liquid refrigerant injected from the supersonic nozzle 5 is 60 kPa. In the case of a commercial turbo refrigerator using R134a refrigerant as a medium, the condensation rate in the condenser 4 is about 40 ° C. Evaporation temperature is about 5 ℃. If the nozzle inlet temperature is 39 ° C. due to the pressure drop from the condenser 4 to the inlet of the supersonic nozzle 5, it is difficult to design the nozzle with a Mach number 4.65 at the nozzle outlet with a sound velocity of 12.9 kPa. If the nozzle inlet temperature is 30 ℃, the speed of sound should be 28.1㎧ and the nozzle with outlet Mach number 2.13 should be designed and attached to give the outlet speed of 60㎧. If the nozzle inlet temperature is set to 30 ° C, a temperature drop of 10 ° C is required and it is difficult to obtain this kind of temperature drop only by the loss of piping.

As such, according to the type, condition, and temperature of the refrigerant, a combination of a conventional orifice expansion device and a nozzle should be used. 3 shows an example in which an expansion mechanism is used in combination with the orifice 1 and the supersonic nozzle 5.

The working effect of the present invention is explained with reference to FIG. 4, which shows a refrigeration cycle of a turbo compressor of a single stage compression type.

In FIG. 3, A is a saturation line of the refrigerant. If there is no subcooling in the condenser 4, the state of the condensed refrigerant is a saturated liquid and is indicated by ⓐ in FIG. When the refrigerant is expanded through the conventional orifice expansion mechanism, the state of the refrigerant flowing into the evaporator 2 becomes ⓑ. At this time, the latent heat of evaporation available in the evaporator 2, that is, the freezing capacity of the freezer per unit flow rate is indicated by B. If the liquid refrigerant of the condenser 4 is expanded using a turbine, the state ⓓ when entering the evaporator 2. At this time, the latent heat of evaporation used by the evaporator 2 is represented by D.

If an expansion mechanism using the supersonic nozzle 5 is used as described in the present invention, the state of the refrigerant flowing into the evaporator will be one point ⓒ between ⓐ and ⓑ. The latent heat of evaporation available in an evaporator is represented by C, and a relationship such as B <C <D is established.

In the following design example, the effect of the present invention can be explained quantitatively.

<Design condition>

Refrigerant: R134a

Condensation Temperature of Condenser Refrigerant: 40 ℃

Evaporator Temperature of Evaporator Refrigerant: 5 ℃

B = 144.86 kJ / kg in a turbocooler with an expansion device using an orifice.

In a turbocooler with an expansion mechanism using a turbine, D = 148.3 kJ / kg (2.4% increase over E).

The total enthalpy up to the condenser and the supersonic nozzle (5) outlet is preserved in the turbo chiller to which the expansion mechanism of the present invention is applied, and if the nozzle outlet speed is v, the kinetic energy is 2 = 1.8 kJ / kg at the nozzle outlet speed of 60 kC. + 1.8 = 146 kJ / kg (1.3% increase over B).

By properly designing the nozzle as in the above example, 1.3% of the latent heat of evaporation was obtained compared to the conventional orifice system which can be processed in the evaporator of the refrigerator.

As described above, according to the expansion mechanism of the turbocooler of the present invention, its structure is simple and economical, it is possible to obtain more latent heat of evaporation than the conventional orifice-type expansion mechanism can implement an efficient refrigeration cycle.

Claims (4)

An expansion mechanism that expands the liquid refrigerant condensed in the condenser of the turbo refrigerator and sends it to the evaporator. And one or a plurality of supersonic nozzles for increasing kinetic energy of the refrigerant on an end of the refrigerant pipe connecting the condenser and the evaporator. The method of claim 1, The expansion mechanism of the turbo-cooler, characterized in that the refrigerant pipe further comprises an orifice expansion valve for reducing the temperature. The method of claim 1, The supersonic nozzle is a expansion mechanism of the turbo-cooler, characterized in that the reduced enlarged diameter changes in accordance with the refrigerant state, the area of the wood, the outlet speed. The method of claim 1, The supersonic nozzle is a turbo chiller expansion mechanism, characterized in that the nozzle outlet is arranged in the transverse direction of the evaporator to prevent liquid splashing by the high-speed refrigerant.