SU1693326A1 - Refrigerating plant - Google Patents

Abstract

The invention relates to refrigeration equipment, namely, refrigeration units with a remote condenser operating year-round in a wide range of outdoor temperatures. The purpose of the invention is to expand the range of applicability, reduce energy consumption and increase reliability at low outdoor temperatures. The refrigeration unit contains the main closed loop, in which the Invention relates to refrigeration equipment, namely, refrigeration units with a remote condenser operating year-round in a wide range of outdoor air temperatures. The purpose of the invention is to increase the reliability of operation at low ambient temperatures. The drawing shows a diagram of the refrigeration unit. The refrigeration unit contains the main closed circuit 1, which includes the compressor 2, the external condenser 3, the compressor is turned on, the external condenser, the evaporator with inlet and outlet channels for the cooled medium and the throttle device, as well as the receiver for the refrigerant, are connected by a separate pipeline to the main refrigerant circuit between the throttles and the built-in channel for supplying or discharging the cooled medium. The volume of the receiver is assumed to be equal to the volume of the condenser on the refrigerant. The throttle device is made in the form of a pair of series-connected chokes, the total resistance of which corresponds to the nominal mode of operation of the installation. In winter, as the outside air temperature decreases, the condensation pressure decreases and the established pressure balance of the Pk Pp + DddT disrupts. In case of Рк .Рр + АРдр7, the heat transfer surface of the condenser from receiver 9 through the throttle 8 is subheated, and at low temperatures of the outside air additionally through the throttle 7, increasing the condensation pressure to the given one. 1 pe. steam 4 with inlet channels 5 and outlet b of the cooled medium, a throttle device made in the form of a pair of series-connected chokes 7 and 8, a receiver 9 for the refrigerant, a separate pipe 10, a solenoid valve 11, a fan 12, supplying air to the condenser cooling. The refrigerant receiver 9 is connected by a pipe 10 to the main refrigerant circuit 1 between the throttles 7 and 8 and is integrated into the coolant supply channel 5. Refrigeration unit operates as follows. (L C i GS o SO s o

Description

The compressor 2 sucks the refrigerant vapor from the evaporator 4 and injects it into the condenser 3 cooled by air pumped by the fan 12. The liquid refrigerant through the throttles 7 and 8 again enters the evaporator 4. The surface of the receiver 9 is washed by the flow of the cooled medium and the temperature of the coolant in the receiver becomes equal to the temperature of the medium to be cooled. A receiver 9 is connected to circuit 1 via a valve 11 electrically connected by a control unit to a compressor 2.

Work on variable modes is considered on the example of an installation with a cooling capacity of 5 kW at a normal cooling air temperature of 30 ° C (dew point 40 ° C) and cooling water of 20 ° C with a working charge of chladon-22 in an amount of 1.8 kg (without accounting of the filling of the receiver). The unit works when the outside air temperature changes from 40 ° С to - 45 ° С. To ensure stable operation at low outdoor temperatures and to prevent a significant decrease in the boiling point, the condition for stabilizing the condensation temperature not lower than 30 ° C is assumed. For this, an additional node, a receiver 9, is introduced, located in a stream of cooled water, which slightly changes the temperature during operation. The volume of the receiver is assumed to be equal to the volume of the freon cavity of the condenser. Total gas station setting 4.2 kg. In addition, the arrangement of the throttles 7 in this way additionally affects the stabilization of the dew point temperature.

During the summer period, the condensation pressure Pc will increase and the established balance of pressures will be broken.

As a result, part of the refrigerant from circuit 1 after the throttles will go to receiver 9, where steam will condense due to heat removal to the cooled medium, since the outdoor air temperature in summer is higher than the temperature of the cooled medium. A part of the flooded surface of the condenser will be released and Pk will decrease. This overflow occurs before the pressure balance is restored. The receiver 9 can be completely or partially filled. Further installation will work without a receiver.

In winter, the condensing pressure decreases. Pk Pp + AR.

For example, a so-called air 10 ° С, at the initial moment after starting the compressor tK 20 ° С, Рк 9.3 at, pressure РР in the receiver 9 Рр 9.3 at, as it is in

the flow of water with a temperature of 20 ° C, and since the receiver is connected by pipeline 10 to circuit 1 after throttles 7, the receiver’s refrigerant maintains a pressure of 9.3 atm, i.e.

There is no refrigerant movement from the condenser. At the same time, at this initial moment, the compressor 2 pumps out the refrigerant and lowers the pressure in the evaporator 4, in the pipeline after the throttles 8 and between the throttles

7 and 8, and the refrigerant from the receiver 9 at a pressure of 9.3 atoms through the inductor 8, the evaporator 4 will flow into the compressor 2 and further into the condenser 3, where it condenses, accumulating in the condenser, heating up the heat transfer surface and increasing the condensing pressure. This process will continue until the condensation pressure rises to PK 12.3 at (t 30 ° C). In the period of increasing condensation pressure

From Pk 9.3 atA to Pk 12.3 ata, which is characterized as an exit to steady state, the flow of refrigerant from receiver 9 gradually decreases and the flow from condenser 3 through throttle 7 increases. At steady mode, the pressure after Drossel 7 will be P Pk - AP 12.3 - 3 9.3 atms and, taking into account that Рр 9.3 atms, there will be no movement of the refrigerant in the pipeline 10, the installation will work in steady state

without receiver.

When the outside air temperature drops to minus 45 ° C, condenser 3 undergo additional warming up at the initial moment due to the flow of refrigerant from receiver 9 through throttle 7 and the heat transfer surface decreases by 7 times; in receiver 9, 2.4 kg will remain - 2.1 kg 0.3 kg refrigerant. With a sharp increase in heat load, it is possible to increase the condensation pressure and the amount of supercooling of the refrigerant, which will increase the throughput capacity of the throttle device and the cooling capacity.

Claims (2)

1. Refrigeration unit containing a closed loop, which includes a compressor with an electric motor, an outdoor air condenser, an evaporator with lines supply and removal of the cooled medium, the throttle device and the receiver with a separate pipeline, characterized in that, in order to increase the reliability of operation at low outdoor temperatures, the throttle device is made in the form of two successively placed chokes, and the receiver is connected by pipeline with the circuit between the throttles and is connected to the supply or removal line of the cooled medium .. 2. Installation under item 1, characterized in that, in order to increase the reliability of operation, the pipeline of the receiver is equipped with a solenoid valve electrically connected through a control system to the compressor engine. W W /// Z6Y / A V ////////////////////