RU193484U1 - TWO-CIRCUIT CHILLER WITH TWO COMPRESSORS IN EACH CIRCUIT - Google Patents

Abstract

The utility model relates to cooling equipment, namely to a chiller designed to cool liquids and supply them to the consumer. Chiller with a control panel, with a controller and two refrigeration circuits. In the main body on the vibration isolators there are two circuits, each of which has two scroll compressors combined in parallel, while four scroll compressors are equipped with three-phase electric motors and integrated winding protection, a double-circuit plate copper-brazed evaporator with an integrated distributor that has two refrigeration circuits and one water circuit, where the compressors of one refrigeration circuit are connected to each of the refrigeration circuits through the solenoid and thermoregulators valves, with a water circuit, with a flow switch, with a safety valve, with a drain outlet and with coolant temperature sensors. Technical result - a utility model provides a chiller that allows you to get four stages of performance. 3 s.p. f-ly, 3 ill.

Description

The utility model relates to cooling equipment, namely, to a chiller designed to cool liquids (water, inhibited aqueous solutions of low viscosity ethylene glycol or low-density propylene glycol with a concentration of up to 40%, etc.) and supply them to the consumer.

 Chillers are used in the field of ventilation and air conditioning (hereinafter referred to as HVAC), as well as in the field of centralized refrigeration supply to trading enterprises and technological processes.

A chiller is a refrigeration unit used for cooling liquid coolants in central air conditioning systems, which may be air handling units or fan coil units. A wide range of capacities makes it possible to use chillers in rooms of various sizes: from apartments and private houses to offices and hypermarkets. In addition, they are used in the food industry for cooling water and drinks, in the sports and fitness sector - for cooling ice rinks and ice pads, and in pharmaceuticals - for cooling medicines.

Known chiller from patent document US2018224147 A1, publ. 08/09/2018, in which the chiller installation is disclosed, which includes at least two chillers operating at different temperatures. Chiller process fluid circuits can generate a fluid message when, for example, one of the two chillers can fail, so that the other chiller can back up the faulty chiller.

Known solutions for arranging the refrigeration circuit (hereinafter - HC) of the chiller (compressors without capacity control, a mechanical thermostatic valve) of average capacity do not allow to obtain four performance levels (25-50-75-100%). Usually this is one (100%) or two stages of productivity (50-100%).

The technical result is a chiller with four stages of performance.

The technical result is achieved due to the dual-circuit chiller with a control panel, with a controller and two refrigeration circuits. In the main body on the vibration isolators there are two circuits, each of which has two scroll compressors combined in parallel, while four scroll compressors are equipped with three-phase electric motors and integrated winding protection, a double-circuit plate copper-brazed evaporator with an integrated distributor that has two refrigeration circuits and one water circuit, where the compressors of one refrigeration circuit are connected to each of the refrigeration circuits through the solenoid and thermoregulators valves, with water circuit, with flow switch, with safety valve, with drain outlet and with coolant temperature sensors.

 The water circuit contains at least one built-in centrifugal circulation pump, together with which an expansion tank is installed.

One compressor is connected to each of the refrigeration circuits.

Two compressors are connected to each of the refrigeration circuits.

Figure 1 discloses the basic structural elements of monoblock air-cooled chillers of 65h80 kW models.

Figure 2 reveals a schematic hydraulic diagram (hereinafter - ASG) of chillers with a cooling capacity of 65h80 kW.

Figure 3 discloses and explains how to connect the chiller.

Positions in figures 1-3:

1 - The first HC.

1.1, 1.2 First, second compressors of the first HC;

2 - Second HC.

2.1, 2.2 The first, second compressors of the second HC;

3 - Schröder service valve.

4 - Condenser (may be air or water cooling, built-in to the unit or remote).

5 - The valve is shut-off and / or non-return.

6 - Filter drier.

7 - Sight glass with indicator of humidity.

8 - Solenoid valves, only 2 pieces.

8.1- Solenoid valve of the first HC.

8.2- Solenoid valve of the second HC.

9 - Thermostatic valve with external equalization of pressure (TRV).

 9.1- TRV of the first HC.

 9.2- TRV of the second HC.

10 - Double-circuit evaporator.

11 - Thermal insulation (based on foamed rubber).

12 - Heat carrier inlet to the chiller (from the consumer).

13 - Automatic vent valve with shut-off valve.

14 - The safety valve of the hydraulic circuit (6/8/10 bar).

15 - Safety valve HC low and high pressure.

16 - Heat carrier outlet from the chiller (to the consumer).

17 - Pressure equalization lines.

18 - Circulation pump (one or two).

19 - Condenser fan (only for air-cooled chillers
cooling).

20 - Case.

21 - Control panel.

TE - Fluid temperature sensors.

FS - Relay duct.

PS - Emergency pressure switches (high and low).

PE - Pressure sensors (high and low).

The chiller, which includes condenser heat exchangers 4 and fans 19, are called air-cooled chillers of a monoblock design.

The chiller, which includes copper-brazed heat exchangers of the condenser 4, which are cooled by water or aqueous glycol solutions, are called chillers with water condensers.

The carrying case 20 of the chiller is made of galvanized sheet steel with double-sided painting. The housing is mounted on vibration isolators. At the base are rubber cable entries for power and control cables. Fasteners made of galvanized steel.

In dual-circuit chillers, two scroll compressors of the same capacity are used in each HC. Scroll compressors with a three-phase electric motor 1.1, 1.2 of the first HK and 2.1, 2.3 of the second HK are equipped with built-in protection of the motor windings from overheating and a crankcase heater. Compressors circulate the refrigerant in the refrigeration circuit of the chiller, providing heat transfer from the evaporator 10 to the condenser 4. The crankcase heaters are needed to evaporate the refrigerant from the oil in the compressor crankcase during their standstill. Evaporating the refrigerant reduces foaming and oil entrainment in the HC when starting the compressors. Oil is necessary for lubricating the rubbing parts of the compressor, the place of oil in the compressor crankcase, and not in HC.

Evaporator 10 is a plate copper brazed heat exchanger with an integrated distributor made of AISI 316 stainless steel. It has two refrigeration circuits and one water circuit. The evaporator is heat and vapor insulated. Evaporator - a heat exchanger that removes heat from the coolant, cooling it.

The air-cooled heat exchangers of the condenser 4 are a copper tubular heat exchanger with fins made of aluminum plates. The condenser cools and condenses the flow of refrigerant; it dissipates the heat received in the evaporator and compressor into the environment (for example, into street air).

Axial low-speed fans with stepless speed control 19, are directly driven by an electric motor with an external rotor and protection class IP 54, have built-in protection against overheating of the windings and are protected by a grate on the discharge side. Fans are used only in air-cooled chillers.

The control panel 21 is located inside the housing and includes: an input switch, a sequence and phase control relay, a programmable controller with a built-in control panel and a clock card, expansion modules of the controller, protection devices for compressor motors and pumps against overcurrent, a fan motor protection circuit and compressors for temperature of windings, high and low pressures in the refrigeration circuit, fan speed controller, low-voltage power transformer for automatic circuits Matic, magnetic actuators.

The controller provides control of the chiller, as well as an indication of all parameters: the set and actual temperature of the coolant, real time, percentage of load, display of the state of the chiller (operation / alarm / blocking). The controller rotates the running hours of the compressors and pumps, keeps a log of emergency conditions with the date and time of their occurrence, keeps a log of the running hours of the compressors, pumps and the entire chiller.

Advanced controller functions (optional equipment): the ability to install one of the boards for connecting to the building integrated automation network - BMS.

Each refrigeration circuit is equipped with a filter drier 6, a sight glass with a humidity indicator 7, a solenoid valve 8, a mechanical thermostatic valve (hereinafter - TRV) with external equalization of pressure and a MOP value of + 15 ° C 9, emergency high and low pressure switches with manual reset in working condition, electronic measuring sensors of high and low pressure and Schroeder service valves 3. A sight glass is necessary in order to monitor the condition of the refrigerant - moisture content, mechanical particles, and ie the presence of steam bubbles. A solenoid valve is required to shut off the HC fluid line during shutdown of the chiller compressors. TRV is necessary to maintain a given superheat of the vapors leaving the evaporator by controlling the flow of refrigerant entering the evaporator. High and low pressure switches are necessary to prevent compressors from operating outside the permissible operating pressure range.

The hydraulic circuit is assembled using easily removable groove joints. The standard version includes TE temperature sensors, at the inlet and outlet of the evaporator, an automatic vent valve 13, with a shut-off valve, an FS flow switch, at the outlet of the coolant from the evaporator and a safety valve (6/8/10 bar) with a drain 14. If the chiller is equipped with integrated centrifugal circulation pumps 18, an expansion tank is installed. When two pumps are installed, a check valve is installed for each of them. An expansion tank is necessary to compensate for the thermal expansion of the coolant.

The main advantages realized in the design of chillers, which gives us the use of a useful model of ASG:

• the use of a double-circuit evaporator and two expansion valves allows you to carry out 25% and 75% -percentage stages of productivity (only four stages 25-50-75-100%), while the flow rate and speed of the refrigerant in one (of two) evaporator circuits will not fall below the minimum permissible value. The minimum refrigerant speed has a significant effect on the return of oil from the evaporator, as well as on the heat transfer coefficient of the plate-brazed evaporator. The higher it is, the better the oil return and the higher the heat transfer coefficient. Four stages of productivity make it possible to do without an accumulation tank, which allows to reduce the cost of installing a “cold” coolant circuit;

• the chiller’s refrigeration circuit is equipped with mechanical expansion valves, which by design characteristics cannot work stably under a load of less than 30%. In a simplified ASG scheme (shown in FIG. 3), the load on one expansion valve of less than 50% is impossible (compressor 1.1 is operating, valve 8.2 is closed, valve 8.1 is open, (figure 3);

The order of connecting the stages of performance in ASG (figure 3):

• the main control parameters are the temperature change ( ^о С) when connecting / disconnecting the next stage, and the time (sec) during which the temperature changes;

• the first signal to open the solenoid valve (pos. 8.1 in figure 3) on the liquid line. The evaporator is filled with sufficient refrigerant in order to prevent an emergency shutdown at low pressure when the compressor starts;

• inclusion of the first (pos.1.1 in figure 3) of the compressors (25% of capacity) occurs 10 seconds after the opening of the solenoid valve. If it is necessary to increase the capacity of the chiller, a signal is supplied to connect a second (50% of capacity) in the first compressor circuit (pos.1.2 in figure 3);

• if it is necessary to increase productivity, the solenoid valve (pos. 8.2 in Fig. 3) is sequentially opened and the third compressor (pos. 2.1 in Fig. 3) is connected to the second compressor (75% of capacity);

• with a further increase in productivity, the fourth compressor of the second HK is connected (pos.2.2 in figure 3, 100% of productivity);

• rotation for operating hours is provided for compressors - the compressor always turns on with a lower operating time;

• steps are switched off in the reverse order.

Claims (4)

1. A two-circuit chiller with a control panel, with a controller and two refrigeration circuits, characterized in that there are two circuits in the bearing housing on the vibration isolators, each of which has two scroll compressors combined in parallel, while four scroll compressors are equipped with three-phase motors and built-in winding protection, double-circuit plate copper-brazed evaporator with a built-in distributor, which has two refrigeration circuits and one water circuit, where each of the cold compressors of one refrigerant circuit are connected through the solenoid and thermostatic valves, with a water circuit, with a flow switch, with a safety valve, with a drain outlet and with temperature sensors. 2. The double-circuit chiller according to claim 1, characterized in that the water circuit contains at least one built-in centrifugal circulation pump, together with which an expansion tank is installed. 3. The dual-circuit chiller according to claim 1, characterized in that one compressor is connected to each of the refrigeration circuits. 4. The dual-circuit chiller according to claim 1, characterized in that two compressors are connected to each of the refrigeration circuits.

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