Obtaining artificial cold is based on simple physical processes: condensation, compression and expansion of working substances. The working substances used in refrigeration units are called refrigerants.

Chillers differ:

• by design (absorption, with built-in or remote condenser - condenser and non-condenser);
• type of condenser cooling (air or water);
• connection diagrams;
• the presence of a heat pump.

Advantages

• Ease of use - all year round, the set parameters are automatically maintained in each room in accordance with sanitary and hygienic standards;
• System flexibility - the distance between the chiller and fan coil units is limited only by the pump power and can reach hundreds of meters;
• Economic advantage - operating costs are reduced;
• Environmental advantage - harmless refrigerant;
• The construction advantage is the flexibility of the layout, the minimum cost of the usable area for the placement of the refrigeration machine, because it can be installed on the roof, technical floor of buildings, in the courtyard;
• The acoustic advantage is the low-noise performance of the units;
• Safety - the risk of flooding is limited by the use of shut-off valves.

Chiller types

The working substance is a solution of two, sometimes three components. The most common binary solutions of an absorber (absorbent) and a refrigerant that meet two main requirements for them: a high solubility of the refrigerant in the absorbent and a significantly higher boiling point of the absorbent compared to the refrigerant. Water-ammonia solutions (ammonia-water refrigerating machines) and lithium bromide-water (lithium bromide machines) are widely used, in which, respectively, water and lithium bromide are absorbents, and ammonia and water are refrigerants. The working cycle in absorption chillers (see the figure below) is as follows: in the generator, to which the waste heat is supplied, the working substance boils, as a result of which an almost pure refrigerant boils away, because its boiling point is much lower than that of the absorbent.

Refrigerant vapor enters the condenser, where it cools and condenses, giving off its heat to the environment. Further, the resulting liquid is throttled, as a result of which it is cooled during expansion) and is sent to the evaporator, where, evaporating, it gives its cold to the consumer and goes to the absorber. An absorbent is supplied here through the throttle, from which the refrigerant boiled away at the very beginning, and absorbs vapors, because we have indicated above the requirement for their good solubility. Finally, the absorbent saturated with refrigerant is pumped to the generator, where it boils off again.

The main advantages of absorption chillers:

1. Ideal solution for creating trigeneration in the enterprise. A trigeneration complex is a complex that allows today, to minimize the cost of electricity, hot water supply, heating and cooling for an enterprise through the use of its own cogeneration power plant in conjunction with an absorption chiller;
2. Long service life - within 20 years, before the first major overhaul;
3. low cost of the produced cold, cold is produced almost free of charge, because absorption chillers simply recycle excess heat;
4. Reduced noise and vibration level, as a result of the absence of compressors with electric motors, as a result - quiet operation and high reliability;
5. The use of refrigeration / heating units with a direct fired gas generator eliminates the need for boilers, which must be used in conventional installations. This reduces the initial cost of the system and makes absorption chillers competitive with conventional systems that use boilers and chillers;
6. Provide maximum energy savings during peak periods. In other words, without consuming electricity for the production of cold / heat, absorption chillers do not overload the power grid of the enterprise even at times of peak loads;
7. There is the possibility of combining into steam district systems with an efficient double-effect refrigeration unit;
8. It is possible to distribute the load under conditions of maximum performance in cooling mode. The device handles the critical load in cooling mode with minimal energy consumption through the use of chillers with a direct-operated flame gas generator or a steam-heated generator;
9. Allows the use of emergency power generators of lower power, since the energy consumption of absorption refrigeration units is minimal when compared to electric refrigeration units;
10. Ozone safe, does not contain ozone depleting refrigerants. Cooling is carried out without the use of substances containing chlorine;
11. The overall impact on the environment is reduced to a minimum, since the consumption of electricity and gas, which causes the greenhouse effect and, as a result, global warming, is reduced.

An absorption chiller is a machine that produces chilled water using residual heat from sources such as steam, hot water or hot gas. Chilled water is produced according to the principle of cooling: a liquid (refrigerant) that evaporates at a low temperature absorbs heat from its environment during evaporation. Pure water is usually used as a refrigerant, while lithium bromide (LiBr) solution is used as an absorbent.

How absorption refrigeration systems work

In absorption refrigeration systems, the absorbent, generator, pump and heat exchanger replace the compressor of the steam compressor cooling systems (mechanical refrigeration). The other three (3) components also found in mechanical refrigeration systems, i.e. expansion valve, evaporator and condenser, are also used in absorption refrigeration systems.

Evaporation stage of absorption coolers

Refer to Figure-2 for a schematic explanation of the absorption refrigeration process. Like mechanical refrigeration, the cycle "begins" when the high pressure liquid refrigerant from the condenser passes through the expansion valve (1 in FIG. 2) into the low pressure evaporator (2 in FIG. 2) and collects the Sump in the evaporator.

At this low pressure, a small amount of Freon starts to evaporate. This evaporation process cools the remaining liquid refrigerant. Likewise, the transfer of heat from the relatively warm process water to the currently cooled refrigerant causes the latter to vaporize (2 in FIG. 2) and the resulting vapor is fed into the lower pressure absorber (3 in FIG. 2). As the process water loses heat to the refrigerant, it can be cooled to significantly lower temperatures. At this stage, chilled water is actually obtained by evaporating the freon.

Absorption stage of absorption coolers

The absorption of refrigerant vapors in lithium bromide is an exothermic process. In the absorber, the refrigerant is “sucked in” by the absorbing solution of lithium bromide (LiBr). This process not only creates a low pressure region that pulls a continuous flow of refrigerant vapor from the evaporator to the absorber, but also causes the vapor to condense (3 in FIG. 2) as it releases the heat of vaporization provided to the evaporator. This heat, together with the heat of dilution that occurs when the refrigerant condensate is mixed with the absorbent, is transferred to the cooling water and released in the cooling tower. Cooling water is a utility at this stage of cooling.

Regeneration of lithium bromide solution

As the lithium bromide absorbent absorbs the refrigerant, it becomes more and more diluted, reducing its ability to absorb more refrigerant. The absorbent must be re-concentrated to continue the cycle. This is achieved by continuously pumping the diluted solution from the absorber to a low-temperature generator (5 in Figure 2), where the addition of residual heat (hot water, steam or natural gas) boils (4, Figure 2) Refrigerant from the absorbent. This generator is often used to recover waste heat from the plant. As soon as the refrigerant is removed, the reconcentrated lithium bromide solution returns to the absorber, ready to resume the absorption process, and the free freon is sent to the condenser (6, in Fig. 2). Waste heat from steam or hot water is beneficial at this stage of regeneration.

Condensation

The refrigerant vapor welded in the generator (5, in Figure 2) returns to the condenser (6), where it returns to its liquid state when the cooling water raises the heat of vaporization. It then returns to the expansion valve where a full cycle is completed. During the condensation stage, the cooling water becomes useful again.

Various technologies for absorption chillers

Absorption chillers can be disposable, double or newer, which is a triple effect. Single effect machines have one generator (see diagram above, Figure 2) and have a COP less than 1.0. Double effect machines have two generators and two capacitors and are more efficient (typical COP values> 1.0). Triple effect machines add a third generator and capacitor and are most efficient: COP> 1.5 typical.

Pros and cons of absorption chiller systems

The main advantage of absorption chillers is lower energy costs. Costs can be further reduced if natural gas is available at a low cost or if we can use a low-grade heat source that would otherwise be lost in the plant.

The two main disadvantages of absorption systems are their size-weight, and their need for larger cooling towers. Absorbent chillers are larger and heavier in comparison with electric chillers of the same capacity.

Then the freon goes to the condenser, where it is cooled (as a rule, due to the environment) to the temperature T3 (~ 45C), while the pressure ideally remains unchanged, but in reality it drops by tenths of an atm. During the cooling process, freon condenses and the resulting liquid enters the throttle (element with high hydrodynamic resistance), where it expands very quickly. At the outlet, a vapor-liquid mixture with parameters P4 (~ 7 atm) and T4 (~ 0С) is obtained, which enters the evaporator. Here, freon gives up its cold to the coolant flowing around the evaporator, heating up and evaporating at constant pressure (in reality, it will fall by tenths of an atmosphere). The resulting cooled heat carrier (Tx ~ 7C) is the final product. And it has parameters P1 and T1 at the outlet of the evaporator, with which it enters the compressor. The cycle is closed. The driving force is the compressor.

Refrigerant and heat carrier

Classification of vapor compression chillers

Outdoor installation (built-in condenser)

Indoor installation (remote condenser)

By the type of condenser version:

Water cooling

Traditionally, cooling towers are used to cool the condenser of refrigeration machines, in which water heated in the condenser is sprayed through nozzles in a stream of moving outside air, and in direct contact with the air is cooled to the temperature of a wet outside air thermometer, then entering the condenser. This is a rather bulky device that requires special maintenance, installation of a pump and other auxiliary equipment. Recently, so-called "dry" cooling towers or condenser coolers have been used, which represent a surface water-to-air heat exchanger with axial fans, in which the heat of water heated in the condenser is transferred to air, which is circulated through the heat exchanger by axial fans.

In the first case, the water circuit is open, in the second case, it is closed, in which it is necessary to install all the necessary equipment: a circulation pump, an expansion tank, a safety valve, and shut-off valves. To prevent water freezing when the chiller is operating in cooling mode at negative outdoor temperatures, the closed circuit is filled with an aqueous solution of antifreeze liquid. When a condenser is water cooled, the heat of condensation is also wasted and contributes to thermal pollution of the environment. If there is a heat source, such as a hot water supply system or a process line, it may be useful to use the heat of condensation during the cold generation period.

By the type of hydronic module:

With external hydronic module

Body pump- this is the chiller operating mode “for heating”. The vapor compression cycle works in a slightly different sequence, the evaporator and condenser change their roles and the coolant is not cooled, but heated. By the way, let us note that although the chiller is a refrigeration machine, which gives three times more cold than it consumes, it is even more efficient as a heater - it will give four times more heat than it consumes electricity. The heat pump mode is most common in public and administrative buildings, sometimes used for warehouses, etc.

Compressor soft start- an option that allows you to get rid of high starting currents exceeding the working ones by 2-3 times.

Chiller typology

The range of chillers produced in recent years has been significantly updated due to the widespread use of new more efficient types of compressors: scroll, single-screw, twin-screw, which in the range of small, medium and large capacities are gradually replacing reciprocating compressors. The range of chillers with an integrated hydraulic module has been expanded, including those with an accumulation tank.

Plate and surface heat exchangers are more often used as evaporators, which made it possible to reduce the dimensions of the units and their weight. Recently, manufacturers have begun to issue chillers based on environmentally friendly R407 ° C freons,. Depending on the method of condenser cooling, refrigeration units are divided into air-cooled and water-cooled chillers. Chillers with an air-cooled condenser are most widely used, when the heat from the condenser is removed by air, usually outside.

This method of heat removal requires installing it outside the building or using special measures to ensure this method of cooling. Air-cooled chillers are available in monoblock design, when all the elements of the chiller are in one unit, and chillers with a remote condenser, when the main unit can be installed indoors, and the condenser, cooled by outdoor air, is located outside the building, for example, on the roof or in the yard. ... The main unit is connected to an air condenser installed outside the building with copper freon lines.

Monoblock chillers

Chillers with axial fans

The chiller can be executed with an additional method of cold capacity regulation. With chiller versions 1, 3, the heat of condensation is transferred to the outside air and is irretrievably lost. In versions 2 and 4 of chillers, additional shell-and-tube heat exchangers are installed, duplicating the condenser completely in the R version (using 100% of the condensation heat for heating water) or partially (using 15% of the condensing heat for heating water).

In option 4, an additional shell-and-tube condenser is installed on the discharge line after the compressor and upstream of the main air condenser. Chiller configuration can be: ST-standard; LN - with a reduced noise level, which is achieved by the device of a sound-absorbing casing for the compressor and a decrease in the rotational speed of the axial fan of the condenser in comparison with the standard configuration; EN - with a significant reduction in the noise level, which is achieved by the device of a sound-absorbing casing for the compressor, an increase in the free area of ​​the condenser for the passage of air and a decrease in the rotation speed of the axial fan, as well as the installation of the compressor on spring anti-vibration mountings, the use of flexible inserts on the discharge and suction pipelines of the refrigeration contour.

The sound power requirements of an operating chiller with axial fans when installed outside a building may not be very high if there are no specific requirements for noise in the building where the building is located. If such restrictions apply, the sound pressure level in the room must be calculated for the noise emitted by the chiller and, if necessary, chillers with a special configuration must be used.

Chillers with centrifugal fans

When choosing this type of chiller and placing it, ensure free supply of cooling air to the chiller and removal of air heated in the condenser. This is done with the help of suction and discharge air ducts, while a ventilation network is formed, consisting of a centrifugal fan, an air heater (chiller condenser), air ducts, intake and outlet ventilation louvers. The dimensions of the latter are selected on the basis of the recommended speeds of air movement in the cross-section of the grilles and air ducts.

It is necessary to determine the pressure loss in the ventilation network on the basis of an aerodynamic calculation. The pressure loss in the ventilation network must correspond to the pressure developed by the centrifugal fan at the value of the air flow rate that cools the condenser. If the pressure of the centrifugal fan is less than the pressure loss in the ventilation network, a more powerful electric motor can be applied to the centrifugal fan by special order. The air ducts must be connected to the chiller with flexible connectors so that vibration is not transmitted to the ventilation network.

Chiller performance

Chiller diagram with integrated hydraulic module

Energy saving technologies in chillers

At the same time, the daily schedule of heat surpluses also has an irregular character with a pronounced maximum. Traditionally, chillers with a capacity of 20–80 kW are equipped with two identical compressors and make two independent refrigeration circuits. As a result, the unit is able to operate in two modes at 50% and 100% of its rated power. The new generation of chillers with a cooling capacity of 20 to 80 kW allows three-stage capacity control. In this case, the total refrigeration capacity is shared between the compressors in a ratio of 63% and 37%.

In new generation chillers, both compressors are connected in parallel and operate on one refrigeration circuit, that is, they have a common condenser and evaporator. This arrangement significantly increases the energy conversion factor (KPI) of the refrigeration circuit when operating at partial load. For such chillers at 100% load and an outdoor temperature of 25 ° C, KPI = 4, and when operating at 37%, KPI = 5. Considering that 50% of the time the chiller operates at 37% load, this gives significant energy savings.

• control all operating parameters of the equipment;
• regulate the set value of the temperature of the water leaving the chiller in accordance with the parameters of the outside air, technological processes or commands from the centralized control system (dispatch);
• to select the optimal step of power regulation;
• perform a defrost cycle quickly and efficiently when really needed (for heat pump models).

As a result, short-term compressor start-ups are automatically minimized, the compressor operating time is optimized and the parameters of the water leaving the chillers are adjusted in accordance with real needs. As shown by the tests carried out, on average, only 22 compressor switch-ons occur during the day, while the compressors of conventional chillers are switched on 72 times.

The average annual KPI of the chiller reaches 6, and the energy savings, when using modern chillers instead of conventional ones, is 7.5 kWh per 1 m2 of the area of ​​the serviced facility per season, or 35%. Another important advantage that the use of new chillers provides is that the need for bulky storage tanks is eliminated, and a circulation pump built into the chiller body eliminates the need for an additional pumping station.

Maintenance of such compressors is laborious and requires highly qualified personnel. In recent years, new SCROLL compressors have appeared on the market, which are devoid of the characteristic disadvantages of reciprocating and screw compressors. Scroll compressors are energy efficient, low noise and vibration, and are maintenance free. This type of compressor is simple in design, very reliable and, at the same time, inexpensive. However, Scroll compressors usually do not exceed 40 kW.

The use of many small but very reliable Scroll compressors in modern chillers, as well as several refrigeration circuits, has made it possible to obtain a very "maneuverable" chiller that is capable of delivering the required refrigeration power with high precision. Obviously, the use of such a chiller makes it unnecessary to install a pumping station, and a wide selection of pumps of different capacities built into the chiller body solves all issues related to the circulation of chilled water. The very small inrush currents of new equipment deserve special mention. After all, the start-up of small Scroll compressors with low power consumption takes place alternately, in accordance with the increase in the load on the unit.

All chillers of the latest generations have a modern microprocessor control system that allows you to adjust the set value of the temperature of the water leaving the chiller in accordance with the outdoor air parameters, technological processes or commands from a centralized control system (dispatch). From an economic point of view, using a large number of Scroll compressors and installing an integrated circulation pump instead of a separate pumping station turns out to be a more profitable option than using expensive, powerful and complex semi-hermetic compressors.

Advantages and disadvantages of chillers

Advantages

• Scalability. The number of fan coil units (loads) on a central refrigeration machine (chiller) is practically limited only by its capacity.
• Minimum volume and area. The air conditioning system of a large building can contain a single chiller, occupying the minimum volume and area, the appearance of the facade is preserved due to the absence of external air conditioning units.
• Virtually unlimited distance between chiller and fan coil units. The length of the routes can reach hundreds of meters, since with a high heat capacity of the liquid heat carrier, the specific losses per linear meter of the route are much lower than in systems with a gas refrigerant.
• Wiring cost. To connect chillers and fan coil units, ordinary water pipes, shut-off valves, etc. are used. Balancing water pipes, that is, equalizing the pressure and flow rate of water between individual fan coil units, is much easier and cheaper than in gas-filled systems.
• Security. Potentially volatile gases (refrigerant gas) are concentrated in the chiller, which is usually installed in air (on the roof or directly on the ground). Internal piping failures are limited by the risk of flooding, which can be mitigated by automatic shut-off valves.

disadvantages

• Chiller-fan coil systems, in a strict sense, are not ventilation systems - they cool the air in each conditioned room, but do not affect the air circulation in any way. Therefore, to ensure air exchange, chiller-fan coil systems are combined with air (roof) air conditioning systems, the chillers of which cool the outside air and supply it to the premises via a parallel forced ventilation system.
• Being more economical than rooftop systems, chiller-fan coil systems are certainly inferior in terms of economics to VRV and VRF systems. However, the cost of VRV systems remains significantly higher, and their marginal performance (volumes of refrigerated rooms) is limited (up to several thousand cubic meters).
• Some aspects of refrigeration design
• A refrigeration machine is an oversized (all three dimensions significantly exceed a meter, and the length can exceed 10m) and heavy (up to 15 tons) equipment. In practice, this means an almost unconditional need for the use of unloading frames to distribute the mass of the chiller over a large area with the choice of acceptable support points. Standard frames are not always suitable for each specific case, therefore, more often than not, special design is required.
• The chiller VMT-Ksiron has 1-4 compressors, 1-12 fans, 1-2 pumps, which causes a whole range of negative vibrations, therefore, the chiller is certainly installed on vibration dampers of the appropriate bearing capacity, and all pipelines are connected through expansion joints of the corresponding diameter ...
• As a rule, the connecting diameters of the chiller pipelines are smaller than the main pipe (more often one, sometimes two standard sizes), therefore, a transition is required. It is recommended to install an expansion joint directly at the chiller and immediately follow the transition. Due to significant hydraulic losses, it is not recommended to remove the transition from the unit.
• To avoid clogging of the evaporator on the coolant side, a filter must be installed at the chiller inlet.
• In the case of a built-in hydronic module, there must be a check valve at the outlet of the chiller to avoid water movement against the design.
• To regulate the forward and reverse flows, a jumper between them with a differential pressure regulator is recommended.
• Finally, in the documentation, you should always pay attention to which heat carrier the data is given for. The use of an anti-freeze coolant reduces the efficiency of the refrigeration system by an average of 15-20%.

Chiller operation diagram with air condenser and winter start system (monoblock version, without hydronic module)

Specification

1. Danfoss compressor
2. High pressure switch KR
3. Shut-off valve Rotolock
4. Differential valve NRD
5. Linear receiver
6. Shut-off valve Rotolock
7. Filter drier DML
8. Sight glass SG
9. Solenoid valve EVR
10. Thermostatic valve TE
11. DAS / DCR filter drier
12. Low pressure switch KP
13. Shut-off valve Rotolock
14. Temperature sensor AKS
15. Liquid flow switch FQS
16. Electric shield

Chiller operation diagram with remote air condenser and winter start system (without hydronic module)

Specification

1. Danfoss compressor
2. High pressure switch KR
3. Shut-off valve Rotolock
4. Oil separator OUB
5. Non-return valve NRV
6. Differential valve NRD
7. Condensing pressure regulator KVR
8. Ball valve GBC
9. Air cooled condenser
10. Ball valve GBC
11. Non-return valve NRV
12. Linear receiver
13. Shut-off valve Rotolock
14. Filter drier DML
15. Sight glass SG
16. Solenoid valve EVR
17. Coil for Danfoss solenoid valve
18. Thermostatic valve TE
19. Evaporator plate brazed type B (Danfoss)
20. DAS / DCR filter drier
21. Low pressure switch KP
22. Shut-off valve Rotolock
23. Temperature sensor AKS
24. Liquid flow switch FQS
25. Electric shield

Operation diagram of a chiller with a water-cooled condenser and with condensing pressure control

Specification

1. Danfoss compressor
2. High pressure switch KP
3. Shut-off valve Rotolock
4. Brazed plate water-cooled condenser type B (Danfoss)
5. Water regulating valve WVFX
6. Filter drier DML
7. Sight glass SG
8. Solenoid valve EVR
9. Coil for Danfoss solenoid valve
10. Thermostatic valve TE
11. Evaporator plate brazed type B (Danfoss)
12. DAS / DCR filter drier
13. Low pressure switch KP
14. Shut-off valve Rotolock
15. Temperature sensor AKS
16. Liquid flow switch FQS
17. Electric shield

Diagram of the hydronic module for a chiller with one pump

Specification:

1. Open-type thermally insulated container
2. Pump
3. Ball valve
4. Collapsible connection
5. Pressure gauge
6. Access to the consumer
7. Water inlet
8. Bypass valve
9. Coarse filter
10. Flow control relay
11. Visual control of liquid level

According to the principle of operation, the fan coil unit is very similar to the internal block of the split system. The main difference lies in the coolant: instead of coolant, the fan coil uses ordinary water or an antifreeze solution. The liquid cools or heats the incoming air, which is brought to the desired temperature and returned to the room. The resulting condensate is discharged to the street or to the sewer using a pump.

As in the case of heating radiators, several fan coil units are often installed in one room at once - the required number depends on the power of the devices and the area of ​​the room. In addition, they can be connected to supply ventilation, which allows the devices to be used in a mixed mode (to mix the air received from the inside with fresh air).

Temperature control is carried out using the electronic system control unit, temperature sensors and various valves. Complex air conditioning systems also use central air conditioners, which are responsible for cleaning and humidifying the incoming air.

Chiller-fan coil system types

• Single-zone system... It is mainly used for servicing large premises with a uniform heat distribution, since all single-circuit fan coil units connected to it are heated and cooled at the same time.
• Multi-zone system... Uses fan coil units with double-circuit heat exchangers, which allows the supply of cold and hot water to be separated. Devices in such a system can simultaneously provide different air temperatures in different rooms.

Varieties of fan coil units

• Cassette;
• Outdoor;
• Wall-mounted;
• Duct.

• Single-flow (air is discharged from the device in one direction);
• Double-flow (two air flows out of the device in different directions);
• Quadruple (models of this type release four air streams, making them the best choice for air conditioning large areas).

How to choose a fan coil unit

• Type (cassette, floor, wall or duct);
• Power (the minimum indicator in watts can be obtained by multiplying the area of ​​the air-conditioned room by 100);
• Energy efficiency (relevant only for large air conditioning systems, since fan coil units consume quite a bit of electricity);
• Noise level (it is recommended to use devices with quiet fans, the noise level of which does not exceed 60 decibels).

• Scalability. The distance between units in split systems does not exceed 15 meters due to the refrigerant used in them. At the same time, the distance between the chiller and fan coil unit can exceed hundreds of meters, making it easy to expand the system if necessary.
• Versatility. Unlike air conditioners in standard split systems, fan coil units are capable of operating non-stop all year round.
• Security. Fan coil units are much safer than gas refrigerants used in split systems.

• Large system sizes. Due to the impressive dimensions of the chiller-fan coil system, its installation is advisable only in spacious buildings.
• Poor filtration quality. Air purification filters built into fan coil units do their job much worse than their counterparts in split systems.
• High complexity of installation. Due to the large size and weight of chiller-fan coil systems, installation takes a lot of time and effort.

How a dry cooler works

• Plate heat exchanger. Can be V-shaped, horizontal or vertical. Most often made from aluminum or copper. Efficient heat transfer is ensured by the high number of fins and, as a result, the large surface area of ​​the heat exchanger.
• One or more fans. Most drycoolers are equipped with axial cooling impellers with a radius of 200 to 350 mm. In large units with V-shaped heat exchangers, fans with a diameter of up to 1000 mm are allowed. In addition, centrifugal fans can be used in high-performance industrial cooling systems.
• Protective and regulating automatic equipment responsible for maintaining the required temperature of the coolant and changing the speed of the fans.
• The heated coolant (ordinary water or antifreeze solution) is supplied to the inlet of the dry cooler, where its temperature is reduced to the temperature of the outside air. The cooling level can be adjusted by changing the speed of the fans. The liquid is supplied using a circulation pump. After that, the cold heat carrier is fed back to the cooled equipment, and then the cycle is repeated.

Advantages and Disadvantages of Dry Coolers

• High energy efficiency;
• Environmental safety (the energy carrier circulates in a closed loop, and, as a result, does not evaporate, keeping the air humidity at the same level);
• Easy to install, operate and service;
• Low cost of equipment;
• Ease of scaling (new units can be easily added to the existing cooling system);
• When working with dry coolers, you can use any anti-freeze solutions.

• The performance of devices depends on the temperature of the outside air (problems are possible during periods of peak temperatures in winter and summer);
• Drycoolers use more energy than standard evaporative cooling towers.

Dry coolers application area

• In industries requiring large volumes of coolant;
• In industry for cooling heat carriers in refrigeration and injection molding equipment, as well as removing heat from motors of extruders, machine tools and generators;
• In construction, to reduce the temperature of refrigeration plants and power generators;
• For free cooling of air in public and industrial buildings (freecooling).
• A wide range of models and configurations of drycoolers allows you to select a unit with suitable characteristics for any operating conditions, therefore, their popularity only increases every year.

A chiller with a remote condenser is similar in design to chillers based on a water condenser. The chiller itself is installed indoors, and the condenser is outside. They are interconnected by a system of freon lines. These chillers are available in several versions. They can vary in power and can be equipped with automatic control systems. The compact indoor unit does not require much indoor space, and the remote condenser is reliably protected from weather conditions.

The main difference of such a chiller from analogs with a water condenser is that in its circuit:

It is not necessary to use an intermediate heating medium and powerful circulation pumps. The probability of the heating medium freezing is minimal, so there is no need to use a two-circuit refrigeration system.

Place only the chiller itself indoors, while the noisiest part of the equipment is the condenser installed on the outer wall of the building or its roof, thereby reducing the noise level in the room and saving the interior space. Both units are connected with refrigerant pipes.

5 reasons to buy chillers from AkvilonStroyMontazh

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1. All necessary accompanying documents

1. Warranty service for purchased equipment

1. Huge selection of products

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Ease of maintenance of the unit. The automation system is reliably protected from adverse weather conditions. Since the entire piping system is located inside the room, there is no need to use anti-freezing liquids. Ordinary water can be used as a heat carrier. Therefore, this type of chiller is usually based on a refrigeration unit with a water condenser. Chillers of this type can be operated all year round for the air conditioning of industrial premises.