What does a water-cooled chiller consist of? What is a chiller and how does it work. Working principle of water cooled chiller

The vapor-liquid mixture is supplied to the evaporator after passing through the expansion valve
Heat exchange of freon and coolant in the evaporator
The compressor sucks refrigerant vapor from the evaporator
The compressor serves to compress the gas and circulate freon through the system by creating a pressure difference
The compressor pumps compressed gas into the condenser
In the condenser, the compressed gas passes into the liquid phase due to heat removal
Liquid freon enters the expansion valve and the whole cycle is repeated

Chiller operation- this is not only the work of the basic components of the refrigeration circuit.

The second integral part of any chiller is the hydraulic module. It can be either built-in - that is, located on the same frame with the refrigeration circuit, or located on a separate frame. The hydraulic module usually includes:

pump
battery tank
set of plumbing and shut-off valves.

The pump serves to circulate the coolant through the heat exchanger and supply it to the consumer. Without a pressure pump, normal operation is impossible, since the evaporator must be filled as much as possible with coolant to achieve highly efficient heat exchange. Sometimes double-pump schemes are used, when the functions of circulating coolant inside the chiller and supplying already cooled liquid are separated. This is necessary, for example, in cases where it is necessary to supply liquid to a greater height, since when passing through the heat exchanger, the pressure decreases, therefore, in order to be as efficient as possible, it is necessary to supply the cooled coolant directly from the tank to the consumer without loss of pressure. The feed pump is selected according to the supply requirements:

pole height (m)
pressure (bar)
required flow rate (m3/hour).

The battery tank serves to store cooled liquid and reduce the number of starts and stops of the compressor, thus operating in optimal mode. If the accumulator tank is too small for the power of the water cooler, then the chiller, programmed for a certain differential, will cool this volume too quickly and stop at the set degree, then, under the influence of the consumer load, quickly heat up again and will resume again. This mode of operation can lead to damage to the chiller compressor. The battery tank is able to reduce the number of starts and stops to the recommended - no more than 5-7 times per hour.

Chiller circuit

With competent engineering calculations, design and high-quality assembly, it will be durable and trouble-free. Specialists from CenterProm-Holod, a Russian manufacturer of chillers, will be happy to help you with this. Buy a chiller to suit your requirements using the website form or select a chiller with the help of a technical specialist by phone - quickly, optimally, inexpensively at CenterProm-Holod.

Based on the principle of operation and the production of cold, chillers can be divided into two types: vapor compression and absorption. The scope of application of both types of refrigeration machines is similar. Both types are primarily used for the production of coolant (coolant) for air conditioning, industrial refrigeration, ventilation or technology needs. In addition, chillers can also be used to heat coolant for heating and ventilation needs. Moreover, steam-compression units are used for heating much less frequently than absorption units due to their low efficiency at negative ambient temperatures. This article will discuss vapor compression type chillers.

Principle of operation.

The main elements of a vapor compression chiller are a compressor, an evaporator, a condenser, and a throttling device. The removal of thermal energy in a vapor-compression refrigeration machine occurs due to a change in the state of aggregation of the substance (refrigerant). As a rule, the refrigerant is freons - fluorine- and chlorine-containing derivatives of saturated hydrocarbons (mainly methane and ethane). The refrigeration machine operates on the following principle: the compressor pumps gaseous refrigerant into the condenser (see diagram in Fig. 1), where, as a result of high pressure and heat removal, gaseous freon condenses. Further, when the liquid refrigerant passes through the throttling device, its pressure drops, and part of the liquid is converted into vapor. This process is accompanied by a decrease in its temperature. Then the vapor-liquid mixture enters the evaporator, where it boils and finally turns into steam. The evaporator is an intermediate refrigerant/water heat exchanger in which heat is transferred from the refrigerant to the cooled liquid. Then the liquid of the required temperature is supplied through a hydraulic circuit to consumers - fan coil units, ventilation units, etc.

Rice. 1

Classification of chillers.

Vapor compression chillers can be classified:

by type of condenser cooling;

with air-cooled condenser;
with water cooled condenser;

by execution:

for installation outside buildings;
for installation inside buildings;

for other design features, for example:

with a free cooling system (free cooling);
with a centrifugal condenser cooling fan;
by compressor type, etc.

According to the method of cooling the condenser:

air cooled chillers;
water-cooled chillers (water-cooled).

Outdoor chillers include monoblock chillers with air-cooled condenser, which are usually installed on the roof of buildings or on special sites near the buildings they serve. Chillers with a remote evaporator can also be classified as outdoor chillers.

Indoor chillers include:

chillers with a remote condenser (condenserless);
water-cooled chillers (water-to-water chillers);
air-cooled chillers with a centrifugal fan.

Indoor chillers are located in special rooms - machine rooms. Due to ease of installation, ease of operation and price, monoblock chillers with air-cooled condenser are most widely used.

Monoblock chillers with air cooled condenser

Monoblock chillers are widely used in central air conditioning systems with air supply units and in chiller-fan coil systems. Monoblocks have two modifications:

with axial fans;
with centrifugal fans (for installation inside buildings).

Chillers with axial fans(Fig. 2) are units mounted on a frame in a single housing and installed on the roof of buildings or nearby on a prepared site. Heat is released into the environment.

Rice. 2

Water or aqueous glycol solutions are used as a coolant to operate the refrigeration machine during the cold season. If the project requirements do not allow the use of glycols, then an intermediate heat exchanger is built into the system (Fig. 3). With this scheme, the temperature parameters of the glycol solution in the chiller should be 2ºC lower than the design temperature in the consumer circuit. For example, in order to ensure the temperature parameters of water in the intermediate heat exchanger output/input: 7/12ºC, it is necessary to obtain a glycol solution at the outlet of the chiller with a temperature of 5ºC.

Rice. 3

In addition, when using an intermediate heat exchanger, it is possible to operate the refrigeration machine at negative ambient temperatures. The main advantages of monoblock air-cooled chillers are ease of installation, ease of maintenance, complete readiness of the units for operation (filled with refrigerant and oil), and relatively low price. Additional advantages of monoblocks include wide placement possibilities due to the unlimited length of coolant routes and the height difference between the chiller and consumers. Modular design chillers also have undeniable advantages:

minimum delivery time due to availability in warehouse;
cost savings - the system is put into operation in parts as needed;
variability - by combining modules of different capacities we obtain a refrigeration machine of the required power (diagram Fig. 4);
energy saving - the system operates at the power level that is currently needed by consumers by turning on/off individual modules.

Rice. 4

Chillers with centrifugal fans(Fig. 5) are intended for installation in premises: basements, attics, special service premises. The main difference from chillers with axial fans is the presence of a high-pressure centrifugal fan/s. Through a network of air ducts, the fan forces air, which cools the condenser and is then removed outside, and the heat is discharged into the environment.

Advantages of chillers with centrifugal fans:

long service life due to location in a heated room.

Rice. 5

Air is taken from the room; blowing can be organized through air ducts in one of three directions (Fig. 6)

Hydromodule. The circulation of coolant (water, glycol solution) between the chiller and consumers (fan coils) is ensured by a hydraulic module (pumping station) (Fig. 7, a). The hydraulic module includes a circulation pump, an expansion tank, shut-off valves, an accumulator tank (buffer tank), control and protection system.

The storage tank (Fig. 4, b) is necessary to increase the coolant capacity in the system. The buffer tank allows you to reduce the number of starts of compressors and pumping equipment, thereby increasing the service life of refrigeration machines. The buffer tank may not be included in the hydraulic module and may be supplied separately.

Chillers with a remote condenser (condenserless) (Fig. 8)

A chiller with a remote condenser is a unit in which all the main elements: compressor, evaporator, throttling device are installed on one frame in a single housing. At the same time, the chiller itself is intended for indoor installation, and the air-cooled condenser is intended for outdoor use and is installed outside.

Rice. 8

The main advantages of chillers with a remote condenser:

possibility of year-round operation using water;
ease of service at any time of the year;
high efficiency due to the absence of a glycol circuit and intermediate heat exchangers;
long service life due to location in a heated room;
the possibility of using a capacitor in a low-noise or explosion-proof design.

A chiller is a full-featured refrigeration unit designed to cool water, as well as non-freezing solutions that are used in air conditioning systems - air handling units, fan coil units, central air conditioners, and other applied processes. Chillers are used as a heat pump, and also for heating water in cold weather. Chillers have a wide range of cooling capacity, as a result of which they are used in air conditioning systems for small buildings (apartments, cottages, small shops) and large buildings (offices, industrial and other buildings). In addition, chillers are used in the food industry to cool water and various drinks, in the sports and fitness field - for cooling ice rinks and skating rinks, in the pharmaceutical field - for cooling medicines. The modern market is represented by several types of chillers in terms of design: chillers with water and air cooling of the condenser; the latest types of chillers are most widespread because they are intended for outdoor installation.

Chiller operating principle is based on the cooling process of the main component of this unit. Superheated low-pressure refrigerant vapor leaves the evaporator, entering the compressor and simultaneously cooling the windings of its electric motor. The refrigerant vapor in the compressor is compressed, and oil is injected into the compressor to lubricate, cool, and seal gaps. Hot steam under high pressure, leaving the compressor, enters an air-cooled condenser, in which it is evenly distributed along the heat exchanger circuits and transfers heat to the cooled outside air, and condenses itself. Before leaving the condenser, liquid refrigerant is sent to a subcooler where its temperature is reduced below its saturation point, increasing cycle efficiency. Passing through a highly efficient filter-drier, where moisture is removed from the supercooled liquid freon, the refrigerant enters the thermal expansion valve, where it is throttled, partially evaporating due to the liquid’s own heat. At the end of the expansion process, the refrigerant is a mixture of vapor and low-pressure liquid entering the evaporator and evenly distributed throughout its tubes. Further, moving through the evaporator, the refrigerant boils, taking heat from the cooled water, as a result of which it acquires a vapor state. Refrigerant vapor that has reached a state of overheating leaves the evaporator, after which the cycle repeats again.

The chiller refrigeration circuit diagram consists of

Compressor

Four-way refrigeration cycle reversal valve used in heat pumps

Condenser heat exchanger

Capillary tube

Evaporator heat exchanger.

How does the automated control system work in a chiller?

Chillers, operating principle which are based on cooling or heating a liquid, are equipped with an automated control system, which consists of a controller, control panel, and protective equipment. The controller is designed to control the operation of the compressor itself, condenser fans, and a four-way valve that reverses the refrigeration cycle.

In the process of increasing the temperature of the water in the air conditioning system circuit, the controller's responsibility is to turn on the chiller compressor, which cools the water in the air conditioning system. When the water temperature in the hydraulic circuit drops below the temperature setting value minus the temperature difference value - the control delta, the built-in automated control system stops the operation of the compressor. Consequently, the controller ensures high reliability of the compressor, as well as other elements of the refrigeration circuit, throughout the entire operation of the installation.

Choosing a chiller is a serious issue that requires a competent decision. Of course, to select a refrigeration unit, there is no need to know all the nuances and subtleties of the operation of the refrigeration machine, but knowledge of the basic principles of the unit’s operation will help you quickly select the right model.

They are cheaper, but they create low air pressure, as a result of which a chiller equipped with an axial fan is placed only in an open place (roof, building wall, or other similar places). Centrifugal fans create stronger air pressure, which means chillers equipped with such fans can be placed indoors, providing air intake and exhaust through air ducts.

We looked at the principle of operation of the chiller. The equipment supplied by the Peter Kholod Company can be found at enterprises in such regions as: Moscow St. Petersburg Yekaterinburg Rostov-on-Don Kazan Krasnodar Nizhny Novgorod Volgograd Ufa Voronezh Chelyabinsk Penza Samara Tolyatti Orenburg Tver Sochi Belgorod Perm Smolensk Vladimir Voskresensk Cheboksary Saratov Kursk Novocherkassk Yaroslavl Chernogolovka Izhevsk Kirov Astrakhan Ryazan Kurgan Surgut Ulyanovsk Tyumen Kostroma Lipetsk Kaluga in Mari El Dimitrovgrad Kamensk-Uralsky Zhukovsky Naberezhnye Chelny Yeisk Ivanovo Nizhnevartovsk Podolsk Tambov Armavir Magnitogorsk in Mordovia Miass Novorossiysk Kalmykia Khanty-Mansiysk Bryansk Volzhsky Syzran Nizhny Tagil Taganrog Orel Leningradskaya In the Leningrad region In len region Zheleznogorsk Vsevolozhsk Vyborg Gatchina Kirishi Pine forest Tikhvin Cherepovets Volkhov Veliky Novgorod In the Novgorod region In the Nenets Petrozavodsk In the Komi Republic Arkhangelsk Vologda Murmansk Pskov Velikiye Lugi Vorkuta Syktyvkar Ukhta Severodvinsk Kaliningrad In the Kaliningrad region Kondopoga Sortavala In the Ivanovo region Obninsk In the Lipetsk region Elektrostal Volga region Dzerzhinsk Sarov Vyksa In the Nizhny Novgorod region Orsk In the Perm region Berezniki Neftekamsk Salavat Almetyevsk Bugulma Nizhnekamsk Zhigulevsk Balokovo Engels in Tatarstan In the Penza region In Bashkortostan In the Ulyanovsk region In Chuvashia Glazov Sarapul Dmitrov South Vladikavkaz In Adygea Anapa Tuapse Volgodonsk Mines in Kalmykia In the Krasnodar region Gelendzhik Yalta Siberia Irkutsk Barnaul Bratsk Ust-Ilimsk Kemerovo Novokuznetsk Krasnoyarsk Norilsk Altai Territory Altai In the Krasnoyarsk Territory Novosibirsk Tomsk Omsk In Buryatia Ulan-Ude in Tyva in Khakassia In the Far East Blagoveshchensk Belogorsk Vladivostok Ussuriysk Khabarovsk In the Jewish Region Kamchatka Territory Magadan in Sakha In Chukotsk Yuzhno-Sakhalinsk In Primorye V Khabarovsk Territory Yakutsk In the Northern Caucasus Northern Caucasus In Chechnya Essentuki Kislovodsk Mineral waters Pyatigorsk In Karachaevo-Cherkessk Cherkessk In the Stavropol region In Dagestan in Ingushetia and North Ossetia Alanya In Kabardino-Balkaria In the Urals Pervouralsk Tobolsk Nefteyugansk Ozersk In the Chelyabinsk region In Khanty -Mansiysk district Novy Urengoy Noyabrsk Salekhard In the Yamalo-Nenets District Udmurtsk In Udmurtia

The operating principle of the chiller-fan coil system is somewhat different from other climate control equipment. It has its own characteristics that make chillers indispensable in many areas. They may have some competition, but they have a different purpose.

The operation scheme of the chiller-fan coil system is based on the transfer of thermal energy, as in air conditioners and heat pumps. But it has a number of design features and a wide range of applications. It is already possible to install a chiller-fan coil for your home, although several years ago such equipment was considered industrial.

Chiller fan coil - what is it?

From English, the terms “chiller” and “fan coil” are translated as “refrigerator, cooler” and “fan with heat exchanger, coil.”

The components of the system are:

Chiller;
Pumping station;
Main distribution (pipelines);
Refrigerant;
Coolant;
Automatic regulation system;
Fan coil units (fan coil).

In the chiller, heat exchange occurs between the refrigerant and the surrounding air. Depending on the operating mode, it can give or receive thermal energy. The refrigerant cools or heats the coolant.

Various brands of freons are used as a refrigerant in chillers. They are not interchangeable; each model and brand has its own freon.

The coolant is water or antifreeze - a mixture of water with ethylene glycol or propylene glycol. Less commonly used as additives are sodium chloride (table salt) and calcium chloride. Depending on their concentration, the freezing point of the mixture changes.

Cassette type fan coil installed in production.

Chiller-fan coil operation diagrams

In this section we will look at connection diagrams for a chiller with a remote and built-in condenser. On them you will see the ability to connect additional systems.

Since the chiller is a universal refrigeration machine, it can be used for different purposes. For example, connect heated floors to it or.

The circuit for a chiller with a built-in capacitor looked exactly the same, but points 1 and 2 would be combined. Sometimes a cooling tower is included in the system for greater energy efficiency.

Refrigerant line;

Line for water or antifreeze;

Air treatment unit;

Forced ventilation;

Fan coil units;

Warm floor.

Chiller fan coil or air conditioners?

Split and multi-split are traditional air conditioning systems for small rooms and buildings. There are small capacity chiller-fan coil systems that can replace an 18,000 BTU air conditioner. More information about chiller models and prices can be found in this online store. What are their differences and advantages?

Any number of fan coil units corresponding to its capacity can be connected to the chiller. An analogue of such a system are multi-zone (multi-split) air conditioners.

The main chiller unit can be placed on the roof or in the basement, where it is easily accessible for maintenance and repair and hidden from public view. The outdoor unit of the air conditioner is installed on the facade of the building, access to it is difficult.

Air conditioners require frequent diagnostics, prevention and repair. They fail more often, are less wear-resistant and have lower energy efficiency.

The temperature range of air conditioners is lower, which affects energy consumption when operating for heating in winter and cooling in summer.

To operate a chiller-fan coil system, longer lines are required than for air conditioners. The cost of installation work is increasing.

If one outdoor air conditioner unit breaks down, one or more rooms will be left without cooling or heating, and not the entire building.

For the operation of air conditioners, a freon line is laid between the outdoor and indoor units. If it breaks, the refrigerant evaporates and requires refilling. If the pipelines leading to the fan coil units are damaged, it is enough to replenish the water supply in the storage tank.

A chiller is a water-cooling machine designed to reduce the temperature of water or liquid coolants. This page will discuss in detail chiller circuit and device , as well as how it works.

Based on an almost non-stop cycle (depending on the type of consumer). is to cool the water heated by the consumer by several degrees and supply it in this form to the consumer or to an intermediate heat exchanger, in which the water (if its temperature does not allow it to be sent directly into the water) is cooled by almost any number of degrees. The required value for reducing the temperature of the coolant is set by the future user of the water cooler, depending on the type and characteristics of the coolant required by the consumer of this same coolant. Equipment that requires cold energy transferred from a water-cooling machine to a coolant can be a wide variety of consumers: machine tools, air conditioning systems, injection molding machines, induction machines, oil pumps, machines for the production of polyethylene film and other systems that require a constant supply of cold water during operation. with chilled water. A variety of modifications and a wide range of cooling capacity allows the use of water coolers both for one consumer with very little heat release, and for enterprises with a large number of machines with high heat output. In addition, water coolers are used in the food industry in many technological lines for the production of drinks and other products, to ensure the cooling of ice at skating rinks and ice rinks, in metalworking (induction furnaces), in research laboratories (ensuring the operation of test chambers), etc. and so on.

Selecting a water-cooling machine is a serious task that requires such specific knowledge as the design of the chiller, as well as the principle of interaction of the chiller together with other elements of the general circuit. To make an intelligent decision about which cooler will optimally fit into the scheme of joint work of all consumers and the cooler itself, you need extensive experience in calculations, selection and subsequent successful implementation of a set of equipment based on water coolers in the technological process, which our specialists have. A separate area is chiller automation, which allows you to make the operation of the device even more efficient, optimizing the control and management of all ongoing processes. Of course, in order to select a refrigeration unit, there is no need to know all the intricacies of the operation of the refrigeration machine and the automation of the chiller, but fundamental knowledge of the principles will help you most clearly formulate the technical specifications for the calculation and professional selection of all elements, from which a scheme will then be assembled jointly with consumers chiller.

Chiller circuit

In the drawing below, it will be disassembled and a description of its elements and their functionality will be given. As a result, you will understand how the chiller and all its elements work.

A water cooling machine works on the principle of gas compression with the release of heat and its subsequent expansion with heat absorption, i.e. release of cold. Water cooling machine consists of four main elements: compressor, condenser, expansion valve and evaporator. The element in which the cold is produced is called the evaporator. The task of the evaporator is to remove heat from the cooled medium. To do this, coolant (water) and refrigerant (gas, also known as freon) flow through it. Before entering the evaporator, the gas in liquefied form is under high pressure, entering the evaporator (where low pressure is maintained), the freon begins to boil and evaporate (hence the name Evaporator). Freon boils and takes energy from the coolant, which is located in the Evaporator, but is separated from the freon by a sealed partition. As a result of this, the coolant is cooled, and the refrigerant increases its temperature and passes into a gaseous state. The refrigerant gas then enters the compressor. The compressor compresses gaseous refrigerant which, when compressed, heats up to a high temperature of 80...90 ºС. In this state (hot and under high pressure), the freon enters the condenser, where it is cooled by blowing with ambient air. During the cooling process, the gas - freon - condenses (therefore, the block in which this process occurs is called a condenser), and during condensation the gas turns into a liquid state. At this point, the chain of converting freon from liquid to gas and back comes to its beginning. The beginning and end of this process are separated by a TRV (thermal expansion valve), which is essentially a large resistance as freon moves from the condenser to the evaporator. This resistance provides a pressure drop (before the expansion valve - a condenser with high pressure, after the expansion valve - an evaporator with low pressure). Along the path of freon movement along a closed circuit, there are also secondary elements that improve the process and increase the efficiency of the described cycle (filter, valves and solenoid valves and regulators, subcooler, oil adding system for the compressor and oil separator, receiver, etc.).

Chiller device

The diagram below shows an image of a compact water cooling machine - a chiller device, monoblock design in a partially disassembled form (the protective sides of the housing have been removed). This image clearly shows all the elements indicated in the diagram of this water-cooling machine, as well as elements of the water circuit that are not included in the schematic diagram (water pump, flow switch on the coolant supply pipeline to the consumer, water filter, pressure gauge for measuring coolant pressure, storage tank for water, filter on the water line).

Peter Kholod is a supplier of Industrial water coolers and machines for air conditioning systems. We are ready to develop and create chillers for you that are suitable for your professional tasks. We also provide service, repair and automation of chillers. Whether you want to remotely control your own equipment, or would like to protect it from common problems, chiller automation will allow you to achieve all these goals. Our team is ready to implement projects of any size and complexity. Just contact us in a way convenient for you, and we will advise you on any issue of interest.