Before refueling the water-cooling unit, it is necessary to check for leaks in the freon part. The procedure is carried out as follows: pump the refrigerant to a pressure of 506 kPa and visually inspect the nuts of the thermostatic valves (TEV).

The better to refuel

It is known that best properties Water has the ability to transfer heat. Low viscosity, high heat capacity and thermal conductivity. But the increased value of the crystallization temperature (00C), as well as the ability to expand after this, negates all its positive properties. Therefore, it is optimal to use coolants with a low freezing point - antifreeze, the properties of which do not change when the temperature drops significantly, and they do not expand during crystallization.

The best heat and coolant carriers are solutions polyhydric alcohols, glycols, for example propylene glycol. It is allowed to use solutions of organic and inorganic compounds. Heat transfer fluids, like coolants, are capable of performing similar functions.

Looking for freon leaks

It is strictly forbidden to use air for injection. The fact is that the water contained in it is absorbed by the compression oil. This will subsequently cause the moisture to freeze and cause it to stop working properly. Leaks can be detected using regular shaving foam. For these purposes, it is diluted with water, and then applied to the intended problem areas using a brush.

If the procedure is carried out in due time, leaks will be identified before more serious difficulties arise. All expansion valve nuts found in this way must be tightened. At the next stage, we begin the thermal insulation procedure. There is nothing complicated or particularly memorable about it, the main thing is to do the work carefully. If you cheat, then open spaces will freeze, becoming covered with a layer of frost, which will melt after shutdown. The resulting water can cause a short circuit or other problems.

Filling with propylene glycol

Now you can proceed to the next stage. Before this, it is recommended to connect the fittings to the water block; it is better to use a simple hose for these purposes. This will help you check the operation after refueling in the future. It will also help the multi-channel water block to play the role of a filter. It will “stop” all the dirt and antifreeze dust. To determine possible leaks coolant needs to wait a little.

We turn on the pump to “drive” propylene glycol through the system circuit for about an hour. Ideally, no leaks should be detected during operation.

Freon refill

Now we remove the water block and connect both processors and the video card. We connect pressure gauge equipment to the chiller. There is a red hose to the shredder discharge valve, a blue hose to the suction valve, and to vacuum pump- yellow. If there is no pump, you can use a modified compressor from an old refrigeration unit.

The freon circuit must be made airtight and a vacuum must be created in it. Disconnect the yellow hose from the vacuum compressor and connect it to the 22 freon cylinder. We use freon to “blow through” the hose. Air that gets inside can cause negative consequences. Ideally, this is done like this: the freon cylinder opens and gas flows into the hose. At the pressure gauge station, loosen the nut, which is tightened after hearing a hissing sound.

Chiller operation

After turning on the device, freon is supplied in small portions to the suction. After a while, the inlet temperature at the heat exchanger drops, which indicates the functionality of the chiller.

Benefits of using propylene glycol

Antifreeze from propylene glycol is produced in two variations: concentrates and ready-made solutions. In the first case, there can be one basic component - glycol, to which the client independently adds water (the best volume ratio is 1:2). The finished liquid already contains demineralized water and, most often, it is a 44% concentrate solution with a crystallization temperature of -300C. To maintain the protective properties of anti-corrosion additives, it is recommended to dilute the propylene glycol solution with demineralized or distilled water.

Propylene glycol solution is used only in technical areas, adding to products or drinking water Absolutely forbidden. 100 ml of propylene glycol solution poses a great danger to human health. Antifreeze does not leave burns if it comes into contact with the skin and is easily washed off with water. It completely decomposes in the soil within a month. A concentration of less than 1 g/l is harmless to aquatic fauna and protozoan microorganisms. It’s also worth adding about the small coefficient surface tension, which promotes penetration into small cracks and pores.

Individual approach to pricing for each client!

Any equipment needs maintenance, for this they call a specialist or enter into a contract with a contractor who monitors the implementation regular Maintenance for the equipment to function without interruption for a long time.

There are several types chiller maintenance:

• Scheduled - carried out according to the schedule recorded in the special documentation for the equipment.
• Unscheduled - carried out as necessary, when emergency situations arise.

Recommended maintenance intervals for chillers

The equipment as a whole is serviced by specialists once every 6 months, and diagnostics of the heat exchanger are carried out depending on operating conditions. However, there are components and assemblies of the system that require maintenance qualified specialists according to technical passport at certain periods. Below we have provided a table indicating the period and name of the chiller part.

Thus, each component and assembly is checked regularly in accordance with the table provided, but this is not all list of required works. Scheduled Maintenance includes a wider range of work.

What is included in scheduled maintenance

• Cleaning the heat exchanger.
  

  Before servicing the chiller, be sure to disconnect it from electricity, and then carefully clean the heat exchanger of debris and dust and blow it with air. Afterwards, the pipes are cleaned to drain condensate.

• Visual inspection of the unit.
  

  Inspect the equipment, check for the presence of corrosion areas, if damage occurs, paint these areas with a special protective paint.

• Electrical equipment testing.
  

  Checking the operation of automation, grounding, correct connection, power. This test is carried out using special electrical equipment, which allows you to measure all the necessary readings of the chiller.

• Diagnostics refrigeration circuit .
  

  On at this stage check the amount of freon in the system. If the amount of refrigerant is insufficient, top up. The absence of leaks in this system is checked - Special attention must be given to the connecting parts of the refrigeration circuit. The compressor must be checked every 3000 operating hours. When this period has expired, a special emergency indicator lights up on the chiller, which reminds you to check of this element. When diagnosing a compressor, check vibration isolation, connections, connections.

• Water circuit testing.
  

  Conduct diagnostics of the differential water pressure switch. Then the air is removed from the water circuit. Then drain the water from the chiller using the drain pipe and shut-off valves.

• The final stage is checking the operation of the pump. Every 5000 hours it is cleaned and its performance checked.

Chiller Maintenance Very important point For quality work equipment. Conclude a subscription agreement for the maintenance of chiller units.

On the market climate control equipment Chillers are in particular demand. They are refrigeration units that serve as main task which is the maintenance of microclimate. The equipment is vapor compression and is installed indoors for various purposes. During the operation of the devices, the air is cooled, filtered and heated.

What devices are the most popular?

Devices can be included in the basic package modern systems conditioning. Technologies make it possible to produce two types of chillers, in which the condenser is operated using water or air. These two methods are in quite wide demand. But devices with air cooled are the most popular, due to the lack of need for coolant. In order to install such a unit, it is necessary to familiarize yourself with the technology of the work.

Main stages

Chiller installation is quite complex look works that require a special approach and high qualifications. From correct installation The efficiency of operation and the duration of its operation will depend. Considering the main stages, we can highlight the design of the system, determination of the installation location, and calculation of the load on the structure.

The next step is to prepare the support frame or base. The installation instructions for the MTA AS299 N chiller, like devices of any other brand, provide for rigging work and installation of the unit itself. The system is connected to the coolant, as well as the power supply network.

Before you start

The final stage is then commissioning. During design, calculations of heat inputs and coolant flows are carried out. This data allows you to select a machine and its design. After approval of the type of chiller, you should decide on the installation location and prepare it correctly.

Main types of design - unit indoor installation and monoblock devices for outdoor installation. Internal equipment may include a water-cooled or remote condenser. If you have to work with a monoblock chiller, then a support frame is made for it, which must have a certain height. It protects equipment from precipitation and evenly distributes the load on the structure. The support must be carried out in compliance with all the rules, because noise and abnormal vibrations may appear.

Work on the base and connection

Installation of a chiller, which will be located from the inside, involves organizing a site. Refrigeration devices operate at significant levels sound pressure, therefore it is not worth placing them near office and residential premises. It is important to select and correctly install vibration supports that will reduce the level of vibration transmitted to building structures.

One of the most critical stages is connecting the equipment to the coolant and power supply. In order to ensure normal work system, you should follow the installation recommendations and understand what components should be in the hydraulic circuit.

Elements for installation

Installation of the chiller is accompanied by the use of certain elements. A bypass and a filter with a shut-off valve should be located along the flow of the coolant. This measure will prevent contamination of the heat exchanger when flushing the system, otherwise you may experience equipment failure.

You will also need balancing valve, which will be located at the outlet of the evaporator. It is required to regulate water flow and bring values ​​to the norm. Shut-off valves will be located at the outlet and inlet of the chiller. If the system depressurizes, the coolant will have to be drained.

Care should be taken to ensure that they are installed at the highest points of the system. Installation of an absorption chiller is carried out in several stages. One of them is the installation of thermometers and pressure gauges before and after the equipment described. This will allow you to monitor the temperature and degree of contamination of the heat exchanger.

A filter is installed in front of the pump. It must face the direction of flow of the coolant. This will exclude mechanical damage in the area of ​​the pump impeller. Emergency valve and damper expansion tank must be located in front of the pump. This will eliminate the increase and decrease in pressure at the pump inlet.

More information about choosing a location

Installation instructions for the chiller are included with the equipment. After reading it, you can find out that the device can be placed at ground level or on the roof, but in these cases, you should ensure that there is space for ventilation. The unit must be located taking into account the requirements for vibration and noise.

The device should be protected from exposure to ultraviolet radiation by placing it away from chimneys. It should not be exposed atmospheric air which could cause corrosion of the condenser coils and copper tubes. If access to the chiller is possible for unauthorized persons, then measures should be taken to limit it. For this purpose, protective devices are used.

The chiller is installed on a base whose height is 300 mm or more. It is important to ensure there are drainage channels that will remove water and deal with leaks. If the unit is located at ground level, the base must be mounted on concrete foundation, which is laid below the soil freezing line. The base should not be in contact with the foundation of the building to eliminate vibrations and noise.

When installing the bases, it is necessary to ensure the presence of holes that will allow fastening to the foundation. When installed on the roof, the latter must support the weight of the chiller and operating personnel. The device can rest on a base or a steel frame.

The steel channel should be aligned with the shock absorber mounting holes. The channel must have a width that is sufficient for mounting the shock absorber. When installing a chiller, it is important to avoid obstacles to connecting water pipes and wires. At the water inlet there should be no sources of heating, steam, harmful gases and noise. The equipment coming from the equipment is hot and cold air should not affect the environment.

Need for additional space around equipment

At installation work should be considered technological features and requirements. For example, the volume for installation should not be limited by the dimensions of the machine, it should include additional parameters, including space:

• for air intake and exhaust;
• for access and maintenance;
• to replace parts.

As for the first recommendation, it is true for chillers that require air intake and exhaust for operation. There are also safety regulations, they dictate the rules in which space for maintenance and access must be taken into account.

No matter how high-quality the equipment is, one should take into account the likelihood that the device may fail. Therefore, space should be left for replacement of parts and repairs, which may be required for compressors and shell-and-tube heat exchangers.

Connecting a fan coil and chiller

Installation of chillers and fan coil units allows for smooth operation of the system. The work involves the use of thermally insulated pipelines. If there is no insulation, then the coefficient useful action the system will drop significantly. Fan coil units have individual piping units, with which you can adjust the performance in terms of heat and cold production.

The refrigerant flow is regulated by special fittings. If it is necessary to separate the coolant and cold agent, the water should be heated in a separate heat exchanger. The scheme is supplemented circulation pump. For smooth adjustment fluid flow when installing a piping circuit, a three-way valve should be used.

If the building has a two-pipe system, then heating and cooling will occur due to the chiller. In order to make heating work more efficient, fan coil units are connected to cold period and are complemented by boilers. If we compare two-pipe system with a four-pipe heat exchanger, then the latter contains the two mentioned units. At the same time, the fan coil operates for heating and cooling, using in the first case the liquid that circulates in the heat exchanger system.

If you decide to install a chiller and fan coil in the building, installation of a cooling system in Moscow can be carried out. The cost of carrying out such work will be mentioned below. Speaking of the above, it can be noted that during installation one of the heat exchangers is connected to a pipeline with refrigerant, while the second is connected to a pipe with coolant. The heat exchanger must have an individual valve that is controlled by a remote control. If a similar scheme is used, the refrigerant does not move with the coolant.

Finally

Installation of chillers in Kaliningrad can be carried out with the help of specialists. Prices in Russia are approximately the same everywhere. Final cost will depend on the power of the equipment. If it does not exceed 100 kW, then you will have to pay 16,000 rubles. With an increase in the mentioned parameter to 250 kW, the price increases by 50 rubles. for every kilowatt. When purchasing a fan coil unit whose power does not exceed 6 kW, you will pay 2,900 rubles for its installation.

What's happened ? Chiller is refrigeration unit, used for cooling and heating liquid coolants in central systems conditioning systems, which can be air supply units or fan coils. Basically, a chiller is used to cool water in production - it cools various equipment. By the water better characteristics compared to a glycol mixture, so running on water is more efficient.

A wide power range makes it possible to use the chiller for indoor cooling various sizes: from apartments and private houses to offices and hypermarkets. In addition, it is used in Food Industry for drinks, in the sports and health sector - for cooling skating rinks and ice rinks, in pharmaceuticals - for cooling medicines.

There are the following main types of chillers:

• monoblock, air condenser, hydraulic module and compressor are located in one housing;
• chiller with a remote condenser outside (the refrigeration module is located indoors, and the condenser is taken outside);
• chiller with water condenser (used when needed minimum dimensions refrigeration module in the room and it is not possible to use a remote condenser);
• heat pump, with the ability to heat or cool the coolant.

Chiller operating principle

Theoretical basis, on which the operating principle of refrigerators, air conditioners, and refrigeration units is based, is the second law of thermodynamics. Cooling gas (freon) in refrigeration units performs the so-called reverse Rankine cycle- a type of reverse Carnot cycle. In this case, the main heat transfer is based not on compression or expansion of the Carnot cycle, but on phase transitions - and condensation.

An industrial chiller consists of three main elements: a compressor, a condenser and an evaporator. The main task of the evaporator is to remove heat from the object being cooled. For this purpose, water and refrigerant are passed through it. As the refrigerant boils, it takes energy away from the liquid. As a result, water or any other coolant is cooled, and the refrigerant is heated and goes into a gaseous state. After this, the gaseous refrigerant enters the compressor, where it acts on the compressor motor windings, helping to cool them. There, the hot steam is compressed, again heating up to a temperature of 80-90 ºС. Here it is mixed with oil from the compressor.

In the heated state, freon enters the condenser, where the heated refrigerant is cooled by a flow of cold air. Then the final cycle of work begins: the refrigerant from the heat exchanger enters the subcooler, where its temperature decreases, as a result of which freon passes into liquid state and fed into the filter drier. There it gets rid of moisture. The next point on the path of refrigerant movement is the thermal expansion valve, in which the freon pressure decreases. After leaving the thermal expander, the refrigerant is steam low pressure in combination with liquid. This mixture is fed to the evaporator, where the refrigerant boils again, turning into steam and superheating. The superheated steam leaves the evaporator, which is the beginning of a new cycle.

Industrial chiller operating diagram

#1 Compressor
The compressor has two functions in refrigeration cycle. It compresses and moves refrigerant vapor in the chiller. When vapor is compressed, pressure and temperature increase. Further compressed gas enters where it cools and turns into a liquid, then the liquid enters the evaporator (at the same time its pressure and temperature decrease), where it boils, turns into a gas, thereby taking heat from the water or liquid that passes through the evaporator of the chiller. After this, the refrigerant vapor enters the compressor again to repeat the cycle.

#2 Air-Cooled Condenser
An air-cooled condenser is a heat exchanger where the heat absorbed by the refrigerant is released into the surrounding space. The condenser usually receives compressed gas - freon, which is cooled and, condensing, passes into the liquid phase. Centrifugal or axial fan a stream of air is supplied through the condenser.

#3 Relay high pressure(High Pressure Limit)
Protects the system from overpressure in the refrigerant circuit.

#4 High Pressure Pressure Gauge
Provides a visual indication of refrigerant condensation pressure.

#5 Liquid Receiver
Used to store freon in the system.

#6 Filter Drier
The filter removes moisture, dirt, and other foreign materials from the refrigerant that would damage refrigeration system and reduce efficiency.

#7 Liquid Line Solenoid
Solenoid valve- it's simply electrically controlled stopcock. It controls the flow of refrigerant, which is closed when the compressor stops. This prevents liquid refrigerant from entering the evaporator, which could cause water hammer. Water hammer can cause serious damage to the compressor. The valve opens when the compressor is turned on.

#8 Refrigerant Sight Glass
The sight glass helps to observe the flow of liquid refrigerant. Bubbles in the fluid flow indicate a lack of refrigerant. The moisture indicator provides a warning if moisture enters the system, indicating that maintenance is required. The green indicator does not indicate any moisture content. A yellow signals indicator that the system is contaminated with moisture and requires maintenance.

#9 Expansion Valve
A thermostatic expansion valve or expansion valve is a regulator whose position of the regulating body (needle) is determined by the temperature in the evaporator and whose task is to regulate the amount of refrigerant supplied to the evaporator, depending on the superheat of the refrigerant vapor at the outlet of the evaporator. Therefore, at any given time, it must supply only such an amount of refrigerant to the evaporator that, taking into account the current operating conditions, can completely evaporate.

#10 Hot Gas Bypass Valve
Hot Gas Bypass Valve (capacity regulators) are used to match the compressor capacity to the actual evaporator load (installed in the bypass line between the low and high pressure sides of the refrigeration system). Hot gas bypass valve (not included) standard equipment chillers) prevents short compressor cycling by modulating the compressor power. When activated, the valve opens and diverts hot refrigerant gas from the discharge into the liquid refrigerant stream entering the evaporator. This reduces the effective throughput systems.
#11 Evaporator
An evaporator is a device in which a liquid refrigerant boils, absorbing heat as it evaporates, from the coolant passing through it.

#12 Low Pressure Refrigerant Gauge
Provides a visual indication of refrigerant evaporation pressure.

#13 Low Refrigerant Pressure Limit
Protects the system from low pressure in the refrigerant circuit to prevent water from freezing in the evaporator.

#14 Coolant Pump
Pump for circulating water through a refrigerated circuit

#15 Freezestat Limit
Prevents liquid freezing in the evaporator

#16 Temperature sensor
Sensor that shows the water temperature in the cooling circuit

#17 Coolant Pressure Gauge
Provides a visual indication of the coolant pressure supplied to the equipment.

#18 Automatic topping up (Water Make-Up Solenoid)
It turns on when the water in the tank drops below the permissible limit. The solenoid valve opens and the tank is filled from the water supply to the desired level. The valve then closes.

#19 Reservoir Level Float Switch
Float switch. Opens when the water level in the tank decreases.

#20 Temperature Sensor 2 (From Process Sensor Probe)
A temperature sensor that shows the temperature of the heated water that returns from the equipment.

#21 Evaporator Flow Switch
Protects the evaporator from freezing of water in it (when the water flow is too low). Protects the pump from dry running. Indicates that there is no water flow in the chiller.

#22 Capacity (Reservoir)
To avoid frequent starts of compressors, use a container of increased volume.

A chiller with a water-cooled condenser differs from an air-cooled one in the type of heat exchanger (instead of a tube-fin heat exchanger with a fan, a shell-and-tube or plate heat exchanger is used, which is cooled by water). Water cooling The condenser is supplied with recycled water from a dry cooler (drycooler) or cooling tower. In order to save water, the preferred option is to install a dry cooling tower with a closed water circuit. The main advantages of a chiller with a water condenser: compactness; possibility of internal placement in small room.

Questions and answers

Question:

Is it possible to use a chiller to cool liquid per flow by more than 5 degrees?

The chiller can be used in closed system and maintain the set water temperature, for example, 10 degrees, even if the return temperature is 40 degrees.

There are chillers that cool water through flow. It is mainly used for cooling and carbonating drinks, lemonades.

What is better: chiller or dry cooler?

The temperature when using a dry cooler depends on the temperature environment. If, for example, it is +30 outside, then the coolant will be at a temperature of +35...+40C. Drycoolers are used mainly in the cold season to save energy. The chiller can achieve the desired temperature at any time of the year. It is possible to manufacture low-temperature chillers to obtain liquid temperatures with negative temperature to minus 70 C (the coolant at this temperature is mainly alcohol).

Which chiller is better - with a water or air condenser?

The water-cooled chiller is compact in size, so it can be placed indoors and does not generate heat. But cold water is required to cool the condenser.

The water condenser chiller has more low cost, but a dry cooling tower may be additionally required if there is no water source - a water supply or a well.

What is the difference between chillers with and without a heat pump?

A chiller with a heat pump can operate for heating, that is, not only cool the coolant, but also heat it. It must be taken into account that heating deteriorates as the temperature decreases. Heating is most effective when the temperature drops at least minus 5.

How far can an air condenser be moved?

Typically the capacitor can be carried up to a distance of 15 meters. When installing an oil separation system, the height of the condenser is possible up to 50 meters, provided correct selection diameter of copper lines between the chiller and the remote condenser.

To what minimum temperature does the chiller operate?

When installing a winter start-up system, the chiller can operate until ambient temperature minus 30…-40. And when installing arctic fans - up to minus 55.

Types and types of liquid cooling installations (chillers)

It is used if the temperature difference ∆T l = (T L - T Kl) ≤ 7ºС (cooling of technical and mineral water)

2. Scheme of liquid cooling using an intermediate coolant and a secondary heat exchanger.

It is used if the temperature difference ∆T l = (T L - T Kl) > 7ºС or for cooling food products, i.e. cooling in a secondary gasketed heat exchanger.

For this scheme, it is necessary to correctly determine the flow rate of the intermediate coolant:

G x = G x n

G x – mass flow rate of intermediate coolant kg/h

Gf – mass flow rate of cooled liquid kg/h

n – circulation rate of the intermediate coolant

n =

where: C Рж – heat capacity of the cooled liquid, kJ/(kg´ K)

C Рх – heat capacity of the intermediate coolant, kJ/(kg´ K)

∆T x = (T Nx – T Kx)– temperature difference of the intermediate coolant in the evaporator