\u003e Production of refrigeration equipment\u003e Fluid cooling installations\u003e VACTEKH chillers and configuration options\u003e
Equipment "With a remote condenser" It is used in case of the impossibility of placing equipment with a significant heat generation within the workshop or machine compartment (for an approximate assessment - heat dissipation in the condenser (in kW) is 30% higher than the cooling capacity of the chiller (in kW)). A chiller itself is installed in the heated room, and the air-cooled condenser is mounted on the roof, next to the building or on the building wall. For some eastern regions of Russia, where the temperature in winter is held for a long period of time at the level - 30 ... - 35c, this is the only option of the configuration of water-cooler installations with a cooling capacity of more than 50-100 kW. When ordering a chiller with a remote condenser, the customer comes with two modules: the refrigeration unit (chiller itself) and air cooling condenser. Depending on the performance of the installation, it is completed with remote condensers of our own production, the production of firms Searle (England) or HTS (Czech Republic).
If a chiller with a remote capacitor is operated in the winter period of time (at ambient temperature below 0 s), it is equipped with a winter start-up system representing a system of overhead valves in the freon circuit that allows you to turn on the chiller after a long-term parking at low ambient temperatures. All valves of the winter start system are embedded inside the refrigeration unit during its production.
(Chiller) is a refrigerator (refrigerator) for or other liquid. Refrigerator Designed for the selection of heat in the cooled medium at low temperatures, while the recovery of heat at high temperatures is a by-process. As part of a refrigerator, several functional elements: compressor (from 1 to 4), capacitor, electric motor, evaporator, refrigerant extension device or thermostatic valve, control unit.Obtaining an artificial cold is based on simple physical processes:, condensation, compression and expansion of working substances. Working substances used in refrigeration units, referred to refrigerators.
Refrigerating machines vary:
Benefits
The working substance is a solution of two, sometimes three components. The most common binary solutions from the absorber (absorbent) and refrigerant corresponding to the two main requirements for them are the most common: high solubility of the refrigerant in the absorbent and a significantly higher boiling point of the absorbent compared with the refrigerant. Wide use was obtained solutions of water ammonia (water-free refrigeration machines) and bromide lithium-water (bromistric machines), in which, respectively, water and lithium bromide are absorbents, and ammonia and water - refrigerants. The operating cycle in absorption chillers (see in the figure below) is as follows: in the generator to which the cam heat is supplied) boils the working substance, as a result of which a practically pure refrigerant rolls out, its boiling point is much lower than that of the absorbent.
Couples of the refrigerant enters the condenser, where it is cooled and condensed, giving his heat environment. Further, the resulting liquid is throtting, as a result of which is cooled when expanding) and is sent to the evaporator, where, evaporated, gives his cold to the consumer and follows the absorber. This is also served by an absorbent through the throttle, from which the refrigerant was swollen at the very beginning, and absorbs pairs, because we have noticed the requirement of their good solubility. Finally, the absorbent pump is pumped into the generator to the producer by the refrigerant, where it drops again.
The main advantages of absorption chillers:
Absorption Chiller is a car that produces chilled water using residual heat from sources such as steam, hot water or hot gas. Chilled water is made according to the principle of cooling: liquid (refrigerant), which evaporates at low temperatures, absorbs heat from its surrounding environment during evaporation. Clean water is usually used as a refrigerant, while the bromide lithium solution (LIBR) is used as an absorbent.
In absorption refrigeration plants, the absorbent, generator, pump and heat exchanger replace the compressor of the cooling system of the steam compressor (mechanical cooling). The remaining three (3) components discovered also in mechanical refrigeration systems, that is, an expansion valve, evaporator and a capacitor are also used in absorption refrigeration systems.
Refer to Figure-2 for a schematic explanation of the absorption cooling process. Like mechanical cooling, the cycle "begins" when the liquid refrigerant high pressure The capacitor passes through the expansion valve (1, in figure 2) to the low pressure evaporator (2, in figure 2) and collects a sump in the evaporator.
In this low pressure, a small amount of freon begins to evaporate. This evaporation process cools the remaining liquid refrigerant. Similarly, heat transfer from relatively warm process water to chilled currently refrigerant leads to the fact that the latter evaporates (2, in FIG. 2), and the resultar pairs is fed to the lower pressure absorber (3, figure 2). As technological water loses heat to the refrigerant, it can be cooled to significantly low temperatures. At this stage, the cooled water is actually obtained by evaporation of freon.
Refrigerant vapor absorption in lithium bromide is an exothermic process. In the absorber, the refrigerant "is absorbed" by the absorbing solution of lithium bromide (LIBR). This process not only creates a low-pressure region, which pulls a continuous flow of a pair of refrigerant from the evaporator to absorber, but also causes steam to condensate (3, in figure 2), since it releases the heat of evaporation provided for in the evaporator. It is warm, together with the heat of dilution arising when mixing the condensate of the refrigerant with an absorbent, is transferred to the cooling water and stands out in the cooling edge. Cooling water is a utility at this stage of cooling.
As the lithium bromide absorbent sucks the refrigerant, it becomes more and more diluted, reducing its ability to absorb a greater amount of refrigerant. To continue the cycle, the absorbent must be re-concentrated. This is achieved by constant pumping down the diluted solution from the absorber to the low-temperature generator (5 in Figure 2), where the addition of residual heat (hot water, steam or natural gas) boosts (4, in Figure 2) refrigerant from the absorbent. Often this generator is used to utilize the spent heat from the factory. As soon as the refrigerant is removed, the reconnected solution of lithium bromide is returned to the absorber, ready to resume the absorption process, and the free freon is sent to the condenser (6, in figure 2). At this stage of regeneration, spent heat from steam or hot water is useful.
Couples of refrigerant boiled in the generator (5, in Figure 2) returns to the condenser (6), where it returns to its liquid state when cooling water raises the heat of evaporation. Then it returns to the expansion valve, where the full cycle is completed. At the stage of condensation, the cooling water becomes useful again.
Absorption chillers can be disposable, double or newest, which is a triple effect. Machines with one effect have one generator (see the scheme above, Figure 2) and have the value of COP less than 1.0. Two-effect machines have two generators and two capacitors and are more efficient (typical COP values\u003e 1.0). The triple effect machines add a third generator and capacitor and are most effective: the typical value of COP\u003e 1.5.
The main advantage of absorption chillers is lower costs of electricity. Costs can be even further reduced if natural gas is available at a low price or if we can use a low-grade heat source, which otherwise is lost at the factory.
Two main lack of absorption systems - their size-weight, as well as their need for larger cooling towers. Absorption more and harder compared to electric chillers of the same power.
Parokompression of chillers are the most common type of refrigeration equipment. The generation of cold is carried out in a parocompression cycle, consisting of four main processes - compression, condensation, choke and evaporation - using four main elements - compressor, capacitor, regulating valve and evaporator - in the following sequence: working substance (refrigerant) in a gaseous state comes to The input of the compressor with pressure P1 (~ 7ATM) and the temperature T1 (~ 5 ° C) and shrinks there before the pressure P2 (~ 30atm), heating to the temperature T2 (~ 80 ° C).
Further, the freon follows 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, it remains actually for tenths of ATM. In the process of cooling, the freon condenses and the resulting liquid enters the throttle (element with high hydrodynamic resistance), where it is very quickly expanding. At the output, a pair-liquid mixture is obtained with parameters P4 (~ 7ATM) and T4 (~ 0C) entering the evaporator. Here Freon gives his cold to the flowing evaporator with a coolant, heating and evaporating at constant pressure (really, it will fall on the tenths of the atmosphere). The resulting cooled coolant (TX ~ 7c) is the final product. And he at the outlet of the evaporator has the parameters P1 and T1, which enters the compressor. The cycle closes. Driving force - Compressor.
Traditionally, cooling cooling towers in which water, heated in the condenser, is used to cool the refrigeration machine condenser, is sprayed through the nozzles in the flow of the moving outdoor air, and with direct contact with air cools to the temperature of the wet thermometer of the outer air, then entering the condenser. This is a pretty cumbersome device that requires special service, pumping the pump and another auxiliary equipment. Recently, the so-called "dry" cooling and coolers of the condenser are used, which represent the water-air surface heat exchanger with axial fans, in which the heat of water heated in the condenser is transmitted to air, the circulation of which through the heat exchanger provides axial fans.
In the first case, the water circuit is open, in the second case - a closed, in which it is necessary to install all the necessary equipment: circulation pump, expansion tank, Safety valve, shut-off valve. To prevent water freezing when the chiller is working in cooling mode at negative outdoor temperatures, a closed circuit is filled aqueous solution non-freezing fluid. When water cooling the heat capacitor, the condensation is also useless and promotes thermal pollution of the environment. In the presence of a heat source, such as a hot water supply system or a technological line, during the production of cold, it is possible to use the heat of condensation.
By type of vehicle of hydromodul:
Body pump. - This is the mode of operation of Chiller "for heating." The parokompression cycle works several in other sequences, the evaporator and the condenser change their roles and the coolant is not cooled, but heats up. By the way, we note that Chiller, though a refrigerator, giving three times more cold than consumes, but it is even more effective as a heater - he will give it four times more than the electricity spent. The thermal pump mode is most common in public and administrative buildings, sometimes used for warehouses, etc.
Smooth start compressor - option that allows you to get rid of high starting currents exceeding workers by 2-3 times.
The nomenclature series of issued chillers in recent years has significantly updated significantly due to the widespread use of new more efficient types of compressors: spiral, single, twin-ventricular, which in the range of small, medium and large manufacturers gradually displaces piston compressors. A number of chillers with a built-in hydraulic module, including accumulating tank, expanded.
Planted and surface heat exchangers are often used as evaporators, which made it possible to reduce the dimensions of the aggregates and their weight. Recently, manufacturers have begun vibrating chillers on environmentally friendly Freons R407 ° C ,. Depending on the method of cooling the condenser, refrigeration units are divided into chillers with air cooled condenser and water cooling capacitor. The greatest application find chillers with air-cooled capacitor when the heat from the capacitor is removed by air, more often outdoor.
This method of removal of warmth requires installing it outside the building or the use of special measures that provide such a cooling method. Capacitor chillers are available in a monoblock design when all chiller elements are in one block, and chillers with a remote capacitor, when the main unit can be installed indoors, and the condenser cooled by the outer air is located outside the building, for example on the roof or in the yard . The main unit is connected to the air capacitor installed outside the building, copper freonofluids. Monoblock chillers
The execution of chiller is possible with an additional way to regulate ho-loving performance. With the variants of the execution of chillers 1, 3 heat condensation is transmitted to the outer air and is irretrievably lost. With the variants of the execution of chillers 2 and 4, additional covering heat exchangers are installed, the duplicate capacitor completely in version R (the use of 100% heat condensation for water heating) or partly (use of 15% heat condensation for water heating).
Under option 4, the additional shell-tube capacitor is installed on the injection line after the compressor in front of the main air capacitor. Chiller configuration can be: ST-standard; LN - with a reduced level of noise, which is achieved by the device of sound-absorbing casing for the compressor and lowering the speed of rotation of the axial condenser fan compared with the standard configuration; En - with a significant reduction in noise level, which is achieved by a sound-absorbing casing device for a compressor, an increase in the area of \u200b\u200bthe live cross section of the capacitor for the air passage and the decrease in the rotation speed of the axial fan, as well as the installation of the compressor to spring anti-vibration supports, the use of flexible inserts on the discharge and suction refrigeration pipelines contour.
Requirements in the level of sound power generated by a working chiller with axial fans when installing outside the building may not be very high if there are no special requirements for noise levels in the development where this building is located. If such restrictions take place, it is necessary to calculate the sound pressure level in the noise room emitted by the chiller, and, if necessary, apply the chillers of a special configuration.
When choosing this type of chiller and its placement, a free supply of cooling air to the chiller and a removal of air heated in the condenser should be ensured. This is carried out with the help of suction and injection ducts, while the ventilation network is formed, consisting of a centrifugal fan, an air heater (chiller capacitor), air ducts, intake and exhaust ventilation louvre lattices. The dimensions of the latter are selected based on the recommended speeds of air movement in the cross section of the lattices and air ducts.
It is necessary on the basis of the aerodynamic calculation to determine the pressure loss in the ventilation network. Pressure loss in the ventilation network should correspond to the pressure developed by the centrifugal fan, with the value of air flow, cooling capacitor. If the pressure of the centrifugal fan is less than pressure loss in the ventilation network, you can use a more powerful electric motor to a centrifugal fan by special order. Air ducts must be attached to the chiller using flexible inserts so that the vibration is not transmitted to the ventilation network.
At the same time, the daily chart of thermal excess is also uneven character with a pronounced maximum. Traditionally, in chillers with a capacity of 20-80 kW, two identical compressors set two independent refrigeration circuits. As a result, the unit is capable of working in two modes by 50% and 100% of its rated power. A new generation of chillers with a refrigerator from 20 to 80 kW allows three-stage performance regulation. In this case, complete refrigeration capacity is distributed between compressors in a ratio of 63% and 37%.
Chillers have a new generation both compressors are included in parallel and work on one refrigeration outline, that is, have a common capacitor and evaporator. Such a scheme significantly increases the energy conversion coefficient (KPE) of the refrigeration circuit when working with incomplete load. For such chillers at 100% load and outdoor temperature of 25 ° C KPE \u003d 4, and when working by 37% KPE \u003d 5. Considering the fact that 50% of the time chiller works with a load of 37% it gives significant energy savings.
To effectively implement a new decision on chillers, microprocessor controllers are installed, which allow:
As a result, it is automatically minimized by the short-term compressor inclusions, optimization of the operation time of compressors and adjusting water parameters at the exit of chillers in accordance with the real needs. As the tests were shown, on average, only 22 on the inclusion of compressors occurs during the day, while the compressor of conventional chillers turns on 72 times.
The average annual CPE of Chiller reaches 6, and energy savings, when using modern chillers instead of the usual, is 7.5 kW of an hour at 1m2 area of \u200b\u200bthe service facility per season, or 35%. Another important advantage that gives the use of new chillers is that it disappears the need to install bulky accumulating tanks, and the circulation pump embedded in the chiller body allows you to do without an additional pumping station.
As is well known, the type of compressors used is important for accuracy of the execution of the load of the cheillers. Traditionally, piston or screw compressors were used in high power chillers. The piston compressor has a large number of moving parts and, as a result, low efficiency due to large friction losses. In the course of operation of piston compressors, there is a high level of noise and vibration, and there is also the need for their regular maintenance. Screw compressors, in turn, have a complex design, and, as a result, a very high cost. The production of screw compressors turns out to be lowered.Maintaining such compressors labor consuming and requires high personnel qualifications. In recent years, new compressors like Scroll appeared on the market, which are deprived of the characteristic drawbacks of piston and screw compressors. Scroll compressors have high energy efficiency, low noise and vibrations and do not need maintenance. This type of compressors is simple in construction, very reliable and, at the same time, is inexpensive. However, the performance of SCROLL compressors, as a rule, does not exceed 40 kW.
Application in modern chillers a plurality of small, but very reliable compressors like Scroll, as well as several refrigeration contours, made it possible to obtain a very "maneuverable" chiller, which is capable of producing the required refrigeration capacity with high accuracy. Obviously, the use of such chiller makes it unnecessary installation of the pumping station, and a wide selection of various productivity pumps built into the chiller housing solves all issues related to the circulation of chilled water. Very small launchers of new equipment should be highlighted. After all, the launch of small Scroll-compressors having low power consumption occurs alternately, in accordance with the increase in the load on the aggregate.
In all recent generation chillers, a modern microprocessor control system allows you to adjust the set value of the water temperature at the outlet of the chiller in accordance with the outdoor air parameters, technological processes or commands from the centralized control system (dispatch). From an economic point of view, the use of a large number of SCROLL compressors and the installation of a built-in circulation pump instead of a separate pumping station turns out to be a more profitable option than the use of expensive, powerful and complex semi-hermetic compressors. Advantages and Disadvantages of Chillers
Specification
Specification
Specification
Specification:
According to the principle of operation, fankyl is very similar internal block Split systems. The main difference lies in the coolant: instead of the refrigerant, the fan closer uses conventional water or non-freezing solution. The liquid cools or heats the incoming air, which is brought to the desired temperature and returns to the room. The condensate arising from this is discharged into the street or into the sewer with the pump.
As in the case of heating radiators, in one room, several fan coils are often installed - the required amount depends on the power of the devices and the room area. In addition, they can connect to supply ventilationthat allows you to use devices in mixed mode (mix the air obtained from the inside with fresh).
Temperature control is performed using an electronic system control unit, temperature sensors and various valves. In complex air conditioning systems, central air conditioners are also used that are responsible for cleaning and moisturizing the incoming air.
Large premises like entertainment or shopping centers, hospitals, hotels, manufacturing workshops and warehouses need a special system of air conditioning. It should be closely related to the operation of heating and ventilation systems, and at the same time it is desirable that it does not simply cooled air, but also moistened it or dried depending on the characteristics of the building. And best with such tasks today, air conditioning systems built on the basis of chillers are coping.
Chiller- or special refrigeration station - it is considered one of the most effective types of climatic equipment.which allows you to create optimal temperature and humidity conditions in any room. Its main function is cooling water, after which the pumping plants transport cold water through pipelines inside the building. At the same time, chillers can be the most diverse, but the system built on their base always has a mass gain:
There are found on sale different variants These aggregates, but only 6 varieties are considered basic.
1. 
Chiller equipped with a capacitor air cooling function.
As a rule, such equipment works on water, which acts as a cold sapper. This option is considered very economical and at the same time light in terms of design and subsequent installation, but air-cooled chillers have a number of shortcomings. Among them:
2. 
Chiller, equipped with a capacitor air cooling function in an external installation and working with non-freezing fluids.
As a rule, glycol acts as a heat exchanger and the farmers in this situation, but it may be water. Such a refrigeration station operates in a chart of 5/10 degrees, and the cooled water after the heat exchanger is characterized by parameters 7/12 degrees.
The advantages of this system are as follows:
On the other hand, similar chillers also have drawbacks. Among them:
3. 
Chiller equipped with built-in cooling towers.
This equipment allows you to realize free cooling in cold seasons, and the automation independently chooses the optimal mode of operation - the operation of only cooling towers, the operation of the compressor only or the mixed mode. This allows you to achieve maximum economy of electricity, which makes such a system very economical and allows the user to quickly recoup the costs of it.
Another advantage of this option is that the refrigeration station with such equipment can be used without intermediate heat exchangers.
4. 
Chiller equipped with a remote condenser.
The system can effectively serve in certain conditions, but in most cases it will be characterized only by disadvantages:
5. 
Chiller, equipped with a capacitor liquid cooling function, as well as dry cooling towers.
Equipment is considered to be not cheap, but it has many advantages:
However, this technique will be about 60% more expensive than the first option.
6. 
Centrifugal chiller or water-cooled station having a centrifugal compressor.
The equipment is considered very effective, with the lower the temperature of the coolant, the higher the efficiency of the chiller. In order to increase it additionally, you can use an evaporative cooling tower, which will maintain water temperature at 30 degrees. This option is perfectly suitable for large buildings that need high-power systems.
At the same time, one more important advantage of such a system should be noted - the capital costs of it are small. But, on the other hand, there are disadvantages - the circuit of cooling water in such a chiller must constantly focus, and the minimum equipment performance will actually be 30% of the nominal indicator.
7. 
Absorption gas chiller equipped with water cooling function.
As a fuel, liquefied gas can be used on this equipment - imported or obtained from the gas pipeline (a reliable connection must be performed to install such a chiller to the gas pipeline). Also, this type of refrigeration system should be completed from evapultational cooling towers.
If the equipment is connected correctly, it will demonstrate excellent advantages:
At the same time, the capital costs of this type of equipment will be sufficiently high, and the minimum cleaner performance will be about 25% of the nominal indicator. Also, such equipment needs to feed the cooling water circuits.
Considering all these options, it is enough just to weigh everything as opposed, and you can approximately imagine what version of Chiller would be arranged. However, the final choice should be done taking into account the specifics of the entire object and your personal wishes and requirements. In particular, it will be necessary to take into account:
For example, if you need to cool the server, be sure to note that the cooling capacity of the equipment must be at least 1 thousand kW, the cost of connecting additional energy will be 1.5 TC. Dollars / kW, and the minimum outdoor temperature will be up to - 40. At the same time, the technique will work all year round and the round day, and the gas will not be used.
Given this data, the optimal chiller option for the server will be free cooling system (Chiller No. 5) or chiller with built-in cooling towers (No. 3). The latter will be 20% cheaper when buying, and the first will be more economical subsequently. However, in any situation, all investments in such a system (with an equal value of maintenance and the same amortization) will be 5-7 years, after which they will give excellent savings. But if you need to connect additional electrosals (at the level of about 100 kW), the first option will definitely be more preferable from the point of view of the economy.
Similarly, chillers should be selected for any other premises. And only spending all accurate calculations and comparing the technical task with different types of stations that you could choose, you can choose the optimal climate technique.
Chillers have long been used to equip air conditioning systems. The area of \u200b\u200btheir use is quite wide: from offices and private houses, to medical institutions and large industrial workshops. Such popularity of the installation was won by high efficiency, convenience of operation, a variety of design options.
Depending on the installation site of the heat exchanger, chillers can be monoblocks (the chiller itself and the capacitor itself are in one case) or with remote condenser block. It is more likely to prefer a solid design, which also includes a pumping station. The most common option - systems with air cooling condenser. This design is mounted on the street to provide a full air flow to the heat exchanger.
There are situations where the chiller and heat exchanger is required. If the installation is used in the warm season, it successfully functions in the usual modification. But if the air temperature decreases and reaches negative values, the possibility of facing the equipment due to the freezing of water increases. To avoid this, water is removed from the system, and the chiller is subjected to conservation.
When it is necessary to ensure the continuous operation of the cooling equipment, the water is replaced by more expensive at the cost of non-freezing fluid. The above procedures are quite laborious and costly financially planned, as they must only be performed by professional workers who have the appropriate experience.
The task is greatly simplified if it is not a monoblock chiller, but equipped with a remote condenser. In this case, you can do without draining or replacing water to another liquid. The chiller and the pumping station are placed in a separate room, which is heated, and the heat exchanger is carried to the street, as it still requires a tributary of a large amount of air.
The principle of operation of the installation and its equipment does not change. The main elements of the chiller will be:
The disadvantage consists only of the need to create a highway connecting the cooling unit and a condenser. It is also necessary to take into account the difference in the height between blocks. Therefore, when choosing equipment, you should pay attention to these two parameters and determine in advance the convenient place of installation.
Chiller in the Smart Treding catalog will not be difficult, you can always count on the help of qualified managers, which not only recommend high-quality equipment at a bargain price, but also organize delivery and professional installation.
