The multizone climate system chiller-fan coil is designed to create comfortable conditions inside a large area building. It works constantly - in the summer it supplies with cold and in winter with heat, warming the air to a predetermined temperature. With her device is to get acquainted, do you agree?
In our proposed article, the construction and components of the climate system are described in detail. The ways of connecting equipment are given and analyzed in detail. We will tell you how this thermoregulation system works and functions.
The content of the article:
- Components of the chiller-fan coil circuit
- System design
- Connection of chiller and fan coil
Main Chiller Classes
- Device absorption unit
- The design of vapor compression installations
- Specificity of vapor compression chiller
- What is the difference between the coolant and the coolant?
- The role of fan coil in the air conditioning system
- Conclusions and useful video on the topic
Components of the chiller-fan coil circuit
The role of the cooling device is assigned to the chiller - an external unit that produces and delivers cold through pipelines with circulating water through them or ethylene glycol. This is how it differs from other split-systems, where freon is pumped as a coolant.
For the movement and transfer of freon, refrigerant, need expensive copper pipes. Here, this task perfectly cope water pipes with thermal insulation. Its work is not affected by the outside air temperature, whereas the split-systems with freon lose their performance at -10⁰. Internal heat exchange unit is a fan coil.
It takes a liquid with a low temperature, then transfers the cold into the room air environment, and the heated liquid returns back to the chiller. Fan coils are installed in all rooms. Each of them works on an individual program.
The main elements of the system are the pumping station ‚chiller‚ fan coil. The fan coil can be installed at a great distance from the chiller. It all depends on how much power the pump has. The number of fan coil units is proportional to the power of the chiller.
Typically, such systems are used in hypermarkets, shopping malls, buildings, erected underground, hotels. Sometimes they are used as heating. Then, along the second contour, heated water is supplied to the fan-coils or the system is switched to the heating boiler.
According to the constructional design of the system chiller-fan coil are 2-pipe and 4-pipe. The type of installation is distinguished by wall, floor-mounted, recessed devices.
Evaluate the system on such basic parameters:
- power or cooling capacity of the chiller;
- fan coil performance;
- air mass transfer efficiency;
- length of highways.
The last parameter depends on the strength of the pump unit and the quality of the pipe insulation.
A photo of
The chiller-fan coil system allows you to create a microclimate necessary for users simultaneously in several rooms.
An important advantage of using a chiller is the ability to create conditions, regardless of the general requirements of users. Each of them can choose the optimal temperature for themselves.
Chillers produce heating or cooling of the coolant, which can be water, antifreeze or air flow
During operation, chillers emit a large amount of thermal energy, because they are often installed on the street. When placed indoors, it is imperative to provide cooling equipment and airflow.
For the supply of air processed in the chiller to the consumer, indoors install fan coils
By the way of air supply, fan coil units are similar to the internal units of split-systems. There are channel and cassette, located on the walls or ceiling
The main components of the fan coil is a heat exchanger with a fan mounted next to it, as well as a filter system for air purification.
Chiller-fan coil systems are considered to be the most flexible and promising climatic equipment, focused on user requests. In addition to cooling or heating the air, they are able to ventilate the room.
Chiller for a large object cooling system
Chiller device for climate systems
Ease of management and maintenance
Installation of the cooling machine in the room
Fan coils of the climate system
Channel version of the fan coil
Standard composition of the fan coil
Air conditioning and ventilation system
Connection of chiller and fan coil
The smooth functioning of the system occurs by connecting chiller with one or more fan coils through pipelines with thermal insulation. In the absence of the latter, the efficiency of the system drops significantly.
Each fincoil has an individual strapping unit, through which they regulate its performance, both in the case of heat generation and cold. The flow rate of the refrigerant in a separate unit is regulated by means of special valves - shut-off and regulating.
To direct the cooled water to the heat exchanger, one pipe is connected to the fan coil and the other, to drain the liquid, to the chiller. The system device allows the mixing of coolant with coolant.
If the coolant cannot be mixed with a refrigerant. the water is heated in a separate heat exchanger and the circuit is completed with a circulation pump. To ensure smooth adjustment of the flow of working fluid through the heat exchanger when mounting the piping scheme, a 3-way valve is used.
If a two-pipe system is mounted in the building, then both cooling and heating occurs at the expense of the chiller cooler. To increase heating efficiency with fan coil in the cold period, in addition to the chiller, a boiler is included in the system.
In contrast to the two-pipe system with one heat exchanger, 2 of these nodes are embedded in the four-pipe system. In this case, the fan coil can work both for heating ‚and for cold‚ using in the first case the fluid circulating in the heating system.
One of the heat exchangers is connected to the pipeline with refrigerant, and the second to the pipe with coolant. Each heat exchanger has an individual valve ‚controlled by a special panel. If such a scheme is applied, the refrigerant is never mixed with the coolant.
Since the temperature of the coolant in the system during the heating season ranges from 70 to 95⁰ and for most of the fan coil it exceeds the allowable one, it is reduced beforehand. therefore hot waterIt comes from the central heating network to the fan coils, passes a special heating point.
Main Chiller Classes
The conditional division of chillers into classes occurs depending on the type of refrigeration cycle. On this basis, all chillers can be conditionally assigned to two classes - absorption and steam compressor.
Device absorption unit
The absorption chiller or ABHM for operation uses a binary solution with water and lithium bromide present in it - an absorber. The principle of operation is the absorption by the refrigerant of heat in the phase of converting vapor into a liquid state.
Such units use heat released during the operation of industrial equipment. In this case, an absorbent absorber with a boiling point much higher than the corresponding refrigerant parameter ‚dissolves the latter well.
The operation scheme of the chiller of this class is as follows:
- Heat from an external source is supplied to the generator, where it heats the mixture of lithium bromide and water. When boiling the working mixture of the refrigerant (water) completely evaporates.
- The vapor is transferred to the condenser and becomes liquid.
- The refrigerant in liquid form enters the choke. Here it cools, and the pressure drops.
- The liquid enters the evaporator, where water evaporates and its vapor is absorbed by a solution of lithium bromide as an absorber. The air in the room is cooled.
- The diluted absorbent is again heated in the generator, and the cycle is restarted.
Such an air conditioning system has not yet become widespread ‚but it is fully consonant with current trends regarding energy saving, and therefore has good prospects.
The design of vapor compression installations
On the basis of compression cooling, most refrigeration units operate. Cooling occurs due to the incessant circulation ‚boiling at low temperatures, pressure and condensation of the coolant in a closed-type system.
The design of this class chiller includes:
- flow control.
The refrigerant circulates in a closed system. This process is controlled by a compressor in which a gaseous substance with a low temperature (-5⁰) and a pressure of 7 atm can be compressed while raising the temperature to 80⁰.
Dry saturated steam in a compressed state goes to a condenser, where it is cooled to 45 ° under constant pressure and turns into a liquid.
The next point on the road is the choke (pressure reducing valve). At this stage, the pressure decreases from the value of the corresponding condensation to the limit at which evaporation occurs. At the same time, the temperature drops to about 0⁰. The liquid partially evaporates and a wet vapor is formed.
The diagram shows a closed cycle, according to which the vapor compression unit operates. In the compressor (1), the saturated saturated steam is compressed until it reaches the pressure p1. In compressor (2), steam releases heat and is transformed into liquid. In the throttle (3), both the pressure (p3 - p4) ‚and the temperature (T1-T2) decrease. In the heat exchanger (4), the pressure (p2) and temperature (T2) remain unchanged.
Having entered the heat exchanger - the evaporator ‚the working substance‚ the mixture of vapor and liquid ‚gives cold to the coolant and takes heat from the refrigerant‚ drying at the same time. The process takes place at constant pressure and temperature. Pumps deliver low temperature fluid to the fan coils. Having passed this way, the refrigerant returns to the compressor ‚to repeat the entire vapor compression cycle again.
Specificity of vapor compression chiller
In cold weather, the chiller can operate in the natural cooling mode — this is called free cooling. In this case, the coolant cools the outside air. Theoretically, free cooling can be used at an external temperature of less than 7 ° C. In practice, the optimum temperature for this is 0⁰.
When configured in “heat pump” mode, the chiller works for heating. The cycle undergoes changes, in particular, the condenser and the evaporator exchange their functions. In this case, the coolant should not be subjected to cooling, and heat.
The simplest are monoblock chillers. In them all elements are compactly combined into a single whole. They go on sale 100% staffed up to the time of refrigerant charge.
This mode is most often used in large offices, public buildings, warehouses. The chiller is a refrigeration unit that produces 3 times more cold than it consumes. Its efficiency as a heater is even higher - it consumes 4 times less electricity than it gives heat.
What is the difference between the coolant and the coolant?
The refrigerant is the working substance, which during the refrigeration cycle can be in different state of aggregation at different pressures. The coolant does not change the phase states. Its function is to transport cold or heat for a certain distance.
Refrigerant transportation is controlled by a compressor, and the coolant is controlled by a pump. The temperature of the refrigerant can fall both below the boiling point and rise beyond its limits. The heat carrier ‚in contrast to the refrigerant‚ constantly operates in conditions of temperatures that do not grow above the boiling point at the current pressure.
The role of fan coil in the air conditioning system
Fancoil - an important element of a centralized climate control system. The second name is a fan coiler. If the term fan-coil is translated from English verbatim, then it sounds like a heat exchanger fan, which most accurately conveys the principle of its operation.
The design of the fan coil includes a network module that provides a connection to the central control device. The robust housing hides the structural elements and protects them from damage. Outside, a panel is installed that evenly distributes air flows in various directions.
The purpose of the device is to receive a low temperature carrier. The list of its functions also includes both recirculation and cooling of the air in the room where it is installed, without air being outside. The main elements of fan-coil are located in its case.
- centrifugal or diametrical fan;
- a heat exchanger in the form of a coil consisting of a copper tube and aluminum fins mounted on it;
- dust filter;
- Control block.
In addition to the main components and parts, the design of the fan coil includes a pan for trapping condensate, a pump for pumping the latter, an electric motor, through which the air flaps are turned.
The photo channel fan coil brand Trane. The performance of two-row heat exchangers - 1.5 - 4.9 kW. The unit is equipped with a low-noise fan and a compact body. It fits perfectly behind false panels or suspended ceiling structures.
Depending on the method of installation, there are ceiling fan coils ‚channel‚ mounted in channels ‚along which there is an air flow ‚airless‚ where all the elements are mounted on the frame ‚wall or console.
Ceiling devices are the most popular and have 2 versions: cassette and duct. The first is mounted in large rooms with suspended ceilings. For suspension structure have a case. The bottom panel is visible. They can disperse air flow on two or all four sides.
If the system is planned to be used exclusively for cooling, then the ceiling is the best place for it. If the design is intended for heating, the device is placed on the wall in its lower part
The need for cooling does not always exist, therefore, as seen in the diagram, which conveys the principle of operation Chiller-Finkoil systems ‚build a capacity in the hydraulic module that acts as a battery for refrigerant. Thermal expansion of water compensates for an expansion tank connected to the supply pipe.
Manage fan coils in both manual and automatic modes. If the fan coil is working for heating, then in manual mode the cold water supply is cut off. When it is working on the cooling block hot water and open the way for the flow of coolant.
Remote control for both 2-pipe and 4-pipe fan coil. The module is connected directly to the device and placed near it. From it connect the control panel and the wires for its power
For work in the automatic mode on the panel expose necessary for the concrete room temperature. Support for a given parameter is carried out through thermostats that adjust the circulation of coolants - cold and hot.
The advantage of the fan coil is expressed not only in the application of a safe and cheap coolant, but also in the rapid troubleshooting in the form of water leaks. This reduces the cost of their service. The use of these devices is the most energy efficient way to create a favorable microclimate in a building.
Since any large building has zones with different requirements for temperature conditions, each of them must be serviced by a separate fan coil or their group with identical settings.
The number of units is determined at the design stage of the system by calculation. The cost of individual units of the chiller-fan-coil system is rather high ‚therefore both the calculation‚ and the design of the system must be carried out as accurately as possible.
Conclusions and useful video on the topic
Video # 1. Everything about the device, the work and the principle of operation of the thermoregulation system:
Video # 2. About how to install and put into operation the chiller:
Installation of the chiller-fan coil system is advisable in medium and large buildings with an area exceeding 300 m². For a private house, even a huge one, the installation of such a thermoregulation system is expensive. On the other hand, such financial investments will provide comfort and well-being, which is quite a lot.
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