The chiller-fan coil multi-zone climate system is designed to create comfortable conditions inside a large building. It works constantly - in summer it supplies cold, and in winter with heat, warming up the air to a given temperature. It’s worth getting to know her device, don’t you agree?

In our proposed article, the design and components of the climate system are described in detail. Methods for connecting equipment are given and analyzed in detail. We will tell you how this thermoregulation system is arranged and functions.

The role of the cooling device is assigned to the chiller - an external unit that produces and supplies cold through pipelines with water or ethylene glycol circulating through them. This is what makes it different from other split systems, where freon is pumped in as a coolant.

For the movement and transmission of freon, refrigerant, expensive copper pipes are needed. Here, they do an excellent job with this task. water pipes with thermal insulation. Its operation is not affected by the outside air temperature, while split systems with freon lose their performance already at -10⁰. The indoor heat exchanger is a fan coil unit.

It accepts a liquid with a low temperature, then transfers the cold to air environment the room, and the heated liquid is returned back to the chiller. Fan coil units are installed in all rooms. Each of them works according to an individual program.

The main elements of the system are - pumping station‚Chiller‚ fan coil unit. The fan coil unit can be installed at a great distance from the chiller. It all depends on how strong the pump is. The number of fan coil units is proportional to the chiller capacity

Typically, such systems are used in hypermarkets, shopping malls, underground structures, hotels. They are sometimes used for heating purposes. Then, along the second circuit, heated water is supplied to the fan coil units or the system is switched to the heating boiler.

System design

According to the design of the chiller-fan coil system, there are 2-pipe and 4-pipe. By the type of installation, they are distinguished by wall-mounted, floor-standing, built-in devices.

The system is evaluated according to the following main parameters:

• the power or cooling capacity of the chiller;
• fan coil performance;
• the efficiency of moving the air mass;
• the length of the highways.

The last parameter depends on the strength of the pumping unit and the quality of the pipe insulation.

Image gallery

Chiller and fan coil connection

The harmonious functioning of the system occurs by connecting to one or more fan coil units through pipelines with thermal insulation. In the absence of the latter, the value of the efficiency of the system drops significantly.

Each fincoil has an individual piping unit, by means of which its performance is regulated both in the case of heat and cold generation. The refrigerant flow rate in a separate unit is regulated by means of special valves - shut-off and control valves.

To direct the chilled water to the heat exchanger, one pipe is connected to the fan coil unit, and the other, to drain the liquid, to the chiller. The system design allows mixing of the refrigerant with the heat carrier

If the mixing of the heat carrier with the refrigerant must not be allowed. the water is heated in a separate heat exchanger and the circuit is supplemented with a circulation pump. To ensure smooth regulation of the flow of the working fluid through the heat exchanger, a 3-way valve is used when installing the piping.

If the building is mounted two-pipe system, then both cooling and heating occurs due to the cooler - chiller. To increase the efficiency of heating with help in the cold season, a boiler is included in the system in addition to the chiller.

In contrast to a two-pipe system with one heat exchanger, two of these units are included in the four-pipe system. In this case, the fan coil unit can work both for heating ‚and for cold, using in the first case the liquid circulating in the heating system.

One of the heat exchangers is connected to the refrigerant pipeline, and the second to the heat carrier pipe. Each heat exchanger has an individual valve controlled by a special panel. If such a scheme is applied, the refrigerant never mixes with the heat carrier.

Since the temperature of the coolant in the system during the heating season ranges from 70 to 95⁰ and for most fan coil units it exceeds the permissible value, it is preliminarily reduced. Therefore, ‚coming from the central heating network to the fan coil units‚ passes through a special heating point.

The main classes of chillers

The conditional division of chillers into classes occurs depending on the type of refrigeration cycle. On this basis, all chillers can be conditionally classified into two classes - absorption and steam compressor.

Absorption unit design

An 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 of heat by the refrigerant in the phase of converting vapor into a liquid state.

Such units use the heat generated during the operation of industrial equipment. In this case, an absorbent absorber with a boiling point significantly higher than the corresponding parameter of the refrigerant ‚dissolves the latter well.

The operation diagram of a chiller of this class is as follows:

1. Heat from an external source is supplied to a generator, where it heats up a mixture of lithium bromide and water. When the working mixture boils, the refrigerant (water) completely evaporates.
2. The vapor is transferred to the condenser and becomes a liquid.
3. Liquid refrigerant enters the throttle. Here it cools down and the pressure drops.
4. The liquid enters the evaporator, where the water evaporates and its vapors are absorbed by the lithium bromide solution - the absorber. The air in the room is cooled.
5. The diluted absorbent is reheated in the generator and the cycle is restarted.

Such an air conditioning system has not yet become widespread, but it is completely in tune with current trends‚Concerning energy saving, therefore it has good prospects.

Construction of vapor compression units

Most of them operate on the basis of compression cooling. refrigeration units... Cooling occurs due to continuous circulation, boiling at low temperatures, pressure and condensation of the refrigerant in a closed system.

The chiller of this class includes:

• compressor;
• evaporator;
• capacitor;
• pipelines;
• flow regulator.

The refrigerant circulates in 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 is compressed when the temperature is brought up to 80⁰.

Dry saturated steam in a compressed state goes to the condenser, where it is cooled to 45⁰ at a constant pressure and converted into liquid.

The next item on the way is the throttle (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 approximately 0⁰. The liquid partially evaporates and moist vapor forms.

The diagram shows a closed cycle according to which the vapor compression unit operates. In the compressor (1), wet saturated steam is compressed until it reaches a pressure p1. In the compressor (2), the steam gives off 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‚ a mixture of vapor and liquid ‚gives cold to the coolant and takes heat from the refrigerant‚ drying out at the same time. The process takes place at constant pressure and temperature. The pumps deliver low temperature liquid to the fan coil units. Having passed this way, the refrigerant returns to the compressor in order to repeat the entire vapor compression cycle again.

Specificity of a vapor compression chiller

In cold weather, the chiller can operate in natural cooling mode - this is called freecooling. In this case, the coolant cools the outside air. In theory, free cooling can be used at ambient temperatures below 7 ° C. In practice, the optimum temperature for this is 0⁰.

When set to heat pump mode, the chiller operates for heating. The cycle is undergoing changes, in particular, the condenser and the evaporator exchange their functions. In this case, the coolant must be subjected not to cooling, but to heating.

The simplest are monoblock chillers. They compactly combine all the elements into one whole. They go on sale 100% complete up to the refrigerant charge.

This mode is most often used in large offices ‚public buildings‚ in warehouses. The chiller is a refrigeration unit that gives 3 times more cold than it consumes. Its efficiency as a heater is even higher - it consumes 4 times less electricity than it generates heat.

What is the difference between a refrigerant and a coolant?

A refrigerant is a working substance that, during the refrigeration cycle, can be in different states of aggregation at different meanings pressure. The coolant does not change phase states. Its function is to transfer cold or heat over a certain distance.

The refrigerant is transported by the compressor, and the coolant is transported by the pump. The refrigerant temperature can fall below the boiling point or rise beyond it. The heat carrier, unlike the refrigerant, constantly operates at temperatures that do not rise above the boiling point at the current pressure.

The role of fan coil in the air conditioning system

A fan coil unit is an important element of a centralized climate control system. The second name is a fan coil. If the term fan-coil is literally translated from English, then it sounds like a fan-heat exchanger, which most accurately conveys the principle of its operation.

The fan coil unit is designed with a network module for connection to a central control unit. The robust housing hides the structural elements and protects them from damage. Outside, a panel is installed that evenly distributes air flows in different directions

The purpose of the device is to accept low temperature media. The list of its functions also includes both recirculation and cooling of air in the room where it is installed, without the intake of air from the outside. The main elements of the fan-coil are located in its body.

These include:

• centrifugal or cross-flow 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 units and parts, the design of the fan coil unit includes a sump for collecting condensate, a pump for pumping out the latter, an electric motor, through which the air dampers are turned.

On the picture duct fan coil the Trane brand. The productivity of double-row heat exchangers is 1.5 - 4.9 kW. The unit is equipped with a low-noise fan and a compact housing. It fits perfectly behind false panels or suspended ceiling structures

Depending on the installation method, there are ceiling ‚duct‚ fan coil units mounted in ducts through which air is supplied ‚open frame, where all elements are mounted on a frame‚ wall or console.

Ceiling devices are the most popular and have 2 versions: cassette and duct. The first ones are mounted in large rooms with false ceilings... A body is placed behind the suspended structure. The bottom panel remains visible. They can disperse air currents on two or all four sides.

If you plan to use the system solely for cooling, then the best place for him - the ceiling. If the structure is intended for heating, the device is placed on the wall at the bottom of it

The need for cooling does not always exist, therefore, as can be seen in the diagram, transmitting the principle of operation of the chiller-fincoil system, a tank is built into the hydraulic module, which acts as an accumulator for the refrigerant. The thermal expansion of the water is compensated for by an expansion vessel connected to the supply line.

Fan coil units are controlled in both manual and automatic modes. If the fan coil operates for heating, then the cold water supply is cut off in manual mode. When operating it for cooling, hot water is blocked and a path is opened for the flow of the cooling working fluid.

Remote control for both 2-pipe and 4-pipe fan coil units. The module is connected directly to the device and placed close to it. The control panel and wires for its power supply are connected from it.

To work in automatic mode, the temperature on the panel is set to the temperature required for a particular room. Support given parameter carried out by means of thermostats that adjust the circulation of coolants - cold and hot.

The advantage of a fan coil is expressed not only in the use of a safe and cheap heat carrier, but also in the quick elimination of problems in the form of water leaks. This makes their service cheaper. 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 temperature requirements, each of them must be served by a separate fan coil or a group of them 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 quite 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, operation and principle of operation of the thermoregulation system:

Video # 2. How to install and commission the chiller:

The installation of a 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 an expensive pleasure. On the other hand, such financial investments will provide comfort and well-being, and this is a lot.

Please write your comments in the block below. Ask questions on points of interest, share your own opinions and impressions. Perhaps you have experience in the field of a chiller-fan coil climate system or a photo on the topic of the article?

Today, in homes, instead of air conditioning systems, they often resort to installing fan coil units - devices that cool and heat the air in the room. The heat exchanger can be installed in different rooms buildings and set an individual temperature regime for each of them.

Principle of operation

The operating principle of a fan coil unit is quite simple. The air is driven by the fan through the heat exchanger and is cooled or heated, depending on the selected mode.

In this case, the air flow is created not from the volume of air in the room, but from the outside air. Fresh air supplied by a special unit - a chiller. This device is paramount when creating an air conditioning and heating system for a building with a chiller fan coil system.

Chiller connected to supply unit, which produces air from the street.

Classification

Devices can be divided into four groups depending on design features:

• cassette;
• horizontal;
• console;
• console in the case.

When choosing a specific device, it is important to pay attention to two parameters: overall air performance and cold air performance.

Water as a carrier

Heat exchanger systems that use water as a carrier can be of two types: two-pipe and four-pipe.

Two-pipe is the most common on the market and its installation is not difficult. It is used to cool the air in the room and only, and therefore the cost of installing a pipe-type fan coil is low. It is possible to switch to heating mode in winter, but for this you have to disconnect the pipes from the chiller and connect them to heating system... This happens with a manually adjustable valve.

The four-pipe one has two heat exchangers: one is connected to the chiller, the other to the heating system. This scheme is more complicated in installation and the principle of operation, and, accordingly, is more expensive. It allows both cooling and heating the air in the room by switching the mode on the control panel.

What are they made of?

Each type of device has its own type of design, but everyone has common details:

• filter element. Protects the fan coil system from foreign particles entering it;
• electric heating element;
• heat exchanger. Cools and heats indoor air.
• fan. Provides a forced air flow that passes through the heat exchanger;
• control Panel.

Installation of chillers and fan coil units of any of the above types can be either wall-mounted, floor-mounted, or built into the ventilation of the building and installed in a suspended ceiling structure.

Advantages

There are several advantages to installing a fan coil unit together with a chiller.

1. Energy saving.
2. Possibility to connect an unlimited number of fan coil units to one chiller. In this case, the distance from the device to the farthest fan coil should not be more than 600 m.
3. High environmental safety. The equipment is much more environmentally friendly than air conditioners.
4. Creation of a comfortable indoor climate.
5. Providing complete cooling and heating in just 5 minutes after starting.
6. Saving money necessary for the organization of pipe routes, if water is used as a carrier. However, such a system has one drawback - the lack of a ventilation function. Therefore, when installing it, it is necessary to equip in parallel a system of forced circulation of air masses in the room.

Installation

Installation of chillers and fan coil units consists of several main stages:

1. First, the device is mounted indoors.
2. Then the strapping unit is assembled.
3. Installation of pipelines and thermal insulation to them is in progress.
4. Air ducts are laid and their sound insulation is organized.
5. A drainage system is being created.
6. The equipment is connected to the mains.
7. Check the tightness.
8. Start the system.

Mounting by device type

Floor

The easiest installation process is to install a floor-standing fan coil unit without a condensate duct. They do not spoil the interior and can be installed independently. The typical design of such equipment consists of two nozzles through which the mixer and the working fluid go.

Cassette, wall and sub-ceiling

Installation cassette fan coil unit and the other two are a little more complicated, since they can be either two-pipe or four-pipe. Moreover, their electrical system may differ significantly from floor systems.

Therefore, it is best to entrust the installation of a wall-mounted fan coil unit, under-ceiling and cassette, to specialists.

With the help of specialists

Connecting a fan coil is a complex process that requires professional approach, so it is best to consult a specialist. Only they will be able to competently do the work on:

• installing the unit in the most efficient location;
• assembly of piping units by installing the necessary taps, temperature and pressure control devices, valves;
• laying and thermal insulation of pipes;
• installation of condensate drain;
• connecting devices to the electrical network;
• pressure testing of the system;
• checking the tightness;
• water supply.

They will do all the calculations before starting work and will take into account the characteristics of the room and the load of each fan coil. Experts will create a safe and reliable system that will serve the user for a long time.

What to remember when contacting specialists

In order to correctly select a company that provides installation services, you should pay attention to the following criteria:

Technical library ›Good to know› Air conditioning ›Tips for choosing and connecting a fan coil unit

Fan coil connection

2015-09-24 00:00:00

A fan coil unit is a complex climatic technique, therefore, when choosing it, special calculations should be made, which only an experienced heating engineer can handle. If the wiring diagram is selected correctly and worked out in detail, then during the installation of devices there will be no unforeseen problems. At the same time, only professionals should be trusted to install such equipment.

Due to the fact that the chiller-fan coil system can operate both for heating and cooling, there are two connection schemes:

1. Two-pipe, in which the devices work as coolers in summer, and as heater... In such a system, there is one heat exchanger, and in the cold season, water enters it from a third-party heater, for example, a boiler, and into a warm one - from a chiller. Such a system will allow either cooling all rooms in the building or heating. Li>
2. Four-pipe. Such a system is mounted in the same way as a two-pipe system, but has 2 independent circuits, each of which operates in its own mode (heating or cooling). In this case, the chiller prepares the coolant and through the hydronic module (pump group) distributes it to each of the fan coil units. The boiler or other device prepares the coolant and supplies it to each fan coil unit (fan coil unit) in its “warm” heat exchanger. As a result, in each separate room, all users can create their own personal temperature regime by turning on the fan coil unit for heating or cooling. This system is more versatile and suitable for constant and comfortable use.

The fan coil piping scheme is designed at the stage of equipment selection. In this case, it is necessary to take into account the heat surplus of each room in the summer and the lack of heat in the winter. It should be remembered that an unlimited number of fan coil units can be connected to the chiller, but each of them should be no more than 600 meters from the center. The power of the devices is determined by the needs of the users and the characteristics of the building.

There are fan coil units that are installed:

• in a false ceiling (cassette fan coil units),
• behind the false ceiling, in wall niche, technical room (duct) and distribute air through a system of air ducts and ventilation grilles and diffusers,
• on the floor or wall (cabinet, floor-ceiling),
• on the wall indoors (wall-mounted).

Most devices are designed for only two-pipe or only four-pipe connection method, so you should decide on the installation method before purchasing the equipment. Only a specialist can determine which technique is suitable in your case, and how it should be installed.

Additional Information

They can work in two modes: for space heating and for cooling. In this regard, there are the following options for piping the chiller-fan coil system:

- two-pipe system: in this case, cooling in the summer and heating in the off-season is carried out by the chiller. Sometimes thermal devices are included in the system in parallel with the chiller for heating in winter.

- four-pipe system: the fan coil unit is capable of operating in two modes (heating / cooling the air in the room), and for the heating mode, water from the heating system is used.

Let's take a closer look at the data of the strapping scheme:

A two-pipe system is a fan coil unit with one heat exchanger. The most common and trivial strapping scheme. One pipe is connected to the fan coil unit to supply chilled water to the heat exchanger, the other to lead it to the chiller (" return water"). In winter, the two-pipe system can be used to heat the room, the pipes are supplied to the boiler or to the heat supply system from city boiler houses, and the water supply from the chiller does not come. In the summer, the water supply from the boiler is blocked by a special valve, and the fan coil units are already operating on the water coming from the chiller. Thus, mixing of heat and coolant is allowed in the system.

Two-pipe connection diagram for fan coil units:

Simplified piping scheme for a 2-pipe fan coil unit (air heater):

Designations on the diagram:

1 - Ball valve.

2 - Filter.

3 - 3-way motorized control valve.

A two-pipe system is cheaper than a four-pipe system, but for its operation, if it is necessary to prevent mixing of the coolant, the water will have to be heated in an additional heat exchanger from the heat supply system and an additional circulation pump is needed. And this is additional operating costs. To supply heat energy in the off-season, you can use a reversible chiller (operating in heat-cold mode), which is able to independently heat water.

This piping scheme for fan coil units will serve as an excellent solution for offices, warehouses and during the reconstruction of buildings, where it is not always possible to lay a complex piping system with large quantity nodes.

Detailed piping diagram of a fan coil unit using a 2-way valve:

Detailed piping diagram of a fan coil unit using a 3-way valve:

Four-pipe fan coil connection diagram:

A four-pipe system is a double-circuit fan coil unit (i.e. with two heat exchangers). In this system, each heat exchanger is connected to a pipeline with a cold and a hot heat carrier, respectively, each of the heat exchangers has its own valve for connecting the fan coil unit, which are controlled by the control panel for the fan coil unit. This system is used when the coolant (eg ethylene glycol) cannot be mixed with the coolant.

The piping diagram for a 4-pipe fan coil unit is a twin piping diagram for a 2-pipe fan coil unit.

A four-pipe piping scheme for fan coil units ensures their year-round operation for the office building; in the off-season, warm water can also be supplied to the circuit from a chiller, which works as a heat pump. In winter, the additional heat exchanger circulates hot water from the central heating system. The temperature of the coolant during the heating season is from 70 ° C to 95 ° C, which exceeds the permissible operating temperature for most fan coil units, therefore it must be reduced first.

The chiller supplies refrigerant to all fan coil units installed on each floor of the building. Hot water comes from the city heating network to all fan coil units through a special heating point, which is usually installed in the basement.

When designing a chiller-fan coil system, first of all, it is necessary to determine the fan coil connection diagram and calculate the hydraulic system. This should only be done by a heating engineer. After determining the heat surpluses for each room, a specialist selects a chiller (with or without an integrated hydraulic circuit) and fan coil units of the required cooling capacity, and also designs a piping scheme for fan coil units.

If you notice an error, select it with the mouse and press CTRL + ENTER.