- Precision air conditioning systems
- Roof and duct air conditioners
- Multizone conditioners
- Cassette air conditioners
- Column conditioners
- Ceiling air conditioners
- Instead of an epilogue
In this Article: Using a Precision Air Conditioner what are the similarities and differences between duct and roof air conditioning systems; multi-zone air conditioning system – one set of equipment for three or four rooms; cassette air conditioner for false ceilings; column air conditioner capabilities; ceiling air conditioner – can be installed on the ceiling or on the wall.
Climate technology has long been no longer a symbol of its owner’s status, these devices are quite common for the urban population. However, for many of us, the term “air conditioner” means either a window model or a wall-mounted split system. Their popularity is simply explained – buyers are not even aware of the existence of other types of climatic devices, since in most household appliances salons air conditioners are usually represented by two or three brands of the same type. Let’s continue our study of climate systems and find out what the less popular types of air conditioners are..
Precision air conditioning systems
The precision air conditioner assembled in the form of a cabinet owes its strange name to the word precision, which means “exact” in English. The task of this device is to maintain constant climatic conditions in technological rooms with telecommunication, hardware, medical and other types of expensive equipment located in them, as well as in warehouses and museums. The need for air conditioners of such a narrow specialization is due to the fact that modern technological equipment generates a large amount of heat during operation and, at the same time, is extremely sensitive to an increase in temperature, to a change in the level of humidity.
The line of precision climate control systems includes monoblock models (similar to window air conditioners, only much larger) and two-unit devices, similar to the usual split systems. In a complete configuration, two-unit precision air conditioners are equipped with a humidifier and an electric heater, otherwise their device does not look different from other split systems – the difference between them is in the high resource of precision units.
Condenser cooling in precision systems can be water or air. The air, which has been conditioned in the air conditioner, is supplied in several ways, most often through the grill panel at the top of the unit and through the lower panel located at floor level. If there is a raised floor in the manned room, the air intake leads from the lower panel of the air conditioner to the sub-floor, from where cold air flows without interference to each device installed in the room. However, there are models that are installed directly under the raised floor. Air intake from the room is from the rear, top or side – the exact location of the air inlet depends on the model.
A precision air conditioner is able to maintain a given temperature with an accuracy of 1 ° C, moisture content in the air with an accuracy of 5% of relative humidity, and work properly when the temperature outside the serviced room varies from +50 to -50 ° C. This appliance is designed for trouble-free operation, i.e. 24 hours a day, 365 days a year, its service life is over 10 years. Cooling capacity of precision systems ranges from 7 to 100 kW, weight from 200 kg and more (depending on power), the cost is about 450,000 rubles. for 7 kW model. There are models from European, American and Chinese manufacturers on the Russian market.
Roof and duct air conditioners
Both of these types of air conditioning systems refer to semi-industrial climatic units (see classification) and, despite the similar air supply to consumers through air ducts, they have significant structural differences. First of all, rooftop air conditioners are monoblock, and duct systems always consist of two units.
The rooftop air conditioning unit is installed, as you might guess, on the roof of the building – for sloping roofs you will need a steel frame mounting kit. Prepared air (cooled or heated) enters the serviced premises through air ducts taken at the exit points by gratings. In addition to heating and cooling, rooftop air conditioners are capable of ventilating rooms, i.e. supply them with pre-purified air from the external atmosphere.
The standard equipment of the rooftop air conditioner is as follows: compressor; condenser equipped with a fan; evaporator and supply fan; automation, metering the supply of refrigerant to the evaporator, heat and cooling capacity, which protects the system from overheating; electronic control system of the device. The supply and exhaust ducts of the air ducts are connected to the rooftop air conditioner by means of a flange connection.
Cooling capacity of rooftop climate systems – from 8 to 140 kW, air consumption – 1500-25000 m3/ h The advantage of these devices over duct systems is their simpler installation, since it is much easier to place such an air conditioner on the roof than to install it indoors. Rooftop air conditioners generate a lot of heat during operation, so it is extremely important to ensure free air access to their unit..
Ducted air conditioning systems consist of an indoor unit, called a fan coil unit, and an outdoor chiller unit, usually near an outer wall. The indoor unit of the fan coil unit is placed as far as possible from rooms where people are, as a rule, in a basement or semi-basement room – it makes a loud noise during operation. The chiller and fan coil units are connected by copper pipes transporting the refrigerant – the distance between the units is not more than 50 m. Outside air flows through the duct to the fan coil, where it is cleaned of dust, cooled or heated, and then enters the serviced premises. If necessary, air purification can be carried out in several stages up to removal of particles of about micron size.
Characteristics of duct air conditioners: cooling capacity from 5 to 140 kW; air consumption up to 25000 m3/ h Producers of the EU, USA and Asian countries produce three groups of units for duct climate systems – low-pressure, developing a pressure of no more than 50 Pa, medium-pressure (up to 150 Pa) and high-pressure, the highest pressure in which is 300 Pa.
The cost of duct and rooftop air conditioners is about the same, for example, a device with a cooling capacity of 50 kW costs about 305,000 rubles.
Advantages of both types of air conditioners in the hidden installation of the air conditioning system, servicing several rooms at the same time, supplying only outdoor air (recirculation). Disadvantages – a high noise level of cooling blocks and air during its transportation through air ducts, careful planning of the installation site is required, a number of measures to reduce noise during installation of the system are required.
The air conditioning system, which includes one outdoor unit with high cooling capacity and several indoor units located in serviced rooms, was created 30 years ago as an addition to domestic split systems. However, after 10 years, manufacturers of HVAC equipment have allocated multi-zone systems into a separate class, which was facilitated by the growing consumer demand for them. Multi-zone air conditioning systems are able to control the internal climate at large facilities, simultaneously providing the required volume of cooled or heated air to rooms of various sizes without placing many external blocks from split systems on the facades of buildings.
Manufacturers produce multi-zone air conditioners of two types: household, consisting of one external unit and two or four internal; semi-industrial, with assembled from several outdoor units combined into a common section and up to 60 (the exact number depends on the specific model) indoor units. The cooling capacity of the outdoor unit of a household multi-zone system can be from 5 to 25 kW, in the case of semi-industrial systems – from 22 to 100 kW. It is allowed to exceed the total capacity of the indoor units in relation to the external by 30–40%; multi-zone systems are capable of working properly under such loads, because usually equipped with an inverter external unit. Indoor units can have a cooling capacity of 2 to 18 kW. The operation of a multi-zone air conditioning system is based on the circulation of freon in a closed loop of copper pipes between the external and internal blocks.
The indoor units of domestic multi-zone air conditioners are identical to the indoor units of conventional split systems, they are controlled by the remote control, each of them is connected to the external unit through an independent circuit. Indoor units of a semi-industrial multi-zone air conditioning system can be floor, wall, ceiling, cassette, or built into the wall, floor or ceiling like duct outlets. The freon circuit between the indoor units and the external is common, two-pipe or three-pipe – in the first version, all serviced rooms can only be cooled or heated, in the second, each unit heats or cools a room independently of the others, acting according to an individual climatic scheme for a given room.
The cost of a household multi-zone air conditioner, which includes one external unit with a cooling capacity of 5 kW and, for example, two internal units with a cooling capacity of 2.5 kW each, will be about 160,000 rubles Prices for a semi-industrial multi-zone system are directly dependent on the architecture of the freon circuit, the power of the outdoor unit and the number of indoor units, as well as the tasks assigned to this climate system.
Cassette air conditioners
These air conditioning systems owe their appearance to the steady popularity of the suspended ceiling – the air conditioner cassette is built into it, forming a single plane. Since cassette air conditioners are a subspecies of split systems, they consist of two units – the internal unit is installed in the suspended ceiling, and the external unit is mounted on the wall of the building, in the basement or attic. Installation of a cassette air conditioner in a suspended ceiling is carried out by means of an independent fastening, i.e. the weight of the unit does not rest on the ceiling supports.
The cooling capacity of cassette air conditioners depends on the overall dimensions, there are two of them: the so-called “Eurosize” or “compact” – 600 x 600 mm, with a capacity of 2-6 kW; the more common block 800 x 800 mm, with a capacity of 5-15 kW. Air conditioners of maximum power are able to serve premises up to 140 m2.
The average height of the suspended ceiling, allowing the installation of a cassette air conditioner, is 2.5 meters, while it must be borne in mind that the installation of this air conditioning system requires at least 250-400 mm of ceiling space (the exact distance depends on the given air conditioner model). In addition, when choosing a cassette air conditioning system, it is necessary to take into account the height to which the pump, which is included in the mandatory package of the device, can lift condensed moisture – the lifting height is 400 mm or 800 mm. The cassette air conditioner is controlled by a wired or remote control.
Advantages of cassette air conditioners: Inherently hidden installation in a false ceiling; the treated air is supplied from two or four sides (wall, floor and under-ceiling models of air conditioners supply processed air from only one direction), air intake is in the center of the device; some models allow the addition of fresh (external) air, although not more than 5%. Air supply allowed in one or two directions specified by the user.
The cost of a cassette air conditioner with a cooling capacity of 3.5 kW is about 16,000 rubles.
Cassette air conditioners are often used in office, retail and administrative buildings where suspended ceilings are used.
This line of air conditioners was created to maintain certain climatic conditions in spacious rooms with a significant area of glass windows and a large number of visitors – supermarkets, restaurants and cafes, cinemas, various administrative institutions. Column air conditioners are also used in rooms where it is impossible to install wall and ceiling models without serious interference in the interior design..
The external and internal units of the column split system weigh more than 25 kg, the mass of the external unit always exceeds the weight of the internal one. The columnar body has only an internal block, the external one is made in a classic format for split systems. Column cooling capacity – 7-50 kW, depending on the capacity, the cooling area is 50-300 m2.
The inner block of a column air conditioning system is similar to a refrigerator or a narrow cabinet, its height is usually 2000 mm, width 500 mm. Inside the unit there are ventilation units, systems for automatic regulation of moisture level and air temperature, control of compressor operation, blinds that distribute the flow of processed air. Air intake from the room is made through the grate in the lower part of the column unit, the air comes back through the opening in the upper part of the column, closed by automatically controlled shutters. The rest of the climatic equipment is located in the column air conditioner similarly to other split systems..
Columns occupy an intermediate niche in the line of modern air conditioning systems – inexpensive household models cannot develop a cooling power of more than 8 kW, and semi-industrial and industrial installations that can maintain the necessary climatic conditions in a large room are too expensive. A model of a column air conditioner with 7 kW of cooling power will cost the buyer 36,000 rubles on average.
Air conditioners of this type supply chilled air up to the ceiling, where the warmest air layer accumulates, and automatically rotating shutters distribute the air stream evenly throughout the room – this cooling method, along with the high power of the climate system, allows you to quickly adjust the atmosphere in the served room to the optimum throughout area. When choosing a place for installing the column, it is important to take into account that this is a rather powerful device – the flow of cooled air emitted by it, when it comes into contact with the human body, will cause a strong feeling of discomfort for the latter. The distance from the column air conditioner to the location of people should be more than 2–3 m, in this case, the effect of cold air blowing will not occur, because the air jet will dissipate.
Ceiling air conditioners
Unlike split systems, the indoor unit of which is located on the floor or on the wall of the served room, the ceiling air conditioner is installed directly on the ceiling, which gives it one important advantage – the air flow produced by the unit enters the room along the ceiling. This method of air conditioning completely eliminates the threat of blowing people inside the room with cold air. If necessary, some models of the ceiling climate system can be installed on the wall, in which case its lower edge is at floor level. Before installing on the wall, make sure that this model allows it – for conventional ceiling air conditioners, on the side of the cabinet facing the floor, there is a container for collecting condensation (drain pan), i.e. in a wall-mounted installation, condensate cannot accumulate in it.
The cooling capacity of ceiling air conditioners varies from 2.5 to 18 kW, which allows them to condition air in rooms ranging from 25 to 180 m2. Regardless of other dimensions, the thickness of the ceiling unit is usually in the range of 180-250 mm.
Ceiling air conditioners are widely used for air conditioning of large offices, libraries, restaurants, commercial and industrial facilities. The price for a model with a minimum cooling power (2.5 kW) is about 30,000 rubles.
Instead of an epilogue
For the most part, the climate systems described in this article are designed for large areas, even their least powerful models can be used for air conditioning houses and apartments only with a big reservation. Therefore, in the following articles, the main attention will be paid to the choice of household air conditioners from the same class, comparing their characteristics and, as a result, choosing the best model. The next article will be devoted to the study of modern models of window air conditioners.