Duct conditioner: what it is, how to install it

Are you sick of enduring the summer’s oppressive heat and the winter’s bitter cold? If so, you should think about adding a duct air conditioner to your house. However, what is a duct conditioner exactly, and how can it improve the comfort of your home? Let’s start with the fundamentals.

First off, a duct conditioner—also referred to as a ductless mini-split system—is a kind of air conditioning and heating system that operates without the need for ductwork. While ductless systems function differently from traditional HVAC systems, they still use ducts to distribute conditioned air throughout the house. They are made up of one or more indoor air handling units and an outdoor compressor unit connected by refrigerant lines. This configuration enables you to precisely heat or cool particular areas or rooms in your house.

The versatility of duct conditioning in terms of installation is one of its main benefits. Ductless HVAC systems are relatively simple to install, in contrast to traditional HVAC systems, which can be difficult to retrofit into existing homes and require extensive ductwork. The only hole needed to connect the indoor and outdoor units is the small one, which can be mounted on walls or ceilings. For older homes or room additions where adding ductwork might not be practical, ductless systems are therefore perfect.

So, how can one install a duct air conditioner in a house? Although installing an HVAC system is something you can do on your own if you have prior HVAC installation experience, hiring a professional is usually advised. An experienced HVAC specialist can evaluate the layout and heating and cooling requirements of your house, suggest the best location for the indoor units, and make sure the system is installed securely and correctly.

A duct conditioner can be the perfect answer for you if you want to improve the heating and cooling in particular rooms of your house or upgrade your current HVAC system. It is understandable why an increasing number of homeowners are choosing ductless systems to maintain year-round comfort in their homes due to their effective operation, simplicity of installation, and customizable zoning features.

What is a duct conditioner, its purpose and design features

The purpose of a duct network is to disperse cooled air when using a duct air conditioner. It can be used to cool multiple rooms uniformly or to serve a single room with a complex configuration (like a U-shaped room). Ducts in the air conditioner also carry heated air from the service area.

View of a duct air conditioner overall

All duct conditioners are split-systems, meaning they are made up of outdoor (mounted outdoors) and indoor (located indoors) blocks that are linked to one another using electric cables and freon pipelines. In contrast to the wall model, the internal block has the simplest design: in a living room or office, the air ducts must always be concealed by a false ceiling in order to conceal the air conditioner itself.

Options for installing duct-type air conditioners

But in production facilities, there’s less emphasis placed on how the equipment looks. Typically, it takes the form of a box with holes for intake and discharge (to which air ducts are connected) and fittings for condensate removal systems and freon pipeline connections.

Everything is the same inside the box as it is in any other split system:

• heat exchanger;
• fan;
• electronic control board;
• condensate drip tray.

Large air cooling causes a significant amount of condensate to form; as a result, some models include an integrated drainage pump to remove the condensate.

An example of a duct air conditioner schematic

The indoor unit’s usage of a stronger fan than the wall model is another distinction. The reason for this is that air must be forced through lengthy ducts with a high aerodynamic resistance.

Principle of action

The duct conditioner operates in exact accordance with the same plan as other air conditioners. A heat pump serves as the device’s foundation. It is made up of two radiators connected by tubes, a closed circuit filled with a special gas called refrigerant, and a compressor that rotates the gas in a circle.

The way duct air conditioner elements operate

The refrigerant undergoes alternating compression and expansion, which causes "pumping" of heat. The circuit’s external radiator experiences compression, which causes the gas’s temperature to rise sharply and become heated. The refrigerant returns the heat energy extracted from the air in the room during the heat exchange that occurs between it and the outside air as a result of the temperature differential. A fan blows air into the external radiator to intensify the heat exchange.

By adding a throttle to the external radiator’s outlet, which permits very little gas to flow through, the pressure inside the radiator can be increased. As a result, the compressor’s charged refrigerant builds up and becomes severely compressed in front of the throttle. A long, thin tube is the most basic type of throttle (capillary).

The choice of compression pressure causes the gas to condense, or change into a liquid, as it cools. The key point is that the heat pump operates much more efficiently in condensation mode because the gas releases a lot more heat during this process than it does during cooling. This procedure has led to the external heat exchanger being referred to as a condenser.

The liquid refrigerant slowly seeps into the room’s internal radiator through the throttle (in the indoor unit). Because of the low pressure in this area, the liquid vaporizes and reverts to gas. An evaporator is the term used for the internal radiator.

The air conditioner operates in this manner.

It turns out that the internal radiator expands to fill its entire volume with a tiny amount of gas. As a result, the refrigerant cools significantly and begins to heat up from the inside air (a blower is also present). The gas enters the compressor after absorbing some heat, whereupon it is forced into the outer radiator, and the cycle is repeated.

The majority of contemporary air conditioners are made to allow for the rerouting of refrigerant flows, which transforms the external radiator from the condenser into the evaporator and the internal radiator from the evaporator into the condenser. At that point, the air conditioner will switch to heating mode as the heat pump begins "pumping" heat in the opposite direction.

Keep in mind that the heat it provides will be essentially free; that is, the user will be paradoxically warmed by the chilly street air. Of course, some electricity will be needed for this (compressor operation), but not in the same ratio as TEN electric heaters, but more like 1:4. That is, the user will receive roughly 4 kW of heat for every 1 kW of electricity used.

It is evident that this ratio will become less and less advantageous as the outside temperature drops, until eventually the air conditioner’s efficiency will be completely gone. It therefore makes sense to use the heating mode on this device only when the manufacturer recommends those outside temperatures.

Types

The following characteristics are used to categorize duct air conditioners into different varieties:

According to the fan head of the indoor unit

Since head is pressure, its unit of measurement is Pascals (Pa). The following are air conditioners:

• low-pressure, with the head up to 50 Pa;
• medium-pressure, with a head up to 150 Pa;
• high-pressure, with a head up to 300 Pa.

The air pressure needed to force air through the air conditioner’s ducts increases with their aerodynamic resistance.

By mode of operation (type of electrical circuit)

Two choices are available:

1. Start/stop air conditioners: in these appliances the compressor always works with the same speed, respectively, and the heat pump capacity remains practically constant. To maintain the temperature at the level set by the user, the automatics periodically switches off the cooler, which is why this mode is called "start/stop".
2. Inverter: more modern air conditioners with an inverter – an electronic device allowing to receive alternating current of any frequency. This makes it possible to regulate the speed of the compressor and, accordingly, the power of the heat pump.

Air conditioner with inverter Sanyo SAP-UCRVV96EH

The inverter air conditioner does not shut off; instead, it selects the best cooling power and operates continuously in this mode.

It should be noted that salespeople frequently claim that inverter air conditioners have benefits that are untrue. It makes sense to want to increase demand for these models given that an inverter cooler is 1.5–2 times more expensive than a standard start/stop air conditioner with the same capacity.

The following are the most common myths:

1. Inverter air conditioner saves electric power: mind-boggling figures – up to 30% are reported. However, any attempts to find information about where, by whom and under what conditions the research was conducted are fruitless. If to reason theoretically, the inverter model can be even more expensive: it has an additional consumer represented by the inverter control board plus its power circuit is characterized by some losses.
2. The mode of operation without switching off prolongs compressor service life: in response to such statement experienced masters advise to remember compressors of Soviet refrigerators, which worked in the "start/stop" mode for decades and did not break down at that. The same can be said about compressors of the first imported air conditioners that appeared in the USSR in the 80s. They served well for a long time, until the device was not replaced due to moral aging or loss of attractive appearance. Thus, we can conclude that the compressor is a very survivable unit, even if it operates in the "start-stop" mode.
3. Inverter air conditioner is less noisy: the compressor in the split-system is specially placed in the outdoor unit so that it could not be heard in the room, so its operation mode does not affect the internal noise background. "Sound accompaniment" is produced by the fan of the internal unit and the moving air flow, on which the inverter does not have the slightest influence.

The primary benefit of inverter air conditioners is that they produce less cold air, which is the only true advantage. The temperature remains constant at around 3 degrees while in the "start-stop" mode. The last situation lessens the chance of getting a cold, which is crucial because sleep is when people are most susceptible to colds.

It is inevitable, though, that inverter air conditioners have more and more indirect benefits over time—that is, advantages that aren’t directly related. The fact that this kind of cooler is the most sophisticated kind used by manufacturers. Thus, they are the main users of all the most recent innovations, including the most affordable compressors. It is anticipated that start/stop air conditioner production will end entirely in the near future.

By the presence of additional functions

A broader range of features is available in certain "channelniki" models:

1. Function of additional air processing: it means presence of humidifier, ionizer, UV-lamp (disinfection) and fine filter, for example, carbon or photocatalytic one.
2. Outdoor air supply function: a very convenient option. Users of air conditioners, which do not have it, are forced to refuse ventilation and sit in a stuffy room. If the window is opened, the inflow of warm outside air will be uncontrolled and all the cold generated by the air conditioner will fly away, and it may break down due to overloading.

External supply of fresh air – the sub-flow function

If there is a fresh air inlet function, the situation is very different. The unit itself draws in air in a permissible amount through the wall-mounted ducting, so there won’t be any noticeable temperature changes or overloading. A solenoid valve causes the air duct to automatically close when the air conditioner is turned off. Typically, 8–15% of the air volume pumped through the cooler is made up of fresh air; however, if needed, this percentage can be momentarily raised to 20–30%.

Planning a ducted air conditioning system

The two subsystems that make up the duct system are supply air, which distributes cooled air to the rooms, and exhaust air, which delivers heated air from the rooms to the air conditioner. Supply ducts have diffusers installed, and exhaust ducts have grilles.

The following should be considered when designing an air conditioning system:

Both diffusers and grilles should be located at the top – on the ceiling or at the top of the wall, but they should be on opposite sides of the room.

An illustration of a grille configuration

A sample of a wiring diagram

An illustration of connecting the grille to the ductwork using an adapter

Locations of the throttle valves

The supply air ducts need to be wrapped with thermal insulation material from the outside in order to prevent condensation.

Calculation of ducts

Due to its complexity, ducted air conditioning system calculations should only be performed by trained professionals. The process is as follows, in brief:

1. For each room, a thermotechnical calculation is made, on the basis of which the required cooling capacity is determined.
2. According to the cooling capacity determine the approximate volume of cooled air, which the conditioner should supply to the given room. For models with a cooling capacity of up to 20 kW, to provide 1 kW of air, approximately 165 cu. m/hr. m/h, for more powerful (up to 40 kW) this figure is about 135 cubic meters. m/h.

Determine the aerodynamic resistance of each branch and the system as a whole by knowing the air duct diameter, the material, and the air movement speed (which varies depending on the volume of supply).

Selection of duct air conditioner with fresh air inlet

The device should be chosen primarily based on its primary features.

On the head

The pressure generated by the indoor unit’s fan needs to be greater than or equal to the ducts’ resistance.

Advice: Those who question the accuracy of the air duct calculation should focus on "ducted" models, where the head value can be varied within a large range.

By flow rate (volume of cooled air supply)

The maximum supply of cold air that the duct conditioner can produce is stated in its characteristics, but it should be noted that this supply can only be achieved at zero resistance on the discharge side, or without the unit connected to the ducts. If they are connected, the higher the system’s aerodynamic resistance, the lower the supply and, thus, the cooling capacity.

The pressure characteristic, which refers to this dependence, is presented in the product passport as tables or graphs. It is recommended that the user examine the charts of multiple models and select the one that can supply the necessary flow rate at the system’s computed aerodynamic resistance (keep in mind that this is dependent on the required cooling capacity).

It’s crucial to consider the conditioner’s brand as well. The companies’ products have the best reputation:

• Daikin, Mitsubishi Heavy, Mitsubishi Electric, Toshiba, Fujitsu General (Japan);
• Samsung Electronics, Lg Electronics (South Korea), Electrolux (Sweden);
• Dantex (Great Britain).

The air conditioners made in China by Midea, Gree, and Ballu are the most dependable.

There are models that come with an integrated drain pump. It typically has a low power output, lifting water only 40–50 cm. However, in the event of a malfunction, the air conditioner will immediately shut down, protecting the user from the risk of condensate leaks. Another issue is a separate pump that is installed; in the event that it fails, the air conditioner will not respond in any way. However, it is simple to locate fairly powerful pumps among them; they can pump water through a 20-meter horizontal pipeline or raise it to a height of 8 meters.

Air conditioner with drain pump and high pressure duct type: schematic

Purchase an electric calorifier to heat outside air during the winter if your air conditioner has a fresh air supply feature and you wish to use it year-round. Even if the device is only used for cooling, the fluffy air still needs to be heated to prevent the room from becoming too cold.

Installation

Install the device in the subsequent sequence:

The place for installation of the outdoor unit is selected. It is desirable that it should be located in a cool place – on the north side of the building or at least in the shade. If you live in a high-rise building, locate the unit near the balcony, so that it is convenient to work with it. It must be below the indoor unit, but not further away from it than the manufacturer allows.

Requirements for installing the air conditioner’s outdoor unit

Attachment of the brackets to the exterior wall

The indoor unit is installed.

The following is the installation order for freon pipelines:

Using a pipe cutter cut two copper tubes of appropriate diameters. In length they should be 1 m longer than the distance between the fittings – this reserve is necessary for smooth bends.

Cut the copper tube with a specialized pipe cutter.

Copper tubing rolled up

Kindly take note! Only use a pipe cutter to make cuts; any use of a hacksaw inside the tubes will result in chips, which should never be tolerated. Soap foam is used to test the tightness of connections; therefore, the system needs to be pre-inflated with air.

Installing the reinforced drainage pipe comes next. It facilitates the drainage of condensate. If the flange is not part of the set, it is connected to the drain pipe using a heat-shrinkable tube or a threaded flange.

Instructions for a few "channelniki" called for setting up hydroseal in the drainage system with a precisely defined water column height. Since the condensate collecting tray on this model is positioned in the rarefaction zone due to the installation of the fan, moisture removal will be challenging in the absence of a water trap.

Location of the odor trap installation

To finish the work, the following procedures are used:

1. From the outside, the freon pipelines, drainage and electrical cable are fixed with clamps to the wall or hidden in a box, and then the hole in the wall is blown out with mounting foam.
2. Vacuuming the system. The vacuum pump should be operated for an hour – during this time the moisture is guaranteed to evaporate completely and leave the refrigeration circuit.
3. Watching the pressure, refrigerant is injected into the system from the cylinder, after which the air conditioner is turned on in the test mode.

Once everything functions flawlessly, the indoor unit is connected to the ducts. Using flexible vibration-absorbing inserts made of tarpaulin or rubberized fabric is preferable.

Maintenance

The appliance must be properly operated by following these steps on a regular basis:

1. Removal of dirt from the condensate drip tray. It is also useful to check the condensate drain pipe for dirt and disinfect the evaporator with a disinfectant – due to abundance of moisture and dust, bacteria, often pathogenic, like to multiply here.
2. Checking the refrigerant pressure. This operation should be performed by service personnel.

Freon pressure is measured using specialized tools.

Cleaning of filters

The amount of air pumped through the evaporator will be greatly decreased if this is not done. These will be the results of this:

• The air conditioner will not be able to maintain the temperature in the room at the temperature set by the user;
• The device may fail due to overload;
• evaporator from lack of warm air will freeze, because of what water can flow out of the internal block after switching off.

The unit’s handbook specifies how often maintenance is required.

Topic	Duct conditioner: what it is, how to install it
Definition	A duct conditioner is a type of HVAC system that regulates temperature and humidity by conditioning air as it passes through ducts in a building.
Function	It cools or heats air and removes excess moisture, improving indoor comfort.
Installation	Installation involves mounting the unit in a central location, connecting it to ductwork, and configuring controls for desired settings.

Energy efficiency and comfort in your house can be significantly improved by installing a ducted air conditioning system. You can improve your living area by choosing wisely if you know what a ducted conditioner is and how to install it. By distributing warm or cool air via a system of ducts, these systems maintain a constant temperature throughout your house.

The capacity of a ducted air conditioner to simultaneously control the temperature in several rooms is one of its main advantages. You can have customized comfort throughout your entire home with well-placed vents. In addition to maximizing comfort, this centralized heating and cooling system reduces energy waste, which will ultimately result in lower utility costs for you.

To guarantee a smooth installation process, it is imperative to seek professional assistance. For your ducted air conditioning system to operate as efficiently and effectively as possible, proper installation is essential. The best location for ducts and vents will be determined by a qualified installer after they evaluate the size, insulation, and layout of your house to guarantee balanced airflow and peak efficiency.

Furthermore, expert installation helps steer clear of frequent pitfalls like insufficient insulation and air leaks, which can reduce the system’s efficiency. You can have peace of mind knowing that your ducted air conditioner is installed correctly and ready to provide dependable comfort for years to come by investing in professional installation.

To sum up, a ducted air conditioning system provides a complete solution for effectively heating and cooling your house. You can improve the comfort and energy efficiency of your home by making informed decisions if you know what it entails and how to install it. You can take advantage of all the advantages of a ducted air conditioner, including customized comfort and large energy bill savings, with expert installation.

It’s critical to comprehend the significance of effective airflow in the context of home insulation and heating. The purpose of a duct conditioner is to maximize and control the flow of air through the duct system in your house. It serves as a conduit between your home’s heating and cooling system and its different rooms, guaranteeing constant, cozy temperatures all around. To maximize its effectiveness, installing a duct conditioner requires precise planning and placement within the ductwork system. Your home’s overall comfort, energy efficiency, and air quality can all be enhanced with a well-installed duct conditioner.

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