Using Air Conditioning Systems

2023 Author: Douglas Hoggarth | [email protected]. Last modified: 2023-05-24 11:23

1. SCV based on split-system air conditioners and a system of natural exhaust ventilation of residential premises (Fig. 1.)

Figure: 1

In fig. 1. Considered a variant of autonomous provision of internal temperature conditions in residential premises using split-system air conditioners of wall type.

The advantage of this type of self-contained air conditioners is ease of installation and installation.

The indoor unit is installed on the wall at a height of h = 2.5 m.

The outdoor unit is on the balcony. The freon line between the indoor and outdoor units is laid along the wall in decorative boxes.

Condensation formed in the indoor unit, when the air conditioner is operating in cooling mode, is brought out into the street by means of the drain pipe.

Ventilation of living quarters is carried out naturally.

Fresh air inflow through open windows. The hood to the street is through the grilles installed in the kitchen and in the bathroom, then through the exhaust shafts. An air purifier is used to clean the air in the kitchen.

SCR based on split-system air conditioners can be used in a large number of cases:

• in existing buildings to maintain a microclimate in separate office premises or in living rooms;

  in new buildings under construction, if maintaining optimal thermal conditions is required in a small number of rooms, for example, in a limited number of suites in a small hotel;

  in newly constructed buildings for individual rooms, the thermal regime in which differs from other rooms, for example, in server rooms saturated with heat generating equipment. Since such air conditioners work, as a rule, for recirculation, if necessary, supply of fresh air to the premises and removal of extract air is performed by a separate supply and exhaust ventilation system.

2. Technical ventilation system based on precise installation and an exhaust roof fan (Fig. 2.)

Figure: 2

In fig. 2. shows an example of mechanical ventilation of living quarters of a cottage. The supply ventilation unit ensures permissible meteorological conditions and sanitary standards for indoor air in accordance with SNiP. The supply unit includes:

- valve with an electric drive at the air intake;

- filter for cleaning air from dust;

- fan;

- an automation system with a control point.

All of these elements are mounted in a single metal soundproofed housing.

Such a compact design of the supply unit allows it to be mounted in the area of the suspended ceiling in the manned room.

In this example, the option of installing the air handling unit on the technical floor is considered. The processed air through the air duct network enters the serviced room through the ceiling lamps with an air flow regulator.

The exhaust ventilation system is designed with a roof fan.

Similar ventilation systems can be used in office premises with suspended ceilings.

3. SCV based on a split-system with supply ventilation (Fig. 3).

Figure: 3

In fig. 3. shows an example of air conditioning in a store using a split system with forced ventilation. The outdoor (compressor-condensing) unit is installed outdoors on the wall of a building (or in a technical room if the outdoor unit is equipped with a centrifugal fan). The indoor unit (including: filter, fan, freon cooler, electronic control panel, air heater) is mounted in the room behind the suspended ceiling.

Fresh air is taken from the street and through a thermally insulated duct is supplied to the mixing chamber, where it is mixed with the air taken from the room. Then the air mixture is filtered and processed in the indoor unit, depending on the set mode (cooling or heating). Further, the processed air enters the serviced premises through the air duct system through the air distribution grilles. At the same time, the interior design is not disturbed in any way, since all equipment is mounted behind a false ceiling. Only graceful decorative grilles for air supply remain in the interior. The indoor and outdoor units are interconnected with a freon pipeline in isolation.

A split system with supply ventilation, equipped with an electronic control system, maintains the required microclimate parameters at any time of the year. In summer, the duct is cooled down and the room temperature is maintained. In autumn and spring, the air conditioner switches to mode and effectively heats the air duct without turning on the color cooler. If the outside temperature falls below 0 ° C, an additional color heater is activated. The electronic control module of the color cooler allows its power to be smoothly regulated depending on the outside temperature, which ensures minimal energy consumption.

To create an air balance in the premises of the store, exhaust ventilation using a duct fan is provided.

4. SCR based on chiller-fan coil units, combined with central heating, and a natural ventilation system of an administrative building (Fig. 4.)

Figure: 4

In this air conditioning system, the cooling source is a rooftop chiller.

Local, non-autonomous, floor-standing fan coil units ensure optimal temperature conditions in the premises of the office building.

Fan coil units include 2 heat exchangers and are connected in a four-pipe scheme, which allows them to be used in winter as central heating devices.

The four-pipe installation assumes year-round use of the fan coil unit. During the cooling period, cold water from the chiller enters the main heat exchanger; in the off-season, warm water also comes from the chiller operating in the heat pump mode; during the heating (winter) season, hot water circulates through an additional heat exchanger (with a heat carrier temperature of 70-95 ° C) from the central heating system.

Air exchange is carried out by natural exhaust ventilation. The chiller supplies coolant to the fan coil units of a multi-storey building. Hot water enters the system from the city heating network through an individual heating point in the basement.

Air cooled chiller with axial fans installed on the roof. This installation option is the cheapest, since no space is required in the building or in the yard. At the same time, an installation with low-noise axial fans was chosen so that their noise would not penetrate into the serviced and adjacent buildings. The pumping station, which circulates the refrigerant in the chiller-fan coil system, is also installed on the roof.

The presented air conditioning system is widely used, as a rule, in the construction or reconstruction of a building as a whole or at least a separate floor in hotels, offices, medical institutions and schools.

5. SCV-based and the system of supply and exhaust forced ventilation of office premises (Fig. 5.)

Figure: five

In fig. 5. shows an example of a complex air conditioning system for a fairly common - office type of public buildings.

The main equipment is located on the technical floor.

A chiller is used to prepare cold water entering the air coolers of the central air conditioner and fan coil units. The air cooling of the condenser of this monoblock chiller is done by a radial fan.

Air for cooling the condenser is supplied and discharged through air ducts passing through the roof of the building. The chiller has a built-in hydraulic group that pumps the coolant, which is used as water. The chiller is designed to switch to the heat pump mode, and therefore on cold days, when the heating system is not yet running, water at a temperature of about 50 ° C is supplied to the air cooler of the central air conditioner and the heat exchangers of the fan coil units to heat the supply air that enters the premises later.

Fan coil units, similar to the indoor unit of the split system, operate on air recirculation in the room and carry out individual regulation of the thermal regime in each room.

The central air conditioner draws in air from the street through a louver installed on the facade of the technical floor.

The central air conditioner, in addition to two stages of the air filter (cell and pocket), includes an air heater, an air cooler and a fan section, after which silencers are installed. For the cold season, the air conditioner has a surface air humidifier. Such an air humidifier is able to provide the required room humidity in a wide range. In addition, in comparison with the irrigation chamber, it is more compact and the sprinklers do not need to maintain excess pressure, as nozzles in the irrigation chamber. In the warm season, the humidity of the supplied air is reduced due to condensation on the heat exchange surface of the fan coil units.

The supply air from the central air conditioner through the air duct network is supplied by independent channels to the premises on each floor through the supply grilles. Exhaust air is removed from each floor through a network of air ducts through grilles in the walls and then discharged into the atmosphere by an exhaust radial fan.

The figure does not conventionally show partitions between the supply and exhaust ventilation chambers and the chiller.

6. SCV-based and forced-air forced ventilation system of the hotel building (Fig. 6.)

Figure: 6

In fig. 6. Considered the option of installing a central air conditioner in the basement, and a chiller and a pumping station on the roof of the building. This system uses flush-mounted fan coil units in a false ceiling.

Outside air enters the air conditioner through an air intake shaft at a height of 2 meters from ground level.

Cooled (summer) or heated (winter) air in the air conditioner is supplied through the duct system to each fan coil unit. Fan coil units provide individual maintenance of the set temperature in each room. In turn, the AHU heat exchanger is supplied with chilled water (or ethylene glycol) from the chiller.

The circulation of water in the system is provided by a pumping station, as well as a chiller installed on the roof of a building, and it regulates an individual thermal regime in each room.

Fan coil units in this case operate on a mixture of outdoor and recirculated air.

Removal of air from bathrooms and washrooms is carried out through a network of air ducts in a centralized manner with a roof fan installed on the roof of the building.

7. SCR of the cinema hall based on the central supply and recirculation air conditioner (fig. 7.)

Figure: 7

The public building is equipped with a central air conditioning system based on a central air conditioner and chiller. The ratio of recirculation and supply air flow rates is variable and depends on the period of the year (winter-summer).

The supply and recirculation air conditioner, ventilation equipment and a chiller for the preparation of the coolant are installed in the basement and separated from the hall by building structures. With the help of a pumping group built into the chiller, the refrigerant is supplied to the air coolers.

A fountain is used as an open cooling tower in the circulating water supply system to cool the chiller condensers.

Air inflow into the hall is carried out by a central air conditioner through ceiling air diffusers. Exhaust from the hall is natural, through a shaft installed on the roof.

8. SCR of the technological room based on a precision cabinet air conditioner (Fig. 8.)

Figure: 8

Technological equipment with significant heat emission is installed in the manned room. A cabinet-type autonomous air conditioner is used to precisely maintain the set temperature and humidity of the internal air.

A natural ventilation system is used. If necessary, fresh air can be mixed into the air conditioner (in small volumes).

The indoor unit of the air conditioner is installed in the adjacent technical room (can be installed directly in the serviced room).

The design of the raised floor in the room made it possible to lay a network of air ducts in the floor and to distribute the air processed in the air conditioner directly under the racks of the technological equipment. The recirculated air is taken from the upper zone of the room and also flows through the air duct network for processing to the indoor unit of the air conditioner.

The air-cooled condensing unit is located on the wall outside the building.

9. SCR of the exhibition hall based on a central air conditioner with exhaust air heat recovery in a cross-flow heat exchanger (fig. 9.)

Figure: nine

Optimum parameters in the showroom are maintained with a central air conditioner.

The central air conditioner includes an additional section of the exhaust fan, as well as a heat recovery system from the exhaust air in a cross-flow heat exchanger. In this case, the sections of the air conditioner itself and exhaust ventilation are placed in two tiers. A chiller installed on the roof serves as a source of cooling for the central air conditioner.

The pumping station, also installed on the roof of the building, pumps the refrigerant through the chiller-heat exchanger system of the air conditioner. Air enters the showroom through the floor air diffusers and is removed through the ceiling shades through the duct system using an exhaust ventilation unit. The air removed from the room gives up its heat to the supply air in a cross-flow heat exchanger.

10. SLE operating room based on a supply and exhaust autonomous air conditioner (Fig. 10.)

Figure: ten

A monoblock supply and exhaust autonomous air conditioner was used for air conditioning the operating room. The air conditioner design uses a two-tier layout.

An air conditioner with a freon air cooler is located in the lower tier. Outside air enters the air conditioner, cools or heats up in it, depending on the outside air temperature, passes two stages of cleaning and enters the operating room through the air duct system. Air is discharged to the upper zone through special grills equipped with special fine filters. Indoor exhaust grilles are installed in the upper and lower zones of the operating room to remove light and heavy anesthetic gases from it. Through the air duct network, the exhaust air enters the air conditioner sections located in the second tier. The air conditioner chiller has an air-cooled condenser. Air from the exhaust system is used to cool the condenser with an additional admixture of outside air. The exhaust air is removed to the atmosphere through a special shaft on the roof of the building.

11. Ventilation system of an administrative building based on floor-by-floor supply and exhaust ventilation units with heat recovery from exhaust air (Fig. 11.)

Figure: eleven

The supply and exhaust ventilation system of the two-storey office building includes supply and exhaust units installed on each floor.

The ventilation units (installations) include an air-to-air heat exchanger (heat exchanger), in which, in the cold season, heat from the extract air is transferred to the supply air. In addition to the heat exchanger, supply and exhaust fans, the ventilation units are equipped with air filters to remove dust from both air streams at the unit inlet and a water heater for additional heating of the supply air. The units also have inlet and recirculation air valves to regulate the air flow in each stream.

The air intake is carried out from the facade of the building facing the green zone, the exhaust air is discharged onto another, deaf (without windows) facade. To distribute the supply air in the room and remove the extract air, supply and exhaust plafonds are used.

12. SCV based on rooftop air conditioners and a system of natural exhaust ventilation of the sales area (Fig. 12.)

Figure: 12

An independent rooftop air conditioner is installed on the roof of a one-story store building.

The air conditioner operates on a mixture of outdoor and recirculated air.

The required amount of outside air enters the mixing chamber, where it is mixed with the air taken from the room.

The total amount of air passes through the freon air cooler and enters the room through a system of air ducts and air distributors.

The exhaust air is removed by a natural exhaust ventilation system through the roof deflector.

13. SCR of a sports hall based on rooftop air conditioners with an exhaust fan section (Fig. 13.)

Figure: thirteen

Autonomous rooftop air conditioners are installed on the roof of a one-story building and operate on a mixture of outdoor and recirculated air. Air conditioners are equipped with an additional centrifugal fan for connecting exhaust ventilation. This design of air conditioners allows you to simultaneously solve the problem of ventilation and air conditioning of the sports hall.

Conditioned air is supplied through wall-mounted ventilation grilles; exhaust air removal - through ceiling shades.

14. SCV based on the air conditioner and the natural exhaust ventilation system of the cottage (Fig. 14.)

Figure: fourteen

The split-system air conditioner with supply ventilation consists of an internal (evaporative) and an external (compressor-condensing) unit. In this example, a condensing unit with a centrifugal fan is used. It is located on the technical floor. To cool it, air is taken from the street. The indoor unit is installed on the technical floor and operates on a mixture of outdoor and recirculated air. Air cooling in summer is carried out using a freon air cooler, and air heating in winter - using a water (or electric) air heater. In this case, a water heater is used, which operates during the heating period from a gas boiler. Outside air intake into the air conditioner and its distribution throughout the premises are carried out through the air duct network. The air for cooling the condenser is supplied by a centrifugal fan through the duct system. To compensate for the supply air from the bathrooms and kitchens, exhaust ventilation is provided.

15. SCR-based and air handling unit with heat recovery from the exhaust air of the cottage (Fig. 15.)

Figure: fifteen

Air conditioning and ventilation equipment is located on the technical floor.

The air conditioning system uses an air-cooled chiller. The cooling air is supplied to the condenser by a centrifugal fan through the duct system.

In residential premises, there are vertical floor-type fan coil units (fan coil units). They carry out individual temperature control in each room. The fan coil piping system is two-pipe, but in the winter (heating) period, it is envisaged to switch them from the chiller to an individual gas boiler installed in a separate room. In winter, fan coil units work as heating radiators.