What is air recirculation in the car interior? Heating, ventilation and air conditioning system. Design description - front door glass blower nozzles

pros

When using this mode, the air temperature in the cabin decreases in a faster manner than the mode of taking air masses from the environment. This mainly happens due to the repeated passage of air into the car, the temperature of which is already below the ambient temperature, through the air conditioning system.

With the reverse procedure - heating, everything is even simpler, since the temperature in the cabin is much higher than outside the car.

Another positive point is the fact that the power consumption for operating the compressor is significantly lower than when taken from the outside.

Recirculation is also an indispensable mode for people sensitive to road dust, pollen, unpleasant odors and other allergenic factors.

As an example, it is worth mentioning a situation that is probably familiar to any driver - this is a KAMAZ driving in front of you or any other vehicle that emits strong specific odors; recirculation in this case is an excellent way out of the situation.

Circulation - cooling air

Cooling air circulates in an open circuit. Cold air is forced by natural pressure through the supply pipes into the chambers between the external and internal shields of the electric motor.  

The circulation of cooling air in the turbogenerator is provided by internal fans mounted on both sides of the rotor barrel. To reduce the ingress of dust into the stator housing, air seals are provided on the shaft. To compensate for air leaks, air is sucked in from the environment; through filters located on external panels.  

The circulation of cooling air in the engine is carried out through internal fans mounted on both sides of the rotor barrel. The fans are made with a rotating guide vane, which ensures shock-free air entry, which makes it possible to increase efficiency and reduce external dimensions.  

The circulation of cooling air in the turbogenerator is carried out by internal fans.  

The circulation of cooling air is carried out due to the pressure difference in channels I and 12, which is formed due to a slight decrease in pressure in channels 4 due to the ejection effect of the flue gas flow.  

To ensure the circulation of cooling air inside the engine, pressure ventilation elements are attached to the magnetic wheel.  

Internal ventilation of electrical machines can be carried out with open or closed cooling air circulation cycles. When the cycle is open, air from the environment surrounding the machine passes through the ventilation duct, heats up during the cooling process of the machine and is released again into the environment.  

In this case, gaps are left between the covers and shields or the engine frame, which are necessary for the circulation of cooling air. Such engines can only be installed indoors, as they do not have provisions to protect them from rain.  

The segments are assembled onto a T-shaped protrusion of the turbine housing, in which an annular groove is made for the circulation of cooling air taken after the third stage of the axial compressor. The cooling air removes part of the heat coming from the segments to the housing protrusion, and thereby protects the turbine housing from local overheating. In the segments along the inner diameter there is a T-shaped groove machined into which guide vanes are assembled.  

The distances between the axes of the wires are taken based on the fact that it is necessary to create a sufficient gap between the turns for the circulation of cooling air.  

Heating system

As a rule, the heating system of a VAZ 2109 car consists of several main elements and components, shown below.

Heater

The heater or stove itself is the main link in the heating system. It is secured with 4 nuts in the car interior under the bolts. There are air ducts installed on the stove, which are fixed to the instrument panel from below. Their design requires sealing gaskets.

What does the stove consist of?

The VAZ 2109 system heater consists of:

• 2 plastic casings connected to each other with brackets (fastening brackets are connected along the perimeter);
• A special harness placed in the grooves for sealing;
• An electric fan that forces air into the cabin and is attached with screws on top of the stove;

Note. The motor is installed on the stove so that its removal is convenient and does not cause any difficulties.

• Heating radiator, which is installed in the heater casings;
• faucet;
• Cooling system pump, which circulates fluid through the radiator;
• Stove handles that allow you to control the heater.

Controlling the stove handles

You can achieve the most comfortable conditions in the cabin by moving the heater control knobs and adjusting the position of the nozzles in the following way:

• The upper right handle regulates the air supply to the feet of the driver and front passenger (if the position is to the extreme left, the supply is maximum, if the handle is in the extreme position to the right, the supply is blocked).

• The upper left knob regulates the air supply to the .
• The lower handle regulates the temperature of the air that enters the cabin (the extreme left position is cold air, the extreme right position is hot air).
• The left rotary button, visible in the photo above, connects the stove fan. It will increase the air supply. The button has 4 positions: 0 – off state, 1 – initial speed, 2 – average speed, 3 – maximum speed.

If the outside air temperature is minus 20 degrees Celsius, the stove begins to provide maximum heating mode automatically. The indicators in this case are as follows:

• +20 degrees Celsius is provided in the vehicle interior;
• +25 degrees Celsius is provided in the passenger and driver foot area.

Radiator

This is one of the most important parts of a car's heating system. Unfortunately, as a certain amount of time passes, time begins to leak. Traces of antifreeze on the passenger carpet or under the carpet are a symptom of a leaking heater core. In this case, the interior heating of the VAZ 21093 will be completely compromised and the radiator will have to be replaced.

Types of radiators

For the VAZ 2109 there are several main types of radiator. The most popular are:

• Aluminum original;
• Aluminum non-original;
• Copper.

Of all this trinity, the most expensive is the copper radiator, which can be soldered if necessary and which is significantly more reliable than the others. less reliable, but cheaper. The original one costs about 700 Russian rubles, while a non-original one can be bought for 400 rubles. The design of both types of aluminum radiators is different:

• The plates in the original radiator are located much denser than in the non-original version.
• The heat exchange area in a non-original radiator is smaller than in the original one.
• The design of the original aluminum radiator is much stronger.
• On an original radiator, the air begins to warm up already at a coolant temperature of 60 degrees, and on a non-original radiator only at 90 degrees and above.
• Inside the original radiators there are special coolant swirlers made in the form of spiral ribbons. They significantly increase operating efficiency, because the coolant does not “fly” through the radiator, but circulates slowly, releasing heat more efficiently.

Radiator replacement

It is needed if the old one no longer functions effectively enough. Replacement is carried out in the following way:

• The front panel unscrews.
• The radiator is dismantled and carefully removed from its place.
• A new one is being installed.

Note. Self-taught experts recommend removing the radiator from the bottom of the instrument panel, where the lower shelf prevents this from being done. This shelf is sawed off, and after installing the new radiator, it is attached with self-tapping screws, and in the future its removal will be easy.

On the VAZ 2109, the interior heating system is notable for its exhaust ventilation, which removes air from the cabin. This ventilation is located on the VAZ 2109 at the rear. In addition to providing air suction, exhaust ventilation is also carried out through the vacuum that occurs at the deflectors when the vehicle is moving.

valves

The exhaust ventilation on some versions of the VAZ 2109 is equipped with valves that serve to increase the amount of fresh flowing air in the cabin. In wet weather, these same valves help reduce fogging of the windows. Basically, VAZ 2109 models are not equipped with these valves, and most owners install them on their cars themselves. What you need to do to install the valve:

• It is enough to make technological holes in the body.
• Remove the rear bumper.
• Mark the seats for the valves.
• Insert valve.

Installation of a recirculation system

Correcting the air-fuel mixture adjustment
What should those car owners who only have a button do? There is no need to be upset - you can install the VAZ-2110 air recirculation system yourself. For this you will need:

• electromagnetic/pneumoelectric valve (article 2105-1127010.02);
• silicone hose (white, present in most modern cars) 0.5 m long, two pieces;
• electrical wire 2 x 0.5 (about 5 meters will be needed);
• check valve (part number 2110-8119110, although you can take any one, for example, used in aquarium compressors).

Sequence of work:

We provide access to the heater (by sliding the glove compartment up). We take out the stove, turning it counterclockwise, remove the casing, clean the stove, casing and other components from dirt and debris. We install the old-style cabin filter in its regular place, if it is not there. We install the VAZ-2110 recirculation damper, attaching it to the pneumatic valve rod, and assemble everything in the reverse order. Let's see where we can install the solenoid valve. It is usually attached to the bolt that secures the sound insulation on the front of the car. This is not entirely convenient, because if you need to change the filter or fix a leak in the radiator or pipes, you will have to remove the valve. But the place near the adsorber is quite suitable, since nothing interferes with anything, and both the receiver and the pneumatic valve are located relatively close. To secure the valve, you can use a bracket by drilling holes with a diameter of 8.5 mm in it. It is desirable that the bracket be stiffer - otherwise, due to shaking, the valve may begin to vibrate at a resonant frequency with the chassis, which will cause unpleasant rattling. The next step is connecting the hoses. The first should connect the heater damper actuator (pneumatic valve) to the output of the solenoid valve, located at an angle of 45 degrees relative to the central pipe. The second hose will connect the power unit receiver to the central pipe of the solenoid valve (connection to the receiver can be made using a tee, and if the additional output of the motor is not used, it is plugged with the same silicone hose)

It is important not to confuse the connection of the hoses to the solenoid valve, since this will cause air to leak from outside when the power unit is running through the switched off solenoid valve. The check valve can be installed in any of the hoses

The main thing is to ensure that the air flow can move to the receiver. The check valve is needed to ensure that the damper opens when the engine stops (provided that voltage was applied to the valve before this). Let's move on to connecting the electrical wiring. If you follow the electrical diagram of the “tens” exactly, then the solenoid valve should be controlled by the negative wire coming from the VAZ-2110 recirculation switch. We take the positive wire from the backlight of the same button. To do this, we remove the key from its regular place, connect our wires to the terminals, the other end of which we pull to the valve behind the instrument panel, then towards the “black box”, through the plug between the passenger compartment and the engine compartment, behind the battery in the direction of the left headlight, there we turn to the right and connect to the valve. The positive wire must be connected to the fuse.

As you can see, you will have to tinker a little, but you will get full air recirculation of the VAZ-2110. It can and should be used when warming up the car in winter, when driving on dirt roads, in a traffic jam, when cleaning windows with a bad-smelling “anti-freeze”.

Features of the stove operation and its modification

Owners of a VAZ 2109 car are often concerned that over time the stove begins to heat poorly. Needless to say, driving in such a car will no longer be comfortable. In such cases, only upgrading the stove can solve the problem.

Refinement methods

There are many ways. Below are a few of them.

Damper control lever

So:

• You can simply tighten the heater damper control cable to solve the problem. Make 1-2 turns of the cable located on the damper control lever (the lever itself is located on the stove body, near the gas pedal).

Note. The joints of the air ducts and the edges of the heater damper are covered with foam rubber, which does not compress completely. In this regard, a gap of several millimeters is formed, and the damper does not close completely. The above method will help you adjust the lever properly.

• There is another way to get to the control lever. There is a place on the driver's side and you need to try to reach with your hand and pull the lever, always with the heater fan on. During the adjustment process, the left ear will be in the area of ​​the air duct nozzle and thus it will be possible to hear how the sound of the escaping air changes.

Heater valve

The reason for the ineffective operation of the heating system can also be incomplete opening of the stove faucet. This problem, by the way, occurs in almost all front-wheel drive cars of the VAZ family.

• The solution to the problem can be to tighten the valve control cable and then adjust the control lever to the maximum open position.

Note. In this case, it is possible that the valve will no longer close completely. But this is not the problem, but the fact that after adjusting the lever, the damper may lose its tightness and begin to leak (seen in the photo). In this case, we can recommend wrapping the leak area with a cloth that has been soaked in sealant and fixing it all with cold welding.

Air ducts

Poor functioning of the heating system may be caused by leaky air ducts. The air that is pumped by the heater fan partially goes into the cracks, and the air flow thereby weakens and cools.

• The solution could be complete sealing and gluing of the connections that are located in the places where air flows from the stove to the outlet.

Air jams

In addition, the cause of poor operation of the stove can be air pockets formed in the heater radiator.

• The solution would be to stop the front of the car on some hill. Then you should open the heater tap completely and press the accelerator pedal several times.

Above were some ways to eliminate problems with the heating and ventilation system of the VAZ 2109. Instructions and advice given by experts are a chance to “cure” your car with your own hands, thereby saving a lot on repairs. As you know, the price of technical procedures at a service station is not low, and if they are carried out regularly, the family budget will become noticeably poorer. It is recommended to use photo and video materials in the process of independent work.

The car heating system of many models is designed and operates on a similar principle. Understanding the principle of turning on and adjusting the speed of the interior heater fan will be very helpful when searching for a fault on your own (for example, if you have).

DIY seat ventilation

The above description of how the seat ventilation system works allows you to make a similar system with your own hands, based on the information received. In this case, seat ventilation can be installed in at least three different ways.

Installation of a ready-made kit (kit)

To do this, use a ready-made set of parts and assemblies that are commercially available, for example, as shown in the photo below:

Do-it-yourself installation of such a kit involves removing the seat trim, perforating it, as well as positioning and connecting the fans in the right places. As a rule, such a system has several speeds for regulating fan performance, which allows you to select the best option based on the current climatic conditions.

Article on the topic: How to remove air from the fuel system of Priora, and diesel cars with fuel injection pump

DIY installation using individual elements

To perform ventilation yourself using individual elements, you need to buy:

1. computer fans;
2. plastic mesh instead of a spacer;
3. buttons, wires.

Their installation begins with the seats being dismantled and the places where the fans will be attached are determined, then holes are cut out in the foam rubber for them.

In these places, excess foam rubber is cut off and instead of it, a cut mesh fifteen millimeters thick is laid.

After the mesh has been installed, previously cut foam rubber must be laid on top of it, in which holes with a diameter of one centimeter must be made.

The fans are connected by wires, the button for turning on the ventilation in the seat is located on the panel, or in any other convenient place.

Seat ventilation system using a car heater

You can do the blowing with your own hands without using fans. How this is done should be clear from the given figure and photo. With this approach, air from the stove is supplied to the seat using a corrugation. Such an air supply system will allow not only cooling, but also heating of the seats. It is best if the corrugation is installed inside the channel.

General air circulation diagram

Air is drawn into the car interior by a fan, which can be installed in the cabin or behind the engine shield. It is located above the electric motor. If heating is necessary, the air flow passes through the heater radiator. The heater radiator is connected to the car's cooling system, so when the engine heats up, circulating fluid from the engine cooling system heats the heater radiator honeycomb. Therefore, passing through the honeycomb, the air flow also becomes warm.

Air dampers

Redirection of air flows to regulate temperature is carried out by a special damper. Types of damper control:

• mechanical. The damper drive is connected directly to the switch in the cabin via rods and cables. In this case, the driver, by moving the regulator, manually doses the temperature of the incoming air;
• electronic. The damper is equipped with a servo drive. The electric motor changes the position of the damper, receiving commands from the control unit. This scheme is used on cars with climate control systems. The driver just needs to set the desired temperature in the cabin in the on-board computer, after which the electronic control unit, focusing on temperature sensors, will control the air damper servomotor.

Channels extend from the stove fan into the cabin, through which air can be supplied to the windshield, to the feet, or through the central deflectors. Depending on the operating scheme, the modes can be either combined or single, when all the intake air is supplied to only one zone. Switching modes can be done mechanically or using a servo drive and a control unit. The mechanical method involves direct connection of the air dampers to the switch on the dashboard. The electric drive of the dampers allows you to control them by pressing a key, as well as to implement automatic control of the electronic unit of the interior air conditioning system.

Recycling

In recirculation mode, the main air damper closes, after which the heater fan begins to draw air from the passenger compartment. This mode of operation allows you to block the access of unpleasant odors and polluted air from the street if, for example, you are driving a car along a dusty gravel road.

In winter, the recirculation mode allows you to warm up the car interior faster, since not frosty air, but warm interior air passes through the heater radiator. Accordingly, in summer, recirculation makes it easier for the air conditioner to cool down.

Types of recirculation drive:

Operation of the ventilation and cooling system

The problem with interior temperature is heating and ventilation. To ensure the necessary thermal comfort, the air temperature in the cabin should be in the range of 18-22°C. The measurements and experiments carried out show that the temperature difference is favorable for humans: at the level of the head the temperature should be 5-8° lower than in the area of ​​the feet in both summer and winter. To ensure such a thermal regime, it is necessary to calculate the ventilation and heating system. The required temperature difference can be achieved through thoughtful distribution of air flows and heating the air in winter. The established temperature regime in the cabin in a stationary state is determined by the balance between the amount of heat coming from the outside (solar radiation) and from the inside (engine, heating, heat emission from people sitting in the car) and heat transfer through the surface of the body and due to heat transfer by ventilation air.

The operation of the ventilation and cooling system is especially difficult in the summer in conditions of direct exposure to sunlight. The density of the incoming heat flux under these conditions is approximately 990 kcal/(m2h) and depends on the quality of the body’s thermal insulation. With an irradiated surface area of ​​2.5 m2 in the interior of an average-sized car, the heat flux is approximately 2300 kcal/h, most of which penetrates through the windows. By using effective thermal insulation (especially the roof), painting the body and interior in light (reflective) colors, and using tinted glass, this heat flow can be reduced.

Color causes a change in temperature in the cabin (if we compare white and black bodies) compared to the external temperature, depending on the size of the car, by 8-15%. Conventional (non-tinted) glass transmits light and heat radiation almost unhindered, so the currently common large windows are not a good solution in this regard. When the car moves, the air flowing around the body has some cooling effect, but if additional cooling devices are not used, the temperature in the cabin is constantly 3-4°C higher than the ambient temperature, mainly for the following reasons.

As a result of the heat generated by the engine, transmission and exhaust system, despite good insulation, the interior air is heated. To this we can add the heat generated by people in the car, which at rest is approximately 100 kcal/h. In summer, the release of this heat must be compensated by ventilation in such a way that the temperature in the cabin is maintained acceptable for people. The heat transfer from the body surface, so desired in summer, is very small due to too small a temperature difference between the interior and the outside. Therefore, if it is impossible to obtain an acceptable temperature in the cabin through natural ventilation, then it is necessary to provide additional cooling of the air entering the cabin using a cooling system. It can be installed in a car regardless of the existing heating and ventilation system, but it is better to combine them, then you get an air conditioning system. Using such a system, you can regulate not only the temperature in the cabin, but also the air humidity.

Below are some general data from the field of thermal engineering.

Additional cooling of the cabin air is necessary when the ambient temperature is above 35°C and there is intense solar radiation. In this case, the air temperature in the cabin, in order to avoid the danger of hypothermia, should not be lower than the ambient temperature by more than 10°C, and the temperature of the cold air coming from the heat exchanger should not be lower than 5°C. It is advisable to cool only part of the fresh air (approximately 30%), the rest of the incoming air should be used to freshen the air in the cabin, then the efficiency of air use increases and the design costs of the air conditioner are reduced. Of course, the car windows (with tinted glass) must remain closed. However, cooling the air requires a lot of power, since it is necessary not only to cool the air, but also to compensate for its heating from solar radiation and the internal “heating” of the cabin. According to Fiala, for an average passenger car this heating is approximately 4500 kcal/h. The big advantage of additional cooling is that it reduces the relative humidity in the cabin. It decreases by approximately 35% due to the cooling of condensation moisture in the heat exchanger, which is especially pleasant at high ambient temperatures and high humidity.

The requirements for an air conditioner look different when it is necessary to increase the air temperature in the cabin in winter conditions. The thermal energy required for this is best obtained from the engine cooling system. The exhaust gas heating system used on cars with air-cooled engines, due to its inherent disadvantages (strong dependence on the realized engine power, low heat capacity, increased noise compared to a liquid heating system), is not considered. When designing a heating system, it should be taken into account that during ventilation, i.e., the release of heated air through the openings provided for this purpose and the gaps in the seals, heat loss occurs from the ventilation air. This significantly reduces the efficiency of the heating system. Efficiency depends on many parameters, some of which are defined below.

This example does not take into account the loss of heat through the surface of the body (radiation, convection, heat transfer), as well as heating of the air in the cabin from the engine, exhaust system and people in the cabin. Heat loss depends on the difference in air temperature in the cabin and outside the car, which in turn depends on the amount of air entering the cabin, therefore, on the speed of movement, as well as on the quality of thermal insulation of the cabin (roof, doors, sides). Therefore, it is impossible to give generalized formulas. In the example above, the heat loss was approximately 1800 kcal/h, which can be used as a guide. When calculating the heating system, only 60% of the maximum air flow in summer operation conditions should be taken into account (all air intake openings are open), therefore, in the example considered, 3.5 m3/h was taken instead of 6.0 m3/h (with completely open air intake openings). air).

The efficiency of the heating system can be dramatically increased by increasing the temperature of the air coming from the heater, as well as the temperature of the engine coolant, using thermostats adjusted to a higher water temperature ("winter" thermostat), in addition, by providing non-linear control of the amount of incoming air, allowing compensate for the increase in air pressure with increasing vehicle speed.

How does a stove fan work?

The car interior heating fan is a conventional AC motor. This can be either a simple axial fan or a diametrical version, which is most often installed on modern cars. The design of the internal part of the stove fan is no different from that of a conventional AC electric motor excited by permanent magnets.

Of greater interest to us is the operation of the electric motor at different speeds. This possibility is realized by including additional resistance in the circuit. Resistors increase resistance, which leads to a decrease in current flowing in the circuit. Consequently, the fan begins to rotate more slowly. The value of the resistor determines how much current will drop in the circuit. The final fan speed is direct because there is no resistance included in the circuit. This allows the heater fan to remain operational even if the resistance has failed.

Connection diagram

The figure shows the simplest circuit diagram for connecting a stove fan. When the positive terminal of the switch, protected by a fuse, is connected to terminal H, current flows directly to the motor, causing it to rotate at maximum speed. When the positive contact is closed to the V pin, current flows through the resistance, which reduces the fan speed.

The electric heater motor of the VAZ 2108, 21099 models already has 3 fan speeds. When the positive terminal of the mode switch is shorted to 1 contact, 2 resistances are connected in series in the circuit, so the rotation speed of the electric motor will be minimal. When power is applied to the second contact of the mode switch, current will flow through one resistor, which will correspond to the average rotation speed. Accordingly, pin 3 is designed to supply power bypassing the additional resistor and corresponds to the fastest rotation speed.

This is exactly the principle of turning on the electric heater motor on most cars. For a better understanding of the scheme, we suggest watching the video.

Automated control system

In the diagram we still see an additional resistor, only now all commands are transmitted to the electric fan not directly from the speed shift knob, but through the heating system control unit (No. 3). The unit also controls the interior recirculation solenoid valve and the damper drive micromotor. This scheme uses only one temperature sensor in the cabin, but in more advanced versions there are also intake air temperature sensors, as well as sensors that measure the temperature of the air supplied to the cabin at several points.

For better or worse, we live in a country with harsh climatic conditions. In the summer everyone suffers from the heat, every year it gets hotter, in the winter we all get cold, spending money on heating. Spring and autumn are not encouraging either.

As a result, it turns out that when you leave the house and get into the car, you are faced with a problem - there is no comfort for normal living conditions in the car interior. The Arabs and Brazilians were lucky with the interior ventilation system - they installed an air conditioner in their car and drove it all year round. And it’s good for Eskimos too - having it in the car is enough.

And from Brest to Vladivostok, we need both of these systems, as they say, in one bottle, or rather, in the cabin. How much money this combination costs and how much gasoline the car “eats” all year round is a separate conversation, but one thing cannot be denied – in cars driving through fields and forests, interior ventilation systems are needed “like air”

.

It would seem that you can drive without them, but the harsh truth of life quickly convinces us that riding in an unheated car in the winter means guaranteeing yourself all sorts of diseases from sinusitis to prostatitis, not to mention problems with the gynecological sphere.

In the summer, everything seems simple - open the window and enjoy the oncoming breeze, but in traffic jams, unfortunately, this breeze is not enough for everyone. Well, where there is a breeze, it does not bring anything good except otitis media, conjunctivitis and other diseases.

Do you know that a short stay in a heated oven, into which a car turns into on a summer day from the sun, even in healthy people can cause a hypertensive or vascular crisis, or worse, a heart attack, stroke, and many other nasty things. And considering the cost of treatment, I don’t really want to pick up anything from this set.

If you consider that it is not that expensive to maintain, then it is worth taking care of your health.

Types of ventilation with recirculation

The ventilation system is installed at the rough construction stage

It is planned at the design stage before the construction of the building begins. Installation of ventilation in a ready-made house involves the need to build in and place ducts, suspended air ducts, grilles, and diffusers. In old rooms, air exchange was partially due to cracks in the window frames.

Modern sealed structures limit the flow of air and prevent drafts, so after installing metal-plastic fillings, ventilation is required. Increased inflow invariably increases heating costs, so it is advisable to reuse the purified and heated air mass.

When calculating and installing a recirculation hood, the following regulatory rules are observed:

• the volume of supplied street flow is at least 20% of the secondary air mass;
• the finished mixture after processing contains no more than 30% of harmful components of the total amount according to the norm.

Recirculation ventilation reduces the load on air handling units, such as air conditioners and heaters.

Heated

Ventilation diagram with heating of incoming air

The system uses cold or heat from technical devices that heat new air and mix it with what is removed from the room. The supply and exhaust fans and heater are turned on. Valves open for the passage of street, exhaust and recirculation flow, the operation of each is set in a certain mode.

Types of heat exchangers:

• cross plate-type energy exchangers show operational efficiency at the level of 50 - 90%, condensation is allowed in them;
• regenerative rotating rotary heat exchangers are characterized by increased efficiency in the range of 70 - 90%, due to the presence of moving elements they are able to redistribute odors between mixed jets;
• recuperators that have an intermediate heater in their design operate with lower efficiency (45 - 65%), the advantage is expressed in good insulation of the energy generator.

When using the system, energy is saved on heating or air conditioning. For example, a circulating hood for the kitchen removes excess heat if it is not needed, cleans it, uses it when mixed with cold air and delivers it where it is needed.

No heating

An unheated recirculation system provides fresh air and removal of used mass from the rooms, while updating occurs constantly, and not in separate episodes. At the same time, noise, the volume of dust, and harmful insects that enter open openings are reduced. The circulation outlets in the hood are located so that those present are not affected by drafts and strong kitchen odors.

The purpose of a recirculation air duct without heating is only to pump in fresh air in the off-season, when the heating system is operating, but the air outside is warming up. This becomes possible if the technical indicators of street flows comply with sanitary standards.

The supply and exhaust fans turn on, the heater does not work. The recirculation valve coordinates the temperature of the streams entering the room. The external valve regulates the temperature of the outside air.

Supply and exhaust ventilation

Supply and exhaust ventilation diagram

If in such a system the outlet and supply pneumatic valves are opened and the recirculation plug is closed, the line will work as simple ventilation. You can direct the flows through a closed ring without supplying atmosphere from the street by closing the inlet and outlet valves and slightly opening the recirculation valve.

Partial opening of the three valves leads to the organization of air supply with the addition of fresh atmosphere. This achieves the optimal ratio of temperature indicators and the degree of oxygen saturation. Choosing one of their schemes allows you to maintain comfort in hot or cold climates. The supply and exhaust system is installed in large rooms with significant crowds of people, for example, restaurants, train stations, and supermarket trading floors.

Additional schemes

Types of fan coil units for ventilation

A system for moving air masses using a duct air conditioner is used. The fan coil is an internal complex air conditioner device that functions as an active battery. It has condensate drainage, an energy exchanger, a filter device and a fan. In summer, the heat exchanger is supplied with cold water (10–12°C); in winter, hot liquid is supplied from the mains (up to 60°C). The fan coil unit is equipped with a control unit and automatic temperature control devices.

A scheme using dampers operates in the form of exhaust and supply ventilation or mixes incoming and outgoing flows. The system is used in private buildings, for example, as a recirculating hood for the kitchen. The temperature values ​​of the external atmosphere change, but the comfortable value has a constant value. The volume of mixed masses is regulated by closing the gates and dampers in automatic or manual mode.

The movement of air masses indoors with the help of a ceiling fan eliminates the stagnation of masses in one part of the room, but does not apply to a full-fledged recirculation scheme. These systems without fan coil are used in large rooms, halls, foyers, and lobbies.

Cabin filter

When the interior ventilation system operates, air passes through and is then heated or cooled, depending on the set parameters. Air is supplied for heating or cooling to the interior of the car through a single casing.

The temperature and air flow speed are regulated using special regulators on the control panel of the interior ventilation system. Ventilation of the car body occurs with a constant flow of air.

Outside air enters the car through the air intake near the windshield, and exits through the exhaust ducts, which are installed under the rear bumper.

Air volumes are regulated by a four-speed fan. When the cabin ventilation system is turned on while the engine is running, heat comes from the heated coolant that is in the cabin. And the mixing damper allows you to adjust the required temperature in the car interior, “making a cocktail” of hot air with cold outside air.

Air humidity problem

From many years of practice and research results, it is known that the most pleasant air is perceived, the humidity of which, depending on the temperature, is in the range of 30-70%. The relatively high (but in terms of absolute values ​​quite low) moisture content in the air at low temperatures leads to the fact that as the cold air warms up, the relative humidity decreases to approximately 20-25%. This phenomenon is positive because it prevents windows from fogging up. Of course, a person in a car releases 40-100 g of moisture into the air within 1 hour as a result of evaporation, breathing, drying wet clothes, etc., so when heating the cabin, the air does not become too dry. In addition, acceptable air humidity can be obtained by mixing heated air from the heater with cold fresh air. By successfully distributing air flows along the windows, you can prevent the glass from fogging up and dry them. On the contrary, with additional cooling of the air by an air conditioner, due to moisture condensation and additional heating of the car, the relative humidity is greatly reduced.

Air conditioning is an excellent interior ventilation system

What saves the day in the summer is the excellent interior ventilation system. In cooling mode, it removes excess moisture and lowers the temperature inside the car.

This happens as follows: the liquid refrigerant moves along the high-pressure circuit; when pumped into the low-pressure circuit, the refrigerant evaporates and gas is formed. At the same time, the refrigerant is greatly cooled, taking away heat from the cabin.

The cooled air is forced into the interior of the car by a fan. Next, passing through the condenser, the liquid refrigerant returns heat to the outside air. Since the refrigerant constantly circulates in a closed circuit, the car interior is constantly cooled and the release of heat can last a very long time.

Moisture is removed from the air mass of the cabin by condensing on the evaporator of the air conditioning refrigeration chamber. As a result, we have an automatic and constant interior ventilation system in our car, which is installed and regulated by the air conditioner.

Principle of recirculation with ventilation

A recirculating supply and exhaust system is a technically complex installation and requires organized coordination and control.

Elements included in the complex:

• two electric fans on which air flow and flow depend;
• a recirculating energy exchanger heats the outdoor atmosphere, mixes the supply and exhaust flow;
• filters clean jets from the external air duct and process internal flows before feeding them into the heat exchanger;
• an electric heater warms the outside air if there is not enough heat from the internal flow;
• air duct valves are placed at the inlet and before the outlet, they regulate the strength of the jets or close the channel when the equipment is turned off.

Heating or cooling of the atmosphere in the room occurs quickly due to the repeated passage of jets through a circulation heat exchanger. The recirculation mode in the hood is also used if it is necessary to stop the flow of outside air into the room (unpleasant odor, dust).

Thinking that the air conditioner does not require maintenance

Over time, every air conditioning system loses coolant—up to 15 percent over the course of a year. It's no surprise that your air conditioning system loses power and eventually stops cooling adequately. This is why you should perform maintenance at least every three or even better every two years.

The service includes not only refilling with coolant, but also checking the air conditioning system for leaks. This is important because the loss of coolant not only pollutes the air conditioning system, but also the environment. An unpleasant odor may also come from it.

Do not get rid of moisture in the car interior

photo: thehawaiiherald.com

If your car smells like mold, it means that the interior of the car is over-humidified - a lot of moisture has accumulated there, which appears most intensely in the winter months.

The problem is aggravated by improper car care: clogged drains (drain holes through which water should drain from the internal surfaces of the body) or torn, cracked door seals are the main gates for water. Snow on your shoes and even just wet clothes when you get into the car during the rain do not add to the dryness.

The first signs of increased humidity in the cabin are windows that quickly fog up. Special car dehumidifiers or cat litter in a sock or fabric bag can help here: How to get rid of foggy car windows.

Ventilate the interior, but also do not forget to turn on the air conditioning. It dries the air and rids the car of excess accumulated moisture.

If you don't act, you risk not only unpleasant odors, but also mold.