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Fuji electric — trademarkwhich belongs to the Japanese company Fuji Electric Holdings Co., Ltd. The holding includes many companies that are engaged in the development and manufacture of a wide range of products in a wide variety of industries. Until October 1, 2003, Holding was called Fuji Electric Group.
The history of the company begins with the organization in Tokyo in 1923 the factory for the production of electrical components. To date, Fuji Electric Holdings Co., Ltd. is one of the world's leading manufacturers of microelectronics: semiconductor parts, processor boards, as well as sources uninterrupted power, pumps, electric herarators, electric motors, fans different species, heat exchangers, steel rolled, plastics, chemical fibers and many other things.
Fuji Denki Sosetsu Co., Ltd. - Fuji Electric division engaged in the production and development of new air conditioning equipment models. Air conditioners are produced under the fuji electric brand.

Wall-mounted FUJI ELECTRIC (RSW-RS):

The most common and most popular type of air conditioners Fuji Electric is wall Type (RSW-RS). Power range from 2.2 to 3.25 kW, which allows you to cool the rooms with an area of \u200b\u200b15 to 35 square meters. m. Management is carried out using a remote IR console.
The air conditioner has a double air damper system that provides the most efficient air distribution to create comfortable conditions in the entire room.

There is also a function of automatic swing blinds in vertical plane and automatic air flow control. Best silent operation mode is provided by the "Silent Work" function. The complete absence of squeaks in the internal unit is achieved due to the use of rubberized materials in places of contact of the parts of the case.

All Fuji Electric air conditioners have the "Authorentar" function - an automatic restart that provides the resumption of the air conditioner in the same mode in which it worked until the power failure and the automatic selection of the mode. Also, Fuji Electric air conditioners are equipped with a sleep timer.

Powerful airflow
Highly efficient diffusers of an improved design
The system of double air dampers provides the most efficient distribution of air to create comfortable conditions in the entire room. From the control panel, you can set seven positions of the direction of the air flow by vertical, and the internal guides will send this stream in the desired direction horizontally.

Timer sleep
Where complete silence is needed, for example, in the bedrooms, recreation rooms and recording studios will be very useful for the silent mode of operation - the "silent work" function. In addition, the elimination of creak in the internal unit is achieved by applying rubberized materials in places of contact of the parts of the case.
The use of a fan of an enlarged size and a high-tech compressor made it possible to significantly reduce the dimensions of the outdoor unit. Models 7,000 - 9 000 BTU dimensions The outer block is only 535 x 650 x 250 mm. The weight of the block at the 7,000 BTU model is only 26 kg.
When you press the SLEEP button, the air conditioner automatically, depending on the operation mode, will change the temperature of the air temperature over the special algorithm within the time you specified. After the set time expires, the air conditioner will fully stop.

The body of the external unit is made of high-strength plastic, which is 100% protected from corrosion. Thanks to the internal location of the valves, simplifying the design of the housing, the external unit has become more compact and requires less space for installation. A special design of the radiator type lattice more evenly distributes the air flow, as a result of which the noise level of the external block is significantly reduced.
Combination of high-pressure fan inner block And the heat exchanger of the lambda-shaped form makes it possible to obtain an effective heat exchange with small sizes.
The indoor unit has standard washable coarse filters.
Each air conditioner has a self-diagnosis feature that can be run from the control panel. The fault code is determined by signal indicator signals on the internal block.

Fuji Electric Air Conditioners are equipped with the following options:

• washing panel;
• sleep timer;
• timer on / off;
• infrared control panel;
• automatic swing of blinds in the vertical plane;
• automatic air flow control;
• silent work;
• automatic restart;
• automatic mode selection.

Specifications of air conditioners Fuji

Lecture 2. Pressure loss in air ducts

Lecture plan. Mass and bulk flow of air. Bernoulli law. Pressure loss in horizontal and vertical air ducts: hydraulic resistance coefficient, dynamic coefficient, Reynolds number. Pressure loss in removals, local resistances, on acceleration of the dusty mixture. Pressure loss in high-pressure network. Power of the pneumatic transport system.

2. Pneumatic air flow parameters

2.1. Airflow parameters

Under the action of the fan in the pipeline the air flow is created. Important parameters Air flow are its speed, pressure, density, mass and volumetric cost of air. Air spectrum costs Q., m 3 / s, and mass M., kg / s are related to each other:

;
, (3)

where F. - cross-sectional area of \u200b\u200bthe pipe, m 2;

v. - airflow speed in a given section, m / s;

ρ - air density, kg / m 3.

Air flow pressure is distinguished by static, dynamic and complete.

Static pressure R art It is customary to call the pressure of the particles of moving air on each other and on the walls of the pipeline. Static pressure reflects the potential energy of the air flow in the pipe cross section in which it is measured.

Dynamic pressure Airflow R dean PA, characterizes his kinetic energy in cross section of the pipe, where it is measured:

.

Full pressure The air flow determines all its energy and equal to the sum of static and dynamic pressures measured in the same section of the pipe, Pa:

R = R art + R d. .

Counting of pressures can be carried out either from an absolute vacuum or relative to atmospheric pressure. If the pressure is counted from zero (absolute vacuum), then it is called absolute R. If the pressure is measured relative to the pressure of the atmosphere, then it will be a relative pressure N..

N. = N. art + R d. .

The atmospheric pressure is equal to the difference of complete pressures of absolute and relative

R atm = R – N..

The air pressure is measured in (n / m 2), mm water column or mm mercury column:

1 mm waters. Art. \u003d 9.81 pa; 1 mm Hg. Art. \u003d 133,322 Pa. The normal state of atmospheric air corresponds to the following conditions: Pressure 101325 Pa (760 mm Hg. Art.) And temperature 273K.

Air density There are a lot of air volume units. By the Clayperon equation, the density of pure air at a temperature of 20ºС

kg / m 3.

where R. - gas constant, equal to air 286.7 J / (kg  K); T. - Temperature on the Celvin scale.

Bernoulli equation. By the continuity of the air flow, the air flow is constant for any pipe cross section. For sections 1, 2 and 3 (Fig. 6), this condition can be written as:

;

When the air pressure changes within up to 5000 pa density it remains almost constant. Concerning

;

Q 1 \u003d Q 2 \u003d Q 3.

Changing the pressure of the air flow along the length of the pipe obeys the law of Bernoulli. For sections 1, 2, you can write

where  r 1,2 - pressure loss caused by the resistance of the stream of the pipe wall on the site between the sections 1 and 2, pa.

With a decrease in the cross-sectional area of \u200b\u200b2 pipe, the air velocity in this section will increase, so the volume flow will remain unchanged. But with increasing v. 2 will increase the dynamic flow pressure. In order for equality (5) to be performed, the static pressure should fall exactly as much as the dynamic pressure will increase.

With an increase in the cross-sectional area, the dynamic pressure in the section will fall, and static exactly the same increases. The total pressure in the section will remain the magnitude of the unchanged.

2.2. Pressure loss in a horizontal duct

Friction pressure loss dusting flow in a straight air duct taking into account the concentration of the mixture is determined by the formula of Darcy Weisbach, Pa

where l. - length of the straight line of the pipeline, m;

 - coefficient of hydraulic resistance (friction);

d.

r dean - dynamic pressure calculated in the average air velocity and its density, PA;

TO - complex coefficient; For traces with frequent turns TO \u003d 1.4; For the trails straight with a small amount of turns
where d. - diameter of the pipeline, m;

TO tM - The coefficient that takes into account the type of transported material, the meanings of which are given below:

Coefficient of hydraulic resistance  in engineering calculations are determined by the formula A.D. Altshul

, (7)

where TO e. - absolute equivalent surface roughness, to e \u003d (0.0001 ... 0.00015) m;

d. - the inner diameter of the pipe, m;

R.e. - Rate Reynolds.

Air Reynolds Air

, (8)

where v. - average air velocity in the pipe, m / s;

d. - diameter of the pipe, m;

 - air density, kg / m 3;

 1 - dynamic viscosity coefficient, NS / M 2;

The value of the dynamic coefficient Air viscosities are found according to the formula MilliKena, NS / M2

 1 = 17,11845  10 -6 + 49,3443  10 -9 t., (9)

where t. - Air temperature, c.

For t. \u003d 16 С  1 \u003d 17,11845  10 -6 + 49,3443  10 -9 16 \u003d 17,9 И 10 -6.

2.3. Pressure loss in vertical air duct

Pressure loss when moving aerosmes in a vertical pipeline, Pa:

, (10)

where  - air density,  \u003d 1.2 kg / m 3;

g \u003d 9.81 m / s 2;

h. - Height of lifting of the transported material, m.

When calculating aspiration systems in which the concentration of aerosmes   0.2 kg / kg Value  r under Given only when  h.  10 m. For an inclined pipeline  h. = l.sIN, where l. - the length of the inclined site, m;  - The angle of inclination of the pipeline.

2.4. Pressure loss in removal

Depending on the orientation of the removal (rotation of the duct for some angle) in space distinguish two types of taps: vertical and horizontal.

Vertical taps Denote as initial letters of words responsible for questions according to the scheme: from which pipeline, where a anesta is sent to which pipeline. Distinguish the following taps:

- M-BB - the transportable material moves from the horizontal section up into the vertical portion of the pipeline;

- Mr. - the same of the horizontal down to the vertical site;

- BB-G - the same of the vertical up horizontal;

- VN-G is the same of the vertical down to the horizontal.

Horizontal taps There are only one type of Mr.

In the practice of engineering calculations, the pressure loss in the disgust is found according to the following formulas.

With the values \u200b\u200bof the expenditure concentration   0.2 kg / kg

where
- the sum of the coefficients of local resistance of the branches of branches (Table 3) with R./ d. \u003d 2, where R. - rotation radius of the axial line of the outlet; d. - diameter of the pipeline; Dynamic air flow pressure.

With values \u200b\u200b  0.2 kg / kg

where is the sum of the conditional coefficients that take into account the pressure loss on the rotation and the overclocking of the material for the tap.

Values  oh Ust. find the magnitude of the table  t. (Table 4) Taking into account the coefficient at the angle of rotation TO p

 oh Ust. =  t. TO p . (13)

Correction coefficients TO p Take depending on the angle of rotation of the taps :

Table 3.

Local resistance coefficients of taps  about for R./ d. = 2

In order for the air exchange in the house "right", at the stage of drawing up the ventilation project, the aerodynamic calculation of air ducts is needed.

Air masses moving through the channels of the ventilation system, when carrying out calculations are taken as an incompressible fluid. And this is completely allowed, for too much pressure in the air ducts is not formed. In fact, the pressure is formed as a result of the friction of air on the wall of the channels, and even when the resistance of a local nature appears (it can be attributed to its pressure - jumps on places of direction of direction, when connecting / disconnected of air flows, in areas where control devices are installed or And where the diameter of the ventilation channel changes).

Note! The concept of aerodynamic calculation includes the determination of the cross section of each of the velocity network sections that ensure the movement of air flows. Moreover, the discharge is also determined due to these movements.

In accordance with many years of experience, it can be bolder to declare that sometimes some of these indicators during the calculation are already known. Below are situations that are often encountered in such cases.

1. The transverse channel section in the ventilation system is already known, it is required to determine the pressure that may be required in order for the desired amount of gas to move. This often happens in those air-conditioning highways, where the sizes of the section were based on the characteristics of the technical or architectural character.
2. Pressure We already know, but you need to determine the cross section of the network to ensure the ventilated room with the required volume of oxygen. This situation is inherent in networks natural ventilationIn which the appearance is already impossible to change.
3. It is not known about any of the indicators, therefore, we need to determine the pressure in the highway, and the cross section. This situation is found in most cases in the construction of houses.

Features of aerodynamic calculations

We will get acquainted with the general methodology for holding such calculations, provided that the cross section and pressure are unknown to us. Immediately alleged that the aerodynamic calculation should be carried out solely after the required amounts of air masses will be determined (they will be held through the air conditioning system) and the approximate location of each of the air ducts on the network is designed.

And in order to carry out the calculation, it is necessary to draw an axonometric diagram in which the list of all network elements will be present, as well as their exact dimensions. In accordance with the plan of the ventilation system, the total length of air lines is calculated. After that, the entire system should be divided into segments with homogeneous characteristics for which (only separately!) And air flow rate will be determined. Which is characteristic, for each of the homogeneous sections of the system, a separate aerodynamic calculation of air ducts should be carried out, because in each of them there is its own speed of movement of air flows, as well as permanent consumption. All obtained indicators need to be added to the above-mentioned axonometric scheme, and then, as you already probably guessed, you need to choose the main highway.

How to determine the speed in the ventilation channels?

As can be judged from all the above, it is necessary to choose that chain of successive network segments, which is the longest; At the same time, the numbering should begin solely from the remote site itself. As for the parameters of each of the plots (and the air flow rate, the length of the site, its sequence number, etc.), then they should also be taken to the settlement table. Then, when the introduction of the cross section will be applied, the shape of the cross section is selected and its sections are determined - dimensions.

LP / VT \u003d FP.

What do these abbreviations mean? We will try to figure out. So, in our formula:

• LP is a specific air flow at the selected area;
• VT is the speed with which air masses on this site move (measured in meters per second);
• Fp is the cross section of the channel you need.

Which is characteristic, during determining the speed of movement, it is necessary to be guided, first of all, considerations of saving and noise of the entire ventilation network.

Note! According to the indicator thus obtained (it is about cross section) It is necessary to choose an air duct with standard values, and the actual cross section (denoted by the Abbreviation FF) should be as close as possible to the previously designed one.

LP / FF \u003d VF.

Having obtained the indicator of the required speed, it is necessary to calculate how much pressure will decrease in the system due to the friction about the channel wall (for this you need to use a special table). As for local resistance for each of the sections, they should be calculated separately, after which it is summed into the overall indicator. Then, by summing the local resistance and loss due to friction, you can get a general loss rate in the air conditioning system. In the future, this value will be used in order to calculate the required amount of gas masses in ventilation channels.

Air-heating unit

Earlier, we told about the fact that the air-heating unit is, they talked about its advantages and applications, in addition to this article, we advise you to get acquainted with this information.

How to calculate pressure in the ventilation network

In order to determine the intended pressure for each individual section, you must use the following formula:

H x G (pH - PB) \u003d DPE.

Now we will try to figure out what it means each of these abbreviations. So:

• H in this case denotes the difference in the marks of the mine mouth and the fence lattice;
• RV and pH is a gas density indicator, both outside and inside the ventilation network, respectively (measured in kilograms per cubic meter);
• finally, DPE is an indication of what the natural disposable pressure should be.

We continue to disassemble the aerodynamic calculation of the air ducts. To determine the inner and external density, you must use the reference table, and the temperature indicator inside / outside should be taken into account. As a rule, the standard temperature is taken as a plus of 5 degrees, regardless of whether the country is planned in which particular region construction works. And if the temperature is lower from the outside, the result will increase the injection into the ventilation system, which, in turn, the volume of incoming air masses will be exceeded. And if the temperature is outside, on the contrary, it will be higher, then the pressure in the highway will be reduced because of this, although this trouble, by the way, can be completely compensated by opening the forces / windows.

What concerns the main task of any described calculation, then it lies in the choice of such air ducts, where the losses on segments (are it a value? (R * L *? + z)) will be below the current DPE indicator or, as an option, at least equal to it. For consumer visibility, we give the time described above in the form of a small formula:

DPE? ? (R * l *? + Z).

Now we consider in more detail that they denote the abbreviation used in this formula. Let's start with the end:

• Z In this case, this is an indicator denoting a decrease in air velocity due to local resistance;
• ? - this is the value, more precisely, the coefficient of what the rootiness of the walls in the highway;
• l is another simple value that denotes the length of the selected area (measured in meters);
• finally, R is an indicator of friction losses (measured in Pascals per meter).

Well, we figured out this, now I still find out a little about the roughness indicator (that is?). This indicator depends only on what materials were used in the manufacture of channels. It is worth noting that the speed of air movement can also be different, so this indicator should be taken into account.

Speed \u200b\u200b- 0.4 meters per second

In this case, the scheduling indicator will be as follows:

• the stucco with the use of the reinforcing mesh is 1.48;
• slagohyds - about 1.08;
• in ordinary brick - 1.25;
• and at the slag concrete, respectively, 1.11.

Speed \u200b\u200b- 0.8 meters per second

Here, the described indicators will look like this:

• for plaster using the reinforcing mesh - 1.69;
• for slag boosy - 1,13;
• for ordinary brick - 1.40;
• finally, for slag concrete - 1.19.

Slightly increase the speed of the air masses.

Speed \u200b\u200b- 1.20 meters per second

For this value, roughness indicators will be such:

• the plaster with the use of reinforcing mesh - 1.84;
• slagohyds - 1.18;
• in ordinary brick - 1.50;
• and, therefore, the slag concrete - somewhere 1.31.

And the last speed indicator.

Speed \u200b\u200b- 1.60 meters per second

Here the situation will look like this:

• for plastering with the use of reinforcing mesh, the roughness will be 1.95;
• for slag boosyps - 1.22;
• for ordinary brick - 1.58;
• and finally, for slag concrete - 1.31.

Note! Roughness figured out, but it is worth noting one more important moment: At the same time, it is advisable to take into account the insignificant margin, hesitating within ten and fifteen percent.

We understand with a common ventilation calculation

Making the aerodynamic calculation of the air ducts, you must take into account all the characteristics of the ventilation mine (these characteristics are shown below as a list).

1. Dynamic pressure (for its definition, is the formula - DPE? / 2 \u003d P).
2. Air consumption (it is indicated by the letter L and is measured in cubic meters per hour).
3. Pressure loss as a result of air friction about the inner walls (denoted by the letter R, measured in Pascals per meter).
4. The diameter of the air ducts (to calculate this indicator, the following formula is used: 2 * A * b / (a \u200b\u200b+ b); in this formula, the values \u200b\u200bof the A, B are the sizes of the channel section and are measured in millimeters).
5. Finally, speed is V, measured in meters per second, which we have already mentioned earlier.

>

As for the direct sequence of actions when calculating, it should look approximately as follows.

Step one. First, it is necessary to determine the required channel area, for which the formula below is used:

I / (3600xvpek) \u003d F.

We understand with the values:

• F In this case, it is, of course, an area that is measured in square meters;
• VPEK is the desired air movement speed, which is measured in meters per second (for channels, a speed of 0.5-1.0 meters per second is taken, for mines - about 1.5 meters).

Step Three. The next step is to determine the corresponding diameter of the air duct (indicated by the letter D).

Step fourth. The remaining indicators are then determined: the pressure (referred to as P), the speed of movement (abbreviated V) and, therefore, the decrease (abbreviated R). To do this, it is necessary to use nomograms according to D and L, as well as the relevant tables of coefficients.

Pitch fifth. Using other factors of coefficients (we are talking about local resistance indicators), it is required to determine how much the effect of air will decrease due to the local resistance Z.

Step six. At the last stage of the calculations you need to define common losses on each separate segment of the ventilation line.

Pay attention to one important point! So, if the common losses below already in the already occasional pressure, then such a ventilation system can be considered efficient. But if the losses exceed the pressure indicator, it may be necessary to install a special throttle diaphragm in the ventilation system. Thanks to this diaphragm, excess pressure will be fried.

Also note that if the ventilation system is calculated for serving several rooms at once, for which the air pressure is obliged to be different, then during the work of calculations it is necessary to take into account the discharge indicator or the subjoiler that must be added to the total loss indicator.

Video - How to make calculations using the Vix Studio program

The aerodynamic calculation of the air ducts is considered a mandatory procedure, an important component of planning ventilation systems. Thanks to this calculation, you can find out how effectively the rooms are ventilated at a particular cross section of the channels. And the effective functioning of ventilation, in turn, provides maximum comfort Your stay in the house.

An example of calculations. The conditions in this case are the following: an administrative building, has three floors.

Calculation of ventilation This calculation of air ducts and ventilation channels in systems i. exhaust ventilation . Ventilation serves to supply and remove air with a temperature of up to 80 ° C. The calculation is made according to the method of specific pressure loss. Total pressure loss, kgf / m², in the network of air ducts for standard air (T \u003d 20 ° C and γ \u003d 1.2 kg / m³) are determined by the formula:

p \u003d σ (RL + Z),

where R-loss of friction pressure on the calculated period of kgf / m² per 1 m; L-length of the duct segment, m; Z- Pressure loss on local resistance on the calculated segment, kgf / m².

Pressure loss of friction R, kgf / m² per 1 m in round air ducts are determined by the formula R \u003d λD V²γ2G, where the coefficient of friction resistance; d is the diameter of the air duct, m; v - air movement speed in the air duct, m / s; γ - bulk air mass transferred through the air duct, kgf / m³; V²γ / 2G- high-speed (dynamic) pressure, kgf / m².

The resistance coefficient is adopted by Altshul formula:

where δ is an absolute equivalent roughness of the surface of the duct of sheet steel, equal to 0.1 mm; d - duplex duct, mm; Reynolds Reynolds.

For air ducts made of other materials with an absolute equivalent roughness of KE≥0.1 mm, R values \u200b\u200bof R are taken with a correction coefficient N on the pressure loss for friction.

The value of ΔE for other materials:

1. Sheet Steel - 0.1mm
2. Viniplast - 0.1mm
3. Asbestos cement pipes - 0.11mm
4. Brick - 4mm
5. Stucco on the grid - 10mm

Recommended air movement speed in air ducts with mechanical motivation. Production buildings Main air ducts - up to 12 m / s, branch ducts - 6 m / s. Public buildings Main air ducts - up to 8 m / s, branch ducts - 5 m / s.

In rectangular air ducts, the equivalent DEV diameter is taken in which the pressure loss in the round air duct at the same air velocity is equal to losses in the rectangular air duct. Values \u200b\u200bof equivalent diameters, m, defined by the formula

where and B - the size of the sides of the rectangular duct. It should be borne in mind that with an equal speed of air, a rectangular air duct and a similar round have different air costs. The value of high-speed (dynamic) pressure and the specific loss of friction pressure for round air ducts.

Pressure loss z, kgf / m², on local resistances are determined by the formula

Z \u003d σζ (V²γ / 2G),

where σζ is the sum of the coefficients local resistances On the calculated cut of the air duct. If the temperature of the moved air is not 20 ° C on the pressure loss, calculated by the formula p \u003d σ (RL + Z), it is required to introduce correction coefficients K1 - friction, K2 - local resistance.

If the lack of pressure losses on the branches of the air ducts within 10%, the iris valves should be installed.