The speed of air movement in rooms, in the openings of exhaust and supply air ducts, in open openings of windows, doors, etc. is measured by anemometers. By design, anemometers are divided into mechanical and electrical, etc. Mechanical anemometers include vane type ASO-3 and cup type MS-13. Anemometers are used in this work mechanical type. Air speeds with these devices are measured by first determining the rotation speed of the device axis, which linearly depends on the speed.
The vane anemometer (Fig. 1 a) is used to measure velocities in the range of 0.2 - 5 m/s with an accuracy of 0.1 m/s. It has eight foil blades as a wind receiver, mounted on an axis at an angle of 45 0, with which measurements is always directed towards the air flow.
The cup anemometer (Fig. 1 b) has a four-cup turntable on its axis and is used to measure speeds from 1 to 24 m/s with an accuracy of 0.2 - 0.5 m/s. Regardless of the direction of air movement, the turntable with cups always rotates in one side.
The axes of the anemometers are connected via a worm gear to counting mechanisms, which are switched on and off by lock 1 during measurements (Fig. 1). The dial of each device has three scales on which thousands, hundreds, tens and units of impeller revolutions are counted. Each speed determination device is equipped with a calibration chart.
Fig. 1. Vane (a) and cup (b) anemometers
Air movement speeds (less than 0.3 m/s), especially in the presence of multidirectional flows, are measured with electric anemometers, as well as catathermometers.
Instructions for working with anemometers
1. Record the initial readings of H 1 pointer on the anemometer dial (for example, 1255).
2. Install the vane anemometer in the air flow working area so that the axis of rotation of the impeller is parallel to the direction of flow
air. The cup anemometer is installed in the flow with the axis of rotation perpendicular.
3. After establishing a uniform speed of rotation of the impeller (cups) in the air flow (after about 10-15 s), simultaneously with turning the anemometer lock clockwise, turn on the counting mechanism and stopwatch.
4. 50 or 100 s after the start of measurement, turn the lock counterclockwise to turn off the counting mechanism and stopwatch.
5. Record the final position H 2 of the anemometer needle (for example, 1460) and the measurement time in seconds (for example, 50 s).
6. Calculate the difference in anemometer readings H 2 – H 1 (1460 – 1255 = 205).
7. Determine the number of axis revolutions per second (for example, H=205:50=4.1 rev/s).
8. Determine the speed of air movement according to the graph (Fig. 2) and enter the results into the table.
Fig.2 Calibration graph for cup (a) and vane (b) anemometers.
Air temperature and humidity when monitoring the air in the working area are determined using aspiration psychrometers(Assmann psychrometer), etc...
Separately, air temperature can be measured with mercury or alcohol thermometers, recording thermometers (thermographs), etc., and relative air humidity - hygrometers, hygrographs, electromoisture meters, thermal moisture barometers and etc.
The operating principle of an aspiration psychrometer is based on the difference in readings of dry and wet (wet) thermometers depending on the humidity of the surrounding air.
The device (Fig. 3) consists of two identical thermometers located next to each other, the reservoir of one of which is wrapped in a layer of fabric (cambric) and moistened before measurements. The evaporation of moisture from the cambric is accompanied by the removal of heat, so the readings of the wet thermometer are lower than the readings of the dry thermometer. A dry bulb thermometer shows the ambient air temperature. Wet thermometer readings depend on the humidity of the air being tested.
Rice. 3 General form(a) and circuit diagram(b) aspiration psychrometer: 1 – thermometers; 2 – protective tubes; 3 – fan: 4 – motor;
Mercury thermometers The psychrometers are enclosed in a metal frame, the thermometer reservoirs are located in double metal tubes, which eliminates the influence of thermal radiation and air speed at the measurement site on the thermometer readings. At the top of the device there is a fan with an electric motor or winding mechanism that draws air at a constant speed along the thermometer reservoirs.
The scale limits of dry and wet thermometers are from minus 31 o C to plus 51 o C. The thermometer division value is 0.2 o C. Measurement time is 3-5 minutes. Humidity measurement error + 5%, temperature + 0.1 o C.
Instructions for using the aspiration psychrometer
The device is installed permanently in a stand that imitates production premises and its reservoir is constantly wetted.
1. Turn on the toggle switch “psychrometer fan” - the electric motor of the fan.
2. Turn on the stopwatch and monitor the fan operating time.
3. After 3-4 minutes. After starting the psychrometer fan, take readings of dry and humid air, respectively.
4. Turn off the psychrometer fan.
5. Using the nomogram (Fig. 4), determine relative humidity air. To do this, restore the perpendicular to the x-axis at the point corresponding to the readings of the “dry” thermometer until it intersects with the curve corresponding to the readings of the “wet” thermometer. The resulting point will be the relative humidity value, the value of which is read on the ordinate axis of the nomogram.
Air temperature in production premises can be measured separately with mercury or alcohol thermometers of various types.
The intensity of thermal radiation (W/m2) is measured by actinometers or bolometers. .
The temperature of heated surfaces is measured by contact devices such as electric thermometers or remotely (pyrometers, etc.)
In this work, measurement of the intensity of thermal radiation and the temperature of heated surfaces is not provided.
Rice. 4 Nomogram for determining relative humidity
It will not be a secret to anyone that the cleanliness and saturation of pure oxygen in the air that is found indoors plays a huge role in a person’s well-being. If the climate in the house is too dry, then a person develops respiratory diseases. Too humid air promotes the spread of bacteria inside the body. The functions of climate control devices help combat all these factors.
What types of climate control devices are there on the modern market?
- Split system. This is the most common type of climate control devices that plays important role in creating an optimal indoor microclimate. It consists of two blocks: internal and external. The external unit can be installed on a balcony, roof, wall, attic or in utility room. Indoor unit installed indoors. A split system is designed for heating, cooling and air filtration.
- Humidifier. These types of climate control devices are necessary to maintain the required level of humidity in the house. No need to carry out special installation and the system can operate even in a confined space without causing discomfort to residents. On modern market There are both steam and ultrasonic humidifier models.
- Air purifier. It will help eliminate problems associated with removing dust particles. The system contains several filters that carry out cleaning, trapping particles harmful to the body. First, the air undergoes normal cleaning, after which it fights allergic particles. The carbon filter removes various gases, tobacco smoke and others unpleasant odors, after which the air spreads throughout the room.
- Air ionizer. After the air passes through air purifiers and air conditioners, it loses some of the particles needed by humans. This reduces productivity and leads to illness. The functions of climate control equipment - an ionizer - can correct the situation. It imparts ions to the air in concentrations similar to those found in mountains, forests and coastal areas.
- Air flavorings. If you want the room to always have a pleasant atmosphere, you need to use air fragrances. It works on the basis of cold evaporation, due to which pleasant odors enter the air without distorting the temperature.
As you can see, there are several types of climate control equipment, and each of them has a positive effect on human health and general condition. If you want to buy climate control devices, contact representatives of the SPETSOBORONA online store, who will select for you the optimal equipment that will meet your requirements, goals, preferences and financial capabilities. We offer only certified equipment that has passed all relevant tests.
A person’s well-being depends on the indoor microclimate. The microclimate of the room is determined by such parameters as temperature, humidity, air composition, and air movement speed.
Microclimate devices include:
Appliances for heating the home (electric convectors, electric fan heaters, electric radiators, electric fireplaces);
Electric fans;
Air conditioners, over-slab filters;
Electric humidifiers, air conditioners.
Electric convectors are a flat stamped box made of sheet steel, in the lower part of which there is a heating element; Warm heated air rises and enters the room through the outlet at the top.
Electric fans heat the room by forced convection and have a directed jet warm air and can be used for local heating.
Electric radiators combine convective and radiation (radiation) methods of heat transfer. There are “dry” electric radiators and oil-filled ones (sectional and panel type).
Electric fireplaces are devices that provide local heating due to infrared radiation, belong to the category of radiation electric heating devices.
As heating element an open or closed spiral is used in a quartz tube and heating element. Electric fireplaces have reflectors various shapes cylindrical, parabolic, spherical, etc.
Electric fans are classified:
By purpose - for supply, exhaust, supply and exhaust, for blowing, blowing and moving air;
According to the operating principle - axial, centrifugal;
According to the number of travel speeds - single-speed, multi-speed with stepped or smooth adjustment speed;
Depending on the installation location - floor, wall, universal, window, car, table.
Comfort level: normal and increased. Fans increased comfort must have at least two of the following devices: control device automatic rotation, a compartment for cleaning the cord, an automatic cord cleaning mechanism, a timer, a device for adjusting the height of the impeller, a circular rotation device and other additional devices.
Fans must have a reliable protective guard for the impeller. If the impeller is made of soft materials, then the fans may not have guards. The sound level of a running fan should not be more than 54-65 dBa, and of fans with a reversible electric motor - no more than 74 dBa.
Air conditioners. Overhead filters.
Air conditioners - multifunctional devices for cooling air, maintaining a given air temperature and reducing its humidity, for ventilation of the room, and purifying the air from dust. Air conditioners come with a split system (English) Split - divided into parts). A modern air conditioner is divided into two blocks - the internal one is located indoors, the external (external) is a noisy air conditioning unit, which is placed outside on the balcony. A multi-split system has several internal air conditioning units and can serve several rooms in a room.
Overhead filters and air purifiers are designed to clean the air from soot, dust, aerosols, and to neutralize odors. The filters have germicidal lamp for air sterilization. Air purifiers are divided according to the degree of purification and filter materials. They differ in service life and may have a negative ion generator.
Electric humidifiers and air conditioners
In winter, indoor relative humidity drops to 25%. Dry indoor air negatively affects people's well-being. To indoors
there was normal relative humidity (45-55%), air humidifiers were used.
Air conditioners are a type of humidifier. The air conditioner housing contains a fan, pump, water sprayer, and filter. The air is sucked in, cleaned of dust, cooled, humidified and released into the room. Air conditioners and humidifiers partially ionize the air. The presence of negative ions has a beneficial effect on the human nervous and vascular system. Negative air ions are the “vitamins of air”, they bring a feeling of peace and harmony. Air purifiers and humidifiers are especially necessary for bedrooms, children's rooms, and living rooms.
The climate complex is a universal electrical automatic device, designed to maintain the indoor microclimate. It is compact and portable. The device performs almost the same functions as an air conditioner, with the exception that it is not mounted in one place, which allows it to be moved. The complexes usually have a light weight of 5-9 kg and consume 60-120 W of energy per hour.
What does the climate complex do?
Indoor climate control systems can perform different functions depending on design features complex.
The most advanced devices have the following capabilities:
- Filtration.
- Ionization.
- Hydration.
- Heat.
- Drying.
- Cooling.
Complexes for microclimate regulation are very controversial equipment, which have varying degrees of efficiency in performing individual functions. In this regard, they cannot be considered an absolute panacea capable of maintaining ideal temperature and clean air in the room. Any air conditioner that has all 6 functions like climate systems can do this many times more efficiently.
Thanks to its light weight, the device is able to arouse interest among buyers who hope that the mobile station will be able to solve any tasks assigned to it, as is always stated in any advertisement for such systems. It should be noted that some functions of the device are absolutely ineffective, so you should not overpay for a complex with a full range of options.
Filtration
The air filtration function of the climate station really works effectively. The device is equipped with two or more filters. One performs coarse cleaning, and the second finer. Filter elements have a long service life. For premium segment stations it can be up to 7 years. It is possible to periodically clean the filters under running water or with a vacuum cleaner. For prevention, manufacturers recommend leaving filter elements in the sun for ultraviolet treatment, which will help destroy microorganisms accumulated in their pores.
In terms of filtration efficiency, climate control systems are inferior to air washers that pass air flow through water. At the same time, the stations are quite capable of reducing the actual dust concentration in the room. Often, many devices have a porous filter that is constantly soaked in water, the effectiveness of which increases many times over.
Ionization
Also, the climate complex may have a built-in ionizer. This function allows you to saturate the blown air flow with charged ions that attract dust. As a result, polluting particles stick together and become heavier. They settle on the surface in the room. Due to their heavy weight, they no longer fly off and cannot enter a person's lungs. This greatly increases the efficiency of actual filtration. In addition, thanks to ionization, it is possible to remove very fine dust from the air, which can even pass through a fine filter.
In terms of operating efficiency, the built-in climate station is in no way inferior to a free-standing similar device, which can be purchased at any store. household appliances. In this regard, purchasing a complex with this function is completely justified. Ionization can be turned on with a separate button, so if it is not needed, the function can be easily turned off.
Hydration
This expansion of the climate system is also quite effective. Air humidification occurs naturally. The device has a special container for refilling with water. A porous filter element is wetted in it, which is subsequently blown with air. As a result of the fact that it is wet, dust settles on it better, while at the same time effective evaporation occurs due to large area surfaces. In rooms where excessive dryness is observed, the use of a complex with the possibility of humidification will be a panacea.
If we compare the climate complex with separately standing humidifiers operating on a similar principle, then they work equally. In the same time ultrasonic humidifiers more efficient, but this technology is not used at climate stations. The vast majority of complexes provide continuous humidification while water is poured into them. It is impossible to disable it. This is due to the special porous filter material. When it is in a bath of water, it constantly draws moisture up.
More expensive complexes can automatically analyze the state of air humidity. When it is dry, a mini pump turns on, spraying a stream of water over the dry filter. This ensures controlled evaporation. As soon as the humidity reaches the set level, the pump is turned off and only normal air flow filtration is carried out.
Heat
The heating function is also quite effective. Typically, devices operate on the principle, since this is the most efficient technology that requires minimal power consumption. In this mode, the device uses the most electricity, but is still not able to fully heat the room if it is really cold. If the existing heating system cannot cope with the task, the climate control system can be used as auxiliary heating equipment.
It can also be used on cool evenings when heating season hasn't arrived yet. The device is quite capable of raising the room temperature by a few degrees, but nothing more. The heating function is quite rare, so the vast majority of stations do not work as a heating system.
Drainage
Many complexes can act as an air dehumidifier. Inside their body there is a special block, which, when blown, collects condensation. In fact, dew settles on it. Subsequently, droplets selected from the air flow into a reservoir designed to store water for the purpose of humidification. An air conditioner with a dehumidification function can often analyze the relative humidity and automatically maintain it at the required level.
The cost of universal devices capable of raising and lowering humidity is much higher than basic devices designed only for humidification and filtration. Into the room in which it is observed excess dampness, it is better to take a separate one that works on other physical principles, since the collection of condensate is not very effective method. Air conditioners that can dry the air also do this much more efficiently than climate control stations.
Cooling
The possibility of air cooling is the most controversial among climate control systems. The fact is that manufacturers of such equipment claim that it can fully replace a wall-mounted air conditioner. In fact, knowledge of the elementary laws of physics gives an absolute understanding that a system that is located in a closed space without the possibility of removing heated air is unable to lower the temperature in the room as a whole.
The operating principle of the climate control system cooling is quite simple. Temperature reduction is carried out only when humidifying. The wetted filter element is blown with air, resulting in evaporation of moisture. As you know from a physics course, the transition of water molecules from a liquid to a gaseous state is accompanied by the consumption of heat. Thus, the device body becomes colder, so the climate control system blows out air at a slightly lower temperature than it absorbs.
Cooling as a result of water evaporation is barely noticeable, which is why full-fledged air conditioners use freon, which provides more efficient cooling.
The fact that climate stations use water is not their main disadvantage. The fact is that to ensure evaporation, the device produces more heat through the fan motor than it actually produces cold. With air conditioners, this is solved by venting the hot air released to the street. In the case of climate control systems, this is impossible, since they are not structurally provided with a ventilation pipe.
Climate complex in best case scenario will leave the actual temperature in the room at the same level, and if the fan is not of sufficient quality, then after a few hours the room may become even warmer. Moreover, if you direct the air escaping from the device towards yourself, you can quite feel the coolness. If you substitute a thermometer, you can see that along the trajectory of the blown flow the temperature is 1-2 degrees lower.
To solve this problem, many manufacturers of climate systems offer cold accumulators included with them. These containers must first be kept in freezer, then place it in the station’s water tank. In this case, cooling will be much more efficient.
But from the point of view of physics, in order to cool the cold accumulator, the refrigerator will make a directly proportional release of heat in the kitchen. Thus, there is no point in overpaying and buying a complex with a cooling function, hoping that it will replace the air conditioner. Of course, if you rely on it to work only as an efficient fan, then the device can really live up to expectations.