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Outdoor air conditioners for foggy cooling of terraces. Mist cooling system. I. High pressure fogging

  1. I'll be wet, it won't work for me or it will work for me. Fogging systems were originally designed to cool open areas, i.e. for outdoor work. Since the principle of the cooling system is based on a phase transition between the liquid and gaseous state of water, two main factors must be taken into account for successful cooling. Air temperature and relative humidity (air saturation with water vapor). Most important factor- this is the possibility of air-exchange, if the room is completely closed without forced ventilation, the fog cooling system will saturate the air with moisture after a while, the water will stop evaporating and the cooling effect will completely disappear. If the room is sufficiently open or has a forced ventilation system, then the fogging system can be adapted for the most productive cooling. Summing up, if someone gets wet from the mist system, then this indicates that the system is not properly designed or operated incorrectly. As an example, the fogging system, without any noticeable humidification, worked in closed exhibition centers, and at a temperature environment about 23 ° C significantly reduced the temperature.
  2. The misting system is an outdoor air conditioner. Indeed, the mist cooling system is designed to cool the air in open spaces, but it has a number of differences with the usual air conditioning system. First, the mist cooling system is an open system, i.e. the refrigerant (in our case, water) evaporates not in the closed volumes of air conditioner evaporators, but directly in the places where people stay, so such a system needs a continuous supply of water. Secondly, fogging systems cannot be programmed to a certain temperature, for example, 23 degrees as we are used to with conventional air conditioners, such cooling systems are controlled by timers and regulate the operating time and pauses of the fogging system, you just need to get used to such control. But instead of a conventional air conditioner, we get a very environmentally friendly system for creating a favorable microclimate in a given area. The fog cooling system will not only reduce the temperature, but also reduce dust, raise the humidity level to a comfortable level, eliminate or significantly reduce the number of flying insects, eliminate unpleasant odors. It will create a so-called comfort zone, and in any case, nothing better has yet appeared on the market for cooling open areas.
  3. Fogging systems low pressure it is cheaper and not inferior in efficiency. Logically, if there are simple cheap low pressure fogging systems, then why produce noisy expensive high pressure fogging systems. The answer is simple low-pressure fogging systems (working pressure from 1 to 25 bar) are mostly created on the basis of spray discs or nozzles with a large outlet, and such technologies do not allow obtaining a drop smaller than 25-40 microns. This droplet size effectively evaporates at an ambient temperature starting from about 40-43 ° C, at more low temperatures such systems work more to moisten surfaces. High pressure misting systems (working pressure from 65 to 80 bar) create a droplet with a size of 5 to 15 microns. And as I already wrote, they can be used at an ambient temperature of 23 ° C and above, it all depends on the configuration and settings of the system. Draw your own conclusions.
  4. High-pressure misting systems increase their efficiency when the pressure is greater than 100 bar. This is not entirely true, or rather not at all, in fact it is important lower limit pressure, i.e. if the pressure gauge on your fogging system is over 60 bar. Then you can be sure that your system is working normally, and the droplet size does not exceed 7-15 microns, which is very good. The optimum pressure for fogging systems is 80 bar (droplet size 7-10 µm.). With increasing pressure, the droplet size does not change significantly, but the amount of water passing through the nozzle per unit time increases. Thus, if you are offered a 100 bar pump. At a price higher than the 80 bar pump. It's just a waste of money.
  5. Curtain or not curtain, how to properly design the misting system nozzles? In fact, there are no certain dogmas and rules by which you can place the nozzles of the fog cooling system or use fogging fans. In each specific case, the designer proceeds from the realities of your object. A lot of factors are taken into account, for example: the material of the roof, if any, the configuration of the room, the number of open and closed walls, the height of the ceilings, the general ventilation of the room, interior elements ( lighting, decorative ceiling coverings, suspended or high-standing flowerpots, etc.), outdoor decor elements, mounting options, fogging systems, removal of the cooling object from the possible installation of a high pressure pump and many different little things and nuances. Only by fully analyzing all possible factors can the maximum efficiency of the fog cooling system be achieved.
  6. Why do you need a timer. The timer is the only device for changing the operating mode of the fogging system. The timer, by changing the operating time and pause, allows you to significantly expand the temperature and humidity range of the fog cooling system. For example: in the morning the air temperature is still not too high, but it is already getting hot, the fogging is too dense and excessive humidification is obtained, the fog cooling system without a timer will have to be turned off, but if your "outdoor air conditioner" is equipped with a timer, you can set the operating and pause times and continue to enjoy the established pleasant microclimate. The same can be said about hot but cloudy days with high humidity air.
  7. A nozzle broken by high pressure can fly off and injure. This is not true, since street air conditioning systems have a very small water intake, even with the smallest water leakage that appears when the nozzle cracks and breaks, the pressure in the system drops with lightning speed, as a result of which the nozzle cannot fly anywhere, let alone injure someone.
  8. Fogging nozzles are afraid of "salted water". It all depends on the degree of salinity, if sea water is supplied, then most likely the pump will fail quite quickly. If we talk about well or tap water, then for 6 years there has not been a case of irretrievable failure of the elements of the fog cooling system. If the fogging system is supplied with well water without softening, and the water is sufficiently strongly saline, then during the conservation of the system it is necessary to rinse it with purified water. Although there was a case when, despite our recommendations, the nozzles, after the end of the operating season, were left without flushing until next summer. It should be noted that the "street air conditioning" system worked from a well with a high level of salts. At the start of the system, out of 35 nozzles, 3 worked. But as a result of simple manipulations with vinegar and toothpicks, an hour later the system worked at the proper level. With tap water no such cases were observed.
  9. The fogging system can be heated if applied to the input of the system hot water. This is not so, even if hot fine dust is sprayed at a low air temperature, since hot water needs much less energy for a phase transition and the air is quite dry, the water will still evaporate, which will lead to cooling, or at a very low temperature to crystallization, that is snow will fall. But one thing is for sure, the high pressure pump will fail very quickly, since the plunger block is cooled by water passing through it, and if hot water is supplied, the pump will overheat and break.
  10. Mobile or stationary fogging system. The biggest disadvantage mobile system mist cooling is its price. A mobile module costs an average of 60-80% more than its stationary counterpart. Meet budget options mobile "cooling-moisturizing" systems, these are usually low-pressure disk systems, they are mentioned above. There are also mobile cooling modules made in the east, such systems are much cheaper than European and American counterparts, but if we compare the cost of eastern stationary fogging systems with mobile systems of the same name, then the price proportion will remain. Usually, expensive quiet ones are used in mobile systems manufactured in Europe or America. high pressure pumps, i.e. Eastern manufacturers do not care about reducing background noise, which is the reason for the significant difference in price between brands. However, the noise factor of a mobile system has great importance. If the high pressure pump of a stationary system can be hidden in technical room away from the zone of direct use, the mobile cooling unit will make noise near you.

FOG COOLING SYSTEMS




Fog cooling systems are used to reduce the temperature in open spaces where the use of air conditioning is impossible or inefficient: on the verandas of restaurants, cafes, tennis courts and patios.



With the help, you can create the microclimate necessary for plants in greenhouses, maintain the humidity required for the production cycle, create favorable conditions for storing food in warehouses, cool animals, birds, and much more.










In factories where running machines generate a lot of heat, systems evaporative cooling used for air humidification and cooling industrial premises, create a barrier to dust and odors.


In enclosed spaces, you can automatically maintain the desired humidity. Due to the high pressure (70 atmospheres), the water drops sprayed from the nozzles have a size of about 6 microns. Droplets of this size instantly evaporate into the air. Evaporating, water cools the air, creating a “natural” coolness. In enclosed spaces, the unit creates a fine mist without creating puddles on the floor.


It is important that the rooms where the fog cooling system works have a minimum humidity. This affects the efficiency of the system. Especially often high humidity is the cause of the broken waterproofing of the room.



nozzles









Mist cooler nozzles are made of 316L stainless steel and the body is made of brass or stainless steel. Main characteristic nozzle is the diameter of the outlet from which water is sprayed. Nozzles with holes are produced: 0.1mm; 0.15mm; 0.2mm; 0.3mm; 0.4mm; 0.5mm; 0.6mm; 0.7mm.


The most commonly used are nozzles with a hole diameter of 0.2 and 0.3 mm. Nozzles of these diameters work at relative humidity up to 80 percent. Smaller diameter holes create smaller water droplets, which contributes to their rapid evaporation and cooling of the air without a significant increase in its humidity.


If the humidity of the air to be cooled is not very low, smaller nozzles should be used. For very low humidity, use larger nozzles.


If you have high-quality water, use nozzles of a smaller diameter. With lime water, larger nozzles should be used.









In order to prevent the water remaining in the pipeline system from dripping from the nozzles when the pump is turned off, a special ANTI-DRIP mechanism has been developed. Its essence is that in the absence of pressure in the system, a spring with a rubber cap at the end closes the outlet of the pipeline and water cannot penetrate into the nozzle channels. This mechanism is convenient when the nozzles are on the ceiling.


Please note that not all nozzle models are equipped with this mechanism. Some systems have special nozzles or tubing for quick drainage in case the system is turned off.












Fitting



Fittings for the mist cooling system are made of brass or stainless steel (ss304, ss316) and are used to attach nozzles to them and connect tubes (tubings) through which water flows. Each fitting is equipped with a SLIP-LOCK mechanism, thanks to which the attachment of tubing to it becomes quite simple and does not require special tools. The thread on the fitting is designed for a specific nozzle, and its inlet and outlet - for a specific diameter of the tubing.











Mist cooling systemusing fittings of various diameters










Tubing-fitting adapter.








Tubing nozzle adapter.











Tubing-pipe adapter.





Plastic clips and clamps with a rubber gasket are used to fasten the tubing to the supporting structures. Special scissors are used for cutting tubing.














High pressure pumps



The pump in the mist cooling system is designed to create a water flow with a pressure of 70 bar (atm.). It is at this pressure that the water droplets ejected from the nozzles of the nozzles are small enough to cause their instantaneous evaporation.


Available or under the order there are pumps of a high pressure with a productivity from 1 to 87 liters a minute. The pumps used in these systems are volumetric (volumetric), i.e. when the operating pressure is increased or decreased, the water flow for which the pump is designed does not change. There are pumps with a variable water flow of 2-10 (10-25 and 20-45) liters per minute.



The number of nozzles that the pump can work with at a pressure of 70 bar



The operating water pressure at the inlet to the pump must be between 1 and 5 atmospheres (bar). High pressure pumps are designed for pumping clean water with a temperature not exceeding 55 degrees Celsius.


The pumps are volumetric, so they must use at least 60% of their standard capacity. For example, if the pump is designed for a water flow of 10 liters per minute, then the minimum throughput of the nozzles should be 6 liters per minute.









If for some reason the total water consumption of the nozzles is below this value, then unloading (outlet) nozzles should be used. For example, this green color coded atomizer has a bore diameter of 1.4mm. and is capable of passing 9.6 liters per minute at a pressure of 70 bar in the system. Thus, it is able to make up for the lack of 128 nozzles with a nozzle diameter of 0.2 mm or 91 nozzles with a nozzle diameter of 0.3 mm in the system.








For greenhouses, the system can also be equipped with humidity sensors that will turn off the pump when a certain level is reached and turn it on again when the humidity drops below a predetermined threshold.









Filters


The filter is a mandatory element of the system. Filters are installed before entering the pump and serve to purify water from contaminants that can clog nozzle nozzles.


The system can have up to three filters that purify water from particles with a size of 20 microns, 10 microns and 5 microns. A low-pressure manometer is installed at the filter outlet (for systems of two or three filters, manometers are installed at the inlet and outlet). For systems pumping small quantities of water, e.g. 1 l/min. You can put one filter 5 microns. with outlet pressure gauge.


The operating water pressure at the pump inlet is 1-5 bar (atm.). If there is working pressure at the filter inlet, and the pressure at the filter outlet drops to 1 bar (atm.), it means that the filter is clogged and the cleaning element needs to be changed.














Assembly


To connect fittings and tubing in the system, special SLIP-LOCK locks are used that do not require the use of any third-party tools (clamps).



  • cut the tubing to the desired length with special scissors

  • insert the tubing into the fitting until you feel a slight resistance

  • continue by adding some pressure and turning the tubing slightly

  • make sure the tubing has reached the stop


Disconnection(Disassembly)



  • hold the end of the fitting with your thumb and forefinger

  • without using any tools, pull out the tubing with the other hand

ATTENTION! Use only semi-flex tubing. Rigid tubing can damage fittings.

Universal remedy

In the water well known to all of us lurks a large number of energy, and if you skillfully extract it, you can get significant benefits. When water changes from its liquid state to a gaseous state, heat is absorbed. And the more it needs to be taken away, the more liquid needs to be evaporated.

Air cooling and humidification by special systems is widely used to create pleasant coolness in sports grounds, in restaurants, etc., humidifying the air of various working areas, eliminating odors, reducing the risk of fire, etc. Fogging is used in summer cottages, in animal husbandry and crop production, and in various industries. It perfectly allows not only to create the necessary microclimate, but also to control it precisely in those areas where people work and where it is necessary to observe whole line work safety requirements. At temperatures in the workshops, sometimes reaching up to +40 °C, workplaces are cooled. Despite the fact that all this requires the use of negligible energy, the effect obtained from cooling is impressive.

The artificial formation of fog allows you to avoid overheating of work surfaces at low financial costs. Partial (or around the entire perimeter) installation of such devices in a residential complex located along a dirt road, a busy highway, reduces the amount of exhaust gases and dust. These systems literally allow you to breathe easily and freely.

Insufficient humidity of the ambient air or changes in its indicators, for example, in a printing house, also entail changes in the linear dimensions of cardboard and paper, as well as binding materials. As a result, there is a discrepancy in colors, inaccuracies in folding and embossing, cutting and gluing, and other printing operations. Moisturizing successfully helps to avoid all these troubles.

The economic performance of livestock farms depends on the state of health of animals and their well-being. Artificial fogging, widely used together with the ventilation system, creates more comfortable conditions for animals and contributes to increased economic benefits.

When storing herbs, vegetables and fruits, the use of special equipment helps to increase their shelf life and allows you to get a higher income.

The ability to add special reagents to the water sprayed by the device with the help of dispensers helps to successfully fight rodents and insects.

In winter, inside the suburban wooden house when active heating system, air exchange is slowed down. Installation of equipment for the formation of fog allows you to soften and humidify the air. Misting systems help to control midges and are also able to suppress the development of various pathogens, they are effective in eliminating odors generated during the processing of solid waste, etc.

Dust, which has become an unfortunate inevitability in almost all warehouses, is eliminated during fine spraying. On the paint and varnish industries with the help of such systems, the amount of harmful volatile compounds can be significantly reduced.

Ordinary air conditioners cannot be compared with the effect of the use of foggers, since air conditioners only cool indoor spaces, and all attempts to operate them outdoors are doomed to failure.

The work of fogging systems is to produce water droplets small size which evaporate very quickly. At the moment of saturating the surrounding air with moisture, fog appears

Simplicity and accessibility

The job of fogging systems is to produce small water droplets that evaporate very quickly. At the moment of saturation with moisture of the surrounding air, fog arises. Depending on the settings, it can be light, almost invisible, or, on the contrary, swirling and thick. Its concentration directly depends on the size of the droplets formed: the larger they are, the denser the resulting foggy curtain is.

It is known that in order to start the evaporation of water, it is necessary to use a sufficiently large amount of energy - up to 600 cal of heat per 1 g of liquid, and the "disappearing" drop takes part of the heat from the air. This is how it cools and hydrates. The efficiency of the system is affected by humidity and temperature indoors or outdoors. The system can create and maintain a given relative humidity. Its optimal indicator, necessary for normal human life, is in the range of 40-55%.

For the production of artificial fog, a special engineering installation is used. The set of equipment includes a high-pressure pipeline, a pump, special nozzles, a water treatment system, as well as automation.

The plunger pump or units developed on its basis can rightfully be called the "heart" of the entire system. The operating pressure of the system at the moment the pump is turned on is 60-80 atm. If it is less, the valves will not be able to open. One such pump can simultaneously serve several nozzles on the line.

Today the market offers a lot of pumping units used in fogging systems. Their main difference is the indicator of the pumped liquid per minute (from 0.6 to 25 l). When servicing a large area, more efficient devices are also installed, and in everyday life simple models are quite effective, allowing pumping from 0.6 to 1 liter of liquid per minute. The installations are quite large.

AT country house they are mounted in a special technical room, where, as a rule, engineering equipment. It is important to remember that the determining conditions for installing the pump are positive air temperature and the ability to connect the device to the mains and water supply. Pumping units can be additionally equipped with an automatic timer.

nozzles

These devices are classified according to one indicator - the diameter of the outlet (from 0.15 to 0.5 mm). This parameter determines the nature of fogging depending on the size of the water drop. In open and closed spaces, nozzles with different outlet sizes are used. So, for example, if it is necessary to humidify residential premises, nozzles with a hole of 0.15 mm should be mounted, which produce droplets ranging in size from 1.2 to 37.9 microns. These nozzles are ideal for residential applications where very low water consumption and minimum humidity are required, as well as complete evaporation. Nozzles with an outlet size of 0.2 to 0.5 mm are mounted in systems for cooling and humidifying large open spaces. They can be a garden, greenhouses, verandas, etc., where air exchange is more intense, and the evaporation of drops is more efficient.

When installing household fogging systems, as a rule, copper nozzles with a stainless coating are used, and in winter gardens, greenhouses or conservatories, where it is supposed to use a fogging system and for spraying fertilizers, industrial nozzles made of stainless steel are installed, which last much longer and can be used in aggressive environments

The small orifice of the laser-produced nozzle requires the use of a demineralized liquid, otherwise clogging of the orifice with salts and impurities, its failure, and general failure of the installation is inevitable.

Of course, the filter will not get rid of calcium salts that fall on furniture and interior items with an unpleasant white coating. Therefore, when humidifying residential premises, it is necessary to install reverse osmosis. It will reduce the content of dissolved salts. The filter type is selected after analyzing the composition of the water supplied to the pump.

However, practice shows that for smooth operation it is necessary to install at least one filter that retains mechanical impurities.

Pipeline

For optimal organization of the high-pressure piping system, nylon or copper tubes with a stainless coating and a diameter of %". Metal, although more expensive than polymer, is worth it. During high pressure water supply, it will not bend and deform, such as nylon. The risk of a defect in a high-pressure pipeline made of metal is minimal, therefore its use in indoor fogging systems is preferred.Nylon will the best option for a long pipeline on the street.

A wide range of fittings and connectors allows you to technically solve any installation tasks. Fittings can withstand the pressure that is injected by any pumping stations to generate fog, regardless of their power.

Automation

Basically, the systems are equipped with automatic regulation, which allows you to minimize water consumption and create an optimal microclimate. It can turn it on and off, for example, every 10 seconds, which is physically impossible to do manually.

Such a system is controlled using a timer or controller, in which the program independently turns on or off the pump at specified intervals, as well as depending on the actual air humidity and its temperature. The mode of operation of the system can be built into the so-called "smart home" system, while fogging receives advanced control capabilities.

It should be noted that a complete set of equipment allows you to solve any problem - even set by the most demanding client. The standard system installation scheme is reduced to the installation of two high-pressure pipeline lines. The first is mounted in the house, the second is installed on the street. In winter, only one first line works, and in summer the second one also turns on.

The small orifice of the laser-produced nozzle requires the use of a demineralized liquid. But filtration will not get rid of calcium salts that fall on furniture and interior items with an unpleasant white coating. Therefore, when humidifying residential premises, it is necessary to install reverse osmosis.

Only one pump is needed to operate such a circuit. The assembly of the pipeline is simple, and it is quite possible to install the system on your own. Before the offensive winter period the street pipeline is freed from water, purged and, as a rule, dismantled.

In the spring it is collected again. It is necessary to periodically replace the cartridge in the filter, and change the oil in the pump itself once every few months. No other additional maintenance of the fogging system is required. It is very important that these devices are completely safe for humans and the environment. The pump of the system is placed in an anti-vandal housing. It is equipped with automation, and at the moment of stopping the water supply, it automatically turns off. Anti-drip valves do not allow the water remaining in the pipes after shutdown to leave the nozzle.