Which type of cooling tower is best?
their design flexibility and cost effectiveness, make mechanical draft cooling towers ideally suited to most cooling duties and plant requirements. Unlike natural draft cooling towers, these towers use fans to circulate air through the tower. Propeller fans and centrifugal fans are most often used.
What two types of fan are used for cooling towers?
Propeller or centrifugal fans are used to circulate air inside the tower. These are much smaller in structure than natural draft towers. Capacity control is easy in these types of towers since the speed of the fan can be controlled. Unlike natural draft towers, these can be located anywhere inside the building.
What are the three types of cooling towers?
There are three main types of cooling towers that are defined by how water or air pass through them. These types include crossflow, counterflow, and hyperbolic. There are also two varieties classified solely on airflow, known as induced draft and passive draft cooling towers.
What is the efficiency of cooling tower?
The temperature difference between inlet and outlet water (ti – to) is normally in the range 10 – 15 oF. The water consumption – or the amount of make up water – of a cooling tower is about 0.2-0.3 liter per minute and ton of refrigeration.
Are cooling towers dangerous?
Cooling towers can be breeding grounds for potentially deadly Legionella bacteria without proper cleaning and maintenance. Dirty cooling towers can be deadly. In July, an outbreak of Legionnaires’ disease in New York sickened 27 people and led to one death.
What is the working principle of cooling towers?
Air enters the tower beneath the fill and is drawn up vertically into the tower. Above the fill, hot water is introduced through low pressure spray nozzles to divide the hot water over the surface of the fill in fine droplets. The cooling air draws heat from the water as it progresses to the bottom of the tower.
How do cooling towers reduce water temperature?
The decrease in the outlet water temperature by using water path cooling is proved by the conventional heat transfer formulae. The second method deals with the decrease the liquid to gas flow ratio(L/G) by increasing the air velocity with the help of cylinder blocks near the louvers of cooling tower.
What causes a cooling tower to overflow?
After water passes through the tower, it collects in the basin and returns to the circulating pumps. If the water level is too low, the pumps suck in air. If the water level is too high, the water overflows, creating roof damage and possible leaks.
What is the lowest temperature a cooling tower can produce?
In colder climates, many designers and operators are concerned with operating cooling towers in subfreezing temperatures. By following some simple operating guidelines, cooling towers can and have been successfully operated in very cold climates (-15°C / 5°F) as shown in the photograph at right.
What causes scaling in cooling towers?
Scale deposits form when the solubility of dissolved minerals in the cooling water is exceeded. Cooling towers function by evaporating a percentage of the water into the atmosphere. This water is “pure”, and does not contain any of the dissolved minerals found in the makeup water.
What is difference between scaling and fouling?
When cooling systems operate, water with fouling factors flow through the system: Hard water causes scaling, whereas seawater can cause biofilm, or growth of micro and macro species. Soft at first, fouling becomes hard if not treated and prevents the proper operation of the system.
What are spray nozzles used for on a cooling tower?
Spray nozzles with plate are used to distribute water in wet cooling towers. Cooling towers are evaporative heat rejection devices, which take out the waste heat to the atmosphere through the cooling of water by the air.
Why are biocides added to cooling tower water?
Biocides are used to control bacteria in cooling water systems. Failure to implement a good cooling water biocide program may lead to bacteria and under deposit corrosion. Under deposit corrosion occurs when bacteria occurring within the water system. Under this bacteria, corrosion occurs.
What is the pH of cooling tower water?
7.0
Which chemical is used in cooling tower?
Organic dispersants – These cooling tower water treatment chemicals can be used to prevent fouling and the accumulation of biofilms. Chlorine dioxide – This chemical can be used as a disinfectant to destroy microorganisms and prevent recurring growth.
What is a non oxidizing biocide?
Non-oxidizing biocide chemicals work through various exterminating processes such as interfering with reproduction, stopping respiration, or lysing the cell walls. Non-oxidizing biocides can be or fed continuously to achieve a high enough concentration for a long enough period of time to kill the bacteria.
How does non oxidizing biocide work?
A fast-acting, non-oxidising biocide formulation containing DBNPA, with a broad spectrum of activity. A liquid biocide often described as a stabilised blend of Hypochlorite and bromide salts. Controls bacteria and other organisms in recirculating cooling water, pasteurisers, air washers and other heat transfer systems.
Is hydrogen peroxide a biocide?
Hydrogen peroxide is extensively used as a biocide, particularly in applications where its decomposition into non-toxic by-products is important. Few studies have investigated membrane damage by hydrogen peroxide, though it is suggested that this is important for the biocidal mechanism.
How do you make biocide?
When added in small amounts to pool water or industrial water systems, the chlorine atoms hydrolyze from the rest of the molecule forming hypochlorous acid (HOCl) which acts as a general biocide killing germs, micro-organisms, algae, and so on. Halogenated hydantoin compounds are also used as biocides.
Is a disinfectant a biocide?
Biocides are commercial products used to kill or control the spread of harmful microorganisms like bacteria and viruses. Biocides include antiseptics and pesticides (e.g., disinfectants, preservatives, herbicides, fungicides, and insecticides).
What’s the difference between biocide and Biostatic?
Biocide agent is any substance that can destroy living organisms. Biostatic agent inhibits further growth of an organism without killing it. As long as the bacterium is exposed to the biostatic agent, biostatic fabric or biostatic fiber, the bacterium will not be able to proliferate.
What is the difference between a biocide and a disinfectant?
As adjectives the difference between biocidal and disinfectant. is that biocidal is able to kill living organisms, especially microorganisms while disinfectant is referring to something that contains a disinfectant or has the properties of a disinfectant.