Drift eliminators are also known as mist eliminators. Cooling tower performance basic theory and practice subject. Cooling tower efficiency calculations cooling tower approach. Protection of workers from exposure to biological and chemical hazards within the cooling water system. The present paper is a detailed methodology for thermal design of cooling tower. Conductivity trend for manual or timed blowdown control. As evaporation continues, the water becomes more concentrated than the original make up water. Minerals can form deposits or scale on the tower materials. Tower water must also be evaluated for solids and mineral content. Cooling tower discharges present a potential problem to the treatment of sanitary sewer and sludge quality especially for the biosolids reuse facility. Legionella bacteria in cooling towers a copy of the document is available. Best management practice and guidance manual for cooling. We are a nonprofit group that run this website to share documents.
Chalk point cooling tower project, volumes 1 and 2, jhu ppspcpctp16. According to them, the design of cooling tower is affected by tower characteristics and different types of losses generated in cooling tower. Scribd is the worlds largest social reading and publishing site. However, due to variations in the water source and their operating in an open environment, cooling towers are subject to four major water treatment concerns. As with biological growth, sedimentation and scaling of tower surfaces reduce the overall heat transfer coefficient and the cooling capability of the tower, as illustrated in figure 2. Which cooling tower is best for tropical climates the climate conditions can somehow affect the performance of cooling towers due mainly to the fact that they make use of the surrounding air as well as water supply to do their job. Research article thermal design of cooling tower ronak shah.
It accomplishes this by providing intimate mixing of water and air, which results in cooling primarily by evaporating approximately 1 % of the flow for each 10. These towers utilize large fans to force air through circulated water. Regular manual logging of water consumption and conductivity data of cooling. If not already known, determine the value of water used in your cooling towers and evaporative condensers. Department of energy idaho operations office idaho national engineering laboratory this is an informal report intended for use as a preliminaryor working document work supported by the u. Cooling is accomplished through the latent heat of vaporization. Large volumes of air flowing through the heat transfer media help increase the rate of evaporation and cooling capacity of the tower. The technical data is taken for mechanical draft cooling tower. Understanding key components of cooling towers and. Vibration monitoring of cooling towers applications cooling tower fans have uses in multiple industries.
This manual is not intended to be all encompassing and thoroughly definitive. Method for analysis of ultimate heat sink cooling tower. Water treatment for cooling towers 1 of 2 email a colleague. They can act as heat exchangers for chiller systems in heating, ventalation, and air conditioning hvac applications, or they can be used in heat exchange processes in other industries such as power generation, manufacturing, and in. Dec 25, 2011 a cooling tower is an equipment used to reduce the temperature of a water stream by extracting heat from water and emitting it to the atmosphere. Other factors, which we will see, must be stated along with flow rate m3hr. Range range is determined not by the cooling tower, but by the process it is serving. Chiller vs cooling tower we often get the question as to when to use a chiller andor cooling tower for process cooling.
Al photograph of the keystone power station a2 a2 cooling water schematic for keystone station a4 a3 evaporation losses from cooling tower a6 a4 the effects of wet bulb temperature and a relative humidity on density difference driving force bl the helicopter used for aerial sampling b3 b2 sampling probe and interior installation of. A cooling tower is a specialized heat exchanger in which air and water are brought into direct contact with each other in order to reduce the waters temperature. Cooling tower control problem by james mcdonald, pe, cwt originally published. Cooling water systems an overview of cooling towers 2012 instructor. Today we are going to talk about how you can choose the right cooling tower system for areas with tropical climates. Concentration concentration is the increase of impurities in the cooling water due to the evaporative process. Cooling tower cycles of concentration as pure water is evaporated, minerals are left behind in the recirculating water. Cooling tower process tower basin distribution deck basin tower fill induced draft fan recirc pump return water supply water a tower cools water by evaporation by drawing high volume air across the water surface, which transfers heat to the atmosphere. Air pendingin cooling water makalah disusun untuk memenuhi tugas mata kuliah. The hybrid cooling tower is a combination of the advantages of a wet and a dry cooling tower. If your requirements are for 90 deg f 32 c then you most likely need a cooling tower or fluid cooler. Design of mechanical draftcooling tower and determination. Water vapor evaporates, leaving dissolved or suspended solids in the recirculating cooling water. Cooling tower fill is the main heat transfer area available for heat transfer from hot water to cold air.
Cstn september 2002 a client had a large, threecell cooling tower system that was having problems maintaining conductivity. The method allows analytical calculation of cooling tower. At these condi tions, the cooling tower rejects 15,000 btuih per nominal cooling tower ton. A cooling tower is an equipment used to reduce the temperature of a water stream by extracting heat from water and emitting it to the atmosphere. They are located in areas that are situated after the fill and water sprays and just before the area where the air exits the cooling tower see figures 6 and 8. Technical reference for water conservation in cooling towers pub. Intent in the foreword of cooling tower fundamentals published by marley cooling technologies, inc.
Design of mechanical draftcooling tower and determination of. Rp m 2 rp m 1 cfm 2 c fm 1 staticpressure 2 static pressure 1 cfm 2 cfm 12. For example, excessive water flow, excessive airflow, and water bypassing the tower drift. For extended lifts over 25 feet in height, use fabric slings underneath the cooling tower and. Cooling water systems an overview of cooling towers. The easy answer is what temperature waterglycol do you need. Cooling tower fill is the main heat transfer area available for heat transfer from hot. Reducing water use in cooling towers and evaporative condensers. A nominal cooling tower ton is defined as cooling 3 gpm of water from 95f to 85f at a 78f entering air wetbulb temperature. See the more detailed explanation of cooling towers systems. In a welldesigned and welloperated power plant, the condenser cooling system has an important role in the generating capacity and efficiency of the plant. Cooling tower basics and common misconceptions introduction in comparison with most other industrial equipments, the water cooling tower is a simple device, based on the direct contact of two of the earths most common substances. Natural draft designs use very large concrete chimneys to introduce air through the media. Preventive maintenance program and plan for cooling towers.
Inadequate flow rates downcomer flow rates can be so low, relative to pipe size, as to allow air to enter at the pipe discharge. With air flow rate, cooling tower performance increases. In a welldesigned and welloperated power plant, the condensercooling system has an important role in the generating capacity and efficiency of the plant. The below writeup identifies accepted guidelines for. Cooling towers can be split into two distinct categories. Cooling tower location must prevent cooling tower discharge air from entering the fresh air intake ducts of any building. In every application the target portion of the nozzle should be located at the correct distance above the top of the cooling tower fill to obtain maximum. This document was prepared as an account of work sponsored by the united states.
Chapter 8 cooling towers system shutdown and startup. Effective thermal design of cooling towers a stepbystep approach to cooling tower design, with an example calculation to make it clear jonny goyal air liquide engineering and construction, lurgi india various misconceptions arise when it comes to the thermal design of cooling towers. Tower maintenance and operation levels also can influence the formation of drift droplets. Cooling tower pumping and piping bottom vented downcomer. A cooling tower is a heat rejection device which rejects waste heat to the atmosphere through the cooling of a water stream to a lower temperature. Cooling tower fill is typically arranged in packs of thin cormgated plastic sheets or, alternately, as splash bars supported in a grid pattern. Alternative water treatment technologies for cooling tower. If your requirements are for 90 deg f 32 c then you most likely need a. Cooling tower systems operation is most efficient when their heat transfer surfaces are clean.
If it is not available it may be assumed as for natural draft cooling tower d 0. Cooling tower performance calculations are usually performed numerically. It must also provide the energy head necessary to raise water from a low to a higher static head level. For the tower piping circuit, the pump must overcome the piping flow friction loss. The cooling tower had two possible makeup water sources. The three basic requirements set forth in that document. In this paper, a simple differential equation for counter flow wet cooling tower is solved analytically taking into consideration the nonlinear dependency of the saturated air enthalpy on temperature. Mechanical draft cooling towers are much more widely used.
F o r m u l a s a n d t a b l es formulasandtables fanlaws. Department of energy assistant secretary for resource. The hybrid cooling tower can serve not only as a dry heat exchanger but also as a wet cooling tower. The term cycles of concentration compares the level. Splash fills disintegrates the hot water from vertical direction and it splits the. Jea, as the control authority, is required to regulate cooling tower discharges to the potw. If you read this book carefully, you can make any cooling tower design programs by yourself. Theory of cooling towers cooling towers fall into two main subdivisions. For modern, highefficiency cooling towers, drift is about 0. Water pipes are used in circular shape due to shape of the cooling tower is circular and circular shape is also beneficial for smooth flow.
Again, this will be a first issue releasing the actual engineering approach. The major concern during i study the cooling tower theory was how to computerize the cooling tower theory from the calculation of ntu to the cooling tower performance analysis. The fanlaws can be used topredi ctthe pe rformance ofa towerwitha nonstandard motor. Confidential cooling tower drift test report, midwest research institute, kansas city, mo, november 1983. Cooling tower system means one or more cooling towers and all of the recirculating water system. Lockout of fan motor and circulating pumps during inspection and maintenance. This section provides an introduction of cooling tower designs. Consider the space between adjacent two water pipe is 0. Cooling tower means a cooling tower, evaporative condenser or fluid cooler that is part of a recirculated water system incorporated into a buildings cooling, industrial process, refrigeration, or energy production system. Chapter 8 cooling towers system shutdown and start. This airflow is generated by fans powered by electric motors.
In open circuit systems the recirculating water returns to the tower after 1 one ton of refrigeration is equal to 12,000 btuhour. Rp m 2 rp m 1 cfm 2 c fm 1 staticpressure 2 static pressure 1 cfm 2 cfm 12 ho rsep ower 2 ho rsepow er 1c fm cfm 3 formulas. The project deals with the performance study and analysis of induced draft cooling tower, which is one of the deciding factors used for increasing the power plant efficiency also modelling and analysis of flow using software. As this occurs, a small volume of water is evaporated, reducing the temperature of the water being circulated through the tower. Here we explain in full detail how cooling towers operate with example text, pictures, diagrams and principles. The purpose is to define a preventive maintenance program and plan for cooling towers at the suny polytechnic quad c building utica new york. The term induced draft denotes that air is drawn by fans through the flow of falling water and up and out of the cooling tower. Column anchor column anchor is a device for attaching the tower structure to the foundation. For example, a cooling tower sized to cool 4540 m 3hr through a. Doc boiler efficiency and cooling tower efficiency engr.
Best management practice and guidance manual for cooling towers. The thermal capability of a cooling tower used for air condition ing is often expressed in nominal cooling tower tons. Drift eliminators are installed to prevent water entrained in the air from leaving the system. Reducing water use in cooling towers and evaporative. Cooling tower location criteria cooling tower spacing requirements for multiple tower sites when there are several cooling towers located on one site, the proper placement of the towers in relation to each other is an extremely important consideration. Drift loss of the cooling tower is normally provided by the cooling tower manufacturer based on the process design. Doc air pendingin cooling water makalah disusun untuk. Use guide lines as necessary, to prevent damage to the cooling tower, and as a safety measure to control and avoid sudden shifts or movements of the load. Confidential cooling tower drift test report for member of the cooling tower institute, houston, tx, midwest research institute, kansas city, mo, august 1984. Cooling towers make use of evaporation whereby some of the water is evaporated into a moving air stream and subsequently discharged into the atmosphere.