Cooling towers are used as part of industrial hvac systems to remove heat from process water by evaporative cooling. Introduction to commercial building hvac systems and energy code requirements reid hart, pe, pacific northwest national laboratory u. These calculations reinforced the concept that molybdenum from cooling tower discharges are a significant source of the mo in the pellets. Cooling tower makeup water quantity calculation saubhaya cooling tower makeup water quantity calculation saubhaya cooling towers understanding key components of and pdf cooling towers estimate evaporation losakeup water. The fanlaws can be used topredi ctthe pe rformance ofa towerwitha nonstandard motor. A suite of cooling tower applications that is indispensable to anyone responsible for the peak performance of cooling towers. Calculate a ton of cooling load using this formula. Calculating the tons for a cooling tower requires you to understand some basic information about it works. Its role is to remove heat from a process, usually either a direct manufacturing process or from the condenser of a chiller. F can increase efficiency of the chiller compressor by 1% to 2 % in most situations. Cooling tower spreadsheet details details of the excel spreadsheet are presented here.
Get back to your priorities and minimize maintenance requirements with highquality marley replacement components for nonmarley towers. For nearly a century, we have provided exceptional quality equipment and service to the hvac, process cooling, industrial, and. You should confirm all information before relying on it. Maintaining water chemistry is an essential part of an effective. Cooling tower calculations xls free software download. Cstn july 2003 l et s take a look at how to calculate cooling tower blowdown. Other factors, which we will see, must be stated along with flow rate m3hr. However, it is possible to lessen this impact in both central and unitary systems by increasing their efficiency.
Test your knowledge on cooling tower online quiz chemical. Cost effectiveness assumptions in the example above, annual energy use and annual water use are based on ari standard 8102003 for a watercooled, imhtype model. K overall enthalpy transfer coefficient, lbhft2 a surface area per unit tower volume, ft2ft3 v effective tower volume, ft3 l water mass flowrate, lbh equation 2 basically says that at any point in the tower, heat and water vapor are transferred into the air due approximately to the difference in the enthalpy of the air at the surface of the water and the main. Water cooled condenser water cooling tower temperature decrease of 1. If you read this book carefully, you can make any cooling tower design programs by yourself. See figure 1 on page 3 for an illustration of the water being recirculated, added to, or lost from a cooling tower.
Introduction an open circuit or evaporative cooling tower is a heat rejection device that rejects heat to the atmosphere by cooling a water stream to a lower temperature. Energy performance assessment of hvac systems bureau of energy efficiency 117 first calculate the kwton rating from the measured parameters. Full hvac training course by ramy ghoraba pdf files. A survey of wet cooling tower literature was performed to develop a simplified method of cooling tower design and simulation for use in power plant cycle optimization. The mass balance around a cooling tower as illustrated in the figure to the right is. Marley nc cooling towers and cooling tower parts spx. Our nearly 100 years of cooling tower engineering knowhow is utilized so that the nc cooling tower you select today provides the broadest range of configurations and the highest cooling capacities available in a package. Under fan decks of counterflow towers an aver age water density of 0. Process leaks, windage, and drift are really just forms of uncontrolled blowdown. Cooling tower efficiency calculations cooling tower approach. Key features lowered required height, which reduces the need for architectural screening. Evaporation losses e it is calculated on the basis of heat. After the water has been chilled, it is distributed via pumps, pipes, and valves the distribution system to the loads, where a heat exchangerfor example, a cooling coil in an airhandlertransfers heat from the air to the chilled water, which is returned to the chiller.
The merkel equation the fundamental equation of heat transfer in wet cooling towers is presented and discussed. Cooling tower selection 5 unit layout 6 cooling tower piping 7 cooling tower accessories 8 iii. Again, this will be a first issue releasing the actual engineering approach. Ideally tower should be raised so the discharge meets the height of the walls as a minimum. Some parameters of the column operation are then calculated. Whether we have to consider cooling tower capacity same as that of cooling tower circulating pump capacity or we should omit the flow rates of ssf side stream filter. If not already known, determine the value of water used in your cooling towers and evaporative condensers. Nov 30, 2016 chemical engineering site already published articles on cooling tower components and cooling tower efficiency calculations. The purpose of a cooling tower is to keep a process from raising temperatures too high were they either can be dangerous or lower the efficiency.
Best practice guidelines water conservation in cooling towers au 1. F o r m u l a s a n d t a b l es formulasandtables fanlaws. In open circuit systems the recirculating water returns to the tower after 1 one ton of refrigeration is equal to 12,000 btuhour. Hvac cooling load calculations and principles sensible heat gain is the energy added to the space by conduction, convection andor radiation. Cooling towers can be split into two distinct categories. Calculation of effect of cycles of concentration on amount of. Cooling tower makeup water calculation xls saubhaya cooling tower makeup water calculation xls saubhaya cooling tower makeup water calculation saubhaya cooling tower makeup water calculation xls saubhaya. 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. Necessary considerations when proposing a cooling tower. Calculations 417 cooling tower blowdown equation by james mcdonald, pe, cwt originally published.
Introduction to commercial building hvac systems and. Department of energy building energy codes program. Water efficiency management guide mechanical systems. The technical data is taken for mechanical draft cooling tower. A neglected or poorly maintained cooling tower can. Cooling tower calculations in excel free downloads, list 1 download cooling tower calculations in excel software.
Cooling tower plays a major role in chemical process industry. The cooling tower makeup water flow is the key parameter that is required to be measured using option b, as this must be equal to all the expected or unexpected losses of water from the system. The theory of heat exchange in wet cooling towers is briefly summarized. Tradional hvac heating and cooling systems are used in schools, large office buildings, and hospital.
Cooling tower calculations in excel free downloads 2000 shareware periodically updates software information and pricing of cooling tower calculations in excel from the publisher, so some information may be slightly outofdate. Cooling load calculations and principles ced engineering. Cooling tower evaporative cooling system measurement. 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. The computeraided design cad files and all associated content posted to this website are created, uploaded, managed and owned by third party users. Mar 18, 2009 calculating fan power involved for a cooling tower posted in student. Following items will be discussed and calculated in this article. Each cad and any associated text, image or data is in no way sponsored by or affiliated with any company, organization or realworld item, product, or good it may purport to portray. Nov 25, 20 cooling tower evaporative cooling is achieved by the evaporation of a small fraction, about 1 to 2%, of the recirculating water flow. Reducing water use in cooling towers and evaporative condensers. Isolated platform for cooling tower vibroacoustics. Assessing the performance of cooling towers and their effect.
In summer the ambient air wet bulb temperature raises when compared to winter thus limiting the cooling tower efficiency. The compressors are most often driven by electric motors, although they can also be powered by natural gas engines or steam turbines. 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. The cooling tower test is conducted in reference with cti code atc 10500, schedule ii performance curve method. Cooling tower performance in free cooling applications is dependent upon both the system and cooling tower design. Based on the project zip code and site design factors, calculations are made to determine the equivalent seismic g force and wind load in pounds per square foot psf on the unit. The marley nc cooling tower has set the standard for high efficiency and low maintenance since its introduction in 1968. The towers essentially a cooling tower is a type of heat exchanger. Cooling tower basics calculation formulas cooling tower.
This may be a case of a refrigerant ton 12,000 btuhr vs a cooling tower ton 15,000 btuhr. On the other hand, cooling towers are much larger than tradional hvac systems and are used to remove heat from cooling tower water systems in petroleum refineries, plants, natural gas processing plants, petrochemical plants, and other industrial processes and facilites. 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. Department of energy assistant secretary for resource. 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.
The estimated mass of mo from cooling towers alone 18 lbsday exceeded the mahl. By using a cooling tower, the plant is kept safe and operational. Indoor and outdoor criteria for heating and cooling load calculations g. An example of a mass and energy balance on the laboratory cooling tower will be presented along with the results of experiments in which the rate of heat dissipated by the tower was calculated at full.
The remainder of this report will explain the theory behind the operation of a cooling tower and how the laboratory cooling tower is operated. Cooling tower makeup water calculation xls saubhaya makeup. The evaporation rate is approximately 3 gpm per 100 tons of refrigeration. Cooling tower makeup water flow calculation rea hvac. This cooling tower quiz module covers the design, calculations, operations and cooling water treatment etc which will be a refresher for the experience and an eyeopener for the fresh chemical engineers. Guidelines for estimating unmetered industrial water use. This includes determination of cycle of concentration, evaporation loss, drift or windage loss, blow down water requirement makeup. Filtered water is then pumped back into the main condenser line through a nozzle or returned to the cooling tower basin called the sump. Cooling tower performance calculations are usually performed numerically. For nearly a century, we have provided exceptional quality equipment and service to the hvac, process cooling, industrial, and refrigeration markets. Evapco supports its worldwide customers with manufacturing facilities and sales offices. Cost effectiveness assumptions in the example above, annual energy use and annual water use are based on ari standard 8102003 for a watercooled, imhtype model with an ice harvest rate of 450 pounds per 24 hours. Cooling tower calculations in excel free download at.
It allows you to quickly calculate the total required cooling and heating loads in btuhr or. Combined heat and power technology fact sheet series. The cooling tower test is conducted in reference with cti code atc 10500, schedule ii. The tower takes the heat from the water stream and rejects it to. Design of mechanical draftcooling tower and determination of. Cooling tower selection wrong hvacr engineering engtips. Calculating fan power involved for a cooling tower student.
Evaporation rate gpm water flow rate gpm x range f x 0. Multiply the evaporation rate by the appropriate correction factor in the table below to calculate the makeup water. Reducing water use in cooling towers and evaporative. 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. This amount of heat could theoretically melt 1 ton of ice in 24. Evapco is dedicated to designing and manufacturing the highest quality products for the evaporative cooling and industrial refrigeration markets around the globe. They reject process heat from the cooling water to atmosphere and keep the water cool.
Technical evaluation of side stream filtration for cooling. Download full hvac training course by ramy ghoraba four parts in pdf files free hvac tutorial download free mep calculation excel sheets, autocad drawings, and training courses for hvac, firefighting, plumbing and electrical systems design. Best management practice and guidance manual for cooling. Supporting information report cooling tower feed water. The fire protection system should be designed on a rate of application basis as follows. Understanding key components of cooling towers and.
The defining measurement for cooling tower operations measuring outdoor wetbulb temperature helps operate cooling towers for peak efficiency. In either case, whether caused by nature or by the tower itself, the owners concern for an ice formation on a cooling tower should be a reflection of both its location and its amount. The recirculation rate and the temperature drop across the cooling tower are the two pieces of data needed to calculate the amount of water lost from the open recirculating cooling system due to evaporation. Cooling tower makeup water calculation pdf saubhaya makeup. Latent heat gain is the energy added to the space when moisture is added to the space by means of vapor emitted by the occupants, generated by a process or through air infiltration from outside or adjacent areas. 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. Isolated platform for cooling tower save up to 40% installed cost over traditional approaches contact us, your local vibroacoustics representative, for a quotation and to see how this isolated platform solution can save you time and significant cost. Cooling tower selection wrong hvacr engineering eng. Tonnage duty calculator flow gallons per minute hot water temperature f. The industry decided many moons ago to match the nominal capacity of cooling towers to the nominal capacity of water cooled chillers, this having a 450 ton chiller matched with a 450 ton cooling tower. Cooling tower efficiency calculations cooling tower efficiency calculation is described in this article. The defining measurement for cooling tower operations. Replace the chaos of disconnected, unorganized files, folders, and spreadsheets with streamlined, automated data housed in perpetuity. The present paper is a detailed methodology for thermal design of cooling tower.
Assessing the performance of cooling towers and their. For example, a cooling tower sized to cool 4540 m 3hr through a. Range range is determined not by the cooling tower, but by the process it is serving. Cooling tower with side stream filtration examples technology characterization side stream filtration systems continuously filter a portion of cooling water to remove debris and particles. The purpose of this test procedure is to describe instrumentation and procedures for testing and performance evaluation of cooling towers. How to calculate tons of cooling for a cooling tower sciencing. The evaporation rate is approximately 2 gpm per 1 million btuhr of heat rejection. Vapor compression chillers use reciprocating, screw, or centrifugal compressors to power the cycle. Additionally, water is lost from any system leaks and tower drift escape of water droplets from the cooling tower structure as a result of system air flow and windeffect air flow. When evaporative cooling can occur is based on local environmental variables that can. To reduce the drift from cooling towers, drift eliminators are usually incorporated into the tower design to remove as many droplets as practical from the air stream before exiting the tower. High walls will create an artificially warmhumid environment from recirculating moist discharge air.
Dear sirmadam, we are in the process of calculating cooling tower duty. Section 1 laboratory data data from the laboratory data sheet are entered into the spreadsheet in the same order as they appear on the data sheet. Hi there, im involved a project where i must determine the power requirements of a forced draft cooling tower that uses a large fan. Cooling tower efficiency calculations chemical engineering site. The method allows analytical calculation of cooling tower. Install chemical feed systems on larger cooling tower systems more than 100 tons install flow meters on makeup and blowdown water lines improve cooling tower water quality consider installing a sand filter or cartridge filter to reduce sediment in basin water consider installing a water softening system on the makeup water line. This app performs ruleofthumb hvac cooling and heating load calculations for many types of commercial, industrial, institutional, and residential buildings. 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 ra nge e ntering water tem per ature leavingwater temperature.