If you are still getting your bearings with cooling tower design terminology, you may wonder what the terms approach and range mean. Mar 01, 2016 properly engineered condenser, chiller and cooling tower piping and controls will improve heat transfer and avoid problems such as air slugging and pumps losing prime. The water falls and collects in a pond at the base of the tower, formed by a base slab and the pond wall. The thermal capability of a cooling tower used for air condition ing is often expressed in nominal cooling tower tons. There are many different types of cooling towers but the cooling tower working principles stay pretty much the same. Use an economical approach difference between water outlet temperature and design wet bulb of 4 c. Drift eliminators are installed to prevent water entrained in the air from leaving the system. The effect of climatic changes is shown to be important in the design of more effective cooling technique and to device methods to compensate for the loss in plant efficiency. 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. See the more detailed explanation of cooling towers systems. However, because of the evaporation that takes place within the tower, the mass flow of water leaving the. Cooling tower mass balance gives an idea about make up water requirement.
Often several materials are used for corrosion resistance, reduce maintenance, increase reliability and more service life. In naturaldraught cooling towers the open structure at the base allows a natural movement of air. How cooling towers function introduction most industrial production processes need cooling water to operate efficiently and safely. Considered will be a 26 ft, 28ft, or 30 ftdiameter fan. Like most other hvac equipment, the commissioning of cooling towers starts during design and continues on through construction, start. It is intended that each potential trouble source be evaluated so that the necessary design safeguards can be erected against. The basics of wet cooling towers back to news water cooling towers are some of the most essential pieces of equipment for commercial and industrial buildings today.
It is the temperature difference between cooling tower entering hot water and leaving. The most common is for a cooling tower that provides the required heat rejection capacity with a high level of reliability at low cost. Cooling tower calculations software program is a powerful, user friendly, software program for the analysis of induced, mechanicaldraft, counterflow cooling towers. Part i outlines the steps necessary to improve cooling tower operations including a simple checklist for easy reference. They represent a relatively inexpensive and dependable means of removing low grade heat from cooling water. A nominal cooling tower ton is defined as cooling 3 gpm of water from 95f to 85f at a 78f entering air wetbulb temperature. Tradional hvac heating and cooling systems are used in schools, large office buildings, and hospital. The inlet may take up an entire side of a towercross flow design or be located low on the side or the bottom of counter flow designs. This derives from the fact that a btu british thermal unit is the amount of heat gain or loss necessary to change the temperature of 1 pound of water by 1 f. There are many design guideline to assist engineers to understand the basic principles of cooling towers. We offer cooling tower services in arizona but can ship cooling tower parts worldwide. The theory of heat exchange in wet cooling towers is briefly summarized.
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 makeup water source is used to replenish water lost to evaporation. Today, multicell cooling tower configurations have common headers for both the supply and return lines figure 2. Here we explain in full detail how cooling towers operate with example text, pictures, diagrams and principles. A cooling tower is a heat rejection device, which extracts waste heat to the atmosphere though the cooling of a water stream to a lower temperature. These studies were complicated by the fact that the cooling tower market is typically driven by one of two powerful, yet often conflicting requirements. Cooling tower efficiency guide property managers improving cooling tower operations how to use this guide this guide is structured in two parts. Cooling tower design jc cooling tower design basics cooling tower design calculations we having 23 years in the field of cooling tower manufacturing and design. Checklists for design, construction, and startup by davesellers, pe, senior engineer, portland energy conservation inc.
High pressure drop tower spray nozzles in combination with tower bypass. The technical data is taken for mechanical draft cooling tower. Pdf industrial cooling tower design and operation in the. It is the requirement of heatenergy to increase the temperature by 1of of onepond of water between 32 and 212of. 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 tower manufacturer heat exchanger manufacturer india. Cooling tower thermal design manual the early investigators of cooling tower theory grappled with the problem presented by the dual transfer of heat and mass. If you read this book carefully, you can make any cooling tower design programs by yourself. Effective thermal design of cooling towers a stepbystep approach to coolingtower 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. This online engineering pdh course provides comprehensive information on cooling water systems and describes different types of cooling towers, their mechanical components and the problems associated with cooling water. Cooling tower design and construction designing buildings. Cooling towers are a very important part of many chemical plants.
Design of mechanical draftcooling tower and determination. Nassef optimum shape and design of cooling towers m. A cooling tower is a device used in industry to cool hot water by partial evaporation before reusing it as a coolant. C constant related to cooling tower design m slope of tower characteristic curve 1 liquidtogas ratio lg. It is based on around fortyfive years of experience in the construction of cooling towers gained by plant and structural design engineers, by construction companies, checkup engi. Cooling towers have certain design values, but seasonal variations require adjustment and tuning of water and air. Cooling towers continuing education for professional.
Range of cooling in f t1 t2 area wet bulb temperature in f twb the design heat load is determined by the flow rate, and the range of cooling, and is calculated using the following formula. Lack of tower treatment with consequent fouling of the condenser. Lets look at a typical case of fan selection for a new tower design. Most cooling towers work based on the principle of evaporative cooling. The water exits the cooling tower and is sent back to other units for further process conditions. Range range is determined not by the cooling tower, but by the process it is serving. Understanding the basics of cooling tower heat transfer. Features include 2d and 3d ductwork drafting, ductwork sizing, pressure drop calculations, and building load calculations. These towers are basically used to remove excess heat that is generated in places such as power stations, chemical plants and even domestically in air conditioning units, and are relatively inexpensive and a dependable means of removing lowgrade heat from cooling water and have developed. Some of the commonly used useful terms, in the cooling tower industry are btu britishthermalunits.
The cooling system is housed in the towers base which is typically the bottom 10 metres, the rest of the tower consisting of an empty shell. The selection of the right cooling tower for your application can be summarized as follows. Midwest cooling towers experienced cooling tower engineering and design group can offer you the best value option for your particular application, whether it is one of preengineered cooling towers, or a custom designed solution. Cooling water systems an overview of cooling towers 2012 instructor. The type of heat rejection in a cooling tower is termed evaporative in that it allows a small portion of the water being cooled to evaporate into a moving air stream to provide significant. Cooling tower basics calculation formulas cooling tower. Houston, texas fans key to optimum cooling tower design nomograph gives the reciprocal of the density ratio. The software program can be used for the analysis of existing towers or for the preparation of specifications for new towers.
Determination of optimum height for counter flow cooling. For purposes of comparison, a real tower is considered in the current study as the reference design tower. These towers are basically used to remove excess heat that is generated in places such as power stations, chemical plants and even domestically in air conditioning units, and are relatively inexpensive and a dependable means of removing low. Cooling is accomplished through the latent heat of vaporization. The fill is contained within a counterflow tower since the air is drawn up and through the failing water. The following design data is required to select cooling towers. Evaporative cooling is the process where warm water from an industrial process is pumped up to the top of the cooling tower where the water distribution. Cooling tower design software free download cooling. Multicell cooling tower configurations that have 100 percent independent systems have limited redundancy. The program can be used for the analysis of existing towers or for the preparation of specifications for new towers. The present paper is a detailed methodology for thermal design of cooling tower. The goal is to assure the implementation of water cooling systems which will satisfy all design and. For specific information on how cooling tower products can meet your cooling tower needs, contact your local cooling tower products representative or give us a call today at 8007331584.
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. There is also the option of counterflow and crossflow design there also exists cocurrent flow but it is seldom used. If it is not available it may be assumed as for natural draft cooling tower d 0. Tower components from a variety of different materials. Fundamentals of heat and mass transfer in wet cooling towers. Houston, texas fans key to optimum coolingtower design nomograph gives the reciprocal of the density ratio. Cooling towers continuing education for professional engineers. It is a wooden, steel or concrete structure and corrugated surfaces or baffles or perforated trays are provided inside the tower for uniform distribution and better. The commissioning of cooling towers 2 prime and paint the condenser water piping, cooling tower structural steel, and other exposed metals to ensure long life and a neater appearance. 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. We are a nonprofit group that run this website to share documents. The lg ratio of a cooling tower is the ratio of the liquid water mass flowrate l to gas air mass flowrate g. The basics of wet cooling towers manufacturers of cooling.
Frame and casing, fill, cold water basin, drift eliminators, air inlet, louvers, nozzles and fans. In these systems, the use of automatic control valves for proper operation is imperative at the. Fundamentals handbook, chapter 26, represents the entering air wet bulb. The merkel equation the fundamental equation of heat. Cooling tower analysis is a powerful, user friendly, program for the analysis of induced, mechanicaldraft, counterflow cooling towers. Cooling tower useful terms and cooling tower performance. Download cooling tower design we are a sharing community.
Cooling tower fundamentals spx cooling technologies. Nov 22, 2014 there are many design guideline to assist engineers to understand the basic principles of cooling towers. Design of mechanical draftcooling tower and determination of. 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. While the mathematics of cooling tower flow design can be. Cooling tower structures vary greatly in size and design, but they all function to provide the same thing. The purpose of a cooling tower is to remove the heat generated by an hvac system cooling of compressor refrigerant and heat generated by the compressor itself. A water legged discharge or discharge reducer will provide automatic siphon draw establishment so long as minimal startup flow velocity in the downcomer is to the order of 1 ft. Buy marley 6 water distribution nozzles nx crossflow nozzle n a truly clogresistant crossflow nozzle n nozzles are spaced on nominal 20 centers n 1. Cooling tower basics calculation formulas cooling tower efficiency in this article explained about basic concepts of cooling tower, types of cooling towers, formula for cooling tower efficiency.
Phd thesis wetcooling tower thermal performance evaluation. Design master hvac is an integrated hvac building design and drafting program for autocad. Galvanized steel, various grades of iron and stainless steel, and concrete are widely used in tower construction. Other factors, which we will see, must be stated along with flow rate m3hr. The cooling load is determined by the size of a building from which heat needs to be extracted. The merkel theory overcomes this by combining the two into a single process based on enthalpy potential. Introduction a cooling tower is a heat rejection device that. 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 water systems an overview of cooling towers. In this design the fill is located outside the tower. For example, a cooling tower sized to cool 4540 m 3hr through a. Cooling tower efficiency calculations cooling tower approach. 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.