Showing posts with label corrosion resistant cooling tower. Show all posts
Showing posts with label corrosion resistant cooling tower. Show all posts

Thursday, January 18, 2018

Corrosion Resistant Cooling Towers

corrosion resistant HDPE cooling tower
One variant of corrosion resistant cooling tower
Image courtesy Delta Cooling Towers
Cooling towers rank highly as included components of heat rejection systems. Building and facility HVAC and industrial process cooling commonly rely on cooling towers as the final phase of transferring heat from inside a system, such as a building, to the outdoor environment. With most relying on the evaporation of water as the means to efficiently move large amounts of heat, cooling towers contain large wetted surfaces in almost continuous contact with solutions of water and various chemicals used to maintain certain fluid conditions. The heat transfer solutions can be aggressive, and many towers are constructed using metal for the wetted parts and case of the unit. This has traditionally been an area of concern with cooling tower ownership, since the combined elements of water, treatment chemicals, and time take their inevitable toll on the equipment.

Avoiding the deterioration of metal clad cooling towers is construction utilizing high-density polyethylene (HDPE). HDPE is not impacted by water, treatment chemicals, or elements often present in the air, whether harsh chemical vapors emitted from nearby industrial plants or natural corrosives such as salt air.

Delta Cooling Towers, Inc., based in New Jersey, USA, manufactures HDPE cooling towers and possesses an extensive portfolio of completed successful applications utilizing HDPE construction features. Below is a short case study showing how one industrial user benefited from installing HDPE cooling towers.

Read the case study and get more information from an application specialist. See how incorporating HDPE cooling towers into your operation can reduce maintenance burden and lead to longer machinery life.

In any business venture or other organization, relying on doing things the way they have always been done can be detrimental to real progress and improvement. Incorporating change involves risk, but good planning and careful analysis will increase the probability of success.


Thursday, November 16, 2017

Forced Draft Cooling Tower With 20 Year Warranty

corrosion resistant HDPE cooling tower rated 50 tons with forced draft
Forced draft corrosion resistant cooling tower
with forced draft, rated 50 tons. Pioneer series.
Image courtesy Delta Cooling Towers
Delta Cooling Towers specializes in the design and construction of corrosion resistant cooling towers and similar equipment. Much of the tower construction is HDPE or other non-metallic material, enabling the company to offer a 20 year warranty on their equipment.

Cooling towers are employed worldwide in HVAC applications and process fluid cooling. In addition to their industry leading corrosion resistance, Delta Cooling Towers also offers anti-microbial protection which combats the growth of microbes responsible for Legionnaires Disease and other respiratory ailments. The various product lines cover heat transfer capacities to accommodate any installation.

There is a lexicon employed in the description of cooling tower performance and operation. Some commonly used terms, along with their meaning, is provided below. The terms and their meanings is pulled from the owner's manual provided by Delta Cooling Towers for their Pioneer series of forced draft cooling towers.

Share your process and HVAC cooling challenges with application experts, leveraging your own knowledge and experience with their product application expertise to develop an effective solution.

Cooling Tower Terms and Definitions

  • BTU - A BTU is the heat energy required to raise the temperature of one pound of water one degree Fahrenheit in the range from 32° F. to 212° F.
  • Cooling Range - The difference in temperature between the hot water entering the tower and the cold water leaving the tower is the cooling range.
  • Approach - The difference between the temperature of the cold water leaving the tower and the wet-bulb temperature of the air is known as the approach. The approach fixes the operating temperature of the tower and is a most important parameter in determining both tower size and cost.
  • Drift - The water entrained in the air flow and discharged to the atmosphere. Drift loss does not include water lost by evaporation. Proper tower design and operation can minimize drift loss.
  • Heat Load - The amount of heat to be removed from the circulating water through the tower. Heat load is equal to water circulation rate (gpm) times the cooling range times 500 and is expressed in BTU/hr. Heat load is also an important parameter in determining tower size and cost.
  • Ton - An evaporative cooling ton is 15,000 BTU's per hour.
  • Wet-Bulb Temperature - The lowest temperature that water theoretically can reach by evaporation. Wet-Bulb Temperature is an extremely important parameter in tower selection and design and should be measured by a psychrometer.
  • Pumping Head - The pressure required to pump the water from the tower basin, through the entire system and return to the top of the tower.
  • Make-Up - The amount of water required to replace normal losses caused by bleedoff, drift, and evaporation.
  • Bleed Off (Blowdown) - The circulating water in the tower which is discharged to waste to help keep the dissolved solids concentrating in the water below a maximum allowable limit. As a result of evaporation, dissolved solids concentration will continually increase unless reduced by bleed off.

Friday, October 20, 2017

Wet Bulb Temperature and Cooling Tower Performance

corrosion resistant cooling tower induced draft type
Corrosion resistant evaporative cooling tower
Image courtesy Delta Cooling Towers, Inc.
Evaporative cooling towers enable many buildings across the globe to enjoy moderate interior temperatures. They serve as the final heat transfer step that moves heat from the building interior to the surrounding environment. In addition to their extensive application throughout large residential, commercial and industrial HVAC systems, their are numerous process cooling applications that employ evaporative cooling towers as an effective means of heat rejection.

Delta Cooling Towers, Inc. is a globally recognized manufacturer of corrosion resistant cooling towers, air strippers and tanks fabricated of HDPE to provide extended life service. The company posted an article entitled "Understanding Wet Bulb Temperatures And How It Affects Cooling Tower Performance". The original post is on this page of the company website, and all credit for the article goes to them. We share it below also, slightly edited for format on this forum.  From the article...

A cooling tower primarily uses latent heat of vaporization (evaporation) to cool process water. Minor additional cooling is provided by the air because of its temperature increase. Cooling tower selection and performance is based on water flow rate, water inlet temperature, water outlet temperature and ambient wet bulb temperature. Ambient wet bulb temperature and its affect on performance is the subject of this article. Ambient wet bulb temperature is a condition measured by a device called a psychrometer. A psychrometer places a thin film of water on the bulb of thermometer that is twirled in the air. After about a minute, the thermometer will show a reduced temperature. The low point when no additional twirling reduces the temperature is called the wet bulb temperature. The measured wet bulb temperature is a function of relative humidity and ambient air temperature. Wet bulb temperature essentially measures how much water vapor the atmosphere can hold at current weather conditions. A lower wet bulb temperature means the air is drier and can hold more water vapor than it can at a higher wet bulb temperature. For example:
Since cooling tower cells cool water by evaporation, the wet bulb temperature is the critical design variable. An evaporative cooling tower can generally provide cooling water 5° - 7° higher above the current ambient wet bulb condition. That means that if the wet bulb temperature is 78°F, then the cooling tower will most likely provide cooling water between 83° - 85°F, no lower. The same tower cell, on a day when the wet bulb temperature is 68°F, is likely to provide 74° - 76°F cooling water. When selecting a cooling tower cell, the highest or the design wet bulb temperature your geographical area will encounter must be used. Highest wet bulb temperatures occur during the summer, when air temperatures and humidity is highest. For example, in Indianapolis, Indiana, the design wet bulb temperature is 78°F. Historically Indianapolis can expect less than one hour per year that the conditions exceed a 78°F wet bulb. Typically, 6,000 hours a year will have a wet bulb of 60°F or lower meaning that a cooling tower cell designed for a 78°F wet bulb will be able to make 65-67°F water for 6,000 hours per year nearly 70% of the year. Most cooling towers are capacity rated at a "standard" wet bulb temperature of 78°F. That means on the days when the wet bulb temperature is 78°F, the tower will produce its stated capacity. In other words, a tower rated to produce 135 tons of cooling will produce 135 tons of cooling at a 78°F wet bulb temperature. At a higher wet bulb temperature, the tower cell capacity to produce colder water decreases. Every location has a unique design (worst case) wet bulb temperature that is published by organizations such as ASHRAE and can be obtained easily.

What does it mean when your cooling tower water temperature is higher than the normal 5-7°F above the current wet bulb temperature?

  1. Your cooling load may be larger than the rated capacity of your cooling tower.
  2. Your cooling tower may have lost efficiency
  • Due to scale build up on the tower heat exchange surfaces.
  • Due to loss of air flow across the heat exchange surfaces.
  • Due to improper water flow from clogged nozzles or pump performance
What can you do to improve your tower performance? 

  • Add tower cell capacity
  • Check for the efficiency losses described above
  • Replace the heat exchange surfaces with new clean fill
  • Check for proper airflow
  • Check the water flow is at design
  • Check that nozzles are not clogged or broken


Cooling tower performance is tied to ambient wet bulb conditions. Higher wet bulb temperatures occur in the summer when higher ambient and relative humidity occurs. Initial system design and proper system maintenance is critical to be certain your cooling tower is providing desired cooling.

For more information, or to discuss your own heat transfer challenges, contact a product application specialist. Combine your own knowledge and experience with their application expertise to develop an effective solution.

Saturday, April 29, 2017

Dual Application for Cooling Tower

Plastic cooling tower air stripper
Plastic cooling tower assembly
Courtesy Delta Cooling Towers
Cooling towers are readily identified by their ubiquitous presence in large commercial cooling systems. They are an effective means of rejecting heat from from a centralized liquid system. The general operating principle of a cooling tower involves a thermal and mass transfer from the cooling water to the surrounding air. The water is distributed by a number of means throughout the cooling tower fill, drastically expanding the surface area of the water. Air from the surrounding atmosphere is moved across the water surface. Assuming that the air is within the performance range of the cooling tower, the resulting evaporation of a portion of the water cools the liquid water remaining behind.

There are other applications for cooling towers, and Delta Cooling Towers, Inc., described one in a March 2017 news post. The application centered around a municipality with two challenges in providing potable water to residents. The water was being sourced from very deep wells and, without treatment, had an unacceptably high delivery temperature. Additionally, the sourced groundwater exhibited unacceptable levels of radon and hydrogen sulfide, naturally occurring gaseous contaminants that required level reductions to render the water suitable for human consumption and use.

Air strippers, equipment that aerates the water, are a common means of reducing the gaseous contaminant levels. In this case, though, there was the additional challenge of reducing the water temperature. All needed to be accomplished at process flow rates commensurate with the size of the municipal water demand.
A solution that solved both issues arose with the use of a cooling tower selected to provide sufficient aeration for gaseous contaminant reduction and cooling of the water to acceptable levels.
You can access the entire case history by reaching out to a product specialist, with whom you should share your own liquid processing challenges. Combining your process knowledge and experience with the product application expertise of knowledgeable professionals will produce effective solutions.

Tuesday, December 1, 2015

Cooling Tower Case Study: HDPE vs. Metal Clad

HDPE constructed cooling tower
HDPE Constructed Cooling Tower
Courtesy Delta Cooling Towers
In any business venture or other organization, relying on doing things the way they have always been done can be detrimental to real progress and improvement. Certainly, incorporating change has risk, but careful consideration and planning can make deciding upon and implementing change a big win for an organization.

Cooling towers are common elements of heat rejection systems, like building HVAC and industrial process cooling. By design, cooling towers have large wetted surfaces in almost continuous contact with aggressive solutions of water and various chemicals used to maintain certain fluid conditions. Many towers are constructed using metal for the wetted parts and case of the unit. This has traditionally been an area of concern with cooling tower ownership, since the combined elements of water, treatment chemicals, and time take their inevitable toll on the equipment.

There is a good solution to the deterioration of metal clad cooling towers. Construction utilizing high-density polyethylene (HDPE). HDPE is impervious to corrosive water treatment chemicals and elements often present in the air, whether harsh chemical vapors emitted from nearby industrial plants or natural corrosives such as salt air.

Delta Cooling Towers, Inc. is a US based manufacturer of HDPE cooling towers with a substantial portfolio of completed projects. Below is a short case study showing how one industrial user benefited from installing HDPE cooling towers.

Read the case study and get more information from an application specialist. See how incorporating HDPE cooling towers into your operation can reduce maintenance burden and lead to longer machinery life.

Monday, October 5, 2015

Cooling Tower Corrosion Resistance - It's Easy

Corrosion resistant cooling tower installation
Corrosion resistant cooling tower
Courtesy Delta Cooling Towers
Machinery that will be continuously bathed in a spray of water throughout its operating life is certainly a good candidate for some corrosion protection. Locate this equipment outdoors, perhaps in a coastal area, and the potential to gain benefits from a corrosion resistant installation are more than clear.

Cooling towers fit my previous description admirably, and their scope of application makes them an essential element of facility operation. Every unit is exposed to combined effects of variable water chemistry, constant saturation at elevated temperatures, and aeration. Some cooling towers also are impacted by potentially harmful agents in the process water and various airborne pollutants, including sulfur oxides and acid rain.

For those not entirely familiar with how a cooling tower works, here are the very basics. Cooling towers transfer an amount of heat from one or more water-cooled machines or systems to outdoor air. Heated water from the water cooled systems enters the cooling tower, distributes over a heat transfer surface (sometimes called the fill), and is cooled by an induced air flow that is forced through the fill. The flowing air causes a portion of the water to evaporate, removing heat and lowering the temperature of the water. The cooled water is collected in a basin and returned to the system to repeat the heat transfer cycle.

Traditionally, cooling towers were fabricated of metal because of its structural strength and ability to be formed using readily available fabricating means. Differing metals were employed, at basic to premium price points, to provide increased levels of resistance to the ever present corroding nature of water and weather. Many cooling towers built today employ the same, or similar, materials and methods used decades ago. There is, and has been for quite some time now, a modern alternative to metal cooling tower construction that provides substantially increased levels of corrosion resistance at a competitive price point.

Delta Cooling Towers, Inc. manufactures cooling towers using structural and other plastics, enabling them to provide a 20 year warranty covering the basic structure of the unit. The product line provides capacity and performance range to cover almost any requirement. If you are in the business of specifying heat rejection equipment for your own facility, or one of your client's, you should get more detailed information about this equipment. Have a discussion about your application requirements, and concerns about operational longevity, with a product specialist. Good decisions come from combining the knowledge and experience of many.

As a quick reference, included below is a list of materials used in the construction of the Delta Cooling Towers unit. A quick glance by anyone familiar with the corrosion susceptibility of metals used in tower construction will see that the superior performance of the plastic materials should be given serious consideration on a cooling tower project.