Original article at ACHR News


“Evaporative cooling — direct, indirect, and two-stage solutions — are being used across the board in a wide variety of commercial and industrial solutions,” said Randy Niederer, director of marketing, Cambridge Engineering. “It is currently experiencing a renaissance, as large manufacturing and distribution facilities are choosing this technology to provide cooling relief for employees.”

This renaissance, along with several new technology factors, creates a backdrop for contractors to benefit from the sale of evaporative cooling solutions.


Effectively selling evaporative cooling solutions to customers begins with understanding the different ways to accomplish evaporative cooling. Direct evaporative cooling is the traditional technology of which most contractors and technicians have a knowledge. According to “Evaporative Cooling 101” on Evapco’s website, “Direct evaporative cooling systems put the process fluid, typically water, into direct contact with air. Water flows through fill as a fan draws air across it, facilitating the transfer of heat from the warm water to the cooler air. This is the system used in open-air cooling towers.”

Indirect evaporative cooling is much the same as direct in concept; however, instead of coming in direct contact with the water, the air is pumped through coils, and water flows across the coils.

Two-stage solutions, a combination of both indirect evaporative cooling and direct evaporative cooling technologies, use a plate heat exchanger with the indirect section’s airstream, which then passes through the direct evaporative media for additional cooling, according to Niederer.

“Direct evaporative cooling works well in dry arid climates, whereas indirect evaporative cooling works well in a much broader geographic area,” he said. “Two-stage evaporative cooling is being used in many situations, and evaporative cooling is also being used to efficiently prechill intake air being used in refrigerant-based cooling applications.”

He explained that there are tradeoffs between evaporative cooling and DX or VRF that should be communicated to the customer.

“Contractors must determine what their end user is trying to achieve with their IAQ and then design that solution with either in-house engineers or with an MEP [mechanical, electrical, plumbing] engineering firm,” said Niederer. “If the end user just wants to set a thermostat at 70°F and be assured that the temperature never gets warmer, then evaporative cooling may not meet their requirements. End users that want to condition their space to be more user-friendly than the outside air, yet perhaps not as cool as a residential setting, will find that evaporative cooling can often meet their needs.”

He gave the example of conditioning a distribution center in Dallas and compared the cost of purchasing and operating a refrigerant-based system for this application versus an evaporative cooling system solution.

“In this application, the cost for refrigerant-based cooling could be exorbitant,” said Niederer. “Yet direct evaporative cooling can provide a delta T drop of 20° for a fraction of the purchase and operating cost.”


With an understanding of what evaporative cooling is and how to better communicate with customers about the topic, contractors will next need to ascertain which solutions will work and where to find the right customers.

“Although awareness and technical understanding of the latest technologies is increasing, I feel the role evaporative cooling and the undoubted impact it can make is completely undervalued by the HVAC industry as a whole,” said Mike Sullivan, CEO of Air2O. “With the phase out of HCFCs and, now, HFCs with a high GWP, it is only natural that the industry will have to start to seriously consider where possible R-718 — water.”

Sullivan noted that when using evaporative cooling as the primary cooling measure, regions with low wet bulb often yield the best results. Dependent on the application, however, evaporative cooling technologies can have benefits to all regions.

Niederer suggests that  HVAC contractors look for customers in industrial manufacturing, warehouse/distribution, higher education, prisons, and utilities for ideal evaporative cooling customers. Other applications mentioned included data centers, confinement farming, hospitals, and indoor sporting facilities.

“Evaporative cooling is the preferred method of cooling whenever reduced footprint and/or reduced energy consumption are of the greatest importance,” said Adam Radford, global product manager, Closed Circuit Coolers, Evapco. “The technology is suited for all areas of the United States, depending on the application and site requirements.”

Identifying a good evaporative cooling application customer is not based solely on location and humidity.

According to Scott Jacobs, director, Engineering, Portacool LLC, there are many tell-tale signs that contractors can identify.

“Look for the current use of subpar attempts of cooling, like barrel fans,” said Jacobs. “Even in hot and humid areas, evaporative cooling can provide some cooling relief when used properly. Evaporative cooling popularity has surged in high-heat areas where people, equipment, and animals need relief.”

He explained that contractors can use the current regulatory environment and laws to highlight the need for worker health and safety to potential customers.

“Even though using evaporative cooling in enclosed buildings becomes much more difficult in humid climates, savvy users can supplement an evaporative system with proper ventilation in order to maintain a comfortable environment,” said Jacobs.


A push for energy and financial savings continues to drive innovation in the evaporative cooling market. Manufacturers take different avenues to improve the technology for further diverse applications.

For example, according to Evapco, both internal tube enhancement and extended surface fin technology have significantly increased the efficiency of the current technology in the evaporative cooling market.

“From data centers located in a dry, desert environment looking to save on water and footprint to large commercial HVAC buildings in Seattle looking to go ‘green’ with the provision of environmentally sustainable cooling solutions, hybrid coolers are really where the present and future of the industry is headed,” said Radford.

Portacool has found that by manipulating different factors in its manufacturing process, the company can get different results.

“This has resulted in a more efficient product and has allowed evaporative cooling to become a legitimate option in many more parts of the world,” said Jacobs.

Cambridge Engineering expects to achieve even more energy efficiency from evaporative cooling units via more efficient fan technologies and variable frequency drives in the future.

“We also foresee adding ERV [energy recovery ventilation] technology to the units and finding ways to reduce water consumption and improve the quality of the water used,” said Niederer.

Air2O is aware of many concepts to improve efficiency and performance, especially at the times of high wet bulb.

“We are working on a few ourselves,” said Sullivan. “In the meantime, great advancements have been made in evaporative cooling technology in recent years, and it is now a viable — and, in many cases, superior — form of cooling for many projects.”