Although many building owners buy equipment, many rent over a long period of time due to the headache of capitalizing equipment vs. using the operation budget to pay for the cooling (Photo courtesy of MovinCool).
Not that long ago, most people thought of portable cooling (aka, spot cooling) as being needed only in case of an emergency. Say, for instance, a chiller breaks down, and while it is being repaired, tenants and/or critical spaces need to be cooled. A portable cooling company can then be contacted to deliver and stage the necessary portable cooling equipment within hours.

That limited scenario has changed over the last few years, as more people have become aware of portable cooling's many uses. Many buildings now require permanent or long-term spot cooling in certain areas of a facility, such as computer rooms, laboratories, assembly areas, entertainment venues, and areas that operate after hours.

In addition to permanent spot cooling, portable cooling can also be used for planned maintenance. For example, if a building owner or property management company decides to perform a major overhaul of a chiller plant, which usually requires a minimum of two to three days, portable cooling is a necessity for critical areas.

The different applications presented here show just three of the many different ways portable cooling can be utilized.

Planned maintenance is a great time to use portable cooling units. Atlas Sales and Rental has a customer that shuts down some of its mechanical systems for maintenance and rents portable units, such as the ones shown here, several times a year (Photo courtesy of MovinCool).

Emergency Needs

Portable cooling really shines in emergency situations. Consider, for example, the plight of a major Southeastern university, which normally operates with two 1,700-ton chillers. The university decided to do some PM work on one chiller, which normally would have been fine, because the other chiller was adequate to handle the cooling load in the middle of winter. Unfortunately, the other chiller broke down and left the campus without the required chilled water.

Enter HVAC Portable Systems Inc. (HPSI)/Carrier Corporation. The company specializes in rental temperature control and electrical power equipment, and it provides temporary equipment including chillers, air conditioners, air handlers, cooling towers, boilers, heaters, dehumidifiers, and generators.

The second chiller broke down on a Friday night, and the university needed portable cooling equipment up and running by Monday at 9 a.m. "We were able to quickly design a system and mobilize three 500-ton water-cooled chillers; three 500-ton cooling towers; 2,500 kW of temporary power; and all of the necessary pumps," said Nick Sickmen, marketing manager of HPSI.

The university's systems were not designed with access valves on the chilled water pipes, and the mechanical contractor had to provide taps quickly on the supply and return pipes in order to utilize the temporary system.

There was also a question of where to put the temporary equipment. Initially, university officials said the chillers and cooling towers could be placed in an adjacent parking lot, but that decision was rescinded after it was determined that traffic flow would be adversely affected. The end result was all the equipment ended up being placed right against the building.

After the initial whirlwind of activity, HPSI was able to pull power from other places on campus and remove the generator. The rest of the equipment stayed in place for 30 days, while the necessary parts were ordered for the university's chillers.

Sickmen said this is exactly the reason why building owners, facility engineers, or property management groups should have a contingency plan in place before an emergency occurs. A contingency plan basically helps facilitate the quick and seamless response of all parties involved in a potentially difficult situation.

A plan should include identifying a facility's critical equipment, creating a list of portable equipment needed in an emergency, providing complete drawings of where the equipment should go, writing up the critical contacts including phone numbers, and determining the piping and duct connections and electrical disconnects needed for temporary equipment installation.

"It's not that the university did anything wrong," said Sickmen. "It's just that most people today design their systems based on their current needs. They don't think about ‘what if' until it happens to them, then all of a sudden, it's an emergency."

Long-Term Use

There are many different applications that could require long-term portable cooling, which is typically defined as anything longer than three months. Construction is a prime example, since it may be necessary to temporarily cool the workers or sensitive equipment that is on-site before the permanent cooling system is up and running.

Another example could be temporary manufacturing, in which a company is contracted to produce so much of a particular product. A temporary line is set up and once the contract is met, the line is torn down and the cooling isn't required anymore. Some companies also use portable equipment during the summer months, when workers get hot on the production line.

Permanent applications also exist for portable cooling. "A perfect example is a server room, a computer room, or a LAN room," said Garth Tagge, vice president of Spot Coolers Inc. "Portable cooling can work well for anything that's operational 24 hours a day that creates an internal heat load that needs to be overcome."

The need for portable cooling in a permanent application is often a function of unexpected growth or just bad planning. It may also occur due to a lack of understanding that putting a lot of equipment in a room will generate heat, and a solution must be found.

When a project has a beginning and an end, chances are the enduser will rent the portable equipment. For permanent applications, it usually makes more sense to buy the equipment. However, according to Tagge, some choose to rent over a long period of time for other reasons. "We have some really long-term rentals, because many times having to capitalize equipment may create more of a headache than using an operational budget to provide cooling for the term that it's needed."

Another reason why some would rather rent than own is it's easier for them to trust the expertise of portable cooling companies to set up, maintain, and service the portable equipment. This is especially the case if the equipment is protecting a vital application, and the portable units need to be kept up and running at any cost.

An example of this scenario was found at a plastics plant in Alabama, which rented 75 tons of cooling from Spot Coolers for almost two years. In this case, portable equipment was needed to cool a rectifier, which was used to process all the power for the entire plant. The 20- by 20- by 10-ft rectifier created tremendous amounts of heat, and ambient air was not sufficient to keep it cool. If the rectifier overheated, the entire plant would be shut down.

The long-term solution was to construct a building around the rectifier and have it air conditioned full time. Until that happened, though, portable cooling was needed. "We provided three 25-ton trailers, and just blowing the air over the rectifier wasn't sufficient. We had to create a plenum to provide the intake air and funnel it where it would do the most good," said Tagge.

Spot Coolers took responsibility for maintaining the equipment, which ran 24 hours a day, 7 days a week for 21 months. Because the equipment was all located outside, there were no space constraints, nor were there issues with heat rejection or condensate removal.

"We're a great Band-Aid," said Tagge. "A great answer to a problem that occurs and needs to be solved quickly. Consulting engineers or building engineers often look to us, because we're the least cost, most effective, quickest and most convenient way to solve that problem."

A contingency plan would have determined where to place temporary equipment in case of an emergency at this university (Photo courtesy of HVAC Portable Systems Inc.).

Portables for Planned Maintenance

The weak economy over the last few years has meant that many building owners or property managers have deferred maintenance. Sometimes they've deferred so long that equipment breaks down, and they end up operating in emergency mode.

For those who plan their maintenance though, portable cooling makes perfect sense. In these cases, the building owner or property manager can contact tenants several weeks ahead of time and let them know when the shutdown will take place (usually over a weekend). This gives the tenants the opportunity to state where their critical areas are and make sure portable equipment is rented for them.

Marco Garcia, regional sales manager of Atlas Sales and Rental (Newark, CA), has a customer that definitely understands the benefits of planned maintenance. Every six months, CAC Real Estate Management Co., Inc. at 303 Second Street shuts down some of its mechanical systems for planned maintenance and rents portable units from Atlas. The rentals are necessary because the high-rise office building in San Francisco contains several tenants that have sensitive equipment that must be cooled at all times.

The property consists of two office towers that have separate condenser water systems. One tower has redundant cooling towers, so they can shut down a cooling tower without interruption. The other office tower only has one cooling tower, so portable cooling units are required for a shut down.

"The last four years, they've asked us to supply MovinCool portable units while they do their planned maintenance," said Garcia.

"Atlas delivers the portable units, then the building engineers move them to appropriate locations and complete the set up," said chief engineer, George Morris.

The majority of the units being used are the 14,000 Btu units, which can be plugged directly into a 120V 20-amp circuit. Heat from the portable units is usually rejected into hallways or ducted up through the ceiling panels. Since the units are usually rented for only two or three days over a weekend, condensate goes into a storage tank on the units, rather than being pumped to a sink or other location.

As it turns out, several of the tenants have liked the portable units so much, they've ended up purchasing units outright from Atlas. "The companies have come to know us well over the years, and some of them have wanted to supplement their air conditioning permanently with our units," said Garcia.

So whether it's an emergency, short-term, or permanent need, portable cooling can make sense for a wide variety of applications. ES

Portable cooling can be a cost-effective solution during the summer months when it is necessary to cool workers on a production line (Photo courtesy of Spot Coolers).

Dealership Uses Spot Cooling For Workers

G&C Honda, located in Shreveport, LA, was losing productivity. On hot days, mechanics were taking frequent breaks or even missing full days of work. It would be too expensive to air condition the entire shop area, so Gene Richardson of Richardson Plumbing and Heating convinced the owner of the dealership that spot cooling the workers was a much more economical way of solving the temperature problem.

To that end, G&C Honda hired Richardson to complete the installation of a 5-ton "UniSpot" system. The UniSpot industrial spot cooling system was designed to spot cool processes or people, which was a perfect fit for the service technicians who repaired Honda motorcycles and ATVs.

The installed system includes a metal insulated plenum with UniSpot supply tubing extending from the plenum. The air handler is located outside the shop area under a weather-proof covering.

UniSpot uses 100% outside air, blowing streams of cooler, conditioned air where and when it's needed. The discharge air temperatures are 25° to 30°F cooler than the outside air. By pointing the 2-in. insulated aluminum tubes in the direction of the worker, a curtain of air is created that is cooler than the stagnant air around them. When the outdoor temperature is in the high 90s, the air temperature at the UniSpot outlet will be in the mid 60s.

It is well known that high temperatures in industrial areas can lead to chronic absenteeism, production declines, safety problems, low morale, and high employee turnover. Those problems have been solved for G&C Honda, where worker absenteeism has stayed low since UniSpot was installed. The mechanics and technicians remain at their workstations longer on those hot days, and productivity has significantly increased.