Event cooling and heating: back to the basics
When it comes to party planning, even the most beautiful and festive décor will not count for much if guests are sweltering or shivering. Using the right portable cooling or heating equipment is vitally important to the success of an event. Here are the basics of providing portable equipment rentals for climate control in tents and other party locales.
Large 12- and 25-ton mobile air conditioning units are popular for event cooling because of their high cooling capacity. These units will typically be located outdoors with the cold air ducted in. Sometimes, however, multiple spot coolers of 1- to 5-ton capacity can do the job and these air-cooled units may be located indoors or out depending on noise and space constraints. Some customers will prefer to use two or three smaller units instead of a single larger machine to provide redundancy in the unlikely event that one of the units experiences component failure.
As a rule of thumb, plan on one ton of cooling for every 100 to 150 sq. ft. of area within a tent. That can add up to a lot of tonnage, but it will be needed to compensate for the thin walls of the tent and the resulting high level of air infiltration. Whether you opt for the low or high end of this range will depend on the calculated heat load, which must take into account such factors as the time of day or evening, predicted temperatures, number of people in the space, type of activity, and the presence of spotlights or other heat-generating equipment. Since comfort is a big part of success, it is wise to build a little extra cooling capacity into the game plan.
If the event is to take place indoors, the formula changes to about one ton of cooling for every 400 to 600 sq. ft. of space. Again, the heat load must be calculated as above to determine more precisely how much cooling is needed.
Another popular rental option for outdoor event cooling in open areas or open-sided tents is evaporative cooling. These units require water and a standard garden hose can be hooked up to the unit, which provides automatic water fill, or the unit can be manually filled up with water as long as the water level is monitored. A fan in the unit pulls the air across the space.
Evaporative coolers are simple and cost-effective, especially for events where power is limited since they can run on standard residential power. Though their use is associated more with desert climates, evaporative coolers can bring a 5- to 15-degree temperature reduction even in higher humidity environments such as Florida. Sometimes you can connect an evaporative cooler to a duct sock that runs down the middle of the tent because it inflates and has perforations that distribute air evenly through the tent. Another useful trick is to put ice into the middle of the evaporative cooler to enhance the cooling capacity. It’s important to note that evaporative coolers do not offer the level of performance and comfort control associated with air conditioning, but they still provide a good way to cool on a budget.
Keeping the event cooling equipment outside the tent is preferable if possible. The area should be as sealed as possible to prevent cooling loss. As you bring conditioned outdoor air into the tent, you will want to direct the air up or down to avoid blowing directly on individuals. Cold air will fall and form a layer of comfort here before it is drawn back into the return air duct to be re-cooled. With this approach, smaller units distributed throughout the perimeter of the tent will be advantageous. An alternative method is to pressurize the tent with no return ducts, which is a very common method to deliver even cooling distribution throughout the tent. The best approach will hinge on the size of the tent, conditions outside, and other factors.
You also will need to consider available power supply. Will you be drawing electricity from an adjacent building or home, and if so, what type of power? A generator is often needed to support adequate tent cooling. Determine the length of electrical cable required to hook up the portable unit(s) to the power supply. The greater the length, the bigger the size needed to maintain voltage and current draw. Don’t forget cable ramps to hide the cables and prevent trip hazards. Diffusers also should be considered for ease of installation.
To heat an event, the same general principles for cooling apply to equipment sizing and location. However, the equipment itself is quite different. The one exception is a portable heat pump. These units, available in 1- to 5-ton capacities, look identical to same-sized spot coolers, but actually, offer both air conditioning and heating capabilities. They are suitable for smaller events and offer an option for rental companies because a single unit delivers two-in-one cooling and heating performance is good for year-round duty.
For larger events, indirect-fired heaters – located outside the tent or other party areas – probably are the most widely used. These units contain a heat exchanger, which encloses a diesel or propane gas heating source and blows air into the space. The result is warm, dry, emissions-free air that is safe for guests. A 40-gal. diesel tank will typically last from 10-12 hours running continuously on a 450,000-Btu unit before refueling is necessary.
These heaters should not be confused with direct-fired gas heaters, also known as construction heaters. With direct-fired units, air is blown across a natural gas or propane flame and into the area to be heated. The open flame produces some level of toxic emissions, so safety issues are of concern, and these units are only suitable for use in very well-ventilated open areas.
Large electric heaters that use resistive heating also provide clean, dry air with no emissions, but they consume large amounts of electricity and often require high voltage wiring (220V or 460V) and generator power, so they are a less practical option than indirect-fired heaters.
Though you likely will not deliver and set up the portable equipment until the morning of the event, plan ahead with the customer. There are many factors that will impact portable equipment selection, so to ensure success, you’ll always want to develop a thorough and well-thought-out plan for event cooling or heating.