Evaporative Cooling V.
Traditional Air-Conditioning

The advantages of various cooling systems and their application have long been the debate of HVAC professionals. But, today, with exorbitant utility costs, dwindling energy resources, and environmental concerns, alternatives to traditional cooling have come to the forefront once again.

TRADITIONAL AIR CONDITIONING IN IT'S HEYDAY
Traditional air conditioning, or refrigerative cooling, is a long time favorite, making huge strides in residential construction during the 1980's through present day. However, traditional cooling is not only expensive, it also has an environmental impact, as evidenced in the "greenhouse gases" and depletion of the ozone layer that is vital to our environment. As you are aware, traditional air conditioning emits CO2, which is a major culprit of ozone depletion and environmental pollution, and accounts for 85% of U.S. greenhouse gas emissions. Traditional air conditioning also emits other harmful gases including methane, nitrous acid, hydrofluorocarbons, perfluorocarbons, and sulfur hexafluorides.

SICK BUILDING, SICK PEOPLE
In addition, traditional air conditioning systems recirculate air, introducing no fresh air into the environment. Evaporative cooling, also referred to as "passive" or "low energy cooling", uses 100% fresh air. Fresh air helps our bodies to ventilate naturally and also introduces a level of humidity, which is advantageous not only to humans, but to pets and wooden structures. With evaporative cooling, opening windows and doors actually enhances the efficiency of the system, but overtaxes a traditional air conditioning system and can cost the consumer more money to operate.
The addition of fresh air also eliminates "Sick Building Syndrome", a phenomenon that recently came into light when employees developed symptoms such as blocked sinuses, eye irritation, headaches, dizziness, wheezing, dry skin rash and/or nausea only when entering the workplace. The longer a person is exposed to conventional air conditioning, the worse the symptoms become. Increasing ventilation and the input of fresh air has been proven to help dilute the pollutants, according to environmental researchers.

ECONOMICAL AND EFFICIENT EVAPORATIVE COOLING
Evaporative cooling systems also require fewer materials to operate, typically only water and electricity. This can reduce energy consumption up to 3/4. These systems also typically require less maintenance ... a considerable savings over the course of a year. Already, generating capacity shortfalls resulting in loss of energy for consumers have been suffered in California, New York, New England, with other areas still showing shortfalls. In addition, transmission is an issue where lines can't carry any more power and lines can't be upgraded fast enough. California, Dallas/Ft. Worth, Chicago, and New York City are all included in that group. With demand up and supply down, energy prices for consumers soared during the lack of energy, further frustrating consumers.

Evaporative cooling provides an energy efficient, environmentally friendly alternative to traditional air conditioning that has existed since the ancient Egyptians hung wet blankets in their doorways and enjoyed cooling whenever the dry wind blew through the saturated blanket. Through the centuries, developments in this industry and improvements in product designs have made evaporative cooling effective in a variety of climates.

DIRECT AND INDIRECT EVAPORATIVE COOLING
There are two types of evaporative cooling systems, direct and indirect.

Indirect evaporation does not add moisture to the air. Water is added to the exhaust air just before it enters the heat exchanger, lowering its temperature.

In direct evaporation, water is evaporated directly into the air that is circulated to the space being cooled. This lowers the ambient temperature and adds moisture to the air. The Port-A-Cool® portable evaporative cooling unit is an product that provides direct evaporative cooling. Portable units offer all the benefits of evaporative cooling, but provide a more economical solution to cooling open areas such as warehouses, tent events or outdoor areas. The Port-A-Cool® unit can be configured into an existing system to supplement cooling of people or equipment. And, portable units are even more economical to operate than a roof top evaporative system or cooling tower, costing less than one dollar a day for water and electricity.

THE PAD'S THE THING
The Port-A-Cool® portable evaporative cooling unit uses a pad system for maximum cooling and efficiency. Küül® pads are cellulous cooling cells produced for durability and longevity and have been tested to be superior to any other pad on the market for highest tensile strength, dry crush strength and wet crush strength, per square inch. Because these pads are fluted and manufactured with specific angles, pollutants from outside air are virtually eliminated. The durability of the pad in a direct evaporative cooling unit is vital to the generation of cool air. Küül® pads are manufactured from 100% virgin kraft paper and each sheet is cured prior to block formation, also referred to as "Thru-Cure". Uncured phenolic resin will wash from or leach out of the paper. The resin in a Küül® pad is fully cured before the individual sheets are adhered to one another. Küül® pads are the only evaporative cooling pad employing the "Thru-Cure" method. These pads typically last from three to five years, depending on frequency of use.

THE GOVERNMENT STEPS IN
The United States government has taken an active interest in preserving our environment through effective use of resources. The Environmental Protection Agency instituted the Energy Star plan to encourage business and individuals alike to purchase Energy Star certified products and developed the EPA Climate Wise program to further promote energy efficiency.

Additionally, the California Energy Commission has instituted Title 24 which are expected to be adopted this year and instituted no later than 2005. These standards include a compliance credit for using evaporative coolers as opposed to conventional air conditioners.
In Arizona and other arid states, residents are instituting combined units, or hybrids, where conventional air conditioning is used when humidity is high and, when humidity decreases, the evaporative cooling system automatically takes over.

EXCEPTIONS TO THE RULE
Generally, evaporative cooling is the most effective alternative to refrigerated cooling. However, there are certain situations where other alternatives should be explored. Specifically, areas with extremely high humidity do not allow maximum evaporation rates, therefore, cooling levels are effected.

Relative humidity describes the quantity of air in relation to its total capacity. Any volume of air at any given temperature has the ability to hold a certain amount of moisture. If the air contains 20% of its total capacity to hold moisture, the relative humidity is said to be 20%. Whereas, a humidity of 100% indicates that the air at this temperature and pressure is holding all the moisture physically possible. If the air has less than 100% relative humidity when entering an evaporative cooling system or unit, then it has the ability to hold more moisture and will evaporate more water and cool more efficiently.

When describing the amount of moisture in the air, the term relative humidity is used because the absorption capacity of air changes relative to air temperature. The warmer the air, the more absorbent it becomes and, consequently, can hold more water. For example, air that has a 100% relative humidity can hold no more water vapor. However, if the air is heated it expands and, as a result, the relative humidity decreases even though the total amount of water vapor in the air has not changed. As a result, we must describe the level of humidity relative to its maximum capacity. Both relative humidity and air temperature must be considered in order to make the best decision regarding the most effective cooling system.

NOT A "SWAMP COOLER"
The public has long regarded any portable cooler as a "swamp cooler." However, improvements to design and materials has created a new breed of evaporative cooling unit that far surpasses the old style "swamp cooler." The Port-A-Cool® unit incorporates state-of-the art engineering principles and superior cooling pads that allow the units to cool even in high relative humidity conditions. In reality, the only thing the two share in common is that they are both evaporative coolers. Comparing these more evolved evaporative coolers to swamp coolers is much the same as comparing a 1920 model automobile to a 2003 model. They may both be cars, but they are vastly different.

For example, the Port-A-Cool® unit operates best when the temperature is above 85° F. and below 75% relative humidity. Swamp coolers are typically ineffective above 30% relative humidity, leaving a 45% ratio between the two. Here's an example, on June 16th, the relative humidity in Hastings, NE, USA, is 44% which means a swamp cooler would be ineffective while a Port-A-Cool® unit would still provide cool air. In fact, the only areas of the U.S. where a swamp cooler would be effective on June 16th are the west coast and the surrounding states, whereas, on that same day, a Port-A-Cool® unit could cool anywhere in the United States, because no place is indicated to have higher than 75% relative humidity.

IS IT THE ANSWER?
There are many factors to consider when designing cooling systems for structures or even for outdoor use.However, due to numerous improvements, evaporative cooling is definitely a contender in a far great array of applications than it has been historically.
It has been said that the ideal air conditioning equipment would sanitize the air, cool the air, humidify the air and evenly distribute the air throughout an area ... and do all this cost efficiently. It looks like we've found our winner.