Cool Breezetm Outside Air Package. In cold climates, this innovative option allows you to utilize a natural resource we have in abundance up here in the North: outside winter air. Rather than relying on the compressor system to produce cold air it simply moves the cold from outside to inside, using just a fraction of the energy. Tapping into this vast resource has been called "free cooling", "outside air refrigeration", "arctic cooling", even "polar power". The system is often called a "walk-in cooler economizer". Whatever you call it, it makes a lot of sense. Every Cooler Controller has the capability to add outside air intake and exhaust fans at any time. This feature will remain unused if a source of clean outside air is not available or the climate is too mild to yield an acceptable payback period.

Effective and Reliable. A Freeaire system with outside air provides uninterrupted refrigeration to the walk-in cooler while automatically selecting the most energy-efficient way of doing so at any given time. During warm weather the compressor operates as usual. During cold weather, when the Cooler Controller calls for cooling, the outside air intake fan begins to introduce fresh, filtered outside air into the walk-in while an exhaust fan lets warmer air escape to the outside. When the Cooler Controller is satisfied that the temperature inside is cool enough, it turns off both the outside air intake and exhaust fans.

Simple and Versatile. Cool Breeze Outside Air Packages can be installed in many different ways depending on the characteristics of the building and spaces involved. They can be used in old or new walk-ins as small as 500 cubic feet and in warehouses with hundreds of thousands of cubic feet, all using the same modular 10" intake and exhaust units. If the walk-in is on an outside wall the air simply passes through the wall in two places. As the size of the space and the refrigeration load increase, you simply add more pairs of intake and exhaust fan units to handle the larger load. If there is a distance of up to 50 feet to connect with the outside, 10" diameter ducting is used to route the air, the duct being insulated if it is used for intake air that travels through a heated space. The intake air should come from a source of clean outside air, away from truck and car exhaust as well as furnace vents and the like. Since every installation is different, the intake and exhaust units are fully insulated and designed to be installed in the cooler's outside wall, inside wall, ceiling, or even floor, in order to make installation and the only maintenance required, yearly filter changing, as easy as possible. The location of the outside air components is also governed by the size and shape of the walk-in cooler so that the coldest air is quickly dispersed throughout the space and the warmest air is exhausted. Freezing of product is completely prevented by proper intake damper and Circ fan placement.

A Matched Pair of Fans. The intake and exhaust units work together to maximize the airflow from the outside, without causing pressurization problems. Each 10" diameter intake fan that brings outside air into the space is precisely balanced by a 10" exhaust fan that relieves the pressure and removes the same amount of warmer air from somewhere else in the space. The number of intake fans in an Outside Air Package is always balanced by an equal number of exhaust fans to keep the air pressure within the walk-in just slightly pressurized. Among other benefits, this helps furnaces inside the building draw better, as well as routing some of the building's normal infiltration through the walk-in cooler where it can do some good. The intake and exhaust fans are different sizes, makes, kinds, and power ratings. They both move the same amount of air through the cooler, but there's about three times the power behind the intake air. They are very different units, and yet a matched pair. This is why we have such a large filter that won't soon clog and unbalance the system causing warm air from the rest of the building to be sucked into the cooler. It is why the components are not sold separately.

Maximum Energy Savings: The graph on the right shows the drastic reduction in energy use that can result from outside air refrigeration, when compared to even the most efficient compressor system. Whenever the outside temperature is at least 4°F cooler than the temperature inside the walk-in, the outside air automatically begins to take over the job of refrigerating the walk-in from the compressor system. There may be months during a winter when the outside air can take over the refrigeration for the entire month, without the compressor system operating at all. For those installations in which there is a charge for demand, this can lead to significant savings in demand charges. These savings can be guaranteed only when the compressor system has been switched off at the Cooler Controller for the entire month.

Patented Differential Thermostat: This constantly senses both the inside and outside temperatures, compares them to each other and to the desired settings, and chooses the best mode of operation at any time. This "floating" setpoint avoids a problem common to all other outside air systems: the need to have a fixed outside temperature setpoint for the outside air fan to begin operating. The Cooler Controller also allows simultaneous operation of each of the two refrigeration systems, so the compressor system is always available to help out if the Freeaire's outside air fans can't bring in enough outside air to handle the cooling load at any time. An ordinary system, with a fixed "changeover" setpoint for the outside temperature at which the compressor system stops and the outside air system begins operating, requires a very careful calculation of the maximum refrigeration load to be handled and of the cooling capacity of the the outside air fan. Too high a setpoint can result in unacceptably high temperatures inside the walk-in, but a lower setpoint results in many hundreds of hours of unnecessary compressor operation a year. In contrast, the Freeaire's differential thermostat maximizes the energy-saving potential of using outside air while ensuring that adequate refrigeration is always maintained.

Two Complete Systems of Refrigeration: Outside air takes over as much of the cooling load as often as it can, and the rest of the load is picked up by the compressor. Despite operating simultaneously when necessary, the outside air system operates alone whenever possible, since it is so much more efficient than the compressor system, even at a small temperature differential. Each system acts as the other's back-up, giving you more reliable refrigeration and extending the life of all the equipment. Whenever the outside temperature is at least 4°F cooler than the walk-in, the outside air system can operate and supply as much cooling as the outside air temperature permits.

Wide Application. This map shows the mean number of days per year that freezing temperatures occur throughout North America. The shaded area that lies to the north and inland of the line representing 120 freezing days per year generally correlates with "Outside Air country". That is, there are usually enough hours per year in which outside air can be used for cooling here to justify installing a Freeaire system in a typical walk-in cooler. A higher than average cost of electricity (6¢/kilowatt-hour), especially large or inefficient refrigeration equipment, or a temperature higher than 40°F for the walk-in are some of the factors that can make an outside air installation in an even warmer climate make sense.