Check out a recent profile by Mary Ann Price of the Canton Citizen about Freeaire:
Walk-in cooler owners have often asked if it is really a good idea to switch off the evaporator fans inside their coolers. Sometimes, this is after a refrigeration serviceperson has flatly declared that the evaporators should never be turned off. Understandably, people are concerned with two key issues. First, they want to make sure the system works and keeps the cooler and its valuable contents properly cold. Second, they do not want to risk damaging their system. As I’ll discuss below, intelligently shutting down your evaporators does not compromise the system’s ability to keep the cooler at the desired temperature, nor does it create potential to damage the compressor system.
First, to get some context, let’s look at how things currently work. Since the earliest commercial mechanical refrigeration systems were installed, evaporator fans have been kept running constantly, 24/7/365. The main reason for this is simple: evaporator coils can become clogged with ice. An iced or frosted evaporator does not have sufficient airflow through it, so it does not cool properly and creates the risk that a cooler will get too warm. It is essential to completely defrost the evaporator coils periodically to provide effective and efficient refrigeration. A traditional system relies on an oversized compressor and a time clock to ensure that the compressor stays off long and often enough when the compressor is not running to melt all the ice. In the old days, before the advent of computer controls, it was safer and easier to simply keep the evaporator fans running than to risk not having them on when needed. Determining when they can safely and efficiently be switched off is too much for old-fashioned mechanical controls.
A modern computerized control like the Freeaire® Cooler Controller can handle that job. When it determines that it is time for a defrost cycle, it will shut down the compressor so that no refrigerant is coming into the evaporator and will run the evaporator fans to warm evaporator coils until they reach a target temperature that indicates that there is no ice remaining. In other words, the Controller will run the fans only long enough to completely defrost the system, but no longer.
Some suggest that it is necessary to constantly run the evaporator fans during the compressor’s off cycle to provide adequate circulation to prevent temperature stratification or temperature variations within the cooler. That job can be easily done with much less energy by installing a low wattage, but high airflow, circulating fan that operates whenever the evaporator fans are off or by switching on the evaporator fans for a few seconds every few minutes.
The second issue that people bring up is whether turning the evaporator fans on and off is somehow dangerous for the system. An “old school” refrigeration guy that brings this up is probably concerned with “slugging” the compressor. In English this means that refrigerant would be sent back from the evaporator to the compressor as a liquid rather than as a gas. This could happen if the compressor is on, sending refrigerant to the evaporator, but the evaporator fans are not running. Our Cooler Controller is designed so that whenever the compressor is running, so are the evaporator fans. This helps to ensure that the refrigerant evaporates and returns to the compressor as a gas.
To prevent slugging of the compressor, however, it is even more essential that two common compressor safeguards be used, especially in winter in a cold climate. The first is a pumpdown solenoid that causes almost all the refrigerant to be pumped out of the evaporator and the return pipe and to be safely stored on the output side of the compressor before it is switched off. The second safeguard is a crankcase heater that makes sure that any refrigerant that does remain behind stays as a gas that cannot harm the compressor when it resumes operation. These two measures are particularly important with a Freeaire system using outside air, since there could be many hours, weeks, or even months between when a compressor shuts off and when it finally switches on again. All Freeaire systems should have these safety features installed if they aren’t already.
Another concern comes from some people’s perception that repeatedly switching the evaporator fan motors and relays will harm the motors. In fact, it is better to have them off than on. Like most mechanical devices, an electrical motor, including a modern ECM evaporator fan motor, is subjected to less wear and tear when at rest than when running constantly. Solid-state relays can switch evaporator fans off and on many times a day for decades without failing.
A Freeaire® system saves energy by not running the evaporator fans unnecessarily. However, this in no way compromises proper refrigeration or does harm to any part of the system.
…well, not quite free, but as close to free as any of us are going to get.
One satisfied customer in upstate New York has used its compressors and evaporators for a total of 45 minutes through the first two months of 2015!!! It has been keeping its 400,000 cubic foot beer warehouse at a cool 38 degrees using only four industrial Polar Power Packages.
Check out the red line on this chart. The only time the compressors were on was that small little squiggle at the beginning of January.
Check out NECN’s feature on the Freeaire system at Curtis Liquors in Cohasset, MA on its Money Saving Mondays segment:
Peter Howe, NECN’s business reporter, interviews Rick Curtis of Curtis Liquors, as well as Ken Strachan and David Mac Isaac and learns how Curtis Liquor is savings 45,000 kWh per year and thousands of dollars per year with his new Freeaire system.
We are working with a client in Alaska right now. With their 38,000 cubic foot cooler, set at 38F, we can see a whopping 172 days per year of Free cooling using
Freeaire’s new Industrial Polar Power Package. That’s six months of fresh, filtered outside-air cooling – now that’s Polar Power!
There have been a couple of significant ribbon cuttings in the Mad River Valley recently. First there was the Mad River Food Hub, and then this week there was the official ‘power cord cutting’ ceremony at Small Dog Electronics to mark the commissioning of a dedicated solar array at their headquarters in Waitsfield, Vermont. The opening was attended by Vermont Governor Peter Shumlin, staff from Small Dog, and Freeaire’s Richard Travers.
The 42kW solar panel array is projected to generate the power needed to run Small Dog’s retail store in South Burlington as well as half of the power for the company’s Waitsfield headquarters.
Solar power, however, is not Small Dog’s only investment in alternate energy technologies.
A Freeaire system has regulated the temperature of the company’s server room since 2008, using cool Vermont air to safely and reliably cool sensitive electronic equipment. A server room can be kept at a relatively high temperature (65 – 70 degrees Fahrenheit) meaning that outside air can be used as a primary cooling medium almost year round. Additionally, Small Dog recently upgraded their Freeaire system to the latest Cooler Controller, which includes humidity monitoring and management settings that further increases the utility of the system in data center environments.
Polar Power and Solar Power — They go together like Yin and Yang. Props to Small Dog for their ongoing commitment to energy conservation and sustainability (and reduced energy bills!).
Tuesday January 17th, 2012 was an important day for the agricultural sector of Vermont’s economy — marking the official opening of the Mad River Food Hub in Waitsfield, Vermont, adjacent to the Freeaire offices.
“Conceived in 2010 and constructed in 2011, the Mad River Food Hub is the first fully equipped, licensed vegetable and meat processing facility in the State of Vermont (& NE USA). It offers farmers and food producers affordable, daily rental of state licensed meat and vegetable processing rooms, together with on-site storage and distribution services to local market outlets.
The design and implementation of the Mad River Food Hub’s services relied extensively on the research, data and analysis from the State’s Farm to Plate Strategic Plan. Funding for this facility was provided by a number of state, federal and foundation funds as well as private investment.” — From Vermont Business Magazine
The food hub is a conceived as a central facility that can be shared between multiple agricultural and food processing businesses, reducing overhead and making it easier for small business to bring locally produced food to market.
Vermont Governor Peter Shumlin stressed the importance of the agricultural sector to the state’s economy in his opening remarks. The MRVFH compliments a similar facility in Hardwick, Vermont and there are plans to add a third food hub in the southern part of the state.
The food hub features large-scale freezer and cooler spaces. Advanced Freeaire Cooler Controllers optimize both of these spaces for maximum energy efficiency and the cooler (pictured above) also has a Freeaire Polar Power package installed, taking advantage of outside air for cooling.
Freeaire’s Richard Travers and Brad Long demonstrated the sophisticated capabilities of the Cooler Controllers for a large delegation of state legislators.
Heard of double IPAs? How about double Freeaire systems? Sean Lawson of Lawson’s Finest Liquids has a newly installed Freeaire system at his small Warren brewery and will also be using food hub’s facilities.
As 2011 comes to a close, we’d like to take a moment to acknowledge the efforts of our Freeaire partners throughout North America who have participated in trainings at our offices in Waitsfield, Vermont.
While some of our partners are from our own backyard — Vermont and surrounding Northeast states — we also have partners from the mid Atlantic, upper Midwest, and throughout Canada. Our most remote dealer is located in the Northwest Territories where winters are very long, dark and cold and allow for ample opportunity to take advantage of outside air for cooling.
Our partners have helped spread the word about Freeaire’s environmentally friendly commercial refrigeration solutions. The image above shows how the word is getting out about Freeaire —
- web page
- van graphics
- newspaper advertising
We appreciate these efforts and the efforts made by all of our valued business partners, and we wish all a prosperous 2012.
If you are an HVAC or energy efficiency professional looking to grow your business in 2012 by offering your customers the most efficient commercial refrigeration components, please contact us to learn about how you can become a Freeaire partner and to learn about upcoming 2012 training opportunities.
If you are an end user interested in the Freeaire system, contact us with some basic information on your application and we’ll be happy to direct to you to a qualified partner in your area.
Unexpected Freeaire System Benefits: Ethylene Gas Dispersion (Apples and Carrots Stored Together, Happily)November 21st, 2011
Freeaire systems provide many benefits, including:
- Reduced energy use saves money.
- Reduced energy consumption leads to reduction in a business’s ‘carbon footprint’.
- Less system run time means reduced wear and tear and maintenance for conventional refrigeration equipment.
But that’s not all.
In the area of the unexpected benefits, bringing fresh, filtered outside air into a cooler can help store fresh produce for extended periods, and also allows for diverse products to be stored together.
A walk in cooler is a closed environment, the atmosphere is usually stale, musty and somewhat unpleasant. When fresh produce is stored in such an enclosed space, the ethylene gas given off by certain fruits and vegetables can accelerate ripening, with detrimental consequences:
Ethylene is a natural plant growth regulator, produced by “climacteric fruit”, such as apples, tomatoes and bananas (see Table 3). It is a colorless gas that is thought to coordinate the ripening of these fruits. Ethylene gas is also produced by tractors and other equipment with internal combustion engines and can accelerate ripening of climacteric fruit. Ethylene can have a number of deleterious effects on other products. These include faster yellowing and senecence of leafy vegetables, browning reactions such as russet spotting on lettuce leaves, development of bitterness in carrots, and sprouting of potatoes. (Source: Cornell University Ecogardening Factsheet #19, Summer 1999)
When a walk in cooler has a Freeaire Polar PowerTM package installed, the system uses highly filtered, cold outside air as a cooling agent and turns off evaporator fans and condensing units for weeks or even months at a time. The air that can be brought in will vary in relative humidity, from very moist to very dry. The Freeaire system uses a combination temperature and (optional) humidity sensors to control the use of outside air and to regulate humidity.
Real world examples:
- One Freeaire owner supplemented the moisture inside a walk-in cooler full of carrots and other root crops with a humidifier that added enough moisture to maintain a temperature of 33°F with a relative humidity of almost 95%, even when using the extremely dry air of mid-winter.
- Another owner reported excellent results over a winter of storing carrots and apples together, a combination that is usually unsuccessful due to ethylene gas given off by the apples causing premature ripening of the other crop.
The exchange of air inside the cooler keeps the ethylene levels very low. Additionally the air quality of many coolers has benefited from using outside air brought in by their Freeaire systems. Even coolers that smelled bad or stale and musty before due to mold spores or un-swept floors littered with food scraps can “smell as fresh as all outdoors” with a Freeaire system.
Disclaimer: We have not formally studied or quantified the precise benefits of ethylene gas dispersion via Freeaire systems. The anecdotal evidence presented above, however, represent real-world examples of two Freeaire system owners who have shared their experiences with us.
Freeaire systems have been used successfully in a wide variety of environments — breweries, food processors, server rooms, etc. — almost any situation where a product needs to be kept in a cooler with a size of 1000 cubic feet or greater. It’s a very flexible, reliable system with many possible applications.
That being said, Freeaire systems have always found particularly wide acceptance in convenience stores, going all the way back to when founder Richard Travers had his “eureka!” moment on a cold Vermont winter night and started tinkering with the refrigeration system at the Warren Store.
Since that moment more than 20 years ago, Freeaire systems have been installed in hundreds of separate retail locations throughout the United States and Canada.
The reason that Freeaire systems are popular in convenience stores is simple: Refrigeration makes up a large percentage of the overall energy consumption in this environment.
The Freeaire system dramatically reduces energy consumption over conventional refrigeration systems and produces significant energy savings.
The president of Champlain Farms, a 38 store chain in Vermont and New Hampshire, said installing Freeaire systems in all of his stores was “one of the best business decisions he ever made” (read the complete case study here).
With this track record in mind, we’re excited to be participating in the NACS (National Association of Convenience Stores) annual trade show, October 1 – 4, in Chicago. Going to an event of this magnitude is a big effort for us but we know that we have a story to tell. We are looking forward to meeting with prospective customers in a face-to-face environment. Our next-booth-neighbors will be Tim Hortons so come by and smell the doughnuts!
Planning on being in Chicago for the show? Please come by booth 2950 and say “Hi” — we’d be thrilled to meet you!