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Flower Refrigeration 101

Flower Refrigeration 101

IT’S NOT JUST ABOUT MAKING THINGS COOL

By Andrew Joseph

The first clue we at Florists’ Review can give to those examining the concept of adding a cooler unit for their flower businesses—it’s right there in the headline: “Flower.”It can be a flower display refrigerator or a walk-in flower cooler display unit—each performing the same function of displaying and keeping cut flowers looking fresh, but each providing florists with options depending on finances and space availability.Despite the temptations to pick up something cheap and simple spotted at an auction or some online used-goods site,refrigeration for one’s flower business is a complicated matter and should be treated as such or the old pros who already have their own perfect cooling systems in place—good for you, but keep reading. We are going to explain the five “W”s of refrigeration and how a flower refrigerator is different from other types of coolers—and why you need one specific to the profession. (Actually, we won’t deal with “Who” specifically to purchase from because we leave that decision to you—so really, there are only four “W”s.) However, we will provide some intel on how standard refrigeration units work, in an effort to educate. It’s always better to have some knowledge of the subject before blindly shelling out money for maintenance and repairs because you don’t care. You should always care. And, keeping in line with “the more you know”-style PSA (public service announcement), we’re also going to examine some of the latest affordable technology available in the flower refrigeration segment

ABC: Always Be Cooling

THE WHY

Here’s a sobering fact: the cut flowers you sell are dead—only they don’t know it quite yet. Cut flowers are the lifeblood of the flower industry, but when they arrive at your shop, they have a limited shelf life and must be sold relatively quickly,or you risk losing the money invested in their purchase.The higher the surrounding temperature,the quicker a cut flower “breathes” and releases moisture. This dehydrates the flower, resulting in wilting, stem sag, petals that won’t open and petal edges that brown—creating an unloved and unsold flower.Refrigeration—i.e.,low temperatures—retard the aging process of cut flowers. Optimally, to achieve the maximum shelflife for nontropical cut flowers in your store, a refrigeration system requires a chilling temperature range of 33 F to 36 F.

No, wait, it’s 33 F to 35 F, or is it 34 F to 37F? It’s definitely in the low to mid-30s. Oris it in the low 40s? Th ere is all kinds of“expert” information out there.Th e truth is, the optimal storage temperature for cut flowers depends on the type of flower—and the condition of the flower when you purchased it from the wholesaler or grower. Additionally,the brand of flower refrigeration unit can play a part in determining the optimal range. For example,Wayne Laue owner of Flot-Aire Floral Refrigerators in Rolla, Mo., says that for his flower cooling units, he has always recommended flower storage temperatures between 38 F and 42 F.

Perhaps the safest thing to state is that the optimal temperature requirements for flowers will vary depending on the type of flower. For most flowers, a temperature range between 33 F and 42 F is a rule of thumb—although much research shows that for most nontropical flowers, temperatures above 38 F are too high. However, for flowers that are sensitive to cold, like tropical flowers, temperatures slightly above 50 F will be called for. Aside from temperature, maintaining cut flower health is highly dependent on humidity levels in a floral cooler, as well. Using a proper floral cooler is crucially important to the length of time a flower holds its beauty, says Lauer. “A proper flower cooler will hold a flower for weeks, as long as the flower was fresh when initially placed inside.”

Flower Cooler Specifics

THE WHAT

When is a cooling unit for flowers not a floral cooling unit? When it’s not a floral cooling unit. For those thinking about using an inexpensive but cool-looking refrigeration system not specifically designated for cut flowers—don’t. As mentioned, it’s not just about keeping flowers cool.

Unlike a pop/soda cooler in a convenience store or a household fridge, a flower refrigerator—regardless of make or model—is designed to gently circulate cooled air to avoid damaging the flowers. A beverage cooler, for example jets out cold blasts of air. Most important, however, a floral cooler offers the much-needed humidity factor. With an applied ambient humidity ranging from 80 percent to 95 percent, a flower cooling unit slows cut flower dehydration, resulting in longer-lasting flowers. Why the 15 percent variance in humidity? Again, it depends on the type of cut flowers one is storing. You want moist air—not dry air—inside the refrigerator, but, if you see water droplets forming on petals and/or foliage, the humidity is too high. Beverage coolers are designed to generate low humidity levels. Because cut flowers need high humidity, your inventory will likely die three to five days sooner when stored in a refrigerator not designed specifically for cut flowers.

Last, but not least, there’s also ethylene management. Ethylene is a gas produced by some—not all—cut flowers, as well as fruits and vehicle exhaust, among other things. It can cause rapid aging of cut flowers as well as petal and leaf loss. While lower temperatures and proper ventilation can both aid in the reduction of ethylene production, air exchange via the opening and closing of a cooler’s door can also mitigate the effects of ethylene. To reiterate, cut flowers need to low temperatures, high humidity levels and gently circulating air, and these things can be achieved only via the use of a true flower cooler.

Location, Location

THE WHERE

In real estate, a common adage is “location, location, location,” and the same holds true within your flower shop’s real estate. Even though many florists put little thought into where in a shop a floral cooler is placed, it does matter. It’s a no-brainer that we want a floral shop to not only look aesthetically pleasing inside and out but also function perfectly. We have to consider material factors, such as the need for the cooler to be in an easy-to-access part of the shop for both employees and customers. Should it also be located in a spot where it can capture the eye of someone walking past your shop? Or, because you already have a great window display, can the cooler capture attention elsewhere? And shouldn’t it also be dependent on electrical outlet placements?

What you don’t want, however, is to place your flower cooler in direct sunlight. Energy usage is the critical factor here. In a sunnier and, thus, warmer location, a flower refrigerator cooling unit will need to consume more energy to maintain its interior coolness and humidity levels, which means higher electrical bills and, quite possible, a shorter life for the cooler—or, at least, some of its parts. A flower refrigerator placed in direct sunlight will utilize 70 percent more energy than one placed in “shadier” locations.

The Art of Cool

THE HOW

How does a floral cooler work? “With the refrigeration of flowers, evaporators are sized to provide optimal low air movement—centered on the cooler’s ceiling to evenly distribute the air,” Lauer explains. “Plug-in display-type coolers employ evaporators that blow the air gently down the inside back wall of the cooler. The other key specific to proper cut flower storage is maintaining a high humidity level.” Lauer says that Flot-Aire provides oversized low-air evaporators that are specifically designed to maintain high humidity levels. Finally, Lauer also points out Flot-Aire’s condensing units are engineered for heavy usage applications. Another factor that manufacturers of cut flower coolers give special consideration to is insulation, Lauer mentions, which can range from inside the walls of the coolers to the types of doors, windows and seals used—and can also involve lighting inside the cooler.

“Fluorescent lights are a thing of the past,” Lauer notes. “Bright LED (light- emitting diode) lights are usually utilized in floral coolers today. A low-radiation, full spectrum LED lighting system will showcase flowers’ natural colors.”

There is nothing wrong with purchasing a used floral cooling unit—as long as it’s not too old. But Lauer makes a strong point for purchasing new as a better option: energy efficiency. “From an energy perspective, today’s compressors, fan motors, lights and insulations are much more efficient,” he reports. Along with the more energy-efficient lighting systems, new flower refrigerators use more energy-efficient wall panels, fan motors and compressors, which result in lower electricity usage and costs.

New Technologies

THE WHEN

What does the future hold? We’re not seers here, but there is a bit of new— and affordable—technology currently available—the twist being you have to build it yourself.

While not everybody is a DIYer, the option of constructing your own CoolBot walk-in floral cooler, from Store It Cold, is an intriguing option.

The CoolBot system operates multiple sensors, a heating element and a programmed micro- controller to make a standard portable air- conditioner cool your storage and/or display area. The company does not mention humidity controls, so perhaps adding a portable humidifier could be discussed.

Per Johnny’s Selected Seeds, the CoolBot can transform “any well-insulated room, shed or trailer into an affordable walk-in cooler using a standard air conditioner,” but warns that a range of 42F to 45F is what is generally afforded. That said, the size of the air-conditioner used in relation to the dimensions of the walk-in cooler you construct can affect—and possibly lower—temperature levels.

For proper cut flower cooling, the “cooler” or cold room must be relatively airtight, with good insulation, and per Johnny’s, the door should not be opened more than six times per hour. If your requirements are for more accessibility, then perhaps a larger, or even multiple, air-conditioning units and more CoolBots would do the trick. We can state that an oversized air-conditioning unit will allow for lower fan speeds, to avoid gusting against your flowers.

Not all brands of air-conditioners are compatible with the CoolBot technology, however, and those that are must have a digital display and automatic restart.

Despite the limitations noted here, CoolBot can be a cost-effective option, with savings achieved via lower purchase and installation costs and, possibly, through lower monthly electricity bills and fewer technician visits compared to traditional refrigeration systems.

For those who already have a proper— but perhaps aging—floral refrigerator, a technology update may be called for, such as adding a readily-available and cost-effective high-precision TMP117 temperature sensor that monitors the refrigerator’s temperature and provides a warning if it gets too hot or too cold for your flowers.

Know Your Cooler Parts

Evaporator Coil : receives the liquid refrigerant

Condensing Unit: allows heat transfer

Expansion Valve: controls refrigerant flow to evaporator

 Compressor: a pump that pressurizes refrigerant

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