Relative Humidity (RH) is the measure of the quantity of water vapor in the air at a certain temperature. Maintaining desired pile temperature is important but equally important is to maintain the optimum humidity, explains JD Wasir, Sr. Vice President at Ontario, Canada based Kooljet Refrigeration Systems.
“RH plays a vital role, as it affects the rate at which produce transpire,” JD Wasir says. “For the best potato storage conditions, it is of great importance that optimum humidity levels must be maintained during the storage season. In general, high relative humidity is required for storing spuds for a longer shelf life,” he says.
Wasir points out that produce lose moisture due to the vapor pressure difference between the product and the surrounding air. High relative humidity reduces the vapor pressure difference between the potato surface and the unsaturated air, thus reducing vapor losses.
“A small temperature change can cause dramatic change in relative humidity. For example, potato storages maintained at 50°F at 90% RH will cause more shrinkage than a storage building maintained at 40°F and 90% RH. Keep in mind that potatoes are sold by weight and not by volume,” Wasir says. “The water loss not only deteriorates the product quality but also reduces the profit margins for the growers.”
He notes that any refrigeration system is a in effect a “natural” dehumidifier. When the outlet air temperature from the evaporator coil is reduced below the Air Dew Point temperature, the water condenses from the air, making the air drier.
According to Wasir, Kooljet Systems are equipped with Optimal Designed Evaporator Coils with a minimal temperature differential between the evaporator coil temperature and produce storage temperature. The Minimal Evaporator Coil Temperature Differential avoids air to cool below
its dew point temperature. “Kooljet Systems helps to maintain high RH levels in the storage facility, and minimizes water loss from the produce, maximizing product quality and value.”
JD Wasir notes that Kooljet has a global footprint, and has been assisting farmers since 2001. Kooljet systems are used by many companies and potato operations in Canada and elsewhere – including McCain Foods, Canada-China, and Calbee Potato in Japan.
Further information:
On the web: www.kooljet.com
JD Wasir, Sr. Vice President: jdwasir@kooljet.com or 1-866-748-7786 (in North America) +1-519-752-2424
