RP-1138 -- Methods to Calculate the Colling Times and Loads of Fruits and Vegetables Using Hydrocooling PDF

The origin of the refrigeration industry and, by far, its most significant application is the preservation of food. It is known that the cooling of food effectively reduces the activity of micro-organisms and enzymes, thus retarding deterioration. In addition, prompt precooling of fruits and vegetables, that is, the removal of field heat prior to shipping, processing or storage, maintains preharvest freshness and flavor.

Hydrocooling is a form of precooling in which the product is sprayed with or immersed in an agitated bath of chilled water. The refrigeration capacity needed for hydrocooling is much greater than that required for holding a product at a constant temperature. Therefore, it is imperative to have an adequate amount of refrigeration for effective hydrocooling, however, it is uneconomical to have more refrigerating capacity available than is needed. Hence, the design of hydrocooling systems requires accurate estimation of the hydrocooling times of fruits and vegetables as well as the corresponding refrigeration loads. Numerous methods for redicting the hydrocooling times of fruits and vegetables have been proposed, and the designer is faced with the challenge of selecting an appropriate estimation method from those available.

Therefore, this project reviewed the state-of-the-art in estimation methods for the hydrocooling times of fruits and vegetables. Estimation methods, suitable for inclusion in the ASHRAE Handbook chapter, were selected. Step-by-step algorithms were developed from the selected hydrocooling time estimation methods. The Handbook chapter, entitled "Methods of Precooling Fruits, Vegetables, and Cut Flowers," will be edited to reflect the results of this research, including a detailed description of the step-by- step algorithms. In addition, a computer program, based upon the selected estimation methods, was developed for calculating the hydrocooling times and refrigeration loads of fruits and vegetables.

Principal Investigator: Byan R. Becker, Ph.D., P.E. Member ASHRAE and Brian A. Fricke, Ph.D., E.I.T. Student Member ASHRAE

Conducted: Sept. 1999 - Feb. 2001

Sponsored by: B E C O, Becker Engineering Company