Fan and Ventilation.
—In northern climates it is a good practice to place a window at each end of the pipe or brine loft to admit a circulation of air during cold weather, locating an exhaust fan centrally over the coolers with a duct connecting with the fan from each room, drawing air from either end toward the center via the open windows in the end of the loft. This induces a circulation through the hot and cold air ducts which produces quite sufficient circulation and a uniformity of temperature in the contents in the room below.
In warm climates the use of roof plugs, and airing or venting the cooler at each filling, is, in our judgment, an expensive method, and not justified by the results obtained.
Spray System.
—The “spray system” has been rejuvenated and is very popular. This system is particularly effective for warm beef and sheep coolers and for hog coolers. It can well be installed at slaughter and shipping points, but its use in hanging rooms where beef is aged and held for sale is questionable, by reason of the probability of shrinkage owing to the rapid air circulation maintained.
Width of Rooms.
—There are various opinions as to the width and height required in a bunker room for installation of the spray system. A room from thirty-two feet to forty-eight feet wide can be successfully operated. Increased width beyond that means increased height and this, in turn, means more construction cost.
Rooms twenty-five feet wide with twenty feet pans have been built and successfully operated, but at less widths the brine is likely to carry over. The value of the spray system, and the rapidity with which a room and its contents can be cooled by its use, seems to be due to two causes, the direct contact of the air with the finely divided brine spray and the induced air currents created by a mechanical circulation.
FIG. 22.—SECTION OF COLD STORAGE HOUSE EQUIPPED WITH SPRAY SYSTEM.