The above comparison shows that theory and practice approach very closely to a common line, although in the calculation the factor of specific heat of the meat is ignored, and in practice this may well be left out, as specific heat of meats at various temperatures has by no means been accurately established.
Chilling Lard.
—The chilling of lard is a severe task on refrigerating equipment owing to the very heavy duty imposed in a short time. For example, with an eight-foot lard roll turning off 4,000 pounds per hour and changing the temperatures of the lard from 90° to 50° F. requires a very large compressor capacity per hour.
Summary—Computations.
—Assuming the killing of 100 cattle and 250 hogs per day; making 10,000 pounds of lard, fifteen tons ice; maintaining a freezer of 100,000 cubic feet and the small work connected with the establishment:
For 100 cattle killed daily, and storage of 400 hanging, about 6,500 square feet area of cooler would be required; the height of this with the lofts would be about twenty-two feet or a capacity of 143,000 cubic feet.
For 250 hogs daily or 750 total hanging, there would be required 3,000 square feet of floor area and a height of 18 feet or 54,000 cu. ft.
The above number of hogs daily would also require a storage or cellar capacity based upon one hundred pounds meat sent to cellar for a turn over in sixty days equal to storing 1,500,000 pounds of product, or 15,000 to 20,000 square feet of floor area, requiring 200,000 cubic feet of building space.
Ten thousand pounds lard daily in four hours running would require the extraction of about two tons of duty, but by reason of the heat transmission and the low temperature brine necessary would require twelve tons duty while applied.
Fifteen tons daily ice making capacity requires about 30 tons refrigerating duty, allowing for radiation and other losses.