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    Refrigeration Test

    Define: Humidity – Amount of moisture in the air. Calorie – The quantity of heat required to raise the temp of one gram of water one degree celcius. Absolute Pressure – psia – Pressure in pounds per square inch above a complete vacuum. Gage Pressure – psig – Pressure in pounds per square inch above normal atmospheric air pressure. 14.696 psi What refrigerant is used in a centrifugal system? Dielene, R11, R113, Methylene chloride What is a hermetic compressor? Motor and compressor in a gas tight housing. What is a hermetic system? A closed centrifugal system to include the compressor, condenser and cooler. The refrigerant cools the m What is…

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    Cooling Tower Terminology

    Cooling Tower Terminology Approach – difference between cold water temperature and the measured wet-bulb temperature. Bleed Off – is the circulating water in the tower which is discharged to waste to help keep the dissolved solids concentration of the water below a maximum allowable limit. As a result of evaporation, dissolved solids concentration will continually increase unless reduced by bleed off. Blowdown – water intentionally discharged from the cooling system to control concentrations of salts and other impurities in the circulating water British Thermal Unit (BTU) – the heat energy required to raise the temperature of one pound of water one degree Fahrenheit in the range from 32° F to 212° F…

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    Boiler Heating Surface

    This is the formula used to calculate the heating surface of a power plant boiler: An HRT boiler is 5 ft in diameter and 16 ft long. It contains 60 tubes of 3 inch outside diameter and 2.732 inch inside diameter. Find the boiler-heating surface. Take the inner surface of tubes, half of the shell surface, and two-thirds of the tube plate area, less the area of the tube holes.   Circumference of shell = 5 * 3.14 = 15.700 ft Half circumference of shell = 15,700 * ½  = 7.850 ft Area of half of shell = 7.850 * 16 = 125.60 sq. ft   Inner circumference of fire…