• Study Material

    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…

  • Adventures

    Fast Easy Way To Shutdown Plant

    We were having a new refrigerant monitor system installed in the plant and the service tech asked where the breakers were located for the two areas he was was installing the equipment. Locating the one for the main monitor was easy, everything was marked. The remote monitor wasn’t that clear cut. After locating a panel I saw a breaker marked flow meter. We used to have a city water pressure monitor installed where the new remote monitor was being mounted, so I switched it off. Bad idea. it shutdown the boilers! While I was trying to get the boilers back online, the service tech come by and said he didn’t…

  • Study Material

    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…

  • Study Material

    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…