How to Calculate the Cooling Effect of Sprayed Water

The process of computing the cooling effect of water is very involved and requires high-level physics and calculation. The mathematician must take into consideration many different variables. The experimenter can find some of the data from various heat charts, but he or she must obtain much of the data from measurements and calculations. By taking the effects of heat loss to the exterior environment to be negligible, the experimenter can solve a difficult problem with only a rudimentary understanding of mathematics.

Things You'll Need

  • Two handheld digital thermometers
  • Collection bucket
  • Scale
  • Stopwatch
  • Tape measure
  • Calculator
  • Pencil and paper
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Instructions

  1. Calculation Preparations

    • 1
      Use a handheld digital thermometer to measure the temperature of the water.

      Measure the initial temperature of the water spray and the material you wish to cool with a handheld thermometer.

    • 2
      Set up a collection device to collect the sprayed water so you can measure its mass.

      Set up a bucket or collection device to catch all of the sprayed water.

    • 3

      Set up one digital thermometer on the material you want to cool and point another thermometer at the water. Spray the material with the water and, using a stopwatch, calculate the amount of time, in seconds, it takes for the water and the material to reach the same temperature; this temperature will be the "equilibrium" temperature. Record the "equilibrium" temperature and the amount of time it took for the water and material to reach it.

    • 4

      Collect all of the sprayed water and measure its mass.

    • 5

      Find the specific heat capacity of the cooled material by using a "Specific Heat of Common Substances" data chart.

    • 6

      Determine the cross-sectional area of material you want to cool with the formula A = 3.14 * (radius)^2. Measure the height of the object.

    • 7

      Convert all measurements to metric units using the following conversions:

      One kilogram = 2.20462 pounds

      One meter = 3.280840 feet

      Fahrenheit to Celsius = 5/9 * (the number of degrees Fahrenheit -- 32)

    Equating the Heat Capacity

    • 8

      Calculate the heat required to change water to steam with the equation Q1 = mass of water * the specific heat index of water at equilibrium temperature * (100 degrees Celsius -- initial temperature of water).

    • 9

      Compute the amount of energy needed to turn water into steam at 100 degrees Celsius with the equation Q2 = mass of water * latent heat of vaporization of water at equilibrium temperature.

    • 10

      Calculate the amount of energy required to change the steam from 100 degrees Celsius to the equilibrium temperature using the formula Q3 = mass of water * specific heat of water at equilibrium temperature * (equilibrium temperature - 100 degrees Celsius).

    • 11

      Calculate the energy change of the material you want to cool with the equation Q4 = mass of material * specific heat index of material at equilibrium temperature * (equilibrium temperature -- initial temperature of material).

    • 12

      Add together the figures in steps one to four; this gives an answer in kilojoules. Divide this figure by the number of seconds it took for the water and material to reach the equilibrium temperature from step two in the "preparations" section; the resultant answer will be in kilojoules per second.

    • 13

      Multiply the number of kilojoules per second by 1000; this puts the answer in joules per second so you can add it to the heat transfer of the cooled material.

    • 14

      Calculate the heat transfer of the material with the equation P1 = cross sectional area of cooled material * the thermal conductivity of the material at equilibrium temperature * ((Initial temperature of the unsprayed side of the material -- equilibrium temperature)/ height of material).

    • 15

      Add the answer from the previous step to the final answer, in joules per second, from step five. The resultant answer gives you the amount of energy loss, or cooling rate, in joules per second of the sprayed water.

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