During a plant visit, it was noticed that a 12-m-long section of a 10-cm-diameter steam pipe is completely exposed to the ambient air. The temperature measurements indicate that the average temperature of the outer surface of the steam pipe is 75°C when the ambient temperature is 5°C. There are also light winds in the area at 10 km/h. The emissivity of the outer surface of the pipe is 0.8, and the average temperature of the surfaces surrounding the pipe, including the sky, is estimated to be 0°C. Determine the amount of heat lost from the steam during a 10-h-long work day. Steam is supplied by a gas-fired steam generator that has an efficiency of 80 percent, and the plant pays $1.05/therm of natural gas. If the pipe is insulated and 90 percent of the heat loss is saved, determine the amount of money this facility will save a year as a result of insulating the steam pipes. Assume the plant operates every day of the year for 10 h. State your assumptions.
Energy transfer
The flow of energy from one region to another region is referred to as energy transfer. Since energy is quantitative; it must be transferred to a body or a material to work or to heat the system.
Molar Specific Heat
Heat capacity is the amount of heat energy absorbed or released by a chemical substance per the change in temperature of that substance. The change in heat is also called enthalpy. The SI unit of heat capacity is Joules per Kelvin, which is (J K-1)
Thermal Properties of Matter
Thermal energy is described as one of the form of heat energy which flows from one body of higher temperature to the other with the lower temperature when these two bodies are placed in contact to each other. Heat is described as the form of energy which is transferred between the two systems or in between the systems and their surrounding by the virtue of difference in temperature. Calorimetry is that branch of science which helps in measuring the changes which are taking place in the heat energy of a given body.
During a plant visit, it was noticed that a 12-m-long
section of a 10-cm-diameter steam pipe is completely
exposed to the ambient air. The temperature measurements
indicate that the average temperature of the outer surface of
the steam pipe is 75°C when the ambient temperature is 5°C.
There are also light winds in the area at 10 km/h. The emissivity
of the outer surface of the pipe is 0.8, and the average
temperature of the surfaces surrounding the pipe, including
the sky, is estimated to be 0°C. Determine the amount of heat
lost from the steam during a 10-h-long work day.
Steam is supplied by a gas-fired steam generator that has
an efficiency of 80 percent, and the plant pays $1.05/therm
of natural gas. If the pipe is insulated and 90 percent of the
heat loss is saved, determine the amount of money this facility
will save a year as a result of insulating the steam pipes.
Assume the plant operates every day of the year for 10 h.
State your assumptions.
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