During a visit to a plastic sheeting plant, it was observed that a 60-m-long section of a 2-in nominal (6.03-cm-outer-diameter) steam pipe was extended from one end of the plant to the other with no insulation on it. The temperature measurements at several locations revealed that the average temperature of the exposed surfaces of the steam pipe was 170°C, while the temperature of the surrounding air was 20°C. The outer surface of the pipe appeared to be oxidized, and its emissivity can be taken to be 0.7. Taking the temperature of the surrounding surfaces to be 20°C also, determine the rate of heat loss from the steam pipe. Steam is generated in a gas furnace that has an efficiency of 78 percent, and the plant pays $1.10 per therm (1 therm = 105,500 kJ) of natural gas. The plant operates 24 h a day 365 days a year, and thus 8760 h a year. Determine the annual cost of the heat losses from the steam pipe for this facility.
During a visit to a plastic sheeting plant, it was
observed that a 60-m-long section of a 2-in nominal (6.03-cm-outer-diameter) steam pipe was extended from one
end of the plant to the other with no insulation on it. The
temperature measurements at several locations revealed that
the average temperature of the exposed surfaces of the steam
pipe was 170°C, while the temperature of the surrounding
air was 20°C. The outer surface of the pipe appeared to be
oxidized, and its emissivity can be taken to be 0.7. Taking
the temperature of the surrounding surfaces to be 20°C also,
determine the rate of heat loss from the steam pipe.
Steam is generated in a gas furnace that has an efficiency
of 78 percent, and the plant pays $1.10 per therm (1 therm =
105,500 kJ) of natural gas. The plant operates 24 h a day 365
days a year, and thus 8760 h a year. Determine the annual
cost of the heat losses from the steam pipe for this facility.
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