Chapter 1, Problem 1.42P

Question:- A cylindrical steel tank with a diameter of 3 m and height of 4.4 m is used to store chilled water (at 9.3 °C) as part of an air conditioning system for a building. The heat transfer (convection) co-efficient for the surface of the tank in contact with the water in this application is 15 W/(m2.K). Given the surface temperature of the metal tank is 40 °C. At what rate must heat energy be removed from the water just to maintain its temperature constant at 9.3 °C ? Assume the tank is an enclosed cylinder and that the tank is always full. Note - the thickness of the tank is not relevant to this problem. Work in base SI units.

An isolating wall (made up of 2-10mm thick plywood with 5mm woven silica sheet in between) encloses a steam-room to prevent the outside area from having the same temperature as the inside of the room. If the total area of the wall is 100 sq.m. and coefficient of thermal conductivity (k) for plywood and silica sheets are 0.12 and 0.015 W/mK respectively, what is the rate of heat transfer if the inside temperature is 800 °C while the outside is 42°C? answer must be in Watts

A transparent film will be glued onto an upper surface of a solid plate within a heated chamber. For common gluing, the temperature between the glue, a film and the solid board must be kept at 70 °C. The transparent film has a thickness of 1 mm and thermal conductivity 0.05 W/mK, while the solid board is 13 mm thick. thickness and thermal conductivity of 1.2 W / mK. Inside the climate chamber, the convection heat transfer coefficient is 70 W/m²K. The bottom surface of the solid plate is kept at 52 °C, determines the temperature inside the heated chamber and the temperature of the surface of the transparent film. Assume negligible thermal contact resistance.

An isolating wall (made up of 2-10mm thick plywood with 5mm woven silica sheet in between) encloses a steam-room to prevent the outside area from having the same temperature as the inside of the room. If the total area of the wall is 100 sq.m. and coefficient of thermal conductivity (k) for plywood and silica sheets are 0.12 and 0.015 W/mK respecțively, what is the rate of heat transfer if the inside temperature is 800 °C while the outside is 42°C? answer must be in Watts * Your answer

The building is in an environment of 30 ° C. The walls are covered with an insulating layer of 4 cm thickness whose thermal conductivity is 1.8 W / (m K), and the temperature of the inner wall of the insulation is 320 ° C. Wall heat loss to the environment occurs by convection. Calculate the convection heat transfer coefficient value on the outer surface of the insulation to ensure that the outer surface temperature does not exceed 40 ° C. Convection coefficient = AnswerW / m² ° C.

Steam is being transported in a pipe at a chemical production facility in Gebze, Kocaeli. Theouter diameter of the pipe is 8 cm, and the surrounding air temperature is 20 °C. On the surface of thepipe, the combined heat transfer coefficient is 35 W/m2*K. The surface temperature of the pipe is 150 °C.Steady-state conditions exist.(a) What is the rate of heat loss from the pipe to the surroundings?(b) The power used to generate the steam is obtained from natural gas. Perform an online search forapproximate values of the calorific value of natural gas, as well as the cost of natural gas per cubicmeter, and estimate the financial loss due to heat loss from this steam pipe within a period of oneyear. Indicate your sources clearly in your answer.

3 Brass cube "p = 8530 kg/m , c= side length =9 mm, are annealed by heating them first to 813°C in a furnace and then allowing them to cool slowly to 130°C in ambient air at 28°C. If the average heat transfer coefficient is 19.9 W/m .°C, If 2204 balls are to be annealed per hour, what is the total rate of heat transfer (watts) from the balls to the ambient air? 380 J/kg.°C, k = 110 W/m.°C, a = 33.9E-6 W/m.°C",

The handle of a saucepan, 30 cm long and 2 cm in diameter, is subjected to 100 degree Celsius temperature during a certain cooking operation. The average unit surface conductance over the handle surface is 7.35 W/m2 degree in the kitchen air at 24 degree Celsius. The cook is likely to grasp the last 10 cm of the handle and hence the temperature in this region should not exceed 38 degree Celsius. What should be the thermal conductivity of the handle material to accomplish it? The handle may be treated as a fin * .insulated at the tip

AnswerCalculate the total resistance (in K/W ) through the vertical walls of a boiler furnace 20 m in area. The walls are constructed from aninner fire brick wall  30 cm thick of thermal conductivity 0.4 W/mK, a 5 mm thick steel protective layer of thermal conductivity 0.055kW/mK and a layer of ceramic blanket insulation of thermal conductivity 0.2 W/mK at 8 cm thickness. The inside temperature of thefire bricklayer was measured at 600 C and the temperature of the outside of the insulation 60 C.