4. A 2-mm-diameter and 10-m-long electric wire is tightly wrapped with a 1-mm-thick plastic cover whose thermal conductivity is k = 0.15 W/m °C. Electrical measurements indicate that a current of 10 A passes through the wire and there is a voltage drop of 8 V along the wire. If the insulated wire is exposed to a medium at T = 30°C with a heat transfer coefficient of h = 24 W/m².°C, determine the temperature at the interface of the wire and the plastic cover in steady operation. Also determine if doubling the thickness of the plastic cover will increase or decrease this interface temperature. Tair = 30°C Electrical wire Insulation 10 m

Question 4 The window of a room is made of 5 mm thick glass which has a thermal conductivity of 1.4 W/m-K. A heater is used to maintain the room temperature at 22 °C. Take the convection heat transfer coefficients on the outer surface of the window to be 12 W/m²-K. Take appropriate assumptions while solving this problem. (a) T₁=15°C TA -A- 1m x 3m = 3m², k=1.4W/m-K -T₂=5°C L=0.005m Figure Q2 Determine the heater thermal load to maintain the room temperature?

A 1,155 ft², 4 in. thick concrete wall has inside and outside surface temperatures of 24°C and 4°C. A 2 in. insulation batt with a thermal conductivity of k= 0.03 Btu/(h. ft. °F) is added to the wall. Determine the reduction in heat transfer rate. What is the thickness of the insulation in meters? 0.0508 x Your response differs from the correct answer by more than 10%. Double check your calculations. m What is the thermal conductivity value of the insulation batt in W/(m. K)? 0.05188 W/(mK) What is the R-value of the concrete wall (in m². K/W)? 0.022578 X Your response differs from the correct answer by more than 10%. Double check your calculations. m². K/W What is the R-value of the insulation batt (in m² K/W)? 1.9584 X Your response differs from the correct answer by more than 100%. m² K/W What is the heat transfer rate (in W) when the insulation is added? X W What is the percent reduction in the heat transfer rate? 96 x %

A 1-in Sch 40 stainless steel pipe with a thermal conductivity of 45 W/m-K can move 1,000 kg of saturated steam per hour at 150 °C. Refractory material 0.25 inches thick with a thermal conductivity of 0.025 W/m-K insulates the pipe. At a temperature of 25 °C, the pipe is exposed to the outside air. There is a 1135 W/m2 internal heat transfer coefficient.40 W/m2-K is the outside heat transfer coefficient, whereas -K. Suppose that only the radial direction is involved in steady-state heat transfer and that radiation effects are negligible. ✓ Determine how much heat is being lost through these pipes to the environment.a. 399.1 W/mb. 1525.0 W/mc.  618.4 W/md. 1128.7 W/me. none of the above √  How about the insulated pipe's surface temperature?a. 118.5 °Cb. None of the abovec. 101.5 °Cd. 216.3 °Ce. 292.2 °C