insulator has a thermal conductivity of 20 W/m ºC s used to separate two heat sinks whose temperature are 600 ºC and 300 ºC, respectively. What is the minimum insulator thickness to separate these two heat sinks when the maximum heat flux between them is 250 W/m2 ?

Assume a steel ball has just been manufactured with a diameter of 10 cm and has a temperature of 877°C. The ball is cooling in air with an ambient temperature of 25°C and a convection coefficient of 20 W/m².°C. The thermal conductivity, density, and specific heat of steel are, respectively, 40 W/m.°C, 7800 kg/m³, and 450 J/kg. °C. Find the time it will take for the steel ball to reach a temperature of 35°C in the center? Neglect radiation. 13002 A

A cold-storage room is constructed of an inner layer of 11 mm of pine with thermal conductivity of 0.15 W/m K, and an outer layer of 75 mm of concrete with thermal conductivity of 0.75 W/m K. The  wall surface temperature is 253 K inside the cold room and 299 K at the outside surface of the concrete. Calculate the heat loss in W per 1 m2. Please keep one decimal and take positive value for the final answer.

A heating cube with a size of 60 x 60 cm on the inside is made of refractory brick (k=1.04 watt/(m.°c) with a wall thickness of 12 cm. The inside of the kitchen is kept at 450°c, and the temperature on the outside is 50%c, calculate the heat loss through the wall.

A house has walls made out of steel with the following properties: Thickness 300 mm Density kg/m3 7800 Thermal Conductivity w/m-K 50 Specific Heat Capacity Embodied J/kg-K 500 MJ/kg 26 Energy Cost $/kg 0.70 The time that it will take, in hours, for the interior temperature to start changing after the exterior is exposed to a sudden temperature is:

One side of a copper block 5 cm thick is maintained at 250 C. The other side is covered with a layer of fiberglass 2.5 em thick. The outside of the fiberglass is maintained at 35-C, and the total heat flow through the copper- fiberglass combination is 52 kW. What is the area of the slab?

SOlve asap plz

It is measured that a 2-m2 wall has a heat transfer rate of 7200 W. If the thickness of the wall is 0.02-m and the temperature difference on either side of the wall is 60ºC, determine the thermal conductivity in W/m K.

A solar collector and storage tank, shown in Figure (a) below, is to be optimized to achieve minimum first cost. During the day the temperature of water in the storage vessel is elevated from 25 °C (the minimum useful temperature) to tmax, as shown in Figure (b). The collector receives 260 W/m² of solar energy, but there is heat loss from the collector to ambient air by convection. The convection coefficient is 2 W/(m²*K), and the average temperature difference during the 10-hour day is (25 + tmax)/2 minus the ambient temperature of 10 °C. The energy above the minimum useful temperature of 25 °C that is to be stored in the vessel during the day is 200,000 kJ. The density of water is 1000 kg/m³, and its specific heat is 4.19 kJ/(kg*K). The cost of the solar collector in dollars is 20A, where A is the area in square meters, and the cost of the storage vessel in dollars is 101.5V, where V is the volume in cubic meters. Storage tank Collector (a) Temperature, °C tmax conforte 25°C, lowest…

the composite wall of a refrigerator has a thermal conductivity of 0.05 W/m-K and a wall thickness of 50 mm. In a room of 25 °C, the refrigerated cold space inside the refrigerator is maintained at 4 °C. Assume the inner and outer convection heat transfer coefficients are 5 W/m² K and 10 W/m².K, respectively. Neglect radiation heat transfer. Determine the rate of heat leaking into the refrigerator per unit surface area.