a piece of beef steak 7 cm thick will be frozen in the freezer room -40 degrees Celsius This product has a moisture content of 73% density 970 kg / m³ and a thermal conductivity of 1.1 W / (m K) frozen using the plank equation. This product has an initial freezing temperature of -1.75 degrees Celsius and the movement of air in the raw chamber gives a convection heat transfer coefficient of 10 W / (m² K). tf =

Insulating material is used to reduce heat loss from the heating furnace walls to the room. The surface temperature of the insulating material is 100 ° C and the other surfaces 25 ° C. Allowable heat loss up to 160 W / m2 from the wall. If the thermal conductivity of the insulation material is 0.05 W / (m ° C), calculate the required thickness of insulation. insulation thickness = Answer cm

Estimate the thermal conductivity of the meat at 35 ° C. (Air content = 62.0% wet basis). Thermal conductivity of the material = AnswerW / m ° C

A piece of beef steak 7 cm thick will be frozen in the freezer room -30 ° C. This product has a moisture content of 73%, a density of 970 kg / m³, and a thermal conductivity (frozen) of 1.1 W / (m K). Estimate the freezing time. using the Plank equation. This product has an initial freezing temperature of -1.75 ° C, and the movement of air in the freezing room gives a convective heat transfer coefficient of 15 W / (m² K). t f = ... hour.

A 4mx5m wall consists of 3 glass windows of 1.5mx1.0m dimensions. The wall has thickness of 0.125 m and a thermal conductivity of 0.5 W/mK, while the glass windows are 6 mm thick with a thermal conductivity of 1.24 W/mK. The values of Internal and external surface conductance for the wall (including glass) are 8.3 W/m K and 34.4 W/m²K, respectively. The internal and external temperatures are 21°C and -30°C, respectively. Calculate the total heat transfer rate through the wall. What percentage of this heat transfer is through the windows?