Consider a wall made of Material A that is 4.5m long, 3.0m high, and 0.22m thick. The interior and exterior design temperatures are Too1 and Too2, respectively, the heat transfer coefficients on the interior and exterior surfaces are 10 and 20W / m2 •C. If insulating material is placed on the inside surface of the wall to maintain the temperature shallow from it to T1. Determine the required thickness of the insulating material.

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 %

6. a. The heat flux applied to the walls of the biomass combustion furnace is 20 W/m2. The furnace walls have a thickness of 10 mm and a thermal conductivity of 12 W/m.K. If the wall surface temperature is measured to be 50oC on the left and 30oC on the right, prove that conduction heat transfer occurs at a steady state!b. Heating the iron cylinder on the bottom side is done by placing the iron on the hotplate. This iron has a length of 20 cm. The surface temperature of the hotplate is set at 300oC while the top side of the iron is in contact with the still outside air. To reach the desired hotplate temperature, it takes 5 minutes. Then it takes 15 minutes to measure the temperature of the upper side of the iron cylinder at 300oC. Show 3 proofs that heat transfer occurs transiently

1) A wall section composed from the outside to inside, of concrete brick 100mm thick, an air space of 50mm, two layers of fiberglass insulation 38mm thick, concrete block 150mm thick and air space of 19mm and a gypsum board of 13mm. The exterior conditions are -20C and RH=90% while the interior conditions are 23C and RH=40%. The surface temperature from the outside to inside are shown in the figure. The permeances are: Still Air: µ = 175 ng/pa.s.m Fiber glass: M=2560 ng/pa.s.m? Concrete block: M= 200 ng/pa.s.m? Gypsum board: M= 2000 ng/pa.s.m? Concrete brick: µ = 4.55 ng/pa.s.m Determine if there is a risk of condensation, and if there is, what is the condensation rate? What would happen if a vapor barrier (M=0.2 ng/pa.s.m²) was installed on the warm side of the insulation (Surface 4). 21с 19C 16 С 12C -10 -15C -18C -19C Gyp Air Concrete Fiber Fiber Air Concrete Outdoor Indoor sum block Glass Glass brick 230 19 50 mm -20C 13 150 mm 38 mm | 38 mm 100 mm RH=90% RH=40% mm mm Surf. 1 Surf.…