Consider the electrical heater of Problem 7.49. If the blower were (o malfunction, terminating airflow while the healer continued to operate at
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- The solar energy collector design shown below has been used for agricultural applications. Air is blown through a long duct whose cross section is in the form of an equilateral triangle. One side of the triangle is comprised of a double-paned, semi-transparent cover, while the other two sides are constructed from aluminium sheets painted flat black on the inside and covered on the outside with a layer of Styrofoam insulation. During sunny periods, air entering the system is heated for delivery to either a greenhouse, grain drying unit, or a storage system. Double- Styrofoam A paned cover Absorber plates Identify all heat transfer processes associated with the cover plates, the absorber plate(s) and the air.arrow_forwardProblem 1: A rectangular (70mm Wide x 60mm Tall x 180mm long) air heater is used to heat 0.04m3 incoming air (Q from 25°C to 60°C. To increase the surface area, the cross-section is split into 6 rectangular channels using aluminum fins, as shown below. The fins are evenly spaced and 2mm thick. What must the average surface temperature of the fins be to sufficiently heat the air?arrow_forwardPROCESS INSTRUMENTATION AND CONTROL 4. A 3m X 2m window has an exterior surface temperature of 220C, and the outside wind is blowing air at -60C across it with a convection heat transfer of h= 125W/m2K. What is the total heat transfer loss?arrow_forward
- It is required to select a suitable blower for the air conditioning system of a touristbus. The blower takes in fresh air from the atmosphere, passes it across the airconditioning coils and delivers the cooled air through small nozzles inside the bus.An exhaust fan then removes the used air from the bus cabin. The other relevantinformation are gives below;Capacity of the bus ----- 45 seatsSolar radiation through the windows -- 8 KWHeat infiltration through the roof, side and floor of the bus --- 12 KWSpecific enthalpy of cooled air entering the bus through nozzles ----289 kJ/kgSpecific enthalpy of used air leaving the bus through the exhaust fan ---- 310kJ/kgBody heat per adult --- 115 WUnder steady state conditions determine the mass flow rate of air handled by theblower whena. the bus is emptyb. the bus is fullarrow_forwardCalculate the power of the submarine’s electrical heater needed, to maintain the interior of outer hull at 30°C. The exterior of outer hull is 10°C. (Assume heat of the submarine is only lost across the outer hull)arrow_forwardI need unique and correct answer. Don't try to copy from anywhere. Do not give answer in image formet and hand writingarrow_forward
- A wood stove is used to heat a single room. The stove is cylindrical in shape, with a diameter of D = 0.400 m and a length of L = 0.500 m, and operates at a temperature of T, = 200 °C. (a) If the temperature of the room is T, = 20°C, determine the amount of radiant energy delivered to the room by the stove each second if the emissivity of the stove is e = 0.920. (b) By definition, the R-value of a conducting slab is given by Atot(Th – To) Poond R = where Atot is the total surface area, Pcond is the power loss by conduction through the slab, Th and Te are the temperatures on the hotter and cooler sides of the slab. If the room has a square shape with walls of height H = 2.40 m and width W = 7.60 m, determine the R-value of the walls and ceiling required to maintain the room temperature at T = 20°C if the outside temperature is T, = 0°C. Note that we are ignoring any heat conveyed by the stove via convection and any energy lost through the walls and windows via convection or radiation.arrow_forwardA Pressurized Water Reactor fuel rod is 12 ft long and 0.374 inches in diameter (outer) on a 0.496 inch square pitch. The fuel pellet diameter is 0.3225 inches. The fuel rod gap is constant with a width of 0.0065 inches. The system pressure is 2250 psia and can be assumed to be constant. The rod operates at linear heat rate of 12.1 kW/ft. At the elevation of interest, the coolant temperature is 575 °F with a convective heat transfer coefficient of 6200- For this elevation determine the temperature BTU hr ft²F margin to boiling according to Jens-Lottes. Also assume constant fluid properties given as: p=46.39 Ibm = ,c. 1.261- BTU Ibm-F BTU -,k=0.334- hr-ft-F Ibm ft-hr M=0.222- -, Tsat 652.7F =arrow_forwardProblem 9-1: An iron-constantan thermocouple is placed in a moving air stream in a duct, as shown in the figure below. The air flows at 70 m/s. The emissivity of the thermocouple is 0.5 and the recovery factor is 0.6. The wall temperature 300°C. The thermocouple reference junction is maintained at 100° C. The emf output from the thermocouple is 16 mV. I w - A. Determine the thermocouple junction temperature. B. By considering recovery and radiation errors, estimate the possible value for total error in the indicated temperature. Discuss whether this estimate of the measurement error is conservative and why, or why not. The heat-transfer coefficient may be taken as 100 W/(m² K). T = 260°C w Air U = 200 ft/s Tref Voltagearrow_forward
- It has been found that condensation forms on the outside of the refrigerator when the temperature on the surface is T1 and lower certain parts during the year. If the temperature on the inside of the refrigerator is T2 , how thick insulation needed to avoid condensation? The cooling effect in the refrigerator is ?. The refrigerator wall is built (from the outside) with 1 mm metal (thermal conductivity is k1),mineral wool (thermal conductivity is k2)and an additional layer of 1 mm metal. T1 (°C)= 15 , T2(°C)=3 , ? (W)=70 , k1 (W/m·K)=15 , k2 (W/m·K)=0.04arrow_forwardA solar water heating plant is using a flat-plate solar collector with an area A of 28 m2. The collector is operating as follows:• Cold water temperature at the collector inlet Tin = 33°C• Hot water temperature at the collector outlet Tout = 57°C• Effective optical efficiency of the collector ηopt = 0.8• Effective overall heat loss coefficient of the collector Uc,e = 3.9 W/m2K• Ambient air temperature Ta = 27°C• Solar radiation flux incident on the tilted collector surface Ic = 830 W/m2• Isobaric specific heat of the water cp = 4187 J/(kg K) Calculate (i) the useful heat output rate of the collector, and (ii) the water mass flow rate in the collector.arrow_forward2arrow_forward
- Principles of Heat Transfer (Activate Learning wi...Mechanical EngineeringISBN:9781305387102Author:Kreith, Frank; Manglik, Raj M.Publisher:Cengage Learning