Compute the total heat gain load from all the sources into the lunchroom, if the lunchroom is located at the top floor of an air conditioned commercial building. The lunchroom has one exposed wall facing SE. -Wall facing SE, (20* 15); 12 brick, the overall heat transmission value(U) is 0.3 Btu/hr.ft. F. -Roof;6" concrete with 2" insulation, Uroof 0.4 Btu/hr.ft².F - Windows facing SE ;No .(3), (3 *3 ),single regular plate,double-hung metal windows,weather-stripped; unlocked ,shaded with white inside roller shade ,half drawn. -Occupants: (10) persons; sedentary work., -Lightening :2 Watt /ft of the floor area (40' *20) -Outside conditions : T= 100 F (db) & T70(wb), DR =25 F, Vwind -10 mph. -Inside conditions : T-70 F (db) & 0-40%. -Location: 40 N.L, Time = 11 A.M.

Compute the total heat gain load from all the sources into the lunchroom, if the lunchroom is located at the top floor of an air conditioned commercial building. The lunchroom has one exposed wall facing SE. -Wall facing SE, (20* 15); 12 brick, the overall heat transmission value(U) is 0.3 Btu/hr.ft. F. -Roof;6" concrete with 2" insulation, Uroof 0.4 Btu/hr.ft².F - Windows facing SE ;No .(3), (3 3 ),single regular plate,double-hung metal windows,weather-stripped; unlocked ,shaded with white inside roller shade ,half drawn. -Occupants: (10) persons; sedentary work., -Lightening :2 Watt /ft of the floor area (40' 20) -Outside conditions : T= 100 F (db) & T70(wb), DR =25 F, Vwind -10 mph. -Inside conditions : T-70 F (db) & 0-40%. -Location: 40 N.L, Time = 11 A.M.

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter9: Heat Transfer With Phase Change

Section: Chapter Questions

Problem 9.19P

See similar textbooks

Similar questions

All of the following are taken into account on a heat gain calculation except A. exterior walls. B. partition walls. C. basement floors. D. top-floor ceilings.
Draw the thermal circuit for heat transfer through a double-glazed or a double-paned window. Identify each of the circuit elements. Include solar radiation to the window and interior space.
You are designing a 3m x 3m floor with radiant heating. The floor has 12 parallel pex pipes (k = 40 W/mK) of L = 3m, OD = 25mm and ID = 20mm. Hot water (TInfintiy 1 = 90oC, h = 200 W/m2K) runs through the pipes continuously. The surface below the pipes is perfectly insulated. Above the pipes, there is a 3mm layer of bonding material (? = 12 W/mK) and a 9mm layer of tile (k = 2 W/mK). Above the tile, there is air (TInfinity 2 = 25oC, h = 20 W/m2K). Properties of Air: k = 0.025 W/mK, Pr = 0.72, v = 1.847 x 10−5, u = 16.84 x 10−6, p = 1.2 kg/m3, B = 1/Tf (ideal gas), Hint: Assume that the “layer” of pipe starts at the center point (e.g. for conduction purposes, the pipe is OD divided by 2 thick). For convection, consider the entire pipe surface. a) What is the total heat rate entering the room above the floor? b) What is the temperature of the top of the tile?
Calculate 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)
The forced convective heater works in two ways: radiative heat in the form of light from the hot nichrome wire coils (like a toaster) and forced air heat (like a hair dryer). Derive an energy balance to determine the total rate of heat transfer from the device to the interior of the trailer. What percentage of the heat is leaving as light versus heating of the air stream?
Qigihar House in Heilongiiang Province, China Heat Loss Problems, BSCl 2101 Climate: Avg. remperature is 3.2°C Degree Days is 5000 Inside Air Temp. is 20°C Wall Construction, Inside to Out: 15mm Gypsum Plaster, Sand Aggregate Concrete Block, rectangular core, Sand and Gravi 15mm Cement Plaster, Sand Aggregate All 4 walls measure the same, 8m wide by 7mtall. The house is heated with electricity at a cost of $0.10kWh Calculate the RSI-total for the walls using the tabular method demonstrated in class, and the temperature drop through each element for the January 2.5% temperature. Calculate the rate of heat flow through the wall again for the January 2.5% temperature. Plot the temperature profile approximately to scale through a vertical cross-section of the wall. Calculate the January heating cost for the building. Calculate the annual heating cost for the building. Now add 2" ( 50.8mm ) of extruded polystyrene, smooth skin surface, 35kgm3 rigid insulation to the inside surfaces…
Two inches of urethane foam will reduce heat loss close to 1000% when applied to a 2-inch diameter uninsulated steel pipe. Assume the pipe wall thickness is 0.25-inches, the pipe interior convective heat loss (hi) is 500 BTU/hr-ft2-oF, and the pipe outside convective heat loss ho 20 BTU/hr-ft2-oF, k steel is 25 BTU/hr-ft-oF, and k insulaton is 0.023 BTU/hr-ft-oF. (hint - calculate heat loss with and without insulation.
Goal Solve for the performance coefficient of a refrigerator using a five-step process the includes:1. Making a state table.2. Making a process table.3. Calculating the totals for Work, Heat, and Internal-Energy-Change.4. Identifying the heat input (cold reservoir) and output (hot reservoir).5. Calculating the performance coefficient of the refrigerator.Problem Shown in the figure to the right is a cyclic process undergone by a refrigerator. Your refrigerator shall use 5.0 moles of helium gas (monatomic). During the process a->b, the volume increases by a factor of 3.0. Solution- (1) Fill in the State Table (all pressures in Pascals, all volumes in cubic meters, all temperatures in K). Pressure Volume Temperature a b c (2) Fill in the Process Table (all entries in Joules). Work Heat dU a->b b->c c->a (3) Find the Totals: Work = J Heat = J dU = J (4) Find the heat input (from "cold…
Compare the different heat flux resulting from conduction through 1 in. of the follow·ing materials when subjected to a 30"F temperature difference: copper, steel, wood,glass fiber.
Answer the problem "If the plant wants to heat the half-sphere of the previous problem keepingit on an insulated surface as shown in Fig. 2..." (use the other problem as reference)
Design thickness of the wall to maintain steady heat flux ??
A Thomas meter is located in an air duct of 2 sq ft cross-sectional area. The air weighs 0.083 lb per cu ft, and its specific heat is 0.24. Assume a controlled temperature differential of 5° and heater potential of 110 volts. Plot the velocity as abscissa and amperage as ordinate for veloc- ity 0 to 300 ft per min. Assume constant amperage of 3, and plot tem- perature difference against velocity. Discuss the curves from the stand- point of accuracy of the system.