Design Problem Design a small chiller room 2.35 m wide by 6 m long and 2.38...
1.3 127 5.3 3.(10 pts) A cold storage room (10 m x 10 m x 10 m) is being maintained at 2 °C using a vapor compression refrigeration system that uses R-134a. The evaporator and condenser temperatures are -20 and 40°C, respectively. The walls and ceiling of the storage room is constructed of 15 cm thick concrete (thermal conductivity-1.37 WIm K]) and 4.3 cm thick insulation (thermal conductivity-0.04 W/[m K). The outside insulation surface temperature of the walls (or ceiling)...
1.3 127 5.3 3.(10 pts) A cold storage room (10 m x 10 m x 10 m) is being maintained at 2 °C using a vapor compression refrigeration system that uses R-134a. The evaporator and condenser temperatures are -20 and 40°C, respectively. The walls and ceiling of the storage room is constructed of 15 cm thick concrete (thermal conductivity-1.37 WIm K]) and 4.3 cm thick insulation (thermal conductivity-0.04 W/[m K). The outside insulation surface temperature of the walls (or ceiling)...
Problem : A cryogenic flui d is flowing in a 304 SS pipe. The pipe is insulated on its outside surface with 6 - mm thick, evacuated, aluminum foil/glass mat insulation. (“Evacuated” means a partial vacuum is drawn on the insulation to remove air that would otherwise fill pores inside the insulation.) The pipe inside diameter is 127 mm; it’s outside diameter is 138 mm. The fluid temperature is - 173 o C . T he air temperature outside the...
4. A water chiller provides 100 tons 3.516 kw/ton of refrigeration to cool water to a temperature of 12.10 C for an air conditioning system. The heat extracted from the water is to be rejected in a cooling tower at 35.4°C, Assuming that the chiller operates on an ideal vapour refrigeration cycle with the temperature in the evaporator equal to the chilled water temperature and the saturation temperature in the condenser equal to the cooling tower water temperature, determine (a)...
1. A steel tube [k 15 W/(m.°C)] of outside diameter 7.6 cm and thickness 1.3 cm is covered with an insulation material [k 0.2 W/(m. C)] of thickness 2 cm. A hot gas at 320°C with a heat transfer coefficient of 200 W/(m2.C) flows inside the tube. The outer surface of the insulation is exposed to cooler air at 20°C with a heat transfer coefficient of 50 W/(m2·°C). Calculate a) The heat loss from the tube to the air for...
2-157 A long electrical resistance wire of radius r.-0.25 cm has a thermal conductivity kwire-15 W/m-K. Heat is generated uniformly in the wire as a result of resistance heating at a constant rate of 0.5 W/cm3. The wire is covered with polyethylene insulation with a thickness of 0.25 cm and thermal conductivity of ks 0.4 W/m K. The outer surface of the insulation is subjected to free convection in air at 20°C and a convection heat transfer coefficient of 2...
The owner of a small office building asked you to design the new air conditioning system for the building. The system cools the air supplied to the offices using a chiller (cold water refrigeration system). The water requirement for the evaporator in each floor is 18.2 mh. The velocity within the pipe must remain between 1.5 m/s and 2.5 m/s, to ensure the appropriate heat exchange process in the evaporators and minimize the noise. The material of the pipe is...
5-111 Consider a refrigerator whose outer dimensions are 1.80 m x 0.8 m × 0.7 m. The walls of the refrigerator are constructed of 3-cm-thick urethane insulation (k = 0.026 W m K and α = 0.36 × 10-6 m2/s) sandwiched between two layers of sheet metal with negligible thickness. The refrigerated space is maintained at 3°C and the average heat transfer coefficients at the inner and outer surfaces of the wall are 6 W/m2 K and 9 W/m2.K, respectively....
2. An aluminum cylinder has a radius (ra) of 3 cm and al n cylinder has a radius (11) of 3 cm and a length (L) of 10 cm. The cylinder is covered with an additional insulation laver which has the critical insulation thickness The insulation surface is exposed to ambient air with the convection heat trans coefficient of h = 5 W/m2.°C. The surface temperature (T1) of aluminum cylinder is 100 The ambient air temperature (T..) is 25 °C....
An industrial freezer is designed to operate with an internal air temperature of -20 °C when the external air temperature is 25 °C and the internal and external heat transfer coefficients are 12 W/m2K and 8 W/m2.K respectively The walls of the freezer have a composite construction, comprising of an inner layer of plastic (k = 1 W/m•K, and thickness of 3 mm), and an outer layer of stainless steel (k = 16 W/mok, and thickness of 1 mm). Sandwiched...