Engineering Answers

12. A 120 tons refrigeration system with COP of 5 has a condenser which is to be cooled by means of a cooling tower. Air enters the tower at 25oC db and 50% RH and leaves at 35oC db and 80% RH. Find the volume of air needed m3/hr. At 25oC and 50% RH: h = 50 KJ/kg, v = 0.86 m3/kg At 350C db and 80% RH: h = 108

17. The moisture removed from a material is 200 lb/hr and change of humidity ratio in dryer is 0.015. Determine the fan capacity if specific volume of air entering is 38 ft3/lb. Explain the answer..

17. The moisture removed from a material is 200 lb/hr and change of humidity ratio in dryer is 0.015. Determine the fan capacity if specific volume of air entering is 38 ft3/lb. Please explain the answer.

Given the definitions of Ethics, write down 5 reasons (in sentence form) as to why it is important. Specifically, why does ETHICS030 should be a part of the learning curriculum?

Brigham Tea, Inc., is a processor of low acid tea. The company is contemplating purchasing equipment for an additional processing line. The additional processing line would increase revenues by $90,000 per year. Incremental cash operating expense would be $40,000 per year. The equipment would cost $180,000 and have a nine-year life. No salvage value is projected.

5. Two shafts 30 in. apart, each carrying a four-step pulley, are to be connected by a cross belt. The driving shaft is to turn 180 rpm while the driven shaft is to turn 50, 150, 250, and 600 rpm. The smallest step of the driver is 10 in. in diameter. Find (a) the diameters of all the steps, (b) angle of contact for each pair of pulleys, and (c) belt length.

4. A pulley 600 mm. in diameter transmits 40 kW at 500 rpm. The arc of contact between the belt and pulley is 144° having a center distance of 1100 mm. Determine: (a) diameter of the driven pulley for open belt drive, (b) speed of the driven pulley, and (c) belt length for open belt connection.

3. Two pulley 12 in diameter and 20 in diameter is connected by a crossed belt with center distance of 45 in. Find the belt length needed to connect them.

2. Two pulleys 10 in. diameter and 25 in. diameter is connected by an open belt with center distance of 40 in. Find the belt length needed to connect them.

1. A lathe having a 5-step pulley is driven by a belt, assumed to be crossed, from a pulley of the same size on the countershaft. The countershaft is to have a constant speed, and the lathe is to have speeds of 60 rpm and 135 rpm when the belt is on the steps either side of the center step. If the minimum speed is 40 rpm and the smallest diameter is 4 in., find the proper speed of the countershaft, maximum speed of the lathe, and the diameter of all steps on the pulleys.