Piping and Pump Homework - HVAC Design 1 | AREN 4110, Assignments of Architecture

Download Piping and Pump Homework - HVAC Design 1 | AREN 4110 and more Assignments Architecture in PDF only on Docsity!

AREN4110/CVEN5110 HVAC System Design Spring 2007

Piping and Pump Homework: Due Thursday, February 15

1. A pump located at ground level circulates water in the chilled water system for a 20- storey building. Each floor is 12 ft of building height. Consider a vertical riser from the pump to an equipment room on the twentieth floor. The lost head due to friction in the riser is 25 ft of water. The pump produces 120 ft of head. What must be the pressure on the suction side of the pump if the pressure in the riser on the 20th^ floor is to be 5 psig?
2. Consider the domestic water service for the building in Problem 1 above. It is desired that the water pressure at the water fixtures on the 20th^ floor be the same as the main pressure. Assuming 20 ft of water friction loss in the riser, how head must the booster pump produce?
3. Two 6 ½ in. 1750 rpm pumps whose characteristics are shown below are used in parallel to deliver 240 gpm at 35 ft of head. A) Sketch the system and pump characteristics. B) what is the shaft power requirement of each pump? C) If one pump fails, what are the flow rate and shaft power requirement of the pump still in operation?
4. A 7 in. 3500-rpm pump shown below is used to transfer lake water to a water treatment plant. The flow rate is to be 300 gpm. What is the maximum height that the pump can be located above the lake surface without risk of cavitation? (Assume that the water has a maximum temperature of 80 F, the friction loss in the suction line is 2 ft of water, and the lake is at an elevation of 5000 ft.)
5. Select a pump from the figure below for a system that requires a flow rate of 250 gpm at a head of 150 ft of water. A) sketch the pump and system characteristics and show the operating flow rate, efficiency, and power, assuming no adjustments. B) Assume that the system has been adjusted by closing a valve to give a flow rate of 250 gpm. What are the pump efficiency and power?
6. Size schedule 40 commercial steel pipe for the following flow rates A) 40 gpm, b) 30 gpm, c) 15 gpm, d) 50 gpm, e) 100 gpm, f) 1500 gpm.
7. Find the lost head due to friction for each of the following fittings. A) 2 in. standard threaded elbow with a flow rate of 50 gpm. B) 4 in. globe valve at 300 gpm. C) branch of a 3 in. standard tee with 150 gpm through the common leg and 75 gpm through the branch.

• AREN4110/CVEN5110 HVAC System Design Spring