Worksheet Grade 10 Engineering & Design

Pellworth Booster Pump Station: Run-Time and Energy Worksheet

A grade 10 engineering worksheet sizing a fictional booster pump's daily run-time, pipe velocity, and energy use, and writing a gallons-versus-time equation.

Objectives

  1. Students will calculate a booster pump's daily run-time from a flow rate and a delivery target.
  2. Students will write and interpret a linear equation relating gallons pumped to time.
  3. Students will calculate pipe velocity and specific energy use for a pumping system.

Vocabulary

Flow rate
Flow rate measures how much water moves past a point in a certain amount of time, like gallons per minute through a garden hose. Bigger pipes and stronger pushes give bigger flow rates.

Also: booster pump, continuity, specific energy, run-time

Teacher overview

A booster pump lifts water into an elevated tank so gravity can serve the neighborhood the rest of the day. The fictional Pellworth Water District runs one booster pump to keep its tank filled, and operators need to know how long the pump must run, how fast water moves inside the discharge pipe, and how much energy the job takes. In this worksheet, students size the pump's daily work, write an equation for the gallons it delivers over time, and check its energy use against typical values. The pump moves water at a steady rate, so gallons delivered grow in a straight line with time, which lets students model the work with a simple linear equation.

Answer Key

  1. Answer: about 6.94 hours.
    500,000 gallons ÷ 1,200 gpm = 416.67 minutes; 416.67 ÷ 60 = 6.944, which rounds to about 6.94 hours.

  2. Answer: G = 1,200t.
    At 1,200 gpm, the gallons delivered equal 1,200 times the number of minutes t, so G = 1,200t.

  3. Answer: 108,000 gallons.
    G = 1,200 × 90 = 108,000 gallons in 90 minutes.

  4. Answer: 1,200 gpm.
    The slope is 1,200 gallons per minute, which is the pump's flow rate, because the line rises 1,200 gallons for every additional minute of running.

  5. Answer: about 1.73 MGD.
    1,200 gpm ÷ 694 gpm/MGD = 1.729, which rounds to about 1.73 MGD.

  6. Answer: about 1.23 square feet.
    Area = 0.785 × 1.25² = 0.785 × 1.5625 = 1.2266, which rounds to about 1.23 square feet.

  7. Answer: about 2.18 feet per second.
    1,200 gpm ÷ 448.8 gpm/cfs = 2.6738 cfs. Velocity = 2.6738 ÷ 1.2266 = 2.180, which rounds to about 2.18 feet per second.

  8. Answer: 1.3 kWh per 1,000 gallons.
    The 500,000 gallons is 500 units of 1,000 gallons: 650 kWh ÷ 500 = 1.3 kWh per 1,000 gallons.

  9. Answer: It falls inside the whole-system range, so this one pump uses about as much as a typical entire system.
    A specific energy of 1.3 kWh per 1,000 gallons is inside the 1-to-2 kWh per 1,000 gallons range, yet that range covers treatment and delivery for the whole system. This single booster therefore uses about as much energy per 1,000 gallons as a typical system uses in total, which is a large share. Accept any answer that makes this comparison and suggests a reasonable follow-up, such as checking how high the pump lifts the water or how efficiently it runs.

  10. Answer: about 9.03 hours.
    650,000 gallons ÷ 1,200 gpm = 541.67 minutes; 541.67 ÷ 60 = 9.028, which rounds to about 9.03 hours.

  11. Answer: Accept any answer noting that a steady pump running longer keeps flow and pressure smooth, avoids the pressure surges and pipe stress of a large pump switching on and off, and often runs closer to its efficient design point, while a much larger pump costs more to buy and can waste energy in short bursts.

Differentiation

Support (below grade level)

Provide the run-time setup and the two conversions (694 gpm per MGD and 448.8 gpm per cfs) on a reference card, and work item 1 together so students see the gallons-divided-by-flow pattern before writing the equation in item 2.

Extension (above grade level)

Ask students to find what steady flow, in gpm, the pump would need to deliver the summer demand of 650,000 gallons in the same 6.94 hours it currently takes for 500,000 gallons, and to explain how that change would affect the pipe velocity from item 7.

ELL supports

Provide a labeled diagram of the pump, discharge pipe, and elevated tank, with flow rate, velocity, and energy marked. Provide a sentence frame for items 4, 9, and 11, and allow the calculations in items 1 through 8 and 10 to be shown as numbered steps.