Question

The lighting requirements of an industrial facility are being met by 700 40-W standard fluorescent lamps. The lamps are close to completing their service life, and are to be replaced by their 34-W high-efficiency counterparts that operate on the existing standard ballasts. The standard and high-efficiency fluorescent lamps can be purchased at quantity at a cost of $1.77 and$2.26 each, respectively. The facility operates 2800 hours a year and all of the lamps are kept on during operating hours. Taking the unit cost of electricity to be $0.08/kWh and the ballast factor to be 1.1, determine how much energy and money will be saved a year as a result of switching to the high efficiency fluorescent lamps. Also, determine the simple payback period.

Answer 1

By switching to high-efficiency fluorescent lamps, a facility saves 11,760 kWh and $940.80 annually on energy costs, with a simple payback period of approximately 4.4 months.

Step-by-step explanation:

Energy and Cost Savings Calculation

To calculate the energy and money saved by switching from standard to high-efficiency fluorescent lamps, we need to consider the power consumption reduction and the operating hours per year. For the 700 lamps, the annual energy savings (in kWh) can be calculated as follows:

• Energy saved per lamp per hour = (40W - 34W) / 1000 = 0.006 kWh
• Total energy saved per year = 0.006 kWh × 700 lamps × 2800 hours = 11,760 kWh

The annual cost savings can then be determined:

• Annual cost savings = 11,760 kWh × $0.08/kWh = $940.80

The simple payback period is the time it takes for the investment to pay for itself through energy savings. To find out, we compare the cost differential of the new lamps against the annual cost savings:

• Initial cost difference per lamp = $2.26 - $1.77 = $0.49
• Total initial cost difference = 700 lamps × $0.49 = $343.00
• Simple payback period = $343.00 / $940.80 ≈ 0.364 years or about 4.4 months

The facility will be saving energy and reducing environmental impact by using less power to light their space and also will save money over time, with a quick payback period for their initial investment.