Question

A building with 200,000 ft² of floor area and lighting power density of 1 W/ft² operates 4,000 hours per year. Calculate:

1. the electrical demand (kW)

2. the energy use (kWh/yr)

3. the total annual electricity costs ($/yr) for lighting.

Answer 1

Given data,

Floor area (A) = 200000 ft² ,

Power density (p) = 1 W/ft² ,

Annual uses (t) = 4000 hr/year ,

1. Electrical demand (D)

D = power density * floor area

     = 1 * 200000 Watt

D = 200 kW

2. Energy use per year (E)

E = Electrical demand * Annual uses

= 200 * 4000

E = 800000 kWh/yr

3. Total Annual Electricity costs (P)

since no unit cost given for electricity uses, let take A = 0.12 $ per unit of electricity

P = Annual uses of electricity * unit price

     = 800000 * 0.12

P = 96000 $/yr

answered by: anonymous