Provide a simple payback period of installing a heat wheel system in a 80,000-cfm constant-volume AHU. During the winter, air is exhausted at 72°F, and during the summer at 76°F. The heat recovery system operates during both heating and cooling seasons with 78 percent efficiency. The boiler is 75 percent efficient and uses natural gas above 50°F ambient and diesel below 50°F ambient. The chiller uses 0.8 kW/ton. Assume that the energy costs are $0.10/kWh, $0.90/gal (diesel), and $1.50/CCF (gas). The heat recovery system costs $1.50/cfm and increases the static pressure in both supply and exhaust ducts by 0.75 in WG. Assume that the fan static efficiency is 75 percent. To move the wheel, a 1.5-hp motor is required. To solve this problem, use the bin calculation for the Denver climate.