A thermal wheel is considered to recover heat from the exhaust air of 20,000 AHU operating in a hospital in Denver, Colorado. The indoor temperature within the hospital is kept at T_in = 68°F during the winter and T_in = 75°F during the summer. The effectiveness of the thermal wheel is 75 percent, and it is operated during both the heating and cooling seasons 24 hours/day (365 days/year). Determine the annual cost savings of using the thermal wheel if the gas-fired boiler efficiency is 80 percent and the chiller COP is 3.5 . Use a bin analysis to estimate the annual savings in heating, cooling, and fan energy use. Estimate the payback period for installing the thermal wheel if its initial cost is $30,000. The gas cost is $1/MMBtu and electricity cost is $0.05/kWh. The static pressure added by the thermal wheel on both supply and exhaust fans is 0.55 in. of water.