Determine the simple payback period of installing a heat recovery system at a cost of $0.15/L/s for a 7,000/L/s makeup air system in a laboratory located in New York, New York. The indoor temperature within the laboratory is kept at Tin = 20°C. The exhaust air temperature is Tea = 50°C. Assume that the cost of gas is $1.50/therm and that the heat recovery system is operated 24 hours/day during 200 days/year.