Consider the cooling load profile for an office building shown in Figure 12.8. The cooling is provided by a chiller having a capacity of 1,000 kW and with an average seasonal COP of 3.5. The noncooling profile experienced by the same office building is illustrated in Figure 12.9. It is proposed to install an ice storage system. When making ice the chiller has an average COP of 3.0. Determine the simple payback period of installing an ice storage system if the cost of electricity is as follows:
Energy Charges: $0.07/kWh for on-peak hours (between 10:00 • and 15:00 during weekdays) and only $ 0.02/Kwh during other hours.
• Demand charges: $15/kW during on-peak hours and $ 0/kW during off-peak hours. The
demand charges are assessed on a monthly basis.
The installed cost of the TES system is $100/kW. Assume that the number of typical cooling days during the entire year both before and after the installation of the TES system is 250 days. The TES system is operated with demand-leveling control so that the power demand during onpeak hours never exceeds 500 kW (which is the maximum noncooling load).