Problem 5 (heating system analysis using the f-chart method) An office building in Philadelphia is to employ Heliodyne Gobi 408-002 flat-plate solar collector for space and water heating. The estimated monthly load is estimated as 130, 120, 100, 70, 25, 20, 20, 20, 20, 25, 70, and 105 GJ (gigajoule) for January, February, ..., December, respectively. The solar energy system is to provide all the heating requirement for the summer months and a yearly solar heating fraction of 50%. (a) How many solar collectors are needed? (b) If natural gas costs $9 per million Btu, how much is saved by the active solar system. Use f-chart method, Excel (or any other software) and NREL insolation data for Philadelphia. Show hand calculations for June. Problem 5 (heating system analysis using the f-chart method) An office building in Philadelphia is to employ Heliodyne Gobi 408-002 flat-plate solar collector for space and water heating. The estimated monthly load is estimated as 130, 120, 100, 70, 25, 20, 20, 20, 20, 25, 70, and 105 GJ (gigajoule) for January, February, ..., December, respectively. The solar energy system is to provide all the heating requirement for the summer months and a yearly solar heating fraction of 50%. (a) How many solar collectors are needed? (b) If natural gas costs $9 per million Btu, how much is saved by the active solar system. Use f-chart method, Excel (or any other software) and NREL insolation data for Philadelphia. Show hand calculations for June