costs 8 cents per kW-hr, determine the minimum theoretical operating cost to heat the house for 24 hours.

Task 1 Write down the energy balance equation from the first law of thermodynamics for a closed system and then put the equation for an open system. Explain the difference between the two equations.

If we wanted to supply all the electricity needs for New York City (NYC), with a popula- tion of about 10 million people, using photovoltaics technology, how much land area would we need? What other elements would be required for such an idea to work for NYC? How large of an investment would this involve, and how would the price of electricity in ¢ per kWeh have to increase in order to recover that investment in 10 years at an interest rate of 8%? For comparison, the average New Yorker paid 12¢/kWeh in 2002.

3. An automobile engine delivers 25hp to the driveshaft with the thermal efficiency of 30%. The fuel has a heat content of 40 000kJ/kg. Calculate the rate of fuel consumption (kg/hr) and the heat rejected (kW) through the radiator and exhaust.

A heat pump with the COP of 3.8 supplies heat at the rate of 289 kJ/min. If a bar heater was used and the electricity cost R2.50 per kWh peak and 200 cents off-peak , how much would be saved using the heat pump for 7 days if the off-peak hours are from 22:00 hr to 6:00 hr for every day of the week.  Provide the answers to 2 decimal places and insert the unit in Rands after the answer

b. The ceiling of a certain room in a student's dormitory has an area of 200 ft'. It contains insulation such that its R-value is 30. If the room is maintained at 22°C and the attic has a temperature of 50°C. How many Joules of heat flows through the ceiling into the room in 1 day?

2. Carbon Dioxide with specific heat ratio of 1.299 is used as a working fluid in a piston-cylinder assembly which is designed handle fluid at constant temperature. The heat was applied to CO2 at 350ºF allowing an expansion in the piston cylinder assembly. If the heat loss accounts to 20Btu/lb, determine the work done by piston displacement (Btu/lb).