Ch 3. First Law of Thermodynamics Multimedia Engineering Thermodynamics Conservationof Mass Conservationof Energy Solids andLiquids Ideal Gas
 Chapter 1. Basics 2. Pure Substances 3. First Law 4. Energy Analysis 5. Second Law 6. Entropy 7. Exergy Analysis 8. Gas Power Cyc 9. Brayton Cycle 10. Rankine Cycle Appendix Basic Math Units Thermo Tables Search eBooks Dynamics Statics Mechanics Fluids Thermodynamics Math Author(s): Meirong Huang Kurt Gramoll ©Kurt Gramoll

 THERMODYNAMICS - CASE STUDY Introduction Problem Description Click to view movie (80 kB) Ann is living in a dormitory room, and she has a small fan in the room. On a summer day, she turns on her fan before leaving for classes, to cool the room before she comes back in the evening. Does it work? What is known: The size of the room is 4 m x 6 m x 6 m The power of the fan is 150 W She leaves at 8:00 am and comes back at 6:00 pm The room temperature is 15 oC when she leaves in the morning Questions What will the temperature of the room be when Ann comes back in the evening? Approach Consider the air in the room as a system Use specific heat values at the average room temperature All the energy from the fan becomes internal energy of the air in the room