
Energy boundary crossing
 closed system  form of heat or work
 open system  (control surface) heat, work, and mass transfer

1st Law of Thermo / conservation of energy principle
 (total energy entinering the system)  (total energy leaving the system) = (change in total energy of the system)
 or delta (E = U + KE + PE)

E_{system}
 E = U + KE + PE
 internal + kinetic + potential

Internal Energy
U  dependent on the state and mass of the system

stationary system
 System not moving with velocity/changing elevation
 delta E = delta U

Heat Transfer
Q  caused by temperature difference between system and surroundings. Heat transfer into system is energy increase, out of system is decrease. Adiabatic system, Q = 0.

Work
W  energy transfer at a system boundary, the force acting through a distance or energy to lift a weight. Transfered into system energy increases, out of system energy decreases.

Mass flow
m  mass flowing into system, energy increases by the amount of energy carried with the mass. m = 0 for closed systems.

Heat and Work similarities
 1. Boundary phenomena
 2. systems posses energy, not heat/work
 3. Associated with process, not state
 4. path function

Total heat transfer/work
 Calculated by following the process path and adding differential amounts along the way
 δQ = Q_{12} or δW = W_{12}

classical sign convention
 positive  heat transfer to a system/work done by a system
 negative  heat transfer from a system/done done on a system

conduction
heat transfer in progressive exchange of energy btwn the molecules of a substance

Fourier's law of heat conduction
 k  thermal conductivity [W/mK]
 dT/dx  temp gradient, direction of heat flow

Convection
heat transfer of the energy transfer btwn a solid surface and adj liquid or gas in motion, and involves combined effects of conduction and fluid motion.

Newton's law of cooling
 h  convection heat transfer coe [W/m^{2}K]
 T_{s}  surface temp, T_{f}  bulk fluid temp

Radiative Heat Transfer
energy in transition from the surface of one body to the surface of another due to electromagnetic radiation.

Radiative Heat Transfer Eq.
 sigma  StefanBoltzmann constant, 5.57x10^{8} W/m^{2}K^{4 }
 epsilon  emissivity

Electrical Power
 rate of electrical work done by electrons crossing a system boundary
 P = VI

Mechanical vs. thermo work
 force of a distance vs. energy to lift weight
 angle bten force and displacement vector
 delta means it is path dependent

Types of Mechanical Work
shaft, spring, elastic solid bars, stretching liquid film, raise/accelerate a body

