Introductions

Design Considerations Conservation of mass It has got to go somewhere Conservation of energy Energy is transferred Forms of energy and energy transfer LATER How much is energy is where?

Conservation of Mass/Energy In – out + generation – consumption = accumulation Energy/mass can’t be generated or consumed First law of thermodynamics

How much energy does something have? Can we measure energy? What CAN we measure? Pressure Temperature Mass Volume So what?

State Postulate If you know two INDEPENDENT, intensive properties of a system, you can know the complete state of the system State – all of a system’s intensive properties

Intensive v. Extensive Extensive property Intensive property Size dependent “extent of system” Intensive property Size independent Specific properties Extensive properties normalized by mass/moles Extensive / extensive = intensive

Intensive v. Extensive (Examples?) Extensive property Intensive property Specific properties

Temperature It is NOT heat It is NOT energy It is RELATED to energy Kinetic energy = ½mv2 = 3/2 k*T It is a measure of molecular velocity Hotter  faster Colder  slower CW?

Pressure Tensor property (learn more in CBE 218) Exertion of force on a boundary How hard are the molecules hitting a boundary Related to velocity through momentum (mv)

Others Volume – amount of space available to molecules Mass – amount of matter Moles – “count” of atoms/molecules Density – mass in a set volume Energy/similar – discuss later

Equilibrium Thermal – temperatures are the same Zeroth law of thermodynamics: “Body A is in thermal equilibrium with body B and body B is in thermal equilibrium with body C, body A and body C are in thermal equilibrium” Mechanical – pressures are the same Chemical – topic for CBE 321 but has to do with phases

Phase Equilibrium All equilibrium is satisfied Phases Temperature and pressure are not independent Phases Solid Liquid Vapor “gradual” transitions

P-T Phase Diagram P T

P-T Diagram

Triple/Critical Point Liquid and vapor indistinguishable Triple point All three phases exist

P-v Phase Diagram FIRST let’s do a Concept Warehouse Question P v

P-v Phase Diagram

Saturation Saturated liquid Subcooled liquid Saturated vapor All liquid, but with one bubble of vapor Vapor has minute number of molecules Subcooled liquid Saturated vapor Similar but opposite Superheated vapor Quality “percent” of vapor in saturated mixture

Property Tables For common fluids (i.e. water) If only we had a code to read the table for us

Concepts/Practice/Relevance Concept warehouse Track progress of pathways Cooling of a gas in a rigid tank Isobarically increase volume Calculate quality of saturated mixture Calculate specific volume