Lecture Objectives: Finish with Electric Energy Generation Learn about Sorption Cooling

Power Generation Cycle

Gas powered turbine http://www.youtube.com/watch?feature=player_embedded&v=rxps0sZ8T3Y

Combustion product gas powered turbines Limited to gas or oil as a major source of fuel Approximately 55 to 65% of the power produced by the turbine is used for compressor. Gas temperatures at the turbine inlet can be 1200ºC to 1400ºC Because of the power required to drive the compressor, energy conversion efficiency for a simple cycle gas turbine plant is ~ 30%

Combined Cycle (gas and steam) http://www.youtube.com/watch?feature=player_embedded&v=D406Liwm1Jc

Combined heat and power (cogeneration CHP or three generation CCHP) Here, we use thermal energy for heating and/or cooling

Other method for CHP Here, we use mechanical energy for powering vapor compression cooling systems

Absorption Cycle Same as vapor compression but NO COMPRESSOR Replace compressor

Absorption cooling cycle Relatively simple thermodynamics with adition of mixtures (water – aminia) Rich solution of Heat H2O H2O + NH3 Rich solution of H2O H2O + NH3

Mixtures (T-x diagram) Dew point curve Saturated vapor Mixture of liquid and vapor Saturated liquid Bubble point curve For P= 4 bar

h-x diagram hfg hfg Isotherms are ploted only in liquid region for H2O for NH3 Isotherms are ploted only in liquid region

Composition of h-x diagram Saturated vapor line at p1 Equilibrium construction line at p1 1e Used to determine isotherm line in mixing region! Start from x1; move up to equilibrium construction line; move right to saturated vapor line; determine 1’; connect 1 and 1’. Isotherm at P1 and T1 Adding energy B A x1 X1’ mass fraction of ammonia in saturated vapor

h-x diagram at the end of your textbook you will find these diagrams for 1) NH3-H2O 2) H2O-LiBr LiBr is one of the major liquid descants in air-conditioning systems

Adiabatic mixing in h-x diagram (Water – Ammonia) From the textbook (Thermal Environmental Eng.; Kuehen et al)

Absorption cooling cycle Rich solution of Heat H2O H2O + NH3 Rich solution of H2O H2O + NH3

Mixing of two streams with heat rejection (Absorber) mixture of H2O and NH3 m2 m3 =pure NH3 (x2=1) m1 m3 m2 m1 2 Q cooling Heat rejection Mixture of 1 and 2 3’ Mass and energy balance: (1) (2) 1 3 (3) x3 x From mixture equation: Substitute into (2) Substitute into (3) From adiabatic mixing (from previous slide)