Lecture Objectives: Finish with Sorption cooling Review Electric power generation

Simple absorption system 3V 3L 3LLP

Simple absorption system Saturated vapor at p2=p3=p4 3V 6 3 5V mixing 1’ Needed thermal energy Useful cooling energy 3L 4 3LLP 5 2 Saturated liquid at p2=p3=p4 1 5L Saturated liquid at p1=p5=p6=p3_LLP

Absorption cooling with preheater System improvement #1 Rich ammonia vapor 4 5 Refrigeration and air conditioning (Ramesh et al)

Absorption cooling with preheater Saturated vapor at p1’ 1’’’V=3 Major heat source 6 1’’’ mixing isotherm 6h 1’’ Useful cooling energy 1’’’L =2 4 5 1’ Saturated liquid at p1’ 2’ , 2’’ 1 Saturated liquid at p1 Cooling tower Pumping energy COP= Q cooling / Q heating (Pump ???)

For Real energy analysis you need real h-x diagram! hfg for H2O hfg for NH3 For Real energy analysis you need real h-x diagram!

Use of precooling (system improvement #2)

Absorption cooling with precooling Saturated vapor at p1’ 1’’’V=3 Major heat source 6’ 6 6h 1’’’ mixing Saturated liquid at p1’ isotherm 1’’ Useful cooling energy (larger!) 1’’’L =2 4 1’ Saturated liquid at p1 2’ , 2’’ 4’ 5 1 Cooling tower (needs to cool more!) Pumping energy

System improvement #3 (described as Rectification) Generator with Enrichment of NH3 Different 8V 9 8L 10 8LLP 11

Heat transfer with separation into liquid and vapor (Generator) How to move point 4 to right ? =2V =2V heating m4 Q12 /m1 2L= 2L= =m2 m1 =m2 mixture Separator sub cooled liquid mixture x1 x1 Q12 m3 Q12 m3

Heat rejection with separation into liquid and vapor (Enrichment NH3 in the vapor mixture) This is our point cooling 1 4=2V Separator 6=5V Q12 /m1 cooling Q45 /m4 x8 m8 8 7 m1 =m2 5 2 sub cooled liquid mixture isotherm m3 2L Q12 x1 x8

Heat rejection with separation into liquid and vapor (Enrichment NH3 in the vapor mixture) This is our point cooling 1 4=2V Separator 6=5V Q12 /m1 cooling Q45 /m4 x8 m8 8 7 m1 =m2 5 2 sub cooled liquid mixture isotherm m3 2L Q12 x1 x8

Ammonia Vapor Enrichment Process (Rectification)

Absorption system with Enrichment (no preheater nor precooler) Saturated vapor at p2 3V 8V 3 mixing 11 8L 1’ Useful cooling energy 8LLP 10 3L 2 9 Saturated liquid at p2 1 Saturated liquid at p1

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

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

Steam powered turbine

Ideal Rankine Cycle h1=hf saturated liquid Wpump (ideal)=h2-h1=vf(Phigh-Plow) vf=specific volume of saturated liquid at low pressure qin=h3-h2 heat added in boiler Usually either qin will be specified or else the high temperature and pressure (so you can find h3) qout=h4-h1 heat removed from condenser) wturbine=h3-h4 turbine work

Reheat Cycle It allows increase boiler pressure without problems of low quality at turbine exit

Regeneration Preheats steam entering boiler using a feed-water heater, improving efficiency

Further improvements

Analogy with cooling cycles