1. Lecture Objectives: Finish with Sorption cooling
Review Electric power generation

2. Simple absorption system3V 3L
3LLP

3. 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

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

5. 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 ???)

6. 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!

7. Use of precooling (system improvement #2)

8. 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

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

10. 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

11. 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

12. 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

13. Ammonia Vapor Enrichment Process (Rectification)

14. 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

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

16. Gas powered turbine

17. 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%

18. Combined Cycle (gas and steam)

19. Steam powered turbine

20. 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-h 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

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

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

23. Further improvements

24. Analogy with cooling cycles