modelling and simulation of absorption solar air conditioning system
DESCRIPTION
Modeling and SimulationTRANSCRIPT
MODELLING AND SIMULATION OF
ABSORPTION SOLAR AIR CONDITIONING SYSTEM
Teclemariam NemariamDepartment of Technology,Royal Institiute of Technology,Stockholm, Sweden
email: [email protected]
Aim
• To obtain best system performance of a solar assisted absorption cooling system– Solar fraction– Overall system efficiency– Total cost
• Initial cost•Maintenance cost•Operational cost
Methodology
• TRNSYS simulation program– Transient Systems Simulation Program
• EES– Engineering Equation Solver
System Description
• Energy source Refrigeration Load cycle
System Description
• Solar collector• Thermal storage tank• Auxiliary heater • Absorption
refrigeration chiller with cooling tower
• Building• Diverter• Tee-piece• Relief valve• Piping system
relief valve
storagetank
absorptionchiller
building
tee-piece
heater
collector
sun
diverter
pump
pump
Trnsys Block Diagram
C o llec to rT Y P E 1
T Y P E 7 1
P ressu rere liev e v a lv e
T Y P E 1 3
T h erm a l sto ra g eta n k
T Y P E 3 8
T ee-p ieceT Y P E 1 1 h
A u x ilia ryh ea ter
T Y P E 6
A b so rp tio nch iller
T Y P E 7
B u ild in gT Y P E 1 9
D iv e rte rT Y P E 1 1 b
P u m pT Y P E 3
P u m pT Y P E 3
C o n tro lle rT Y P E 2 b
co o lin gto w er
Absorption Refrigeration System
g e n e ra to rc o n d e n se r
a b so rb e re v a p o ra to r
h e a t e x c h a n g e r
o u tp u th ea t
in p u th ea t
o u tp u th ea t
in p u th ea t
e x p a n s io nv a lv e
p u m p
s tro n gso lu tio n inre fr ig era n t
w ea k so lu tio nin re fr ig era n t
v a lv e
va p o u rre fr ig era n t
vapourrefrigerantP con
P ev
Tev Tcon, Tab Tg
liq u idre fr ig era n t
Absorption Refrigeration System
• Refrigerant– water
• Absorbent– Lithium
bromide
• Stages– Single-effect
• G. temp 80 – 100 C• COP 0.6 – 0.8
– Double-effect• Gen. Temp 100 – 160 C• COP 1.0 – 1.2
– Triple-effect• Gen. Temp 160 – 240 C• COP ABOUT 1.7
Absorption Refrigeration System
pure
refri
gera
nt (x
=1)
pure
refri
gera
nt (x r
)
pure
refri
gera
nt (x p
)Pressure
P 1
P 2
t2 tabs=t1 tgen
evaporator absorber
condenser generator
crys ta llisa tion
Strong refrigerant Poor refrigerant
Absorption Refrigeration System
• Drawbacks– Water
• Temperature greater than zero• High water vapour pressure
– Large volume
– Lithium bromide• Precipitate at low temperature
Building
• Details of a building are:– Location: latitude, longitude, altitude– Type: Office, recidential, hospital,...– Size: volume, area of walls, roof, floor,
windows, door, ..etc – Types of construction materials– Outside design conditions– Inside design conditions– Internal gains
Work done so far
• More than 75% course work• More than 80% literature survey• Modelling and simulation of a
complete system using standard TRNSYS components
Sample Simulation Results
• Solar collectors:– Evacuated collector, high quality flat plate
collector and ordinary flat plate colector
• Storage tank: cylinderical, vertical stand• Heater: gas fired• Single-effect absorption machine
– Refrigerant water and absorbent lithium bromide
– Capacity 24.44 kW
Sample Simulation Results
• Building:– Location: Assab, Eritrea. Latitude 13.07
N, longitude 42.6 E, altitude sea level– Type: two storey office – Size: volume, area of walls, roof, floor,
windows, door, ..etc are given in detail– Types of construction materials– Outside design conditions– Inside design conditions– Internal gains
• Every detail is given
Sample Simulation Results
• System Optimization– e.g. collector slope
0.00E+00
5.00E+07
1.00E+08
1.50E+08
2.00E+08
2.50E+08
0 10 20 30 40 50 60
collector slope (degree)
sola
r en
erg
y g
ain
(kJ
)
ESC DGC SGC
Sample Simulation ResultsSolar fraction as a function of colector area and storage volumee.g. using evacuated collector
0
10
20
30
40
50
60
70
80
10 20 30 40 50 60 70 80
collector area (m 2)
so
lar
fracti
on
(%
)
V1=1.0m3
V2=2.0m3
V3=3.0 m3
V4=4.0m3
V5=5.0m3
Sample Simulation Results• System efficiency as a function of
colector area and storage volume– e.g. using evacuated collector
0
10
20
30
40
50
60
10 20 30 40 50 60 70 80
collector area (m2)
syst
em e
ffic
ien
cy (
%)
V1=1.0m3 V2=2.0m3V3=3.0 m3 V4=4.0m3V5=5.0m3
Sample Simulation Results
• Solar fraction and system efficiency as function of collector area for a given storage volume
0
10
20
30
40
50
60
70
10 20 30 40 50 60 70 80
solar collector (m 2)
eff
icie
ncy
ESC syseff ESC solfr DGC syseffDGC solfr SGC syseff SGC solfr
Sample Simulation Results
• Yearly insolation energy, max possible solar heat gain and cooling load
0.00E+00
5.00E+06
1.00E+07
1.50E+07
2.00E+07
2.50E+07
3.00E+07
3.50E+07
4.00E+07
1 3 5 7 9 11
time (month)
en
erg
y (
kJ)
QIRT ESC DGC
SGC QLOAD
Notice
• The sample simulation result is extracted from a paper presented in the ISES Conference June 14-19 2003 in Götemberg, Sweden.
• If you have more interest please refer the paper.
• Thank you.