SINGLE-EFFECT HOT WATER-FIRED ABSORPTION CHILLERS
16LJ/16LJ-A
The absorption cycle
2
1
3
6
4
7
5
9
10
COOLING
8
11
12
Legend
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
Condenser
Refrigerant vapour
Generator
Cooling water
Liquid refrigerant
Concentrated solution
Heat source
Chilled water
Cooling water
Evaporator
Absorber
Absorbent pump
HEATING HEATING
The basic single-effect absorption cycle (see Figure 1)
includes generator, condenser, evaporator and absorber
with refrigerant (liquid) and lithium bromide as the working
solutions. The generator utilizes a heat source (steam or hot
water) to vaporise the diluted lithium bromide solution. The
water vapour that is released travels to the condenser where
it is condensed back into a liquid, transferring the heat to the
cooling tower water. Once condensed, the liquid refrigerant
is distributed over the evaporator tubes, removing the heat
from the chilled water and vaporising the liquid refrigerant.
The concentrated lithium bromide solution from the generator
passes into the absorber, absorbs the refrigerant vapour
solution from the evaporator and dilutes itself. The diluted
lithium bromide solution is then pumped back to the
generator where the cycle is started again.
Figure 1 - Simplified absorption cycle
Cooling cycle schematic
LJ 01/02/03
LJA 11-82
Heat 1.0
Heat sink 1.78
Heat 1.0
4
3
2
4
C
1
D
5
A
6
A
6
7
7
B
B
8
9
11
10
9
Refrigeration capacity 0.70
13
14
15
16
17
12
18
13
Refrigeration capacity 0.78
14
15
1.
2.
3.
4.
5.
6.
7.
8.
9.
C
Generator
Cooling water
Condenser
Hot water
Evaporator
Chilled water
Absorber
Refrigerant pump
Absordent pump
A
R
R
I
E
10.
11.
12.
13.
14.
15.
16.
17.
18.
R
2
0
1
6
Heat exchanger
Cooling water
Concentrated solution
Diluted solution
Liquid solution
Refrigerant vapour
Cooling water
Chilled water
Hot water
/
2
0
1
7
Temperature of refrigerant (°C)
Temperature
of refrigerant (°C)
60
Legend
11
10
0%
50
16
%
40 45% 0%
5
CD
40
18
17
%
55
100
%
60
80
5%
6
%
70
30
50
40
30
20
20
10
B
A
0
10
8
Absolute
(kPa)
Absolutepressure
pressure (kPa)
8
12
C
1
D
5
3
2
AIR TREATMENT
Heat sink 1.70
5
Temperature of absorbent (°C)
Temperature of absorbent (°C)
307
CONTROLS
The absorption cooling cycle, like the mech anical vapour
compression refrigeration cycle, utilizes the latent heat of
evaporation of a refrigerant to remove heat from the entering
chilled water. Vapour compression refrigeration systems use
a chlorine-based refrigerant and a compressor to transport
the refrigerant vapour to be condensed in the condenser.
The absorption cycle, however, uses water as the refrigerant
and an absorbent lithium bromide solution to absorb the
vaporised refrigerant. Heat is then applied to the solution
to release the refrigerant vapour from the absorbent. The
refrigerant vapour is then condensed in the condenser.