Environmental Engineering Reference
In-Depth Information
260m
2
office space. The ACM is driven by 77.3m
2
of VTCs at working conditions
of
T
h
95/88
◦
C,
T
c
27/31
◦
C,
T
o
14/8
◦
C and COPs between 0.4 and 0.5 (Safarik
et al
.,
2002).
A further small-scale ACM project is the 20 kW NH
3
/H
2
O ABB ACM, which was
installed in 2001 at the Innovation Centre Wiesenbusch (IWG) in Gladbeck, Germany.
The produced refrigeration is used to demonstrate comfort cooling, refrigeration for
food preservation and also for 1.0m
3
of ice storage. The driving heat
T
h
of 100/90
◦
C
is produced by 72m
2
of VTCs. Evaporator temperatures
T
o
down to
6
◦
C are reached
−
at a COP of 0.63 (Albring, 2001; Braun and Hess, 2002).
A field test has been being carried out on a 10-17 kW NH
3
/H
2
O ACM developed
by the Joanneum Research-Institut fur Energieforschung and S.O.L.I.D. GmbH (both
from Austria), which has been installed at the Peitler winery in Schloßberg, Austria
(2003). The 100m
2
of FPCs, 4m
3
hot water storage tanks and a 0.5m
3
sole storage
tank are parts of the solar cooling system which operates at
T
h
100/85
◦
C,
T
c
25/35
◦
C
and
T
o
8/3
◦
C and at higher driving heat temperatures at
T
o
−
10
◦
Cdownto
15
◦
C
−
(Meißner
et al
., 2004).
Only a few laboratory prototypes of air-cooled SENH
3
/H
2
OACMs and components
have been developed and set up so far.
A prototype of an air-cooled, SE, NH
3
/H
2
O ACM from AoSol, Portugal, and
INETI/IST, Portugal, is driven by 14.3m
2
of CPC VTCs or gas. The ACM has a
cooling capacity of 5-6 kW at COPs between 0.54 and 0.62. The heating temperature
T
h
is between 105 and 110
◦
C and the evaporator temperature
T
o
is 10
◦
C (Afonso
et al
., 2003).
The Technical University TU Delft, in the Netherlands, developed a prototype of an
air-cooled solar-driven absorption NH
3
/H
2
O ACM with a cooling capacity of 10 kW.
The required heating temperature T
h
is around 92
◦
C and the coolingwater temperature
T
c
is 30
◦
C (Kim
et al
., 2003).
An air-cooled Solar-GAX absorption prototype (GAX stands for heat exchange
between absorber and generator) with the working pair of NH
3
/H
2
O and a 10.6 kW
cooling capacity has been developed at the University Aut onoma de Baja California,
Mexico, and the University Aut onoma de Mexico. The unit is powered in a hybrid
manner by natural gas and solar energy. The determined COP of the ACM is 0.86
(Velazquez
et al
., 2002).
The ITW institute of the University of Stuttgart, Germany, set up a test and demon-
stration prototype of a solar-driven absorption NH
3
/H
2
OACMwith a cooling capacity
of 10 kW and which is mainly based on plate heat exchangers. The cooling machine
has been in operation since September 2004 and is exclusively cooled by a closed
water cycle with ambient air. The heating temperatures
T
h
vary for different operating
parameters between 70/65
◦
C and 127/117
◦
C and, with that, the cooling water tem-
peratures
T
c
for the condenser are 22.5/24.5
◦
C or 38/41
◦
C and for the absorber,
T
a
24/27
◦
C or 38.5/43.5
◦
C. The reached evaporator temperatures
T
o
are between 13 and
5
◦
C at COPs of 0.6 and 0.77 (Brendel
et al
., 2004).
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