the appropriate pair in adsorption cooling application,
the running conditions and the aim of the application should be taken into account considering different
effects of factors in Table 2. For solar cooling the
important parameter governing the choice is the driving temperature as it should be the minimum allowable
temperature. The most important running conditions
are the driving temperature, evaporation temperature
and COP.
The highest COP value reported in the composite
adsorbents category is between silica gel with chlorides and water pair attributed to the ionic nature
of chlorides which enhance conductivity and the
high heat capacity of water. The minimum value
for COP occurs in the physical adsorbents category between zeolite and water pair. Metal hydrides
and hydrogen show the lowest value for evaporation temperature because hydrogen has a very low
normal boiling point (−252.87
◦ C). For the case of
driving temperature, silica gel and chlorides with
methanol pair has the lowest driving temperature
while zeolite and water pair has the highest driving
temperature.
Research results on solar adsorption systems
from Table 3 indicate attainment of maximum COP
value of 0.49 and cooler temperature of 4
◦ C from
methanol/olive waste pair compared to COP of 1.65
achieved from composite adsorbents.
7 CONCLUSION AND RECOMMENDATIONS
Although investment costs for adsorption chillers are
still high, the environmental benefits are impressive,
when compared to conventional compression chillers.
The absence of harmful or hazardous products such
as CFCs, together with a substantial reduction of CO2
emissions due to very low consumption of electricity, creates an environmentally safe technology. Low
temperature waste heat or solar energy can be converted into a chilling capacity as low as 5
◦ C with
minor maintenance costs. Nevertheless, some crucial
points in the development of sorption systems still
exist and those are closely connected to the low specific power of the machine and the investment costs.
Recently, more close attention was paid to the development of combined systems of solar cooling and
heating in order to make use of all types of energies rationally. All these works will be of great favour
to the development of the solar sorption refrigeration
system.
More research on adsorbent materials, improved
heat and mass transfer, advanced cycles, etc. to make
adsorption technology competitive is necessary. This
work will help to understand basics and research
progress on adsorption systems.
From this research, it is recommended to assess the
suitability of steatite as a co-adsorbent material for
purposes of improving adsorption capacity of various
working pairs to enhance operation with low driving
temperature hence boost deployment of solar energy
usage.
ACKNOWLEDGMENT
This work was supported by theAfrica Centre of Excellence II in Phytochemicals, Textile and Renewable
Energy (ACE II – PTRE) at Moi University of the
Eastern and Southern Africa Higher Education Centers of Excellence Project through the Association of
Energy Professionals in Eastern Africa, AEPEA.
REFERENCES
Abu-Hamdeh N.H., A. K. (2013). Design and performance
characteristics of solar adsorption refrigeration system
using parabolic trough collector: Experimental and statistical optimization technique. Energy Conversion and
Management, Vollume 74, 162–170.
Alghoul MA, Sulaiman MY, Azmi BZ, & Wahab MA.
(2007). Advances on multi-purpose solar Adsorption
systems for domestic refrigeration and water heating.
Applied Thermal Engineering, Volume 27(5–6), 813–822,
http://dx.doi.org/10.1016/j.applthermaleng.
Al-Hemiri, A., & Nasiaf, A. (2010). The use of direct solar
energy in absorption refrigeration employing Ammonia –
water system. Iraqi Journal of Chemical and Petroleum
Engineering, Volume 11, No. 4, 13–21.
Allouhia, A., Kousksoub, T., Jamila, A., El Rhafikic T., E.,
MouradaY., & ZeraoulibY. (2015). Optimal working pairs
for solar adsorption cooling applications. Energy, Volume
79, 235–247.
Al-Mousawi, F., Al-Dadah, R., & Mahmoud, S. (2016). Low
grade heat driven adsorption system for cooling and power
generation with small-scale radial inflow turbine. Applied
Energy, Volume 183, 1302–1316.
Amar Sadoon A. (2006). Design, built and performance study
on adsorption ice maker", M.Sc. thesis. Iraq.: University
of Technology.
Ammar, M. H., Benhaoua, B., & Balghouthi, M. (2015).
Simulation of tubular adsorber for adsorption refrigeration system powered by solar energy in sub-Sahara region
of Algeria. Energy conversion and management, Volume
106, 31–40.
Anyanwu E.E. (2004). Review of solid adsorption solar
refrigeration II: an over view of the principles and theory.
Energy Conversion and Management, Volume 45(7–8),
1279–1295; http://dx.doi.org/10.1016/j.enconman.2003.
08.003.
Anyanwu, E. E. (2003). Design, construction and test run of
a solid adsorption solar refrigerator using activated carbon/methanol, as adsorbent/adsorbate pair. Energy Conversion and Management, Volume 44(18), 2879–2892.
Askalany, A., Ismail, I., Salema, M., Ahmed, H., & Morsy,
M. (2012). A review on adsorption cooling systems with
adsorbent carbon. Renewable and Sustainable Energy
Reviews, Volume16, 493–500.
Bajpai V. K. (2012). Design of solar powered vapour
absorption system", proceeding of the world congress
on engineering, Vol.3. London, U.K. World congress on
engineering, Volume 3. London, U.K.
Boubakri A., Arsalane M., Yous B., Ali-Moussa L., Pons M.,
& F., M. (1992). Experimental study of adsorptive solar
powered ice makers in Agadir (Morocco)-1. Performance
in actual site. Renewable Energy, Volume 2(1), 7–13.
Boubakri, A., Arsalane, M., Yous, B., Ali-Moussa, L., Pons,
M., & Meunier, F. (1992). Experimental study of adsorptive solar powered ice makers in Agadir (Morocco)2, influences of meteorological parameters. Renewable
Energy Volume 2(1), 15–21.
271
the running conditions and the aim of the application should be taken into account considering different
effects of factors in Table 2. For solar cooling the
important parameter governing the choice is the driving temperature as it should be the minimum allowable
temperature. The most important running conditions
are the driving temperature, evaporation temperature
and COP.
The highest COP value reported in the composite
adsorbents category is between silica gel with chlorides and water pair attributed to the ionic nature
of chlorides which enhance conductivity and the
high heat capacity of water. The minimum value
for COP occurs in the physical adsorbents category between zeolite and water pair. Metal hydrides
and hydrogen show the lowest value for evaporation temperature because hydrogen has a very low
normal boiling point (−252.87
◦ C). For the case of
driving temperature, silica gel and chlorides with
methanol pair has the lowest driving temperature
while zeolite and water pair has the highest driving
temperature.
Research results on solar adsorption systems
from Table 3 indicate attainment of maximum COP
value of 0.49 and cooler temperature of 4
◦ C from
methanol/olive waste pair compared to COP of 1.65
achieved from composite adsorbents.
7 CONCLUSION AND RECOMMENDATIONS
Although investment costs for adsorption chillers are
still high, the environmental benefits are impressive,
when compared to conventional compression chillers.
The absence of harmful or hazardous products such
as CFCs, together with a substantial reduction of CO2
emissions due to very low consumption of electricity, creates an environmentally safe technology. Low
temperature waste heat or solar energy can be converted into a chilling capacity as low as 5
◦ C with
minor maintenance costs. Nevertheless, some crucial
points in the development of sorption systems still
exist and those are closely connected to the low specific power of the machine and the investment costs.
Recently, more close attention was paid to the development of combined systems of solar cooling and
heating in order to make use of all types of energies rationally. All these works will be of great favour
to the development of the solar sorption refrigeration
system.
More research on adsorbent materials, improved
heat and mass transfer, advanced cycles, etc. to make
adsorption technology competitive is necessary. This
work will help to understand basics and research
progress on adsorption systems.
From this research, it is recommended to assess the
suitability of steatite as a co-adsorbent material for
purposes of improving adsorption capacity of various
working pairs to enhance operation with low driving
temperature hence boost deployment of solar energy
usage.
ACKNOWLEDGMENT
This work was supported by theAfrica Centre of Excellence II in Phytochemicals, Textile and Renewable
Energy (ACE II – PTRE) at Moi University of the
Eastern and Southern Africa Higher Education Centers of Excellence Project through the Association of
Energy Professionals in Eastern Africa, AEPEA.
REFERENCES
Abu-Hamdeh N.H., A. K. (2013). Design and performance
characteristics of solar adsorption refrigeration system
using parabolic trough collector: Experimental and statistical optimization technique. Energy Conversion and
Management, Vollume 74, 162–170.
Alghoul MA, Sulaiman MY, Azmi BZ, & Wahab MA.
(2007). Advances on multi-purpose solar Adsorption
systems for domestic refrigeration and water heating.
Applied Thermal Engineering, Volume 27(5–6), 813–822,
http://dx.doi.org/10.1016/j.applthermaleng.
Al-Hemiri, A., & Nasiaf, A. (2010). The use of direct solar
energy in absorption refrigeration employing Ammonia –
water system. Iraqi Journal of Chemical and Petroleum
Engineering, Volume 11, No. 4, 13–21.
Allouhia, A., Kousksoub, T., Jamila, A., El Rhafikic T., E.,
MouradaY., & ZeraoulibY. (2015). Optimal working pairs
for solar adsorption cooling applications. Energy, Volume
79, 235–247.
Al-Mousawi, F., Al-Dadah, R., & Mahmoud, S. (2016). Low
grade heat driven adsorption system for cooling and power
generation with small-scale radial inflow turbine. Applied
Energy, Volume 183, 1302–1316.
Amar Sadoon A. (2006). Design, built and performance study
on adsorption ice maker", M.Sc. thesis. Iraq.: University
of Technology.
Ammar, M. H., Benhaoua, B., & Balghouthi, M. (2015).
Simulation of tubular adsorber for adsorption refrigeration system powered by solar energy in sub-Sahara region
of Algeria. Energy conversion and management, Volume
106, 31–40.
Anyanwu E.E. (2004). Review of solid adsorption solar
refrigeration II: an over view of the principles and theory.
Energy Conversion and Management, Volume 45(7–8),
1279–1295; http://dx.doi.org/10.1016/j.enconman.2003.
08.003.
Anyanwu, E. E. (2003). Design, construction and test run of
a solid adsorption solar refrigerator using activated carbon/methanol, as adsorbent/adsorbate pair. Energy Conversion and Management, Volume 44(18), 2879–2892.
Askalany, A., Ismail, I., Salema, M., Ahmed, H., & Morsy,
M. (2012). A review on adsorption cooling systems with
adsorbent carbon. Renewable and Sustainable Energy
Reviews, Volume16, 493–500.
Bajpai V. K. (2012). Design of solar powered vapour
absorption system", proceeding of the world congress
on engineering, Vol.3. London, U.K. World congress on
engineering, Volume 3. London, U.K.
Boubakri A., Arsalane M., Yous B., Ali-Moussa L., Pons M.,
& F., M. (1992). Experimental study of adsorptive solar
powered ice makers in Agadir (Morocco)-1. Performance
in actual site. Renewable Energy, Volume 2(1), 7–13.
Boubakri, A., Arsalane, M., Yous, B., Ali-Moussa, L., Pons,
M., & Meunier, F. (1992). Experimental study of adsorptive solar powered ice makers in Agadir (Morocco)2, influences of meteorological parameters. Renewable
Energy Volume 2(1), 15–21.
271