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					   SOLAR AIR
   CONDITIONING
   A technological
   development
   opportunity in
   renewable energy

ROBERTO C. CALLAROTTI
  PREC Scientific Director



III Symposium
RENEWABLE ENERGY: MITHS, REALITIES and OPPORTUNITIES
             Universidad del Turabo May 13-14 2010
                   © - R. Callarotti




                CONTENTS

☯ Introduction: cooling systems based on
       direct solar energy

☯ Ejector-compressor systems

☯ Additional systems

☯ Conclusions
Sun              Moon – tides
170 000 Tw       3Tw=3x1012 watts
1.7x1017 watts




Geothermal
30 Tw
Annual electrical breakdown for typical household in Florida: Parker D.S. et al, Monitored energy
use patterns in low income housings in a hot and humid climate, 10th Symposium on improving
building systems in hot climates, pp 316, Forth Worth, TX,


                   HVAC Heater ventilation air conditioning 40%
                   + Water heater                            19%
                                                          ========
                                                             59 %
SOME HISTORY


In 1758, Benjamin Franklin and John Hadley, professor of chemistry at
Cambridge University, conducted an experiment to explore the principle of
evaporation as a means to rapidly cool an object. Franklin and Hadley confirmed
that evaporation of highly volatile liquids such as alcohol and ether, could be
used to drive down the temperature of an object past the freezing point of water.
They conducted their experiment with the bulb of a mercury thermometer as their
object and with a bellows used to "quicken" the evaporation they lowered the
temperature of the thermometer bulb down to 7 deg F while the ambient
temperature was 65 deg F.
Franklin noted that soon after they passed the freezing point of water (32 deg F)
a thin film of ice formed on the surface of the thermometer's bulb and that the ice
mass was about a quarter inch thick when they stopped the experiment upon
reaching 7 deg F.
Franklin concluded, "From this experiment, one may see the possibility of
freezing a man to death on a warm summer's day".[1]
In 1820, British scientist and inventor Michael Faraday discovered that
compressing and liquefying ammonia could chill air when the liquefied
ammonia was allowed to evaporate.
In 1842, Florida physician John Gorrie used compressor technology to create
ice, which he used to cool air for his patients in his hospital in Apalachicola,
Florida.[2] He hoped eventually to use his ice-making machine to regulate the
temperature of buildings. He even envisioned centralized air conditioning that
could cool entire cities. Though his prototype leaked and performed irregularly,
Gorrie was granted a patent in 1851 for his ice-making machine. His hopes for
its success vanished soon afterward when his chief financial backer died;
Gorrie did not get the money he needed to develop the machine. According to
his biographer Vivian M. Sherlock, he blamed the "Ice King", Frederic Tudor, for
his failure, suspecting that Tudor had launched a smear campaign against his
invention.
Dr. Gorrie died impoverished in 1855 and the idea of air conditioning faded
away for 50 years.
Early commercial applications of air conditioning were manufactured to cool air
for industrial processing rather than personal comfort.
In 1902 the first modern electrical air conditioning was invented by Willis
Havilland Carrier in Syracuse, NY. Designed to improve manufacturing process
control in a printing plant, his invention controlled not only temperature but also
humidity. The low heat and humidity were to help maintain consistent paper
dimensions and ink alignment.
Later Carrier's technology was applied to increase productivity in the workplace,
and The Carrier Air Conditioning Company of America was formed to meet rising
demand.
Over time air conditioning came to be used to improve comfort in homes and
automobiles.
Residential sales expanded dramatically in the 1950s.
In general the energy required for driving
air conditioning systems, refrigerators
and freezers is the distributed electrical
energy or the energy derived from the
combustion of gas or other fossil fuels.


What are the available options for
cooling with the energy directly
derived from the sun ?
COP Coefficient Of Performance for a refrigeration cycle
(We illustrate the COP for an ideal Carnot cycle refrigerator on the plane T-S)
Inverse Carnot cycle 1->4->3->2 REFRIGERATION CYCLE
2->1 heat Q1 leaves the system
4->2 heat Q2 enters the system
1->4->3->2->1 work W is done ON the system W=Q1-Q2

                                                       The COP Coefficient Of
                                                       Performance for a refrigeration
     --- T1                                            cycle is defined as a measure of
                                                       efficiency:
     --- T2                                            COP= Q2 / W
                                                       Heat removed per unit of work
                                                       required – In general – and in the
                                                       case of the ideal Carnot cycle:
                                                       COP = T2 / (T1-T2)
                                                       COP = 1 / [ (T1/T2)-1]
   Inverse Carnot Cycle on the temperature - entropy
   plane                                               ( COP might be > 1)
The conventional systems where the electrical
power is provided by photovoltaic panels




       Commercial efficiencies 11-17%




            STORAGE
De WIKIPEDIA Solar cell
Among the conventional systems where the electrical power is
provided by photovoltaic panels which move a motor, we have the
Stirling cycle
                    Several Stirling cycle
                    structures using displacers:
                    compress gas in a region
                    where the heat is removed,
                    displace the compressed gas
                    to a region thermally
                    insulated, where the gas
                    expands and the temperature
                    is lowered
Distillation
column:
liquid air
enters at
center,
gaseous O2
is given out,
and liquid
nitrogen is
collected




   IVIC 1964 Low temperatures Laboratory –
   Liquid Nitrogen generator based on a Stirling
   Cycle


            T freeze (C)        T boil (C)
   N2           -210             -196
   AIR          -216.7           -194.35
   O2           -222             -182.96
1 Ton = 12 000 Btu/hr = 3.516 Kw
2.84 Tons = 10 Kw about 2000 $
A room 5m x 4m requires some 4000 Btu 1/3 Ton
Thermoelectric AC based on the Peltier Effect : fans are
the only moving parts and no refrigerant fluid is required
                       EJECTOR CYCLE




70-100 C   100-150 C             > 150 C



   FPC                   ETC
Heat pipe evacuated tube collectors contain a copper heat
pipe, which is attached to an absorber plate, inside a vacuum
sealed solar tube. The heat pipe is hollow and the space
inside is also evacuated. Inside the heat pipe is a small
quantity of liquid, such as alcohol or purified water plus
special additives. The vacuum enables the liquid to boil at
lower temperatures than it would at normal atmospheric
pressure. When sunlight falls the surface of the absorber, the
liquid in the heat tube quickly turns to hot vapor and rises to
the top of the pipe. Water or glycol, flows through a manifold
and picks up the heat. The fluid in the heat pipe condenses
and flows back down the tube. This process continues, as
long as the sun shines.
 Since there is a "dry" connection between the absorber and
the header, installation is much easier than with direct flow
collectors. Individual tubes can also be exchanged without
emptying the entire system of it's fluid and should one tube
break, there is little impact on the complete system.

Heat pipe collectors must be mounted with a minimum tilt
angle of around 25° in order for the internal fluid of the heat
pipe to return to the hot absorber
An evacuated-tube collector contains several rows
of glass tubes connected to a header pipe. Each
tube has the air removed from it (evacuated) to
eliminate heat loss through convection and
radiation. Inside the glass tube, a flat or curved
aluminum or copper fin is attached to a metal pipe.
The fin is covered with a selective coating that
transfers heat to the fluid that is circulating
through the pipe. There are two main types of
evacuated tube collectors:
Direct-flow evacuated-tube collectors
A direct-flow evacuated tube collector has two pipes
that run down and back, inside the tube. One pipe is for
inlet fluid and the other for outlet fluid. Since the fluid
flows into and out of each tube, the tubes are not easily
replaced. Also, should a tube break, it's possible that all
of the fluid could be pumped out of the system - if a
closed loop is used, or your water will flow out as in a
broken pipe, if an open loop is used.
n this type of Collector, the Absorber is inside
an air-evacuated glass tube, and, compared
to a Flat-Plate Collector, energy loss can be
further reduced and temperatures up to 150
°C (302 °F) can be reached. Because of their
high Efficiency, evacuated-tube collectors
also work on slightly cloudy days.


Efficiency
General: The relationship between potentially
usable energy and actually used energy. To
illustrate: Conventional light bulbs transform
about 3-4 % of the used energy into light;
Solar Cells reach efficiencies of about 11—17
% when converting light into electricity; and a
Solar Heating System can transform 25—40
% of Solar Radiation into usable heat.
     EJECTOR BASED SYSTEMS


WHAT IS AN EJECTOR CYCLE ?


   EJECTOR in a COMPRESSION CYCLE


      V. CHANG EJECTOR SYSTEM FII 1983


          J. MEYER EJECTOR SYSTEM MSc
          THESIS Stellenbosch University 2007


               UK ejector system
Solar driven ejector heat pump compared to a conventional electric heat pump
The Australian National University Solar Thermal Group February 2010
Typical ejector cross-section, pressure and velocity profiles along an ejector operating in
critical mode. Primary, secondary and discharge streams are indicated in red, blue and
green respectively. Adapted from Chunnamond & Aphornratana (2004)The Australian
National University Solar Thermal Group February 2010
Typical CFD output, a mach number plot for an ejector
EJECTOR in a COMPRESSION CYCLE
Solar powered ejector based solar
cooling system (Sokolov, 1993)

The Australian National University Solar
Thermal Group February 2010
Solar availability in not coincident with cooling demand
The Australian National University Solar Thermal Group February 2010
Key Research Challenges

Ejector based systems are characterised by their simplicity and high reliability, tolerance
to a range of working fluids, but also poor performance and range of operating
conditions. The performance issues must be addressed if ejectors are to become
mainstream. In particular, the low thermal COP and poor off-design performance must
be improved.

Performance is usually interpreted relative to cost. The cost of the ejector system is
dominated by the cost of the heat source which can be high if solar collectors are
required. Commonly temperatures around 70-100ºC are required to drive an ejector,
making them suitable for use with non-concentrating solar collectors or waste heat from
cogeneration systems. Successful ejector based systems will seek to maximise annual
utilisation of the heat source by providing multiple services: summer space cooling,
winter space heating and water heating.

Such systems do not exist although the technology is available.


     The Australian National University Solar Thermal Group February 2010
Key Research Challenges


The third set of challenges relate to system integration. There are challenges in design
and sizing of ejector system components such that the cooling system maximises the
use of the (varying) solar collector output to produce the highest solar contribution to the
cooling load. This has implications for including energy storage and smart control
schemes into the system design. Little research has been performed in this area to date.
Indeed, there has been little research into real-time dynamic control of ejector systems
since most operate at steady state in a laboratory environment




     The Australian National University Solar Thermal Group February 2010
Thermodynamic Modelling

For over fifty years, ejectors were empirically designed based on rules of thumb and
experience with steam driven devices. Early attempts to thermodynamically model the
steam ejector were carried out by Keenan (1950). Keenan was able to reasonably
predict the ejector performance characteristics firstly for constant area mixing ejectors
then also for constant pressure mixing ejectors. Further clarification of the mixing
mechanism was provided by Munday and Bagster (1977).


Perhaps the most important improvement in understanding was provided by Eames
(1995) and Huang et al (1999) with the description of a one dimensional design
methodology. These advances provided researchers with a means to design an ejector,
including the effect of supersonic shock and three calibration constants such that model
and experimental data generally agreed within about 10%.


Since Huang’s method, there have been several modifications that give refined
descriptions of ejector operation. The first is the Shock circle method (Zhu, 2007) which
better accounts for the boundary layer secondary flow in the mixing chamber prior to
mixing. This gives typical errors of less than 5% compared to published experimental
data and would be considered the current state of conventional thermodynamic
modelling of ejectors.
Hybrid Cycles


Despite recent advances in understanding of ejector operation, the COP of a simple
ejector cooling system remains stubbornly low. As a result, many researchers have
proposed hybrid cooling systems incorporating combinations of ejectors and another
cooling system. The most common hybrid systems are:

Multiple ejector hybrids

                  Mechanical vapour compression / ejector hybrids

                                   Absorption / ejector hybrids




     The Australian National University Solar Thermal Group February 2010
Chang Victor, Chitty Alejandro and
Grávalos José
Funcionamiento de un sistema de
refrigeración por eyecto-compresión
usando energía solar …….
Funadación Instituto de ingeniería 1983




                        The purpose of this part of the presentation
                        is to indicate the possibility of R&D efforts
                        under monetary limitations
V. CHANG EJECTOR SYSTEM FII 1983
             ηR
ηC



     η
         T
Chang et al 1983
Steam jet ejector cooling system
58.2 m2 (7m x 8.3 m)               one Ton   3.5 Kw
From Huang et al
Solar energy 71 (4)
269-74 2001
R-113 (Trichlorotrifluoroethane)



R-142b 1-chloro-1,1-difluoroethane



R-141b Dichlorofluoroethane
From Huang et al
Solar energy 71 (4)
269-74 2001
From Huang et al
Solar energy 71 (4)
269-74 2001
        Adriaan Jacobus Meyer
        Steam jet ejector cooling powered by low
        grade waste or solar heat
        MSc THESIS
        Stellenbosch University September 2006




The purpose of this part of the presentation
is to indicate the nature of the limited
expenses involved in this type of
experimental projects
UK ejector system
       IN SUMMARY
WHY SHOULD WE USE THERMAL
   SOLAR ENERGY FOR AIR
  CONDITIONING SYSTEMS ?
 WE MINIMIZE THE USE OF ELECTRICAL ENERGY AS
   COMPARED TO CONVENTIONAL AC SYSTEMS

      PARTIAL COINCIDENCE OF MAXIMAL SOLAR
        IRRADIATION WITH MAXIMAL DEMAND

             HEAT CAN BE EASILY STORED

            REDUCTION OF CO2 EMISSIONS

                  MONETARY SAVINGS

ERoEI = (1.6-1.9) / 1 > 1 Hall et al 1986
(ENERGY RETURN ON ENERGY INVESTMENT = RATIO
OF ENERGY DELIVERED IN AN ENERGY OBTAINING
ACTIVITY TO THE ENERGY REQUIRED TO GET IT)
                       CONCLUSIONS

SURPRISINGLY --- THERE ARE FEW EXPERIMENTAL RESULTS WITH
SOLAR REFRIGERATION SYSTEMS IN THE CARIBBEAN REGION WHERE
HIGH SOLAR IRRADIATION IS AVAILABLE AND WATER HUMIDITY IS HIGH


MANUFACTURING OF PHOTOVOLTAIC CELLS IS A COMPLEX
PROPIETARY TECHNOLOGY – IT IS HARD TO SEE A LOCAL
MANUFACTURING WORLD WIDE COMPETITIVE EFFORT

THE AVAILABILITY OF ROOF SPACE IN SINGLE FAMILY HOUSES IN
PUERTO RICO IS A POSITIVE FACTOR FOR THE IMPLEMENTATION OF
SOLAR AIR CONDITIONING / HEATING SYSTEMS

DUAL SOLAR AC / WATER HEATING SYSTEMS CAN AND SHOULD BE
PRODUCED AND USED LOCALLY – WITH THE CORRESPONDING
ELECTRICAL ENERGY SAVINGS (ABOUT 90%)

EXPERIMENTAL R&D EFFORTS ARE REQUIRED
                      CONCLUSIONS

MECHANICAL ENGINEERING AND ELECTRICAL ENGINEERING
PROGRAMS SHOULD INCLUDE SOLAR ENERGY – AND ENERGY IN
GENERAL IN UNDERGRADUATE CURRICULA

MECHANICAL ENGINEERING AND ELECTRICAL ENGINEERING
GRADUATE PROGRAMS, SHOULD STRESS EXPERIMENTAL R&D IN
SOLAR ENERGY CONVERSION IN PUERTO RICO – EVERYWHERE FOR
THAT MATTER

UNIVERSITIES IN THE CARIBBEAN REGION – SHOULD SEEK R&D
FUNDS FOR SOLAR ENERGY RESEARCH AND/OR PROVIDE SEED
FUNDS FOR THESE EFFORTS. THIS CONCLUSION ALSO APPLIES FOR
COUNTRIES WITH FOSSIL FUEL RESOURCES, AS THESE ARE FINITE –
CHEAP R&D CAN BE ACHIEVED IN MODELING SYSTEMS

THE TECHNICAL LITERATURE SHOWS THAT MOST OF THE SOLAR
ENERGY RESEARCH TAKES PLACE IN EUROPE, THE US, JAPAN AND IN
CHINA
Haining Lucky Solar Energy Technology Co.,Ltd.
is a high-new technology enterprise specializing in producing and applying solar water
heaters. The company covers about 10,000 square meters, Now it has more than 200
workers and staff members, above 65% are medium and high grade technicians. with a
powerful technician team and advanced facility, the company capacity can reach 250,000
sets per year.
The company owns the international first-class numerical control production equipment and
the vacuum collection heat pipe process line, researches and develops the first domestic full
automatic foaming production with constant temperature curing process line. Company pays
great attention to the innovation, the craft innovation and the function innovation, owns many
patents of invention and the patent of utility model, plays the crucial position in the profession
technological innovation aspect.
The company passed the ISO9001:2000 international quality system certificate, European
Union CE authentication certificate. The individualized outward appearance, delicate design
of the streamline pattern and the excellent quality has gained a lot of consumers’ trust and
good remarks. The products have been successfully sold to US, Europe, Middle East etc.
The products are well received by vast number of consumers and colleagues from the same
field. We are willing to join hands with you for the promotion of developing the international
green environmental protection undertaking and jointly build up a fine green homeland.
 Address:Xincang Industry Zone of Haining,Zhejiang,China
Phone :86-573-87283166
Fax :+86-573-87283177
Email :cnchenyu@163.com
     sales@cnchenyu.com
Contact:Mr. Peter Zhu
Haining Lucky Solar Energy

The system is operated intelligently and automatically
It can be added and changed partial function Scientifically and modularizedly
1.Collector system use temperature difference cycle. There is a temperature sensor
in the collector and in the water tank respectively, sensors will send the measured
temperature signal to controller box . When temperature difference between the
collector and the water tank is higher than temperature difference by setting, the
control system start operating circulation pump, thereby it can make the cold water
from the collector into water tank, then a cycle be finished and gradually warming
the water in the tank.
2.Control system can show the temperature and the water level intelligently, add
water and control temperature automatically. Installed with a temperature sensor in
the system , will automatically activate the working of the circulation pump within the
scope of setting the temperature difference.
3.Set temperature probe in the end of controller box in tank, this water temperature
is higher than the temperature setting, It will automaticall activate the circulating
pump, make cold water from tank enter into the pipe collector, and ensuring tank is
always full of hot water.
COPYRIGHT@ 2008 Haining Lucky Solar Energy Technology Co.,Ltd. All RIGHT
RESERVED
                       Rafael A. Pérez Reisler, Heat and Mass
                       Transfer in air cooled verical tube
                       absorbers, MSc ME thesis, University of
                       Puerto Rico at Mayaguez Campus, 2007




Mathematical modeling of a vertical absorber chiller using a water
lithium-bromide solution
Includes a summary of solar AC efforts in Puerto Rico
Thank you for your
attention
                                 References

Varga S. et al., Analysis of a solar-assisted ejector cooling system for air
conditioning, Int. Journal of Low_Carbon Tech. Advance Access, March 5
2009, 1-7
Helm M. et al, Solar heating and cooling system with absorption chiller and low
temperature latent heat storage, International Journal of refrigeration xxx
(2009) 1-11
Kim D.S. and Infante Ferreira C.A., Air cooled LiBr-water absorption chillers for
solar air conditioning in extremely hot weathers, Energy conversion and
management 50 (2009) 1018-25
Torrella E. et al, On site real time evaluation of an air-conditioning direct-fired
double effect absorption chiller, Applied Energy 86 (2009) 968-75
KTH-EGI Solar cooling 1997-2009 http://www.energy.kth.se
Huang B.J. et al, Development of an ejector cooling system with thermal
pumping effect, International Journal of Refrigeration 29 (2006 476-484
Huang B.J.et al, Collector selection for a solar ejector cooling system, Solar
Energy Vol 71, No. 4, 269-74 (2001)
Wang J.H. et al, Performance of ejector cooling system with thermal pumping
effect using R141b and R365mfc, Applied Thermal Engineering 29 (2009)
1904-12
Abdulateef J.M. et al, Review of solar driven ejector refrigeration technologies,
Renewable and sustainable energy reviews 13 (2009) 1338-49
Maggio G. et al, Simulation of a solid sorption ice-maker based on the novel
composite sorbent “lithium clhoride”in silica gel pores, Applied thermal
engineering 29 (2009) 1714-20
Meyer A. J, Steam jet ejector cooling powered by low grade waste or solar
heat, MSc ME thesis, Stellenbosch University, South Africa 2006
Boccaletti C., Aspetti termodinamici e di scambio termico nel funzionamento di
macchine frigorifere ad assorbimento, Tesi di Dottorato in Energetica,
Universitá della Sapienza, Roma, 200?
Dieng A.O. and Wang R.Z., Literature review on solar adsorption technologies
for ice-making and air conditioning purposes and recent developments in solar
technology, Renewable and sustainable energy reviews 5 (2001) 313-42
Rosiek F. and Batlles F.J., Integration of the solar thermal energy in the
construction: analysis of the solar assisted air conditioning system installed in
the CIESOL building, Renewable energy 34 (2009) 1423-31
Dietz M.E. et al, The UTAH house: an effective educational tool and catalyst
for behavior change ?, Building and environment 44 (2009) 1707-13
Ritschel A. and Wright J., Development of a solar energy research and test
center at the University of California, Merced, xxxxx 2517-19
Cammi A., Chillers, available on the web
Sisó Miró L., Curso de climatización solar, www.aiguasol.coop, 2008
Zhai X.Q. and Wang R.Z., A review for absorption and adsorption solar cooling
systems in China, Renewable and sustainable energy reviews 13 (2009) 1523-
31
Yu J. et al, Evaluation o energy and thermal performance for residential
envelopes in hot summer and cold winter zones of China, Applied Energy 86
(2009) 1970-85
Syed A. et al, A study of the economic perspectives of solar cooling schemes,
available on the web (2001 ?)
Rafael A. Pérez Reisler, Heat and Mass Transfer in air cooled verical tube
absorbers, MSc ME thesis, University of Puerto Rico at Mayaguez Campus,
2007 MAYAGUEZ PUERTO RICO
Chang V. et al, Funcionamiento de un sistema de refrigeración por eyecto-
compresión usando energía solar, Memorias de las Primeras Jornadas
Técnicas de la Fundación Instituto de Ingeniería (1983) 106-9
Chitty A. et al, Diseño y ensayo de eyecto-compresor para un sistema de
refrigeración por energía solar, Memorias de las Primeras Jornadas Técnicas
de la Fundación Instituto de Ingeniería (1983) 110-113 CARACAS
VENEZUELA
AIL Research, SOA Series, Liquid desiccants for solar cooling, www.ailr.com
2006
Lowenstein A., A zero carryover liquid-desiccant air conditioner for solar
applications, Draft for ASME/SOLAR06, July 8-13, 2006, Denver (Co)
www.ailr.com
Gommed K. and Grossman G., Experimental investigation of a liquid desiccant
system for solar cooling and dehumidification, Solar Energy 81 (2007) 131-8
Hildebrand C. et al, A new solar powered absorption refrigerator with high
performance, Solar Energy 77 (2004) 311-8
Freni A. et al, Optimization of a solar-powered adsorptive ice-maker by a
mathematical model, Solar Energy 82 (2008) 965-76
Chwieduk D., Some aspects of modeling the energy balance of a room in
regard to the impact of solar energy, Solar Energy (2008) 870-84
Mauran S. et al, Solar heating and cooling by a thermochemical process: first
experiments of a prototype storing 60 Kwh by a solid/gas reaction, Solar
Energy 82 (2008) 623-36
Clausse M. et al, Residential air conditioning and heating by means of
enhanced solar collectors coupled to an adsorption system, Solar Energy 82
(2008) 885-92
Elsarrag E., Evaporation rate of a novel tilted solar liquid desiccant
regeneration system, Solar Energy (2008) 663-668
Juanicó J, A new design of a roof-integrated water solar collectot for domestic
heating and cooling, Solar Energy 82 (2008) 481-92 BARILOCHE
ARGENTINA
Alizadeh S., Performance of a solar liquid desiccant air conditioner – An
experimental and theoretical approach, Solar Energy 82 (2008) 563-72
Eickler U. and Pietruschka D., Design and performance of a solar powered
absorption cooling systems in office buildings, Energy and Systems (2007)
doi:10.1016/j.enbuild.2008.07.015
Irizarry-Rivera et al, Achievable Energy Targets for Puerto Rico’s Renewable
Energy Portfolio Standard – Summary of Final report, PR Energy Affairs
Administration, Contract 2008-B2009, October 2008- November 2009
PUERTO RICO

				
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