2. • PV and compressor system
• Heat driven systems (Sun or bio-fuel):
o Absorption
o Steam engine – mechanical compressor
o Solar Stirling – mechanical compressor
5. PV Ice Production: The Luis Leon reservoir in the heart of the
Chihuahuan desert with the Chorreras ice-house. The
Chorreras community at the inauguration of their 2.4 kWp PV
ice-making system in March, 1999. Everybody appreciates a
little extra shade in the desert as well.
Ref. http://www.re.sandia.gov/en/pb/pd/Icemaker_final.pdf
6. ISAAC Solar Ice Maker
The ISAAC Solar Icemaker is an Intermittent Solar Ammonia-water
Absorption Cycle. The ISAAC uses a parabolic trough solar
collector and a compact and efficient design to produce ice with no
fuel or electric input, and with no moving parts.
The ISAAC Solar Icemaker operates in two modes. During the day,
solar energy is used to generate liquid ammonia refrigerant. During
the night, the generator is cooled by a thermosyphon and ice is
formed in the evaporator compartment as ammonia is reabsorbed
to the generator.
Six ISAAC Solar Icemakers in the Coastal region of Kenya. The
purpose of installation is to preserve milk so the farmers can
transport their milk to market before it spoils. This will increase the
income of the farmers and decrease poverty in the area.
11. Parameters: Life cycle cost analysis of a diesel operated
icemaker (investment US$15,000) compared to 18 ISAAC
solar icemakers (investment US$72,000), both producing
0.9 Tons of ice per 24hrs. Discount rate is 15%, economic
life is 20 years, scrap value is US$0,00 and at year 10 a
new Diesel generator will be purchased at a cost of
US$5,000. It is assumed that local assembly will make the
ISAACs available at US$4,000 each. Because of the
country specific cost for transportation, import tax,
maintenance and labour costs, these cost are assumed
equal for both operations and therefore not taken into
account in this cost comparison. Assumed energy use is
90kWh/ton of ice and the efficiency of the generator is
assumed at 3kWh/liter of Diesel.
15. Explanation
Der Spiegel ist ein kleiner, seitlicher Ausschnitt eines wesentlich
größeren, runden Paraboloids. Durch die schräge Schnittführung
entsteht dabei die typische elliptische Kontur des Scheffler-Reflektors.
Das von diesem Ausschnitt des Paraboloids reflektierte Licht fällt von der
Seite auf den ein Stück weit entfernten Brennpunkt.
Die Achse für die tageszeitliche Nachführung liegt in Nord-Süd Richtung
parallel zur Erdachse und läuft durch den Schwerpunkt des Reflektors.
So ist er immer im Gleichgewicht und das mechanische Uhrwerk muß
nur mit einer geringen Kraft angetrieben werden um ihn synchron mit der
Sonne zu drehen.
Damit sich der Brennpunkt dabei nicht bewegt liegt er auf der
Rotationachse. Der Abstand zwischen Brennpunkt und Reflektormitte
hängt von der gewählten Ausgangsparabel ab.
Das konzentrierte Licht wird so während des Tagesverlaufs nur um sein
eigenes Zentrum rotieren, sich aber in keiner Richtung seitlich bewegen.
Der Brennpunkt bleibt also fixiert, was natürlich praktisch ist, da der
Kochtopf nun auch nicht bewegt werden muß.
17. Cummins Power Generation of Columbus, Indiana.
5 kW free-piston engine dish/Stirling system. The
concentrator incorporates 24 stretched-membrane facets
(5 feet in diameter). A slight vacuum is drawn between the
membranes to obtain an approximately spherical shape.
18. German/Saudi 50 kW dish/Stirling system ; These machines are located at the Solar
Village of the Saudi Arabian National center for Science and Technology, near Riyadh.
The solar concentrator is a single facet stretched membrane dish 17 mtrs in diameter.
The engine used is a 50kW United Stirling 4-275. The max operating temperature is 620
deg C and max gas pressure 2175 psi. Eficiency of 23% solar to electric have been
achieved at an insolation of 1000 W/m2.
20. What is the best option?
How can we realize this option?
• Solar Steam -> E -> Ice (300 kg/day)
o 5 HP steamengine from India
o Ice machine from the Netherlands
o Solar Steam from Germany?
• What must be the form of the Ice
• Building Pilot 0,5 year
• Testing Pilot: how simulate the sun? 0,5 year
• Pilot in Gambia: Aqua-Aero WaterSystems
21. This presentation is 4 years old. To day I am
convinced, that solar ice production is
possible, but too expensive.
I prefere now to use a biogas fired 10 kVA
steamgenerator, connected to an icecube
machine.
Apeldoorn
11-03-2013