Donald ERICKSON
ISAAC Solar Icemaker
Energy Concepts Co., LLC
627 Ridgely Ave.
Annapolis, MD 21401
Tel: 410-266-6521
Fax: 410-266-6539
email: enerconcep@aol.com
http://www.energy-concepts.com
http://solaricemaker.com/
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.
The daily ice production of the ISAAC is about 5 kg per square meter of
collector, per sunny day. The construction of the ISAAC Solar Icemaker
involves only welding, piping and sheet metal work, and there are no
expensive materials. It is estimated that, when produced in-country
where wages are low and transportation costs can be minimized, the 11
square meter
ISAAC can be produced for less than $7,000. When produced in-country,
the creation of urban employment is an additional advantage of ISAAC
technology.
The characteristics of the ISAAC which make it particularly well suited
to provide refrigeration to unelectrified rural communities are:
1. It is solar thermally powered, avoiding expensive diesel fuel or
photovoltaics.
2. Low cost construction requires only welding, piping and sheet metal
work.
3. Very low maintenance.
4. The quantity of ice is sufficient to support small scale businesses
while maintaining sustainability in fragile environments, or provide
low cost household refrigeration.
The ISAAC design was developed by Energy Concepts Company. Over forty
systems have been built and twenty installed in seven countries. The
ISAAC is on display in Annapolis, Maryland and at Sandia National Lab,
Albuquerque, New Mexico. ISAAC is now being distributed and
commercialized by Solar Ice Co.
Providing Jobs to Remote Communities -
By Providing Ice
The ISAAC Solar Icemaker makes enough ice at low cost to support many
small scale businesses in rural unelectrified areas. Enterprises using
ISAAC will be environmentally sustainable because no fuel is required.
They will be economically sustainable because the cost of producing the
ice by the ISAAC is sufficiently less than the value of the ice that it
can easily be recovered by a micro-enterprise.
Ice is of major economic importance. In rural communities of developing
countries, there is frequently a shortage of ice to support business
activities. The result is loss of revenue, jobs, and substantial food
spoilage.
Three important community needs for electricity are:
* lights
* communications and entertainment
* refrigeration.
Lights, communication and entertainment require modest amounts of
electricity and are affordable even at the high cost of electricity
from emergency generators, diesel mini-grids or photovoltaics.
When refrigeration is needed also, the amount of electricity required
from the power system increases drastically. Thus it is usually omitted
to keep costs down. An ISAAC Solar Icemaker supplies refrigeration
without the intermediary step of electricity and at a much lower cost.
Thus ISAAC Solar Icemakers, in combination with mini-grids and/or
photovoltaics, are a good method of supplying remote community needs.
For example, ISAAC can provide domestic refrigeration. An ISAAC
produces six blocks of ice each day, weighing ten kilograms each. If an
icebox requires five kilograms of ice per day to stay cool, then one
ISAAC will be able to supply domestic refrigeration to twelve
households. The cost of a standard electric refrigerator, plus the
constant requirement of expensive electricity, would be much higher.
The Absorption Cycle was invented in 1846 by Ferdinand
Carré for the purpose of producing ice with heat input. It is
based on the principle that absorbing ammonia in water causes the vapor
pressure to decrease. Absorption cycles produce cooling and/or heating
with thermal input and minimal electric input, by using heat and mass
exchangers, pumps and valves.
An absorption cycle can be viewed as a mechanical
vapor-compression cycle, with the compressor replaced by a generator,
absorber and liquid pump. The absorption cycle enjoys the benefits of
requiring a fraction of the electrical input, plus uses the natural
substances ammonia and water, instead of ozone depleting halocarbons.
The absorption cycle enjoyed widespread use from the 1920’s as gas
powered refrigerators/ice-makers.
The basic operation of an ammonia-water absorption
cycle is as follows. Heat is applied to the generator, which contains a
solution of ammonia water, rich in ammonia. The heat causes high
pressure ammonia vapor to desorb the solution. Heat can either be from
combustion of a fuel such as clean-burning natural gas, or waste heat
from engine exhaust, other industrial processes, solar heat, or any
other heat source. The high pressure ammonia vapor flows to a
condenser, typically cooled by outdoor air. The ammonia vapor condenses
into a high pressure liquid, releasing heat which can be used for
product heat, such as space heating.
The high pressure ammonia liquid goes through a
restriction, to the low pressure side of the cycle. This liquid, at low
pressures, boils or evaporates in the evaporator. This provides the
cooling or refrigeration product. The low pressure vapor flows to the
absorber, which contains a water-rich solution obtained from the
generator. This solution absorbs the ammonia while releasing the heat
of absorption. This heat can be used as product heat, or for internal
heat recovery in other parts of the cycle, thus unloading the burner
and increasing cycle efficiency. The solution in the absorber, now once
again rich in ammonia, is pumped to the generator, where it is ready to
repeat the cycle.
An absorption cycle can use a variety of working pairs.
The working pair is made up of a refrigerant, typically ammonia or
water; and a solution which absorbs the refrigerant. Other working
pairs include lithium-bromide-water; TriDroxide-water; and
Alkitrate-water. Tridroxide and Alkitrate are Energy Concepts patented
working pairs with specialty applications in industry.
Absorption cycles can operate at high efficiency by
utilizing advanced cycles, using generator-absorber heat exchange,
multiple pressures, and multiple effects. These cycles use extensive
internal heat recovery to require less prime fuel input to produce the
same thermal output. High efficiency operation, plus benefits of
environmentally friendly refrigerants, clean-burning fuels, and few
moving parts requiring maintenance make absorption a very good choice
for consumers.
Absorption cycles can produce a variety of thermal outputs. In common
commercial use today are gas-fired absorption chillers, which produce
chilled water for space cooling applications. The absorption cycle can
produce low temperature cooling for ice production or cold storage.
Turbine inlet cooling is a very efficient use of absorption cooling,
boosting turbine efficiency by up to 15%. Many other applications exist
in industry, where waste heat is available and cooling is required.
Advanced cycles can also produce electrical or shaft power by producing
steam or high pressure vapor to power a turbine/generator pair.
Publications -- ISAAC™
SOLAR ICEMAKER
Pierpont, J. P. "Energy Concepts Rises From Ashes To International
Market." Baltimore Business Journal. February 1989.
"What’s New: News in Brief." Maryland Business Weekly: The
Baltimore Sun. December 18, 1989.
"Hot Refrigeration" Environmental Protection Week. June 1990.
"Solar Refrigeration Brings Ice to Developing Countries." Solar
Industry Journal. Second Quarter. 1990.
Maier, Timothy A. "Solar-Powered Refrigerator Heats Up Energy
Concepts." Baltimore Business Journal. November 1990.
Erickson, Donald C. "Isaac Solar Absorption Icemaker." Soltech 91
Erickson, Donald C. "Isaac Solar Refrigerator." Environment-Friendly
Technologies for the 21st Century. Proceedings of the Japanese
Assocition of Refrigeration Absorption Heat Pump Conference. Tokyo.
September 1991.
Erickson, Donald C. and Jorgensen, Paul. "Solar Absorption Ice-Making
in a Mexican Fishing Village." Hawaii 1992.
Erickson, Donald C. "Solar Icemakers in Maruata, Mexico." Solar
Today. July/August 1994.
ThermoSorber™
The ThermoSorber™ is a
gas-fired heat pump which supplies air conditioning or refrigeration at
the cold end, and which uses all the reject heat (gas heat plus cooling
duty ) to heat hot water. The high temperature glide achieved with the
GAX absorption cycle makes it possible to heat hot water to 160°F,
thus meeting the needs of commercial users. The hot water is normally
the primary product, with the cooling in a supplementary role. This
ensures high year round utilization and short paybacks. This appliance
reduces the utility bill for hot water and cooling by more than half,
compared to the most economic commercially available equipment.
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US6584801
Absorption Cycle with Integrated
Heating System
2002-06-13
Inventor(s): ERICKSON DONALD C [US]
Classification:- international: F01K23/10; F01K25/06; F02C6/18;
F25B15/02; F25B33/00; F01K23/10; F01K25/00; F02C6/18; F25B15/02;
F25B33/00; (IPC1-7): F25B27/00
- European: F01K23/10; F01K25/06B; F02C6/18; F25B15/02; F25B33/00
Also published as: US6584801
Abstract -- An absorption
system powered by low temperature heat for producing at least one of
refrigeration and power is disclosed, wherein a low-pressure drop heat
reclaimer 1 reclaims heat from the source into a heating agent, which
in turn supplies heat to the absorption cycle desorber 5 via internal
coils 7. The extra temperature differential normally present in closed
cycle heating systems is avoided by using the absorption working fluid
as the heating agent, in an integrated system.
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US6269644
Absorption Power Cycle with Two
Pumped Absorbers
2001-08-07
Inventor(s): ERICKSON DONALD C [US]; ANAND GOPALAKRISHNAN [US]
Classification:- international: F01K25/06; F01K25/00; (IPC1-7):
F01K25/06 - European: F01K25/06B
Also published as : WO0194757
Abstract -- An absorption power
cycle is disclosed which achieves a closer match to heat source
temperature glide, and also lower heat source exit temperatures, and
hence higher conversion efficiencies, in practical equipment. Referring
to FIG. 7, two separate absorbers (725 and 706) are provided, each with
a pumping path for a different concentration absorbent liquid to a
different temperature location within counter-current high-pressure
desorber 721. Heat source 710 heats the high-pressure desorber 721 and
superheater 724 in parallel, and subsequently heats
intermediate-pressure desorber 761. Dotted lines in the figures signify
vapor.
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US5309985
Stationary Continuous
Multimodular Trisorption Heat Pump
1994-05-10
Inventor(s): ERICKSON DONALD C [US]
Classification: - international: F24F5/00; F25B17/08; F24F5/00;
F25B17/00; (IPC1-7): F25B17/08 :- European: F24F5/00; F25B17/08
Also published as: WO9411683
Abstract -- Apparatus and
process are disclosed for sorption heat pumping at high efficiency in a
smooth and continuous manner using a multiplicity of stationary triplex
sorption modules. The hermetically sealed trisorption modules, each of
which contains at least two solid sorbents, are free of pumps, valves,
restrictors, or any similar devices for flow control of refrigerant or
sorbent. The apparatus contains no moving parts beyond a small number
of control and motive devices for the heat transfer fluids. The
preferred refrigerant is ammonia and the preferred sorbents are the
solid type with monovariant equilibrium, e.g., BaCl2, SrCl2, CaCl2,
MnCl2, FeCl2 and SrBr2. The apparatus is preferably adapted for
residential or small-scale commercial space-conditioning applications,
and operates at double-effect efficiency in both the heating and
cooling modes without inter-module heat transfer.
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US5279359
Rotary Trisorption Heat Pump
1994-01-18
Inventor(s): ERICKSON DONALD C [US]
Classification:- international: F25B17/08; F25B17/00; (IPC1-7):
F25B17/04 :- European: F25B17/08C
Also published as: WO9400721 // JP7508338 // CA2138772//
Abstract -- Apparatus and
process are disclosed for sorption heat pumping at high efficiency in a
smooth and continuous manner using a multiplicity of intermittent cycle
triplex sorption modules. The hermetically sealed trisorption modules,
each of which contains at least two solid sorbents, are free of pumps,
valves, restrictors, or any similar devices for flow control of
refrigerant or sorbent. The preferred refrigerant is ammonia and the
preferred sorbents are the solid type with monovariant equilibrium,
e.g., BaCl2, SrCl2, CaCl2, MnCl2, FeCl2 and SrBr2. The apparatus is
preferably adapted for residential or small-scale commercial
space-conditioning applications, and operates at double-effect
efficiency in both the heating and cooling modes without inter-module
heat transfer.
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US5272891
Intermittent Sorption Cycle with
Integral Thermosyphon
1993-12-28
Inventor(s): ERICKSON DONALD C [US]
Abstract -- Intermittent
sorption cycles with fixed heat supply and removal and comprised of a
generator/absorber (4), a condenser (2), and a receiver/evaporator (10)
are adapted and simplified so as to require at most only two control
valves (8) and (15) for their operation. With an integral thermosyphon
(6) for absorption heat removal, only a single refrigerant charge is
necessary. The two valves are advantageously combined into a single
three-way ball valve, and key gravity drains (14) and (17) are
provided. Applications include hot water heating, solar refrigeration,
and steam generation.
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US5653116
Triple-Effect Absorption Cycle
with Condensate-to-Solution Sensible Heat Exchanger
1997-08-05
Inventor(s): ERICKSON DONALD C [US]; POTNIS SHAILESH V [US]
Classification:- international: C09K5/04; F25B15/00; C09K5/00;
F25B15/00; (IPC1-7): F25B15/00 :- European: C09K5/04D; F25B15/00F
Also published as: WO9725573
Abstract -- A triple-effect
cycle is disclosed which avoids the two primary limitations of
currently known triple-effect cycles: super-atmospheric pressures
and/or low pressure absorbers that operate without mass transfer
enhancers. The cycle is comprised of two hermetic loops-one a
conventional LiBr double-effect loop, and the other a single-effect
loop which overlaps the high pressure portion of the double-effect
loop, and exchanges heat with it at three locations. Referring to FIG.
3, the latent heat exchanges are with absorber 302, condenser 304, and
evaporator 305 of the single-effect loop. Sensible heat losses are
reduced by incorporating inter-loop condensate-to-solution sensible
heat exchanger 314. The inter-loop CSSHX also applies to other
triple-effect cycles.
US5771710
Thermosyphon Cooled Absorber for
Air Cooled Absorption Cycles
1998-06-30
Inventor(s): ERICKSON DONALD
Classification: - international: F25B15/02; F25B15/02; (IPC1-7):
F25B37/00; F25B15/00- European: F25B15/02
Abstract -- The absorption step
of a continuous absorption cycle apparatus (refrigerator or heat pump)
is externally cooled by an air-cooled thermosyphon having hot end 107
(FIG. 1), air-cooled end 115, and reservoir 123. The absorption step is
further recuperatively cooled by internal fluids, in absorber heat
exchanger 108 and/or GAX 109. Thus the absorber is highly compact and
the cycle is highly efficient. A hotter hermetic thermosyphon can
advantageously supply additional cooling.
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US5660049
Sorber with Multiple Cocurrent
Pressure Equalized Upflows
1997-08-26
Inventor(s): ERICKSON DONALD C [US]
Classification: - international: B01D53/18; B01J8/02; F25B33/00;
F25B37/00; B01D53/18; B01J8/02; F25B33/00; F25B37/00; (IPC1-7):
F25B15/00; F25B37/00
- European: B01D53/18; B01J8/02; F25B33/00; F25B37/00
Abstract -- A sorber for
sorbing a vapor into (absorber) or out of (desorber) a liquid sorbent
comprised of a sequential plurality of highly effective and intensified
locally cocurrent sorptions, but with non-cocurrent flow of vapor and
liquid between the individual sorptions. The structure containing the
locally cocurrent upflow is preferably comprised of enhanced heat
transfer surface, making the sorption diabatic, further enhancing the
intensification, and improving the sorption efficiency. Referring to
FIG. 12 , vertical cylinders (70) and (71) form an annular space within
which desorption occurs, powered by external heat source (72) and
internal heat recuperation (77). The liquid portion of the annulus is
divided into multiple compartments by folded rectangular fin (73). The
space above fin (73) allows pressure equalization of all compartments.
Each compartment is divided by insert (80) into separate vapor-liquid
riser channels and a liquid downcomer channel. The sorbent liquid flow
sequentially through the compartments via flow ports (74). The same
high effectiveness sequential liquid recirculating cocurrent upflow
desorption can also be accomplished in a horizontal cylindrical
annulus, in plate fin exchangers, and in other geometries.
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US5713216
Coiled Tubular Diabatic
Vapor-Liquid Contactor
1998-02-03
Inventor(s): ERICKSON DONALD C [US]
Classification: - international: F25B33/00; F25B37/00; F28D7/02;
F28F3/02; F25B33/00; F25B37/00; F28D7/00; F28F3/00; (IPC1-7):
F25B15/00; F25B15/12; F28D7/02
- European: F25B33/00; F25B37/00; F28D7/02D; F28F3/02D
Also published as: WO9639600
Abstract -- A non-diabatic
vapor-liquid contact device is disclosed which achieves high heat
transfer effectiveness without sacrificing mass transfer effectiveness.
Referring to FIG. 2, a helical coil of crested tubing 84 is contained
within the annualr space between shrouds 82 and 83. Liquid flows
downward through the annulus, and vapor flows countercurrently upward.
The mass exchanging fluids pass through the space between tube crests
and the shroud, achieving very effective mixing. Heat transfer fluid is
flowed through the tubing via connections 87 and 88. The heat and mass
transfer is preferably additionally enhanced by interspersing contact
media with the coiled tubing, either longitudinally or radially.
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US5798086
Intensified Locally Cocurrent
Tray Contactors
1998-08-25
Inventor(s): ERICKSON DONALD C [US]
Classification: - international: B01D3/20; B01D3/14; (IPC1-7): C10J1/08
:- European: B01D3/20
Abstract -- An intensified
means of multicomponent fluid multistage vapor-liquid contact is
disclosed. The contactor achieves the thermodynamic advantages of
global countercurrency, the tray efficiency advantages of tray
crosscurrency, and the point efficiency advantages of local cocurrency
with liquid recirculation. Referring to FIG. 6, each tray has multiple
compartments formed by compartment dividers 62, 63, and 64, and each
compartment has a channel divider 69, 66, 67 which forms separate
locally cocurrent riser channels and liquid downcomer channels.
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