Peter MAIER-LAXHUBER, et al.
Zeolite/Water Adsorption Cooling/Heating
ZEO-TECH
http://www.zeo-tech.de/e_index.htmOhmstr. 3
D-85716 Unterschleissheim / Germany
Tel.: +49 89 3 10 44 84
Fax: +49 89 3 10 44 85
E-Mail: info@zeo-tech.de
Environmental Friendly Cooling and Heating by using the Innovative Zeolite/Water Adsorption Technology
Zeo-Tech has developed a new energy conversion process for the efficient generation and storage of heat and/or cooling power. Driven by a heat source, this process is solely based on the material zeolite and water and is therefore fully compatible with the most stringent environmental regulations. Up to 160% efficient.
Dr Peter Maier-Laxhuber & Zeolite Cooler
Fundamentals of the Zeolite/Water Adsorption Technology
The natural mineral Zeolite has the property to attract (adsorb) water vapor and to incorporate it in its internal crystal lattice while releasing heat at the same time.
If this process proceeds in an evacuated (airless) environment the attraction of water by the zeolite is so forceful that the internal pressure drops dramatically. The remaining water in an attached vessel evaporates, cools down and freezes immediately due to the heat of evaporation. The resulting ice can be used for cooling and air conditioning while the simultaneously produced heat of adsorption within the zeolite tank can be utilized for heating. If a valve is included between the two vessels, the heat or cold production can be interrupted for any periods without loss of energy.
The first phase of this process proceeds up to the point when the zeolite is saturated with water. The reverse process is initiated by heating the zeolite at high temperatures in the second phase. The adsorbed water molecules are forced to evaporate (desorption). Condensation takes place in the water tank (condensor). The sequence of adsorption/desorption processes is completely reversible and can be repeated indefinitely.
A nearly continuous cooling power is accomplished if two or more of these sorption devices are operated in a phase-shifted manner. The regeneration can be performed with electric energy or – preferably from the perspective of primary energy usage – with heat from combustion processes or even with solar collectors.
As shown in the figure, the driving energy source is heat (100 %) which picks up an additional 30 % of net cooling power and thus provides a usable net heating power of 130 % as the overall result of the conversion cycle. If this system is applied in dual use mode for heating as well as cooling in parallel, the overall net effect amounts to 160 % of the expended heat input (100 %), provided as heat output (130 %) and cooling power (30 %).
Even with electrical heating, a sorption system provides
considerable energy savings and a corresponding reduction of
carbon dioxide production.
With other input heat sources the energy saving potential is
much higher, with corresponding environmental benefits. Even the
single use mode, utilizing only heating or only cooling power,
is comparable or better (with respect to energy utilization)
than any conventional technology.
Zeolite
The name zeolite is a general term for a stonelike material which consist of crystalline metal-alumo-silicates with a large internal surface area of up to 1000 m²/g, strong electrostatic fields in the crystal lattice and with a volumetric density of about 0.8 kg/dm³. The word zeolite is of greek origin and means – directly translated – »boiling rock« which describes the effect which is to be seen if water is poured over dry zeolite. In 1925 the process of water and methanol separation using zeolites was observed for the first time. And due to this separation action (sieve action) the name "molecular sieve" was later attributed to zeolites.
Zeolites are non-poisonous, inflammable, are naturally available in abundance and are therefore compatible with the environment. More than 40 natural and 100 synthetic zeolites are known.
The most important property of a number of zeolites is their ability for reversible adsorption of water. Even after several thousand adsorption/desorption cycles the structural changes of the crystal latice are insignificant if the process parameters pressure and temperature do not exceed certain limits. – The application diversity of zeolites is tremendous: they are applied as molecular sieves, as adsorbents, as catalyst in cracking of hydrocarbons in the pretro-chemical industry, as filler component in paper production and as ion exchange material in detergents
Currently the chemical industry produces more than 1.4 million tons of synthetic zeolite annually and it can be expected that the world wide demand and consequently the production will further increase. The price, e.g. for laundry detergent zeolite is between 1.00 and 8.00 DM/kg, depending on the type and consistency of material delivered. The price for specialized zeolites is higher.
The basic building blocks of zeolites are tetrahedras consisting of four oxygen anions and one centrally positioned silicon or aluminum cation.Zeolites are classified according to the various tetrahedral frameworks formed by these basic building blocks. The structure of the synthetic zeolites of types A, X and Y which have gained importance in industrial processes, are shown in the figure. The aluminum and silicon atoms are positioned at the junctions while the oxygen atoms form the bridges between the tetrahedras. The difference in electro-chemical charges between the aluminum and silicon atoms per one aluminum atom results in a non-compensated negative charge. The balance is restored by metal cations which occupy preferred positions. Because of the strong local electrical dipole moment in the lattice framework, zeolites adsorb all polar and non-polar molecules that will fit into their specific framework. This adsorption process is accompanied by release of heat, the »heat of adsorption«. Theoretical and experimental studies have determined quantitative heat of adsorption values for zeolite based thermal processes.
Ice-Quick Demonstrator
The Ice-Quick is a small device to demonstrate the adsorption technology with the sorption pair water/zeolite. It consists of a zeolite filled cartridge, connected via an adaptor to a plastic cup, which contains some water, and which is evacuated by means of a hand-vacuum pump.
After approx. 10…20 strokes with the hand-vacuum pump the inside pressure is reduced below the vapour pressure of the water at ambient temperature, and the water start to boil. Air gases go out of the water and starts to bubble on the bottom of the glass. (The more air is removed out of the system, the better the adsorption of water vapour. The vapour above the water surface is adsorbed in the cristalline structure of the zeolite. As a result, the remaining liquid water cools down.) After a few more strokes the water calms down and finally begins to freeze. After some time the water is completely frozen: 50 g of water at a temperature of 10 °C can be cooled down and frozen within 30 sec with 500 g of zeolite. The average specific cooling power results to 390 W/kgZeo.
This process can be repeated 8…10 times with arbitrary intervals until the zeolite is saturated. The zeolite has always to be cooled down to the ambient in between processes for the adsorption to function properly. For desorption (regeneration) the zeolite has to be heated up to 250 °C for a short time. When the zeolite is cooled down again to 20 °C it is ready for further ice production.
Solar Powered Refrigerator
Developing countries have a great need for cooling of food and medical supplies. Refrigerators are very expensive and require a electric power source. While reliable electric power supply is only available in the industrialized centers of developing countries, solar power is available and – especially in the southern areas – is reliable. Up to now, solar power has not been used for cooling.
Zeolite/water sorption systems can now provide a reliable and economic solution for these cooling needs.
The equipment consists of a refrigerator (in this case a 55 liter box-shaped cooler), powered by solar energy, with a built-in evaporator, one or more zeolite containers and a parabolic, concentrating solar collector, developed by E.G. Solar.
The cooling system is designed such that it can be produced locally without need for expensive electrical tools; maintenance and repair can be performed locally due to the simple design.
The investment for the cooling device is much lower than a solar driven compressor system of the same size which is powered by electric solar cells (costs about DM 3,000.--)
The solar collector can also be used for cooking.
Standard-Cooling
The Standard-Colling system is used – as described above – for the trolleys, for beverage dispensers and for food refrigerators. It consists of two adsorbers, one condenser and one evaporator (and some addi- tional compenents which are not shown in the right figure).
The two adsorbers with 8 kg zeolite granulate each operate in alternating fashion. Via heat exchanger loops the heat available after desorption and also the heat produced during adsorption is removed. Adsorber and evaporator are coupled by one-way valves which are opened or closed depending on the pressure in the two vessels. The desorbed water vapour flows to the condenser and (after condensation) through a capillary pipe (which also contributes to the heat removal) back to the evaporator. The water charge in the eva- porator is about 5 ltrs. For optimisation of the evaporation the surface area in the evaporator is enlarged considerably by constructive means. The »cooling power« is transferred by a heat transfer medium pumped in a closed cycle through flexible hoses between evaporator and the cabinet to be refrigerated, where the cooling effect is achieved through a heat exchanger.
Monitoring and control of the system are performed by a programmable electronic controller. For a heating power of 6.6 kW maximum the cooling power of this system, which is available as protoype, amounts to about 2.8 kW. This covers a cooling temperature range of down to 0 °C.
Zeolite Heat Pump with Integrated Ice-Storage
Characteristics of the zeolite heatpump with integrated ice-storage:
Significant energy savings – referring to the state of the art technologies (e.g. condensing boiler): approx. 25 % ; at hot water temperatures of 60 to 70 ºC
Approx. 75 % less heat from the ambient needed compared to an electrical heat pump
Ambient heat can easily be provided, for example with CPC collectors also in the autumn and in the winter ; possible ambient heat sources are: heat recovery systems
Flue gas can be cooled down below 0 ºC, therefore a significant cleaning of the flue gas due to condensation of harmful substances is more easily possible than with conventional condensing boilers
Add-on capability: gas-fired air-conditioner; supply of considerable electrical power for the functioning of the air-conditioner is not needed
Zeolite heatpump with integrated ice-storage is very easy to maintain and a long system lifetime
Cost savings due to the use of small ambient heat exchangers
Zeo-Tech GmbH is going to build and optimise a zeolite heatpump with integrated ice-storage for a typical one-family house with a rated heating power of approx. 10 kW.
Dr. Peter Maier-Laxhuber, et al.
Zeolite Adsorption Refrigeration/Heating
Patents
System Comprising at least One Absorption Heat Pump
US4408468
1983-10-11
Sorption Units and Methods for their Operation
US4479364
1984-10-30
Continuously Acting Adsorption Devices and Process for their
Operation
US4660629
1987-04-28
Zeolite Blanks with a High Heat Conductivity and Process for
Making the Same
US4674563
1987-06-23
Adiabatic Heating and Cooling Process and Portable Devices in
Accordance with the Adsorption Principle
US4752310
1988-06-21
Adsorption Cooler
US4924676
1990-05-15
Adsorption Apparatus used as an Electro-Heating Storage
US4956977
1990-09-18
Sorption Cooling System
US5038581
1991-08-13
Cooling Container for a Sorption Apparatus
US5050403
1991-09-24
Sorption Container for Solid Sorption Medium
US5054544
1991-10-08
Ice Makin System & Method Utilizing Sorption Principle
US5207073
1993-05-04
Adapter for an Adsorption System and Method for Utilizing the
Same
US5359861
1994-11-01
Sorption Agent Container Device and Sorption Method with a
Regenerative Heat Exchange
US5404728
1995-04-11
Cooling System having a Vacuum Tight Steam Operating Manifold
US5415012
1995-05-16
Apparatus for Cooling a Medium within a Container
US5440896
1995-08-15
Sorption Cartridge
US5482541
1996-01-09
Manually Operable Vacuum Pump
US5494410
1996-02-27
Sorption Apparatus and Method for Cooling and Heating
US5518069
1996-05-21
Adsorbent Bed Coating on Metals and Processing for Making the
Same
US5585145
1996-12-17
Apparatus and Method for the Cooling of a Liquid in a Container
US6349560
2002-02-26
Cooling Container with an Adsorption Cooling Apparatus
US7213403
2004-10-28
Cooling Sorption Element with Gas-Impermeable Sheeting
US2006191287
2006-08-31
Method and Device for the Rapid Solidification of Aqueous
Substances
US2005061022
2005-03-24
Adsorption Cooling Apparatus with Buffer Reservoir
US2004079106
2004-04-29
Sorption Device for Heating and Cooling Gas Streams
US2002005271
2002-01-17
Sorption Cooler
US2001025510
2001-10-04
Foreign Patents
Adsorption refrigerator with heat accumulator
DE50307123D
2007-06-06
Sorption cooling element with gasproof film
EP1746365
2007-01-24
Sorption device for heating or cooling gas flows
ES2244516T
2005-12-16
METHOD AND APPARATUS FOR QUICK SOLIDIFICATION OF AQUEOUS
SUBSTANCE MATERIAL
JP2005095888
2005-04-14
COOLING CONTAINER EQUIPPED WITH ADSORPTION COOLING DEVICE
JP2004233039
2004-08-19
Pneumatikelement mit Sorptionsmittelfüllung
DE10229958
2004-01-15
Sorptionsvorrichtung zum Heizen und Kühlen von Gasströmen
DE50106610D
2005-08-04
SORPTION COOLER
JP2002013835
2002-01-18
Sorption container with flexible casing
ES2233510T
2005-06-16
Sorptionsbehälter-Anordnung mit flexibler Hülle
DE50104349D
2004-12-09
Vorrichtung und Verfahren zur Kühlung von wasserhaltigen
Flüssigkeiten bei direkter Vakuumverdampfung
DE10104972
2002-08-08
Vorrichtung und Verfahren zum Kühlen einer Flüssigkeit in einem
Behäler
DE50009255D
2005-02-24
Method for heating and cooling a sorber
EP1046870
2000-10-25
Refrigerating and freezing method for water containing products
EP0913652
1999-05-06
Verfahren zum Kühlen und Gefrieren wasserhaltiger Produkte
DE59812213D
2004-12-09
Sorber with a sorbent charge
EP1020689
2000-07-19
Cooling device
EP0726433
1996-08-14
Kühlvorrichtung
DE59601741D
1999-06-02
Removal of disturbing gases containing carbon dioxide during
sorption process
DE4444252
1996-06-20
Coffee extract evacuated drying process and assembly
DE19641404
1998-04-09
Handbetätigbare Vakuumpumpe
DE59400563D
1996-10-10
Cooler which can be operated continually
DE4403360
1995-08-10
Sorptionsmittel-Patrone
DE59309530D
1999-05-27
Adapter für ein Sorptionssystem und Sorptionsverfahren unter
Verwendung dieses Adapters
DE59305757D
1997-04-17
Sorption device and method for cooling and/or heating
DE4331145
1995-03-16
Cooling device and method of cooling a fluid in a receptacle
EP0543214
1993-05-26
Kühlvorrichtung und Kühlverfahren zur Kühlung eines Mediums
innerhalb eines Gefässes
DE59208660D
1997-08-07
Sorption apparatus for cooling and/or heating
EP0527466
1993-02-17
Refrigeration system with a vacuum-tight collecting conduit for
the vapor of the working fluid
EP0577869
1994-01-11
Sorptionssystem mit regenerativem Wärmetausch
DE59203354D
1995-09-28
Heating and/or cooling using periodically working absorption
system...
DE4217610
1993-12-02
Eiserzeuger nach dem Sorptionsprinzip
DE59005022D
1994-04-21
EISERZEUGER NACH DEM SORPTIONSPRINZIP
AT103060T
1994-04-15
Sorptionsbehälter für feste Sorptionsmittel
DE59007177D
1994-10-27
KUEHLVERFAHREN FUER EINEN SORPTIONSAPPARAT
DE58904909D
1993-08-19
KUEHLVERFAHREN FUER EINEN SORPTIONSAPPARAT
AT91542T
1993-07-15
Sorptionskühlsystem
DE58907091D
1994-04-07
SORPTIONSKUEHLSYSTEM
AT102334T
1994-03-15
IC engine reactor without inserts - contains zeolite heated by
exhaust...
DE3922736
1990-07-19
ADSORPTION COOLER
DE3661965D
1989-03-02
ADSORPTIONSKUEHLER
AT40459T
1989-02-15
Apparatus for and method of water heating by an intermittent
adsorption process
EP0203558
1986-12-03
VORRICHTUNG UND VERFAHREN ZUR ERWAERMUNG VON WASSER DURCH EINEN
PERIODISCHEN ADSORPTIONSPROZESS
DE3681824D
1991-11-14
VORRICHTUNG UND VERFAHREN ZUR ERWAERMUNG VON WASSER DURCH EINEN
PERIODISCHEN ADSORPTIONSPROZESS
AT68257T
1991-10-15
Device for the leak-tight transmission of rotary motion through
a wall
EP0345456
1989-12-13
Leckagefreie Drehvorrichtung zur Übertragung einer Drehbewegung
durch eine Gehäusewand
DE58905362D
1993-09-30
LECKAGEFREIE DREHVORRICHTUNG ZUR UEBERTRAGUNG EINER
DREHBEWEGUNG DURCH EINE GEHAEUSEWAND
AT93597T
1993-09-15
Method of evacuating vacuum systems having a zeolite packing
DE3604910
1987-08-20
Heat-transmission element for evaporator
DE3604909
1987-08-20
Ice accumulator with direct vacuum evaporation
DE3604228
1987-08-13
Device and method for operating periodic sorption apparatuses
DE3601427
1987-07-23
Air dehumidifier according to the sorption principle
DE3525237
1987-01-15
Solar cooler
DE3521448
1986-12-18
Heating boiler
DE3519086
1986-12-04
ADSORPTIONSAPPARAT
AT57250T
1990-10-15
Device and method for the preheating of parts of an internal
combustion engine
DE3504718
1986-08-14
ZEOLITHFORMLING MIT HOHER WAERMELEITUNG UND VERFAHREN ZUR
HERSTELLUNG
AT50515T
1990-03-15
KONTINUIERLICH WIRKENDE SORPTIONSAPPARATE UND VERFAHREN ZU
DEREN BETRIEB
AT32373T
1988-02-15
Process and apparatus for heating a medium
EP0140380
1985-05-08
VERFAHREN UND VORRICHTUNG ZUR ERWAERMUNG EINES MEDIUMS
AT78578T
1992-08-15
Discontinuous dehumidification device using zeolites
DE3413487
1985-10-24
Boiler adsorber for sorption apparatus
DE3336776
1985-04-25
Method for operating a plant for generating useful heat and/or
useful cold and plant for carrying out this method
DE3312875
1984-11-22
Storage heating plant with sorption reservoir
EP0091095
1983-10-12
STORAGE HEATING PLANT WITH SORPTION RESERVOIR
DE3372229D
1987-07-30
SPEICHERHEIZANLAGE MIT SORPTIONSSPEICHER
AT27995T - 1987-07-15
Method and means for storing and bringing heat to a higher
temperature
EP0042160
1981-12-23
METHOD AND MEANS FOR STORING AND BRINGING HEAT TO A HIGHER
TEMPERATURE
DE3175535D
1986-12-04
VERFAHREN UND EINRICHTUNG ZUM SPEICHERN UND HOCHTRANSFORMIEREN
DER TEMPERATUR VON WAERME
AT23219T
1986-11-15
PLANT COMPRISING AN ABSORPTION HEAT PUMP
DE3072006D
1987-09-17
ABSORPTIONS-WAERMEPUMPEANLAGE
AT28929T
1987-08-15