Peter MAIER-LAXHUBER, et al.
Zeolite/Water Adsorption Cooling/Heating
D-85716 Unterschleissheim / Germany
Tel.: +49 89 3 10 44 84
Fax: +49 89 3 10 44 85
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.
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.
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.
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
System Comprising at least One Absorption Heat Pump
Sorption Units and Methods for their Operation
Continuously Acting Adsorption Devices and Process for their Operation
Zeolite Blanks with a High Heat Conductivity and Process for Making the Same
Adiabatic Heating and Cooling Process and Portable Devices in Accordance with the Adsorption Principle
Adsorption Apparatus used as an Electro-Heating Storage
Sorption Cooling System
Cooling Container for a Sorption Apparatus
Sorption Container for Solid Sorption Medium
Ice Makin System & Method Utilizing Sorption Principle
Adapter for an Adsorption System and Method for Utilizing the Same
Sorption Agent Container Device and Sorption Method with a Regenerative Heat Exchange
Cooling System having a Vacuum Tight Steam Operating Manifold
Apparatus for Cooling a Medium within a Container
Manually Operable Vacuum Pump
Sorption Apparatus and Method for Cooling and Heating
Adsorbent Bed Coating on Metals and Processing for Making the Same
Apparatus and Method for the Cooling of a Liquid in a Container
Cooling Container with an Adsorption Cooling Apparatus
Cooling Sorption Element with Gas-Impermeable Sheeting
Method and Device for the Rapid Solidification of Aqueous Substances
Adsorption Cooling Apparatus with Buffer Reservoir
Sorption Device for Heating and Cooling Gas Streams
Adsorption refrigerator with heat accumulator
Sorption cooling element with gasproof film
Sorption device for heating or cooling gas flows
METHOD AND APPARATUS FOR QUICK SOLIDIFICATION OF AQUEOUS SUBSTANCE MATERIAL
COOLING CONTAINER EQUIPPED WITH ADSORPTION COOLING DEVICE
Pneumatikelement mit Sorptionsmittelfüllung
Sorptionsvorrichtung zum Heizen und Kühlen von Gasströmen
Sorption container with flexible casing
Sorptionsbehälter-Anordnung mit flexibler Hülle
Vorrichtung und Verfahren zur Kühlung von wasserhaltigen Flüssigkeiten bei direkter Vakuumverdampfung
Vorrichtung und Verfahren zum Kühlen einer Flüssigkeit in einem Behäler
Method for heating and cooling a sorber
Refrigerating and freezing method for water containing products
Verfahren zum Kühlen und Gefrieren wasserhaltiger Produkte
Sorber with a sorbent charge
Removal of disturbing gases containing carbon dioxide during sorption process
Coffee extract evacuated drying process and assembly
Cooler which can be operated continually
Adapter für ein Sorptionssystem und Sorptionsverfahren unter Verwendung dieses Adapters
Sorption device and method for cooling and/or heating
Cooling device and method of cooling a fluid in a receptacle
Kühlvorrichtung und Kühlverfahren zur Kühlung eines Mediums innerhalb eines Gefässes
Sorption apparatus for cooling and/or heating
Refrigeration system with a vacuum-tight collecting conduit for the vapor of the working fluid
Sorptionssystem mit regenerativem Wärmetausch
Heating and/or cooling using periodically working absorption system...
Eiserzeuger nach dem Sorptionsprinzip
EISERZEUGER NACH DEM SORPTIONSPRINZIP
Sorptionsbehälter für feste Sorptionsmittel
KUEHLVERFAHREN FUER EINEN SORPTIONSAPPARAT
KUEHLVERFAHREN FUER EINEN SORPTIONSAPPARAT
IC engine reactor without inserts - contains zeolite heated by exhaust...
Apparatus for and method of water heating by an intermittent adsorption process
VORRICHTUNG UND VERFAHREN ZUR ERWAERMUNG VON WASSER DURCH EINEN PERIODISCHEN ADSORPTIONSPROZESS
VORRICHTUNG UND VERFAHREN ZUR ERWAERMUNG VON WASSER DURCH EINEN PERIODISCHEN ADSORPTIONSPROZESS
Device for the leak-tight transmission of rotary motion through a wall
Leckagefreie Drehvorrichtung zur Übertragung einer Drehbewegung durch eine Gehäusewand
LECKAGEFREIE DREHVORRICHTUNG ZUR UEBERTRAGUNG EINER DREHBEWEGUNG DURCH EINE GEHAEUSEWAND
Method of evacuating vacuum systems having a zeolite packing
Heat-transmission element for evaporator
Ice accumulator with direct vacuum evaporation
Device and method for operating periodic sorption apparatuses
Air dehumidifier according to the sorption principle
Device and method for the preheating of parts of an internal combustion engine
ZEOLITHFORMLING MIT HOHER WAERMELEITUNG UND VERFAHREN ZUR HERSTELLUNG
KONTINUIERLICH WIRKENDE SORPTIONSAPPARATE UND VERFAHREN ZU DEREN BETRIEB
Process and apparatus for heating a medium
VERFAHREN UND VORRICHTUNG ZUR ERWAERMUNG EINES MEDIUMS
Discontinuous dehumidification device using zeolites
Boiler adsorber for sorption apparatus
Method for operating a plant for generating useful heat and/or useful cold and plant for carrying out this method
Storage heating plant with sorption reservoir
STORAGE HEATING PLANT WITH SORPTION RESERVOIR
SPEICHERHEIZANLAGE MIT SORPTIONSSPEICHER
AT27995T - 1987-07-15
Method and means for storing and bringing heat to a higher temperature
METHOD AND MEANS FOR STORING AND BRINGING HEAT TO A HIGHER TEMPERATURE
VERFAHREN UND EINRICHTUNG ZUM SPEICHERN UND HOCHTRANSFORMIEREN DER TEMPERATUR VON WAERME
PLANT COMPRISING AN ABSORPTION HEAT PUMP