Giuseppe Cruciani Department of Physics and Earth Sciences University of Ferrara, Italy cru@unife.it

Scuola del Gruppo Nazionale di Mineralogia: La fisica dei minerali: implicazioni Casa della Gioventù, Università di Padova Bressanone-Brixen,(BZ), 2-5-febbraio 2015 APPLICATIONS OF MINERAL PHYSICS: THE USE OF ZEOLITES IN SOLAR THERMAL ENERGY HARVESTING Giuseppe Cruciani Department of Physics and Earth Sciences University of Ferrara, Italy cru@unife.it

The Magic Mineral 5 000 4 800 4 600 4 400 4 200 4 000 3 800 3 600 3 400 3 200 3 000 2 800 2 600 2 400 2 200 2 000 1 800 1 600 1 400 1 200 Muscovite 3.51 % Chabazite 54.80 % Sanidine 7.21 % Augite 3.37 % Corundum 20.00 % Phillipsite 1.68 % Analcime 0.70 % Amor. 8.74 % Biotite Analcime Volcanic Phillipsite glass Augite K-feldspar Chabazite 1 000 800 600 400 200 0-200 -400-600 -800-1 000-1 200-1 400-1 600-1 800-2 000 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42

La zeolite, il minerale che riscalda ( Zeolite, the heating mineral ) (Geo Scienza, RAI3, November 26 th, 2012)

The Magic of Thermal Cooling (http://www.annex34.org/the-magic-of-thermal-cooling) heat from a low T source (solar, geothermal, waste) Heat Pump ice formation useful heating regeneration from high T source useful cooling

A few keywords cooling and heating of ambient heat pumps low temperature driving heat renewable energy sources solar thermal energy the magic zeolite water adsorption high temperature regeneration

Solar Cooling: a new technology? September 29, 1878 World Exhibition in Paris: Augustin Mouchot produced the first ice block with solar energy using a periodical absorption machine of Edmund Carré

History of adsorption machines USA 1929: Silica gel SO 2 adsorption refrigerator Wait for 40 years Vapour compression units and CFC s are dominating the market 1980-1990: New interest in heat driven systems due to oil price shocks, resource limitations... 1990-2000: First commercial products, no strong enough to survive 2000-today: Solid products developed in the EU. Many contributions from China and Japan. Still very little in USA Market deployment of solar thermal collectors in Austria (G. Faninger, 2012) Giuseppe Cruciani Harvesting, Storage and Saving of Energy using Microporous Minerals 7 of 30

Solar energy applications of chabazite from Bowie (USA) (Tchernev, USA, late 70 s 90 s) 6.75 kg ice/day 100 kg ice/day (Tchernev, 1978) (Tchernev, 1995) Solar heated and cooled house in Denver (Tchernev, 1995)

Solar cooling with synthetic NaX (FAU) F. Meunier & co-workers (Paris), late 70 s: NaX (13X) zeolite-water solar refrigerator and 12 m 3 cold store in the south of France (solar COP's in the range of 0.1 corresponding to a gross production of ice inside the evaporator of the order of 7 kg/m 2 of solar collector for an incident solar energy of 22 MJ/m 2 ).

Household energy consumption in Europe major part of the energy use in the EU25 is related to applications in heating and cooling which operate at temperatures far below 250 C Solar thermal energy systems will provide up to 50% of low temperature heating, cooling, and hot water demand.

Fossil fuels vs. Renewable energy sources Global CO 2 emissions (23,579 million tonnes/year) transport 21% buildings 14% industry 17% power generation 40% air-conditioning systems in Europe was ~11 TWh in 1996, is expected to increase to ~44 TWh by 2020 growth of World energy demand ~55% by 2030, potentially double by 2050

Primary & Secondary Energy sources Giuseppe Cruciani Harvesting, Storage and Saving of Energy using Microporous Minerals

Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs. (Brundtland Commission of the United Nations, 1987) It contains within it two key concepts: the concept of 'needs', in particular the essential needs of the world's poor, to which overriding priority should be given; and the idea of limitations imposed by the state of technology and social organization on the environment's ability to meet present and future needs. Three key questions: What is an appropriate technology? In aiming to better determine the real needs of the people in developing countries and in which way technology can address these needs; How to ensure an integrated sustainable development? In promoting interdisciplinary research and establishing partnerships that bring together various actors in development, public authorities, civil society, industry, and international organizations; What are the conditions for the co-creation and transfer of such technologies? By ensuring through appropriate methods and the exchange of knowledge, the sustainability of the innovations in the field and Giuseppe Cruciani - Applications of mineral physics: the use of zeolites in solar thermal energy that their harvesting impact is beneficial to all.

Lack of access to energy at household level 1.4* (1.2 in 2030) billion people lack access to electricity (87% rural areas) 2.7** (2.8 in 2030) billion people rely on the traditional use of solid biomass for cooking (*~20% of global population; ** (*~40% of global population) International Energy Agency (IEA). (2011). Energy poverty. How to make modern energy access universal? Special Early Excerpt of the World Energy Outlook 2010 for the UN General Assembly on the Millennium Development Goals.

Same technology for the rich and the poor?? International Energy Agency (IEA). (2011). Energy poverty. How to make modern energy access universal? Special Early Excerpt of the World Energy Outlook 2010 for the UN General Assembly on the Millennium Development Goals. World s biggest importers of crude oil (in millions of tonnes) Source: IEA Key World Energy Statistics Oct 2011

Harvesting Sunlight Immediate use/daily average: Adsorption Heat Pumps (AHP) and Solar Coolers (SC) Seasonal average: Systems for Sorption Heat Storage (SSHS)

Rooftop solar heater: a cost effective way to heat water for a single home. Scuola GNM - "La fisica dei minerali: implicazioni The world s largest solar furnace is in Odeillo, France. Its sixty-three moving mirrors collect sunlight and direct it into a huge curved reflector. The reflector focuses a beam onto a spot on top of a tower, where temperatures can reach 3,000 C Solar power station near Toledo, Spain: thousands of solar arrays that supply electricity to the surrounding region. Parabolic mirrors at the Nevada Solar One power plant concentrate heat on pipes that contain oil, heating it to more than 700 degrees Fahrenheit.

Market drivers in Solar Thermal applications Scuola GNM - "La fisica dei minerali: implicazioni Solar Thermal Markets 2006 in Europe (Source: ESTIF, 2007) 1. reduce Greenhouse Gas emissions (i.e. Kyoto protocol, 1998) 2. reduce the Ozone Layer depletion (i.e. Montreal protocol, 1988) 3. achieve higher building star rating (access to green tenants) 4. benefit to the electricity system (reduced demand charges) 5. compliance with minimum renewable energy targets

Recent systems on the market ~10kg zeolite heating COP close to 1.35 (for water delivered at low T: 35 40 C) energy saving of the order of 30% or more with respect to a conventional boiler Giuseppe Cruciani Harvesting, Storage and Saving of Energy using Microporous Minerals 19 of 30

SELF-COOLING BEER KEG

BusinessPeople

Zeolite heat storage in Munich A. Hauer (2000), ZAE Bayern, Center for Applied Energy Research, Germany Heat a school building in winter and cool a jazz club in summer time Starting operation: 1997/1998 Total cost: 60.000 euro Pay-back time: 7-8 years

Heat Pumps: basic principles 1 st law of thermodynamics useful heating useful cooling (mechanical)

Mechanical vs. thermal (chemical) compression

Adsorption Heat Pumps (AHP): the thermodynamic cycle ln P Clausius-Clapeyron: 1 T ads, min T des, min H ln P R 4 2 vap 1 (a-b): isosteric heating (preheating) 1 T C 3 T ads, max T des, max -1/T cooling heating thermal compressor 2 (b-c): isobaric desorption and condensation 3 (c-d): isosteric cooling (precooling) 4 (d-a): isobaric adsorption and evaporation

Working cycles: typical conditions PREHEATING and DESORPTION adsorber bed PRECOOLING and ADSORPTION adsorber bed Condensation HEAT HEAT condenser HEAT vapor Evaporation evaporator space to be cooled HEAT

Advanced adsorption heat pump cycles Uniform temperature adsorber process antiphase operation of multiple adsorber tanks thermal wave cycle (F. Meunier et al. 1997)

AHPs: advantages and disadvantages Some important advantages of the AHPs: can directly utilize the primary thermal energy sources (e.g. solar and geothermal energies); can operate with waste heat generated in various industrial processes; can work with low temperature driving energy sources; can be employed as thermal energy storage device; do not contain any hazardous materials (environmental friendly); do not require moving parts for circulation of working fluid; operate without noise and vibration; have long life time; do not require frequent maintenance; have simple principle of working. Major disadvantages of the AHPs: have low COP values; intermittently working principles; require high technology and special designs to maintain high vacuum; have large volume and weight relative to traditional mechanical heat pump systems.

AHPs: problems and solutions Major difficulties and problems with the application of AHPs: intermitted principle of working; high technology for working under high vacuum; design of adsorbent bed with coupled heat and mass transfer. Research on AHPs mainly are focused on developing AHP systems which have continuous cooling or heating process; have high COP values; can operate with lower temperature driving energy; have practical design for construction and application; can technically and economically be an alternative to the conventional systems. The ongoing studies on the AHPs can be categorized into three areas: advanced adsorption cycles in order to increase COP, operate with lower temperature driving heat source and provide continuous cooling or heating process; design of an adsorbent bed for appropriate heat and mass transfer; research on adsorbent adsorbate pairs: developing new or promoting the existing materials/pairs in order to increase adsorption rate, enhance COP, decrease the temperature of driving heat source and provide economically competitive solutions.

The adsorbent adsorbate pair several pairs have been thoroughly tested and are in use (silica-water, zeolite water, zeolite methanol, activated carbon-methanol, etc.) The working fluid (adsorbate): working fluids must satisfy the Montreal and Kyoto protocols desirable lowest adsorption T; for the adsorption refrigerator is RT (the boiling point should be preferentially higher than 20 C) Water is an excellent working fluid for AHPs: high latent heat of vaporization and a convenient boiling point for ad/desorption cycle (typical operating T range: 80 C -150 C) available in abundance, non-toxic, non-flammable corrosion free, low cost, ease of handling it Major disadvantages: the low volumetric heat capacity (kj/m 3 ) large compressors, especially at low T extremely low saturation pressure impossible to produce evaporator temperature below 0 C.

Goldschmidt2013 - GEOLIFE - Geomaterials for environment, technology and human activities Adsorption on zeolites Zeolites and similar microporous minerals (and their synthetic analogues) are among the most suited adsorbing materials Exothermic enthalpy of hydration stabilizing from the thermodynamic viewpoint the otherwise metastable anhydrous zeolite structure (Navrotsky et al. 2009) endothermic nature of the dehydration phenomenon. Adsorption process in microporous minerals (zeolites and zeolite-like) is of purely physical nature ( physisorption ): weak interactions between sorbates and zeolite framework, sorbates and zeolite cations, and sorbate-sorbate interactions: short-range van der Waals forces dispersion London forces long-range electrical coulombic forces (polarization, field dipole and field quadrupole interactions) H-bonds between sorbate (i.e., water) and framework O atoms complexation of sorbate with Broensted acid sites (imp. in catalysis) complexation of sorbate electrons with sorbent active sites (fully) reversible ad/desorption some zeolite structures are not affected by adsorption and thermal regeneration processes.

The zeolite-water pair for AHPs The zeolite-water pair is one of the most preferred adsorbent adsorbate pairs in AHPs: extremely non-linear pressure dependence of its adsorption isotherms (isotherms saturate at low partial pressure, after which the amount adsorbed becomes almost independent of pressure) at ambient temperature zeolite can adsorb most of the vapour even at high partial pressure, (i.e. high condenser temperature). especially important in the case where a high condenser temperature and only a moderate regeneration temperature might be employed. surface sorbents (e.g. activated carbons, silica gel) adsorption depends exponentially on H/RT microporous materials (e.g. zeolites) adsorption depends exponentially on the 2 nd to the 5 th powers of H/RT

Nature of water in zeolites Three types suggested by Bish & Carey (2001): H 2 O continuously varying in content as a function of T and P ( true zeolitic water); H 2 O with discontinuous changes at a unique T for a given P ( similar to that in hydrates, e.g. gypsum); H 2 O sorbed to external surfaces. Water loss as a continuous function of T (or P) does not imply that H 2 O is present in a range of energies; Energetic type of H 2 O do not necessarily correspond to distinct crystallographic sites; H 2 O confined in zeolite pores show ice-like character.

Ice-like water confined in zeolite pores Hemingway & Robie, 1984 Geiger et al. (2010) Giuseppe Cruciani Harvesting, Storage and Saving of Energy using Microporous Minerals

Water and cation distribution in Li-LSX (A. Wozniak et al., 2008) Li cations at sites SII C and SIII and the first adsorbed water molecule at site W3 at low hydration of Li-LSX zeolite (8 D 2 O). Water network in the fully hydrated Li-LSX Network of W4, W5, and W6 in the super cage representing a section of the cubic Ice Ic structure. The very first water molecules which were added to the dehydrated Li-LSX material are positioned at site W3 close to the asymmetrically coordinated Li+(SIII). The cations at SIII are only weakly shielded by framework oxygen atoms and obviously present the energetically most attractive site for the water dipoles.

Desired adsorbent for AHPs New generation of adsorption machines requires novel adsorbent materials with optimal adsorption properties Very narrow operating range at low humidity

Universal relation between the three cycle T From the Truton s rule or the Polaniy principle of temperature invariance (Aristov et al., 2008)

Search for optimal zeolite for solar apps different solutions for different tasks, depending on: levels of 3T cycle time scale of the heat storage climatic conditions social conditions much research needed on materials: reduce the costs increase the energy storage density increase the efficiency increase the stability understand the structure interaction with cations test the (hydro)thermal stability under operating conditions explored strategies: novel synthetic materials best performances costly!!! characterization of natural zeolites performances? cost effective! ion exchange/chemical or physical upgrading developing composites/supports finishing/shaping to improve the mass and heat transport properties

What are zeolites? Primary Building Units (PBUs) Secondary Building Units (SBUs) Cages

Factors controlling adsorption (and diffusion) in zeolites and microporous materials For different zeolites (and zeolite-like materials) and a given adsorbate: framework density (FD) and topology T-atom substitution(s): Si by Al, P, Ti, Ga, Co, Zn,... Si/Al ratio (Si/Al = 8 is the cut-off between hydrophilic and hydrophobic) number of compensating E-F cations type and size of E-F cations location and accessibility of extra-framework (E-F) cations (minimal shielding by zeolite framework) size of windows (lower diffusion activation energy with larger rings) For the same zeolite, different adsorbate: molecular polarity (molecules with large polarity or polarizability are adsorbed preferentially under identical conditions) For the same zeolite and adsorbate: working temperature thermal activation profile

More than 200 framework topologies CHA topology FAU topology (X,Y)

Water content: effects of FD and E-F (Breck, 1974) Void fraction vs. FD Water content vs. ionic strengh and size of E-F cation Water Saturation Capacity vs. FD (Barrer, 1982) Clinoptilolite (Bish, 1988) Zeolite RHO (Barrer, 1982)

Thermal curves of chabazites TG, DTG, and curves of natural chabazites (Gottardi & Galli, 1985) DTA and TG curves of exchanged chabazites (Barrer and Langley, 1958) Affinity for water: Ca>Li>Na>K,Rb>Cs a) Sr-, Al-rich b) Na-rich c) Ca-rich

Heats of hydration/adsorption 1: 0.5 cat./large cage 2: 2 cat./large cage 3: 6 cat./large cage Heats of adsorption of water for zeolite 13X (Breck, 1974) Heats of hydration for zeolite 13X (Breck, 1974) Molar enthalpy of hydration vs. the ratio of Al content to the water molecules at saturation (Carey and Navrotsky, 1982)

Tested microporous materials for solar energy Silica gel (for comparison) Classical (Si/Al) zeolites Zeotype (Silico)Alumino phosphates Metal Organic Frameworks (MOFs) (Henninger et al. 2010)

Effects of thermal activation in zeolite Ag-LSX (Hutson et al., 2000) Ag-LSX (a) after drying at RT followed by vacuum dehydration at 450 C (b) after drying at RT followed by vacuum dehydration at 350 C (c) after drying in air at 100 C followed by vacuum dehydration at 350 C (d) after drying in air at 100 C followed by heat-treatment in air at 450 C and finally vacuum dehydration at 450 C.

Reversible dehydration TG /% 100 95 90 85 80 TG /% 100 95 After 30 dehydration cycles Variaz. di massa: -21.74 % 90 Variaz. di massa: -20.45 % 0 85 20 40 60 80 100 120 140 160 Tempo /min DTA /(uv/mg) Temperatura / C exo [1] 0.08 0.06 200 DTA 0.04/(uV/mg) Temperatura / C 0.02 exo [1] 0-0.02-0.04-0.06-0.08-0.10 0.05 150 200 0 100 150-0.05 50 100-0.10-0.15 50 80 0 20 40 60 80 100 120 140 160 Tempo /min

Thermal stability upon ad/desorption cycles (Henninger et al. 2011)

Zeotype microporous phosphates FAM (Functional Adsorbent Materials) by Mitsubishi Chemical

Best performance zeotype materials (from H. Kakiuchi, Mitsubishi Chemical)

Hydrophilic hydrophobic structural change (from H. Kakiuchi, Mitsubishi Chemical) HT-XRD DSC

Thermally induced changes in zeolites Upon water removal (by heating), zeolites may undergo different kinds of structural changes: 1. Cell volume contraction due to the removal of water and/or templating organic molecules (dehydration and calcination) 2. Displacive or reconstructive phase transformation(s) to more or less metastable phase(s) 3. Dealumination 4. Breaking (and new formation) of T-O-T bonds 5. Negative thermal expansion (NTE) 6. Zeolite collapse ( collapsed zeolites retain sorption properties and a recognizable XRD patterns) 7. Polyamorphism 8. Structural breakdown (i.e. complete amorphization or recrystallization)

Factors controlling zeolite thermal stability no simple rules several extrinsic factors (relative umidity, near- or farther-from-equilibrium conditions, heating rate, surrounding atmosphere, crystallite size, etc.) known/suggested intrinsic factors: i. the framework Si/Al ratio (Si, Al ordering?); ii. the size and ionic potential (Z/r) of exchangeable (chargecompensating) cations; iii. the framework topology: denser frameworks, more stable; open channels (10- and 12MRs), less stable?; regular n-rings, more stable than distorted or twisted rings with same n; collapsible or non-collapsible (co- or anti-rotating hinges) frameworks?; 3MRs (highly strained), less stable?; 4MRs (with constraints on Si-O-Si angles), less stable?; D4Rs (in most cases requiring fluoride route), less stable? 5MRs more energetically stable?; presence of specific sub-units (e.g. pillars of 5-rings or double 6-rings)? iv. the coordination of bare cations after water expulsion.

Structural behavior upon heating by XRD ex-situ single crystal X-ray diffraction isothermal method conditions not far from the equilibrium; temperature and vacuum effects not easily discriminated; single crystals mosaicity only a few snapshot of the process. in-situ single crystal X-ray diffraction high-quality data @ in-situ and near-equilibrium conditions; still limited number of snapshots over the heating process. in-situ time-resolved powder diffraction + Rietveld synchrotron X-rays (or neutrons); dynamic heating conditions far from the equilibrium; continuous picture of the zeolite structural response to dehydration; record non-quenchable structural modifications.

Thermal behavior of chabazite DTA and TG curves of chabazite (Van Reeuwijk, 1974) Continuous-heating X-ray diffraction of chabazite using Guinier-Lennè XRD powder photographs (Van Reeuwijk, 1974)

Energetics of hydration/dehydration of chabazite (C. Fialips et al.2004)

Cation migration upon dehydration in chabazite (M. Zema et al. 2008) C2 C4 C1 C3 (Ca 1.1,Na 0.4,K 0.7 )Al 3.4 Si 8.6 O 24 14.4H 2 O. C1: green C2: blue C3: brown C4: orange C5: purple discontinuities at 100 C and 200 C structural modifications are almost complete at 250 C breakdown of Ca/Na solvated ion at C3 whole process reversible under the study conditions

Thermal behavior of CHA-type willhendersonite (R.X. Fischer et al. 2008) Unit-cell parameters as a function of T under dry nitrogen (white squares) and under humid air (gray squares) K x Ca 3-x Al 6 Si 6 O 24 10H 2 O Ca coordination at RT (a) and 150 C (b) transition from triclinic to rhombohedral symmetry upon dehydration due to cation migrations partly to low-coordinated sites relaxation of the elliptically deformed 6-rings of TO tetrahedra to a more circular shape. in contrast to chabazite (same topology disordered T atoms) the 6-rings in the D6R units are twisted relative to each other in the HT form. transition temperature depends on the degree of humidity: from ~100 C (dry N 2 ) to ~200 C (humid air)

Energy Storage Density (Tchernev, 2001)

2-theta

Relative merits of CHA and 13X (according to Tchernev) Zeolite 13X with working T 70-120 like in SC, the use of natural chabazite is a costeffective alternative to synthetic NaX (13X) which in turn remains to be preferred for the long-term SHS (Tchernev, 2001) (Tchernev, 2000)

Chemical upgrading of natural chabazite (Kuznicki et al, 2007) upgraded raw prolonged digestion in an alkaline silicate mixture at temperatures varying from 60ºC to 100ºC for periods of 4 to 48 h elemental composition of purified chabazite resembling the original components at Si/Al 3.0

Worldwide distribution of chabazite deposits chabazite (http://www.mirofoss.com/minerals/mineral_silicates/mineral_frames/chabazite_frame.html)

Scuola GNM - "La fisica dei minerali: implicazioni Worldwide distribution of zeolite deposits currently, the world s annual production of natural zeolites is about 4 million tons the most important deposits are in the United States, Mexico, Ukraine, Slovakia, Italy, Greece, Turkey, Russia, Serbia, Romania, Bulgaria, Georgia, Armenia, Cuba and Croatia

The annual global solar radiation Global annual solar radiation (kwh m -2 yr -1 ).

Solar adsorption refrigerators commercially available on the market. Brissoneau et Lotz-Marine (BLM) system (daily ice production 5.5 kg) ~US $1500 The Zeopower refrigerator ~ US $1700 per unit EG Solar refrigerator ~ 900 Solaref refrigerator (based on the design developed by Dind et al. 2005), intended to be mainly commercialized in Africa, between 2600 and 3700

(1) solar powered zeolite 4A-water adsorption refrigerator using an array of two concentrating parabolic collectors with 1.029 m 2 areas and 1.8 concentration ratio (2) hourly instantaneous COP ranges from 0.2 to 2.5; hourly insolation ranges from 34 W/m 2 to 345 W/m 2. Evaporator temperature of 11 C and maximum adsorber temperature of 110 C. Minimum daily hourly mean COP of 0.838 with the corresponding maximum COP value of 1.48. (2) total mean daily-hourly insolation of 170 W/m 2.

Not patented systems design by Needful Provision, Inc. (NPI) to meet food storage needs for remote areas and poor families not intended to be a commercial system effort made to avoid any possible patent infringement related to existing, somewhat similar, commercial solar powered refrigerators vacuum hand-pump is used to help maintain a partial vacuum no power other than solar

Solar-powered ice maker by a team of students from King's College in London. Ice maker designed by engineering students from San Jose State University.

Conclusions and future outlooks ready to start for a 4 th zeolite-supported solar boom matching market-driven (sophisticated) with cheap (potentially accessible to everyone) technologies? mature technology but still much work to be done on materials close cooperation (and mutual understanding) between thermal engineers and mineral scientists required natural zeolites might provide cheap and sustainable solutions to SC in developed and developing countries

Acknowledgements People: Davide Casotti & Matteo Ardit (UniFe) help with the live experiment Luigi Crema & Alessandro Bozzoli (REET group, FBK, Trento) and Andreas Hauer (Bavarian Centre for Applied Energy Research, ZAE Bayern, Munich), for useful discussion Funding: project SolTec Agenzia Provinciale per l Energia (APE) Trento project SoWaZe (GEO-TECH) MIUR-PRIN2008-2010 Giuseppe Cruciani Harvesting, Storage and Saving of Energy using Microporous Minerals 78 of 30