Romanian Academy of Science Institute of Physical Chemistry

Romanian Academy of Science Institute of Physical Chemistry “Ilie Murgulescu” Spl. Independentei 202, 060021 Bucharest, M. Constantinescu 1, L. Dumitrache 2, S. Serban 2, P. M. Pavel 1, A. Stoica 1, M. Ghiurea 2, M. Ladaniuc 2 and M. Olteanu 1. 1. ICF-AR “Ilie Murgulescu” 2. ICECHIM Bucuresti Objectives and importance of energy storage in PCM Nanocomposites preparation 1)Glauber(Na 2 SO 410 H 2 O)+5%Borax(Na 2 B 4 O 7)+Ad -Temperature domain: 15 -30 C -Phase change temperature -31 C. -Microencapsulation in epoxi resin as a cross-linked structure -Geometric form of the material is application dependant 2) an epoxi mixture of polyethylene glycol of different molecular weights (1000, 1500, 2000) with Al powder). 3)-Eutectics of the binary and ternary systems : --Acetamide+ sodium acetate trihidrate -sodium tiosulfate(Na 2 S 2 O 3. 5 H 2 O)+ sodium acetate trihidrate - Working temperature <60 C Energy storage aims to reduce the conventional energy consumtion with a direct impact on CO 2 emissions. The advantages of phase change materials: A constant temperature domain for the phase transformation, chosen for each application. High storage density 70 -100 k. Wh/m 3 Directions of researches on heat storage in phase change materials : Finding new materials with superior performances Elimination of existent material disadvantages. PCM +Ad melted and mixed with epoxi resin The PCM-epoxi nano-composite materials obtained as cross-linked three dimensional structures are attractive for space heating and cooling of buildings able to reduce the space and costs for containerization. Properties of nanocomposites substantially improved: ØMechanical properties : strength, modulus and dimensional stability i. e. by using a nanocomposite PCM-epoxi increases the strength by 100% ØThermal stability Thermal resistance, flame retardancy and reduced smoke emissions : Nanocomposites, with their superior thermal resistance, are also attractive for applications as housings for electronics ØChemical resistance The use of polymer-based nanocomposites are used as anticorrosion coatings on metals, and thin-film sensor. ØDecreased permeability to gases, water and hydrocarbons Polymer-matrix nanocomposites can also be used to package films, due to their superior barrier properties and low permeability + Phase Change Materials Glauber(Na 2 SO 410 H 2 O)+5%Borax (Na 2 B 4 O 7)+Al Nanocomposites PEG 1000 , 1500 +Al DSC for epoxi-PEG 1000 +Al Demands for Phase Change Material PCM Salt hydrates Melting temperature C Melting heat k. J/kg PCM Organic materials Melting temperature heat C k. J/kg KF. 4 H 2 O 18. 5 231 Butilstearate 19 140 Ca. Cl 26 H 2 O 29. 7 171 1 -dodecanol 26 200 Na 2 SO 4. 10 H 2 O 32. 4 254 Parafins 20 -26 200 Na 2 HPO 4. 12 H 2 O 35. 0 281 45/55 capric/lauric acid 21 143 Zn(NO 3)2. 4 H 2 O 36. 4 147 Propil palmitate 19 186 Ca(NO 3)2. 4 H 2 O 47. 0 153 Polyethylenglycole 1000 -2000 37 -64 83. 2 218. 4 Li. Cl. O 3. 3 H 2 O 46. 5 253 1 -tetradecanol 38 205 Mn(NO 3)2. 6 H 2 O 58 165. 5 -Phase change temperature in the required domain -High latent heat of phase change and caloric capacity -High thermal conductivity -Low undercooling -Low volume changes -Reversible phase transition -Good physical and chemical stability Hardening reaction of epoxi resin with PCM Kinetical : -High nucleation and crystal grow velocity Economical : Material characterization and testing Glauber+borax+amonium sulphate decahydrate +Al nano Polyethylene Glycol- M 2000 Physico-chemical: -low cost -Reciclability -Non-toxicity DSC for PEG 1500 Innovative applications Phase change materials have been employed in: Thermal energy storage Conditioning of buildings Waste heat recovery Off peak power utilization Heat pump systems Space applications Laptop computer cooling Cool suits Telecom shelters melted PCM in the epoxi matrix SEM micrographs for polyethylene glycol(PEG) 2000 SEM micrographs for Glauber –epoxi Al nano Solar houses Kirally Passive and active cooling Rubiterm Blood motion Rubiterm CONCLUSIONS 1. The nanocomposite materials for buildings were obtained by using melted (PCM +additives) 70 wt%, incorporated in an epoxidic resin 30 wt%. For all Epoxi-PCM materials was used Ropoxid 501 (Policolor), with a hardener threeethylentetramine (TETA) or I 3361 (Policolor). The composition of the inorganic PCM was: (Glauber salt)70 wt %, additives (borax 10 wt%, NH 4 HCO 3, (NH 4)2 SO 4, or Ca. CO 3 20 wt% and Al powder 0. 1 wt% for enhancing thermal conductivity of the material, whereas the organic PCM ( polyethyleneglycoles 1000, 1500 and 2000) were also 70 wt% and 0. 1 wt%Al powder. The system hardened at the ambient temperature. 2. The materials present good mechanical, thermal and chemical properties suitable for building materials. 3. They can be used for different applications in active or pasive systems, depending on their melting temperature. The geometry used depends also on their melting temperature and on the chosen application. 4. Energy storage in building materials will reduce the conventional energy consumptions, will increase the living comfort, decreasing the CO 2 emissions.