1,385 Works

Numerical investigation of a novel phase-change renewable energy system for underground mine heating and cooling.

S. AKHTAR, P. SASMITO A. & A. MADISEH
This study analyzes the performance of spray freezing, a novel renewable technology, to supplement the heating and cooling load of underground mines. This opportunistic technology provides a cost-effective way to utilize the sub-arctic conditions of Northern Canada for meeting the heating needs. The current study employs a Multiphysics, multi-scale approach to model the phenomena of spray freezing. The discrete phase computational fluid dynamics model developed, can reproduce both the local effects of droplet freezing and...

Supercooling stability of sodium acetate trihydrate composites in multiple heat storage units.

M. DANNEMAND & S. FURBO
Keeping sodium acetate trihydrate (SAT) in supercooled state can be utilized to store heat loss free over long periods. The main risk with this technology is that the SAT may crystalize spontaneously and release the stored heat before desired. A test rig with 10 marketed heat storage units with water and 35 kg sodium acetate trihydrate composite was built and multiple heating and cooling cycles were carried out with the units. It was monitored if...

Study on the effect of nanoparticle dispersion on the melting of PCM in hemicylindrical cell.

S. DHAIDAN N. & M. AL-JETHELAH
The melting process of nano-enhanced phase change material (NePCM) contained in a horizontal hemicylindrical vessel isothermally heated on straight wall is numerically investigated. A simulation adopts enthalpy-porosity technique and finite volume method to solve the simultaneous governing equations. The behaviour features of melting such as the progress and the shape of melting interface, melt fraction and charging time are studied according to the influence of the concentration of the nanoparticles loading, and the temperature of...

Investigation of heat transfer and rheology of a phase change material emulsion with a high concentration in surfactant.

V. VASILE, A. BADEA, H. NECULA & Et Al.
The thermohydraulic characteristics of a secondary refrigerant consisting of a phase change material emulsion (PCME) were investigated. This PCME is a paraffin-in-water emulsion containing 30 wt.% of paraffin and a relatively high concentration of surfactant (5 wt.%). A fully instrumented 1 m long rectangular channel was used to conduct heat transfer experiments. Heat transfer coefficients during cooling inside the rectangular channel were determined. Furthermore, a specific test rig was used to perform experiments on the...

Concept and performance of a solar assisted heat pump using ice slurry as a phase change storage medium.

M. POIRIER, J. TAMASAUSKAS & D. GUIGUERE
In Canada, there is often enough solar energy to meet building heating demand in the winter months. However, solar availability and heating loads generally do not coincide, requiring innovative ways to store and later retrieve captured solar energy. A new concept utilizing a glycol-water-ice tank (fluid temperature < 0°C) to store the energy collected from solar thermal collectors, and an ice slurry heat pump to extract the energy from the tank for building heating was...

Generation, crystal fraction and viscosity of K2HPO4·6H2O-PCS.

H. SCHMIT, D. PAUCKNER, J. LINN & Et Al.
The salt hydrate K2HPO4·6H2O has a melting temperature of around 14 °C, a melting enthalpy of 177 J g-1, and shows inhibited crystal growth. Due to these properties, K2HPO4·6H2O is a candidate as a phase change slurry (PCS). In this work, it is demonstrated, that the crystal fraction of K2HPO4·6H2O-PCS can be determined by using a turbidity sensor. Generation of K2HPO4·6H2O-PCS is possible by using the hydroscraped slurry generator method. However, with the used test...

Investigation of compatibility of organic and inorganic PCMs with the materials of containers.

M. OSTRÝ, S. BANTOVÁ, P. CHARVÁT & Et Al.
Phase change materials (PCMs) are latent heat storage media that are still under development for various building applications. Because the PCMs store/release heat during the melting/solidification process they must be hermetically sealed in a proper container without the risk of leakage or loss of required mechanical properties. The compatibility of the PCMs with the material of the container is a very important issue in the lifespan of heat storage systems and their safety. In the...

Model-based prediction and experimental verification of eutectic PCM.

H. SCHMIT, C. RATHGEBER, L. SUN C. & Et Al.
In certain application-relevant temperature ranges, there is a lack of cost-effective phase change materials (PCM). Eutectic mixtures of salt hydrates (or salt hydrates and anhydrous salt(s)) could fill the existing temperature gaps. In this work, a new method consisting of model-based prediction and subsequent experimental verification is introduced and validated. A self-programmed phase diagram prediction software on the basis of the modified BET model was validated on the existing phase diagram of the system Mg(NO3)2+LiNO3+H2O....

High power thermal energy storage research at Lucerne University of Applied Sciences and Arts.

J. WORLITSCHEK, J. FISCHER L. & A. STAMATIOU
Latent heat storage with phase change materials is a promising technique to store thermal energy. The high latent heat of these materials and their near-steady charging/discharging temperature offers a unique energy density compared to conventional sensible-only heat storage and allows for more compact and efficient systems. However, the low heat transfer rate inherent to such storage units, presents a significant barrier for their widespread application in processes which require fast-response, high-thermal-power outputs and steady operational...

Porous media for advanced hybrid thermal energy storages.

R. LAZZARIN, S. MANCIN, M. NORO & Et Al.
It is well-known that the use of the latent heat absorption phenomenon associated with the melting process of a suitable Phase Change Material (PCM) can be considered an effective way to improve energy storage capabilities in many applications. Among PCMs, paraffin waxes show some desirable features. Unfortunately, they have also two main limitations, a low thermal conductivity and a high volume change during the melting process, that limit their potential applications as PCMs. This work...

Ammonia alum hydrate-based phase change materials for effective use of excess exhaust heat from gas engines.

K. NAKAMURA, T. INA, R. HIDEMA & Et Al.
For effective use of excess exhaust heat from gas engines, a novel PCM was prepared by adding anhydrous sodium sulfate and D-mannitol to ammonia alum hydrate. It melted and stored latent heat at the temperature range of exhaust heat from gas engines (around 90°C). Heat storage and release characteristics of the novel PCM were investigated with a heat storage tank containing hot water and the novel PCM packaged into resin bags. As a result, the...

Characterization of PCM, standardization in the frame of the IEA ECES Annex 33 and SHC Task 58.

S. GSCHWANDER, M. DELGATO GRACIA, M. BRÜTTING & Et Al.
This contribution will give an introduction in into the DSC procedure developed within the IEA ECES Annexes 24 and 29 as well as SHC Task 42. Additionally results are presented on work which has been carried out to develop procedures for the measurement of PCM´s thermal conductivity and viscosity. This development started within Annex 29 and SHC Task 42 and will be continued in the following up ECES Annex 33 and SHC Task 58. As...

A novel PCM accumulator for refrigerated display cabinet: design and CFD simulations.

K. BANASIAK, J. BAKKEN, A. SEVAULT & Et Al.
In supermarkets, power outages, temperature fluctuations due to defrosting cycles and peak demands when loading warm items, contribute to reducing shelf life and quality of food products. The objective of the study is to investigate the integration of a phase change material (PCM) accumulator along the air circulation path in the lower part of a refrigerated display cabinet to maintain the product temperature within safe limits. The PCM accumulator consists of three fluids: PCM (pure...

Dynamic study efficiency of the use of phase change materials integrated on the ceiling of a community hall.

S. ASFOUR, P. TITTELEIN & L. ZALEWSKI
In this article, we study the influence of the insertion of a phase change materials (PCMs) in the ceiling of a community hall on its comfort during the summer period. This study was realized using a dynamic thermal simulation of the building using a modelica library (BuildSysPro). Initially, we have defined materials used for the building including the characteristics of the phase change material used (thermal conductivity, melting temperature, specific heat capacity, latent heat and...

Solidification monitoring of supercooled phase change materials.

N. BEAUPERE, U. SOUPREMANIEN & L. ZALEWSKI
Salt hydrates are often used as heat storage materials according to their interesting thermal properties (high latent and specific heat). Their main drawback is their large supercooling, where the material may remain liquid below its melting point. However, this property should be turned into a benefit if a reliable way of triggering crystallization is developed, as heat could be released on demand. Sodium Acetate Trihydrate (SAT, CH3COONa.3H2O), which can exhibit 90K of supercooling, was used...

Preparation and properties of paraffin / tailing ceramic composite phase change energy storage materials.

R. LI, Y. ZHOU & X. DUAN
Tailing/paraffin composite phase change energy storage material (CPCM) is fabricated by spontaneous melt infiltration where industrial waste-iron tailing is used as raw material to prepare porous carrier with a foamgel casting method. By adjusting parameters of the sintering and infiltration processes, optimal CPCM properties are obtained with paraffin content of 71~89%, thermal energy storage density of 118 J/g, thermal conductivity of 0.251~0.424 W/(m·K). The measured thermal conductivity is in good agreement with results predicted from...

Overview of industry applications of deepchill™ slurry.

A. SOMANI
In light of the PCM 2018 conference, the scope of the conference is to highlight the novel technologies using Phase Change Materials (PCMs) and Slurries (ice or hydrate slurries). This report summarizes the application of DeepChill™(DC) slurry ice for servicing the fisheries, food processing, supermarkets and ice thermal storage industries. The report focuses to highlight the novel technologies that DC is and related it to the focus of the PCM2018 conference: - Thermophysical and rheological...

Effect of phase change kinetics on energy efficiency of secondary refrigeration with hydrate slurries.

M. PONS, L. FOURNAISON, A. DELAHAYE & Et Al.
Secondary refrigeration is one of the currently available means for reducing refrigerant leaks in large cooling units. Compared to the well-known ice slurry, hydrate slurries present new features, especially when they involve a gaseous phase, the pressure of which influences the fusion temperature. The clathrate-hydrate system considered herein is the mixed hydrate of CO2 plus tetra-n-butyl-phosphonium-bromide (TBPB) melting around 12°C. The concern of energy efficiency focuses attention on the total energy consumption of the process...

Decorative wood-based panels loaded with biosourced PCMs.

D. MATHIS, L. BLANCHET, V. LANDRY & Et Al.
Decorative wood-based panels loaded with biosourced phase changing material (PCMs) were manufactured. In order to test their possibilities in province of Quebec, two test-huts of 2 X 2.5 X 3m were built. The two test-huts have been built with a large window facing south. The construction was performed following the Canadian building code. In the first hut, decorative wood-based panels loaded with biosourced PCM were installed while none-PCM panels were installed in the other hut....

Behaviour of phase change material during discharge stage in a thermal energy storage system: an experimental and numerical study.

V. SONI, A. KUMAR & K. JAIN V.
In this work, an investigation of the discharge stage of Phase Change Material (PCM) based Thermal Energy Storage (TES) system is carried out. Particle Image Velocimetry (PIV) technique is used for velocity measurement during the PCM solidification process and various real-time characteristics (flow, interface, mushy zone) are captured using High-Speed Imaging technique. Thermal stratification phenomenon led by gravity-driven convective cells is observed and analyzed. An interesting phenomenon of the detachment of dendrite particles from the...

Life cycle assessment of phase change materials, component and system concepts.

B. NIENBORG, S. GSCHWANDER, R. HORN & Et Al.
The main objectives of research on Phase Change Materials (PCM) for thermal storage are the development of low-loss and compact storage systems with high capacity (sensible water storages being the benchmark). If the storage is to be implemented in an application with the aim to increase its energy efficiency, beside the technical/thermal properties and cost factors, also the environmental impact of the storage production and operation need to be considered during development. Yet up to...

Experimental investigation on heat transfer characteristics in a phase change dispersion.

J. FISCHER L., S. MARANDA, A. STAMATIOU & Et Al.
A Phase Change Dispersion (PCD) consists of a carrier fluid and a dispersed Phase Change Material (PCM) that changes from solid to liquid while absorbing heat at nearly constant temperature. Due to the phase change of the PCM, the PCD is an efficient heat transfer fluid that enables storing latent heat. To use PCD in technical applications, comprehensive understanding of the heat transfer mechanism is required. A test rig to measure bulk fluid and inner...

A pseudo-single-phase continuum model for melting ice slurries in pipe flows.

L. ONOKOKO, N. GALANIS, S. PONCET & Et Al.
Thermal behaviors of ethylene glycol-water ice slurry flowing through a horizontal heated tube is investigated numerically. The ice slurry is assumed to behave as a single-phase Newtonian fluid with effective properties depending on temperature and ice fraction. The 3D steady-state model includes the mass, momentum and energy conservation equations as well as a transport equation for the ice particles (balance between convective and diffusive fluxes). The diffusive fluxes include those induced by the shear rate...

Performance analysis of a double pass solar air heater with and without thermal storage medium.

A. BASHIR, P. AMBER K., W. ASLAM M. & Et Al.
An experimental performance analysis of a double pass solar air heater (DPSAH) is performed with three different configurations under climatic conditions of Pakistan. These configurations include, without fins and without phase change material (PCM), with fins but without PCM, with fins and PCM in circular tubes with fins. Paraffin wax of melting point 56˚C has been used as PCM. Data were collected from 9am to 10pm on hourly basis. Important parameters such as solar irradiance,...

The rate problem: search for application specific optimization of energy storage density and exchange rate.

D. GROULX
The use of phase change materials (PCMs) in energetic systems today is in large parts restricted by dynamic issues, or what could be termed the “rate problem”; i.e., how long will it take (heat transfer rate) to store, or recover, a given amount of thermal energy in a latent heat energy storage system (LHESS) for a specific application? This problem comes in part because PCMs have relatively low thermal conductivities in both solid and liquid...

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