Experimental investigations on cylindrical latent heat storage units with sodium acetate trihydrate composites utilizing supercooling

Dannemand, Mark; Kong, Weiqiang; Furbo, Simon

doi:10.1016/j.apenergy.2016.05.144

Cited by 58 publications

(22 citation statements)

References 36 publications

(46 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The actual design and its characteristics with SAT as the heat storage material were investigated by Dannemand et al under laboratory conditions [35]. It was proved and documented that the stable supercooling of SAT composites in flat boxes and cylindrical vessels [44] is enabled by: a) avoiding pressure changes in the PCM container (e.g. by using a membrane expansion vessel), b) smooth inner container surfaces, and c) heating up the whole material volume to a minimum temperature of ~77 ºC.…”

Section: State Of the Art 13mentioning

confidence: 99%

Design and functionality of a segmented heat-storage prototype utilizing stable supercooling of sodium acetate trihydrate in a solar heating system

et al. 2018

Self Cite

View full text Add to dashboard Cite

Document Version Peer reviewed versionLink back to DTU Orbit Citation (APA): Englmair, G., Moser, C., Furbo, S., Dannemand, M., & Fan, J. (2018). Design and functionality of a segmented heat-storage prototype utilizing stable supercooling of sodium acetate trihydrate in a solar heating system. Applied Energy, 221, 522-534. https://doi. Highlights Combined short-and long-term heat-storage prototype for domestic solar heating  Interplay of solar collectors, four 200 kg PCM units and a 735 L water tank  Functionality of a segmented heat storage utilizing stable supercooling of SAT  Solidification of supercooled SAT was started by a seed crystal injection device  Supply temperatures and thermal power during PCM charge and discharge were evaluated Abstract A solar heating system with 22.4 m² of solar collectors, a heat storage prototype consisting of four 200 kg phase-change material (PCM) storage units, and a 735 L water tank was designed to improve solar heat supply in single-family houses. The PCM storage utilized stable supercooling of sodium acetate trihydrate composites to conserve the latent heat of fusion for long-term heat storage. A control strategy directed heat from a solar collector array to either the PCM storage or a water buffer storage. Several PCM units had to be charged in parallel when the solar collector output peaked at 16 kW. A single unit was charged with 27.4 kWh of heat within four hours on a sunny day, and the PCM temperature increased from 20 ºC to 80 ºC. The sensible heat from a single PCM unit was transferred to the water tankstarting with about 32 kW of thermal power after it had fully melted at 80 ºC. A mechanical seed crystal injection device was used to initialize the crystallisation of the sodium acetate trihydrate after it had supercooled to room temperature. The unit discharge during solidification peaked at 8 kW. Reliable supercooling was achieved in three of the four units. About 80% of latent heat of fusion was transferred from PCM units after solidification of supercooled sodium acetate trihydrate to the water tank within 5 hours. Functionality tests with practical operation conditions on the novel, modular heat-storage configuration showed its applicability for domestic hot water supply and space heating. Keywords: Solar heating system; heat storage prototype; phase change material; sodium acetate trihydrate; stable supercooling. P pump PCM phase-change material SA sodium acetate SAT sodium acetate trihydrate SH space heating V 2-way valve

show abstract

Section: State Of the Art 13mentioning

confidence: 99%

Design and functionality of a segmented heat-storage prototype utilizing stable supercooling of sodium acetate trihydrate in a solar heating system

et al. 2018

Self Cite

View full text Add to dashboard Cite

show abstract

“…Numerous experimental studies have been performed in this area [23][24][25][26][27]. Dannemand et al [23] studied cylindrical PCM systems utilizing stable super-cooling sodium acetate trihydrate composites.…”

Section: Introductionmentioning

confidence: 99%

“…Dannemand et al [23] studied cylindrical PCM systems utilizing stable super-cooling sodium acetate trihydrate composites. They found that low heat exchange capacity was due to limited convection in the molten PCM.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the Dynamic Melting Process in a Thermal Energy Storage Unit Using a Helical Coil Heat Exchanger

et al. 2017

View full text Add to dashboard Cite

Abstract:In this study, the dynamic melting process of the phase change material (PCM) in a vertical cylindrical tube-in-tank thermal energy storage (TES) unit was investigated through numerical simulations and experimental measurements. To ensure good heat exchange performance, a concentric helical coil was inserted into the TES unit to pipe the heat transfer fluid (HTF). A numerical model using the computational fluid dynamics (CFD) approach was developed based on the enthalpy-porosity method to simulate the unsteady melting process including temperature and liquid fraction variations. Temperature measurements using evenly spaced thermocouples were conducted, and the temperature variation at three locations inside the TES unit was recorded. The effects of the HTF inlet parameters were investigated by parametric studies with different temperatures and flow rate values. Reasonably good agreement was achieved between the numerical prediction and the temperature measurement, which confirmed the numerical simulation accuracy. The numerical results showed the significance of buoyancy effect for the dynamic melting process. The system TES performance was very sensitive to the HTF inlet temperature. By contrast, no apparent influences can be found when changing the HTF flow rates. This study provides a comprehensive solution to investigate the heat exchange process of the TES system using PCM.

show abstract

“…SAT is considered an incongruently melting salt hydrate, which suffers from phase separation. The problem of phase separation has been sought solved by adding thickeners or extra water to the SAT [7,8,[16][17][18][19][20]. The key properties, which determine the capacity of a PCM heat storage, are the specific heat capacity in solid and liquid phase, latent heat and the density of the PCM.…”

Section: Materials Propertiesmentioning

confidence: 99%

Porosity and density measurements of sodium acetate trihydrate for thermal energy storage

Dannemand

Delgado

Lázaro

et al. 2018

Applied Thermal Engineering

Self Cite

View full text Add to dashboard Cite

Sodium acetate trihydrate (SAT) can be used as phase change material in latent heat storage with or without utilizing supercooling. The change of density between liquid to solid state leads to formation of cavities inside the bulk SAT during solidification. Samples of SAT which had solidified from supercooled state at ambient temperature and samples which had solidified with a minimal degree supercooled were investigated. The temperature dependent densities of liquid and the two types of solid SAT were measured with a density meter and a thermomechanical analyzer. The cavities formed inside samples of solid SAT, which had solidified after a high or minimal degree of supercooling, were investigated by X-ray scanning and computer tomography. The apparent density of solid SAT depended on whether it solidified from a supercooled state or not. A sample which solidified from a supercooled liquid contained 15% cavities and had a density of 1.26 g/cm 3 at 25 °C. SAT which had solidified with minimal supercooling contained 9% cavities and had a density of 1.34 g/cm 3 at 25 °C. The apparent densities of the solid SAT samples were significant lower than the value of solid SAT reported in literature of 1.45 g/cm 3. The density of liquid and supercooled SAT with extra water was also determined at different temperatures.

show abstract

Experimental investigations on cylindrical latent heat storage units with sodium acetate trihydrate composites utilizing supercooling

Cited by 58 publications

References 36 publications

Design and functionality of a segmented heat-storage prototype utilizing stable supercooling of sodium acetate trihydrate in a solar heating system

Design and functionality of a segmented heat-storage prototype utilizing stable supercooling of sodium acetate trihydrate in a solar heating system

Investigation of the Dynamic Melting Process in a Thermal Energy Storage Unit Using a Helical Coil Heat Exchanger

Porosity and density measurements of sodium acetate trihydrate for thermal energy storage

Contact Info

Product

Resources

About