scholarly journals Compatibility Tests between Three Commercially Available Organic PCMs and Metals Typically Used in Fin-and-Tube Heat Exchangers

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5172
Author(s):  
Paulina Rolka ◽  
Jaroslaw Karwacki ◽  
Maciej Jaworski
Keyword(s):  
Heat Transfer ◽  
Energy Storage ◽  
Heat Exchangers ◽  
Phase Change Materials ◽  
Energy Savings ◽  
Gravimetric Method ◽  
Optical Microscope ◽  
Heating And Cooling ◽  
Air Conditioning Systems ◽  
Surface Changes

Energy storage is one of the most effective ways to increase energy savings and efficiency of heating and air conditioning systems. Phase change materials (PCMs) are increasingly used in latent heat thermal energy storage (LHTES) systems to increase their capacity. In such systems, costs are a very important factor of viability so the typical heat transfer elements like fin-and-tube heat exchangers are used to construct the LHTES. The problem of this approach is a possibility of corrosion of metals in contact with PCM that shortens the life cycle of LHTES. Therefore, the main objective of this work is an experimental study of the compatibility of metals typically used in fin-and-tube heat exchangers (copper and aluminum) with three commercially available organic PCMs (RT15, RT18HC, and RT22HC). Compatibility of PCMs with copper and aluminum was tested for a period of approximately two months, during which a total of 35 heating and cooling cycles were carried out, each with a complete phase transition of the tested materials. In the course of the tests it was assessed whether the PCM caused corrosion of the tested metals. The evaluation was based on the gravimetric method, calculation of corrosion rate, and visual observations and measurements of the features on the metal sample’s surface using optical microscope. It was determined that RT15, RT18 HC, and RT22 HC show low corrosion rates for aluminum and copper samples. The visual tests indicate that there was no change in the PCM solutions during the tests, only a sediment was observed for the samples with the combination of copper and aluminum. Microscopic examination of the surface of the samples did not show any significant surface changes, except for the aluminum samples, on the surface of which local microdefects were observed. It follows from the present results that copper and aluminum can be used to design the heat transfer surface in contact with the chosen PCMs.

Latent Heat Storage: Container Geometry, Enhancement Techniques, and Applications—A Review

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
S. Arunachalam
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Energy Storage ◽  
Phase Change ◽  
Latent Heat ◽  
Thermal Energy ◽  
Heat Exchangers ◽  
Phase Change Materials ◽  
Heat Storage ◽  
Low Thermal Conductivity

Energy storage helps in waste management, environmental protection, saving of fossil fuels, cost effectiveness, and sustainable growth. Phase change material (PCM) is a substance which undergoes simultaneous melting and solidification at certain temperature and pressure and can thereby absorb and release thermal energy. Phase change materials are also called thermal batteries which have the ability to store large amount of heat at fixed temperature. Effective integration of the latent heat thermal energy storage system with solar thermal collectors depends on heat storage materials and heat exchangers. The practical limitation of the latent heat thermal energy system for successful implementation in various applications is mainly from its low thermal conductivity. Low thermal conductivity leads to low heat transfer coefficient, and thereby, the phase change process is prolonged which signifies the requirement of heat transfer enhancement techniques. Typically, for salt hydrates and organic PCMs, the thermal conductivity range varies between 0.4–0.7 W/m K and 0.15–0.3 W/m K which increases the thermal resistance within phase change materials during operation, seriously affecting efficiency and thermal response. This paper reviews the different geometry of commercial heat exchangers that can be used to address the problem of low thermal conductivity, like use of fins, additives with high thermal conductivity materials like metal strips, microencapsulated PCM, composite PCM, porous metals, porous metal foam matrix, carbon nanofibers and nanotubes, etc. Finally, different solar thermal applications and potential PCMs for low-temperature thermal energy storage were also discussed.

scholarly journals Effect of Insulation on the Energy Demand of a Standardized Container Facility at Airports in Spain under Different Weather Conditions

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5263
Author(s):  
Miguel Ángel Álvarez-Feijoo ◽  
Pedro Orgeira-Crespo ◽  
Elena Arce ◽  
Andrés Suárez-García ◽  
José Roberto Ribas
Keyword(s):  
Energy Demand ◽  
Phase Change Materials ◽  
Energy Savings ◽  
Weather Conditions ◽  
Climate Conditions ◽  
Heating And Cooling ◽  
Energy Demands ◽  
Shipping Containers ◽  
The Right ◽  
Air Conditioning Systems

Airports, broadly spread world-wide, present continuously increasing energy demands for heating and cooling purposes. Relocatable facilities within them could be built on recycling shipping containers provided with the right insulation layer, to reduce the outstanding consumption of the heating, ventilation and air conditioning systems (HVAC). This research focuses on studying the effect of added insulation on the thermal performance of a construction in the scope of an airport facility, based on a recycled shipping container. Passive heating and cooling insulation strategies have shown good results in terms of energy savings. A series of simulations were performed along six different Spanish airports locations, selected to represent several climate conditions. Temperature evolution inside the container, and energy demands of the HVAC system were obtained to show that the insulation provided by phase change materials (PCM) is performing better than traditional insulation, or a raw container. Although there are slight behavior differences according to the climate, PCM can increase inside temperature even with no HVAC under certain circumstances.

scholarly journals Performance Improvement of a Household Refrigerator using Phase Change Material

2021 ◽  
Vol 16 (1) ◽  
pp. 032-041
Author(s):  
Pradeep N ◽  
Somesh Subramanian S
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Phase Change Material ◽  
Phase Change Materials ◽  
Energy Savings ◽  
Storage System ◽  
Thermal Storage ◽  
Latent Heat Storage ◽  
Peak Loads ◽  
Change Material

Thermal energy storage through phase change material has been used for wide applications in the field of air conditioning and refrigeration. The specific use of this thermal storage has been for energy storage during low demand and release of this energy during peak loads with potential to provide energy savings due to this. The principle of latent heat storage using phase change materials (PCMs) can be incorporated into a thermal storage system suitable for using deep freezers. The evaporator is covered with another box which has storage capacity or passage through phase change material. The results revealed that the performance is increased from 3.2 to 3.5 by using PCM.

scholarly journals Development of High Added Value Products from Industrial Minerals for Hybrid Energy Storage

2021 ◽  
Vol 5 (1) ◽  
pp. 31
Author(s):  
Antonis Peppas ◽  
Chrysa Politi
Keyword(s):  
Energy Storage ◽  
Thermal Energy ◽  
Phase Change Materials ◽  
Supply And Demand ◽  
Real Data ◽  
Energy Performance ◽  
Added Value ◽  
Industrial Minerals ◽  
Heating And Cooling ◽  
Research Activities

Industrial minerals are at the forefront of innovation and play an essential role in many innovative applications. Their functionalities and properties make them very versatile materials which are essential to many industries. A combination of properties such as heat capacity, density, price, availability, and eco-friendliness are exceptional and crucially advantageous of industrial minerals utilisation as thermal energy storage (TES) systems. This technology stocks thermal energy by heating or cooling a storage medium so that the stored energy can be used at a later time for heating and cooling applications and power generation. In this context, the utilisation of industrial minerals as carriers for impregnating phase change materials (PCM) can deliver new innovative products acting as short-term energy storage systems for construction applications to the market. TES is a technology that can solve the existing mismatch of energy supply and demand and improve buildings’ system performance by smoothing temperature fluctuations, as well as improving the reliability of the heating and/or cooling source. However, the most recent publications in this area are focused on PCM-enhanced building components thermal and kinetics analysis rather than focusing on the building component scale. This study is focused on the industrial minerals-PCM application as part of the building’s envelope, aiming to determine the benefits for buildings in terms of thermal energy performance and renewable energy penetration based on real data, harvested by an intelligent monitored building in Lavrion Technological and Cultural Park operated solely for research activities.

Solid/Liquid Phase Change Heat Transfer in Latent Heat Thermal Energy Storage

2009 ◽  
Author(s):  
D. Zhou ◽  
C. Y. Zhao
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Energy Storage ◽  
Phase Change ◽  
Calcium Chloride ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Phase Change Materials ◽  
Metal Foams ◽  
Chloride Hexahydrate

Phase change materials (PCMs) have been widely used for thermal energy storage systems due to their capability of storing and releasing large amounts of energy with a small volume and a moderate temperature variation. Most PCMs suffer the common problem of low thermal conductivity, being around 0.2 and 0.5 for paraffin and inorganic salts, respectively, which prolongs the charging and discharging period. In an attempt to improve the thermal conductivity of phase change materials, the graphite or metallic matrix is often embedded within PCMs to enhance the heat transfer. This paper presents an experimental study on heat transfer characteristics of PCMs embedded with open-celled metal foams. In this study both paraffin wax and calcium chloride hexahydrate are employed as the heat storage media. The transient heat transfer behavior is measured. Compared to the results of pure PCMs samples, the investigation shows that the additions of metal foams can double the overall heat transfer rate during the melting process. The results of calcium chloride hexahydrate are also compared with those of paraffin wax.

A General Model for Analyzing the Thermal Performance of the Heat Charging and Discharging Processes of Latent Heat Thermal Energy Storage Systems*

2001 ◽  
Vol 123 (3) ◽  
pp. 232-236 ◽  
Author(s):  
Yinping Zhang ◽  
Yan Su ◽  
Yingxin Zhu ◽  
Xianxu Hu
Keyword(s):  
Heat Transfer ◽  
Energy Storage ◽  
Latent Heat ◽  
Thermal Performance ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
General Model ◽  
Phase Change Materials ◽  
Melting Process ◽  
Specific System

During melting of phase change materials (PCM) encapsulated in a container, the solid PCM sinks to the bottom or floats to the top of the container according to the gravitational force and buoyancy resulting from the difference between solid and liquid densities. Compared with the solidification process, the melting process has a quite different behavior. Although the heat transfer characteristics of melting processes in various typical kinds of containers have been studied, the general model for analyzing the thermal performance of both melting and solidification processes of latent heat thermal energy storage (LHTES) systems composed of PCM capsules has not been presented in the literature. The present paper describes such a model which can be used to analyze the instantaneous temperature distribution, instantaneous heat transfer rate, and thermal storage capacity of a LHTES system. For solidification, the model is validated with the results in the literature. The thermal performance during melting of a LHTES system composed of PCM spheres is analyzed as an example. The model is not limited to a specific system or a specific PCM, so it can be used to select and optimize system design and to simulate the thermal behavior of various typical LHTES systems.

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