Use of phase change materials in concrete: current challenges

Sustainability awareness in the building industry has increased in recent years, and several initiatives have been developed. One of the areas gaining attention recently is the application of phase change materials (PCMs) in concrete. PCMs are materials capable of storing and releasing energy based on the temperature of the environment in which they are situated. This capability makes them provide heat during cold times, and absorb heat when the temperature is higher. As concrete is the most used building material in the world, the use of PCMs in concrete will be a great way to widen the application of PCMs. However, as the composition of concrete determines its properties; hence, the use of PCM in concrete can be detrimental to the properties of concrete. Some of the negative effects on the properties of concrete include reduced mechanical properties and corrosion of reinforcements. In addition, PCMs suitable for concrete are not readily available in the market, and extremely expensive when available. Also, lack of long-term data on the effect of PCM on concrete's durability has discouraged stakeholders to accept the use of PCMs in concrete. This paper explored the current challenges faced by the application of PCMs in concrete which, and possible opportunities that will open more pathway for extensive research and applications of PCM in concrete. It was concluded that the use of right type and proportion of PCM in concrete can result in similar strength to those of control samples. Also, certain methods of incorporating PCMs into the concrete were found to be more effective. Therefore, it is imperative that building engineers carry out initial tests to determine the most appropriate incorporation method to be used. Finally, huge energy savings can be achieved through the use of PCM in concrete without any significant reduction in mechanical strength.

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Energy Saving and Charging Discharging Characteristics of Multiple PCMs Subjected to Internal Air Flow

Fluids ◽

10.3390/fluids6080275 ◽

2021 ◽

Vol 6 (8) ◽

pp. 275

Author(s):

Ahmed J. Hamad

Keyword(s):

Phase Change ◽

Energy Saving ◽

Air Temperature ◽

Temperature Control ◽

Phase Change Materials ◽

Energy Savings ◽

Heating System ◽

Air Heating ◽

Room Model ◽

Model Temperature

One essential utilization of phase change materials as energy storage materials is energy saving and temperature control in air conditioning and indirect solar air drying systems. This study presents an experimental investigation evaluating the characteristics and energy savings of multiple phase change materials subjected to internal flow in an air heating system during charging and discharging cycles. The experimental tests were conducted using a test rig consisting of two main parts, an air supply duct and a room model equipped with phase change materials (PCMs) placed in rectangular aluminum panels. Analysis of the results was based on three test cases: PCM1 (Paraffin wax) placed in the air duct was used alone in the first case; PCM2 (RT–42) placed in the room model was used alone in the second case; and in the third case, the two PCMs (PCM1 and PCM2) were used at the same time. The results revealed a significant improvement in the energy savings and room model temperature control for the air heating system incorporated with multiple PCMs compared with that of a single PCM. Complete melting during the charging cycle occurred at temperatures in the range of 57–60 °C for PCM1 and 38–43 °C for PCM2, respectively, thereby validating the reported PCMs’ melting–solidification results. Multiple PCMs maintained the room air temperature at the desired range of 35–45.2 °C in the air heating applications by minimizing the air temperature fluctuations. The augmentation in discharging time and improvement in the room model temperature using multiple PCMs were about 28.4% higher than those without the use of PCMs. The total energy saving using two PCMs was higher by about 29.5% and 46.7% compared with the use of PCM1 and PCM2, respectively. It can be concluded that multiple PCMs have revealed higher energy savings and thermal stability for the air heating system considered in the current study.

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Carbonized Wood Loaded with Carbon Dots for Preparation Long-Term Shape-Stabilized Composite Phase Change Materials with Superior Thermal Energy Conversion Capacity

Renewable Energy ◽

10.1016/j.renene.2021.04.078 ◽

2021 ◽

Author(s):

Xinghui Li ◽

Ziqi Zhu ◽

Pei Yang ◽

Zhenping You ◽

Yue Dong ◽

...

Keyword(s):

Phase Change ◽

Energy Conversion ◽

Thermal Energy ◽

Carbon Dots ◽

Phase Change Materials ◽

Thermal Energy Conversion ◽

Composite Phase Change Materials ◽

Carbonized Wood

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Methods for Separation of Copper Oxide Nanoparticles From Colloidal Suspension in Dodecane

Journal of Nanotechnology in Engineering and Medicine ◽

10.1115/1.4027219 ◽

2014 ◽

Vol 5 (1) ◽

Cited By ~ 2

Author(s):

Mohammed H. Sheikh ◽

Muhammad A. R. Sharif

Keyword(s):

Energy Storage ◽

Copper Oxide ◽

Phase Change ◽

Phase Change Materials ◽

Research Work ◽

Cuo Nanoparticles ◽

Health Hazards ◽

Suspension Stability ◽

Reduced Pressure

Phase change materials (PCM) are used in many energy storage applications. Energy is stored (latent heat of fusion) by melting the PCM and is released during resolidification. Dispersing highly conductive nanoparticles into the PCM enhances the effective thermal conductivity of the PCM, which in turn significantly improves the energy storage capability of the PCM. The resulting colloidal mixture with the nanoparticles in suspension is referred to as nanostructure enhanced phase change materials (NEPCM). A commonly used PCM for energy storage application is the family of paraffin (CnH2n+2). Mixing copper oxide (CuO) nanoparticles in the paraffin produces an effective and highly efficient NEPCM for energy storage. However, after long term application cycles, the efficiency of the NEPCM may deteriorate and it may need replacement with fresh supply. Disposal of the used NEPCM containing the nanoparticles is a matter of concern. Used NEPCM containing nanoparticles cannot be discarded directly into the environment because of various short term health hazards for humans and all living beings and unidentified long term environmental and health hazards due to nanoparticles. This problem will be considerable when widespread use of NEPCM will be practiced. It is thus important to develop technologies to separate the nanoparticles before the disposal of the NEPCM. The primary objective of this research work is to develop methods for the separation and reclamation of the nanoparticles from the NEPCM before its disposal. The goal is to find, design, test, and evaluate separation methods which are simple, safe, and economical. The specific NEPCM considered in this study is a colloidal mixture of dodecane (C12H26) and CuO nanoparticles (1–5% mass fraction and 5–15 nm size distribution). The nanoparticles are coated with a surfactant or stabilizing ligands for suspension stability in the mixture for a long period of time. Various methods for separating the nanoparticles from the NEPCM are explored. The identified methods include: (i) distillation under atmospheric and reduced pressure, (ii) mixing with alcohol mixture solvent, and (iii) high speed centrifugation. These different nanoparticle separation methods have been pursued and tested, and the results are analyzed and presented in this article.

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Performance Improvement of a Household Refrigerator using Phase Change Material

Journal of Manufacturing Engineering ◽

10.37255/jme.v16i1pp032-041 ◽

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.

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Thermo-physical characteristics of building integrated phase change materials (PCM) and their applicability to energy efficient homes

10.32920/ryerson.14660997 ◽

2021 ◽

Author(s):

Omar Siddiqui

Keyword(s):

Compressive Strength ◽

Phase Change ◽

Phase Change Materials ◽

Energy Savings ◽

Physical Characteristics ◽

Comfort Level ◽

Thermal Mass ◽

Lower Phase ◽

Physical Test ◽

The Impact

The applicability of utilizing a variety of thermal mass including phase change materials with commonly used building materials is investigated through the use of simulations and physical testing. The thermal performance and occupant comfort potential of a novel solid-solid phase change material, known as Dal HSM, is compared and contrasted to commonly available forms of thermal mass. Detailed experimentation is conducted to successfully integrate Dal HSM with gypsum and concrete. The measurement of physical characteristics such as compressive strength and modulus of rupture is conducted to ensure that the PCM-composite compound retains the structural integrity to be utilized in a typical building. The use of thermal mass in the Toronto Net Zero house was found to contribute to energy savings of 10-15% when different types of thermal mass were used. The comfort level of the indoor occupants was also found to increase. The performance of Dal HSM was found to be comparable to a commercially available PCM known as Micronal in the heating mode. The cooling mode revealed that Dal HSM provided slightly lower energy savings when compared to Micronal due to a lower phase transition temperature and latent heat. The performance of physical test revealed a decrease in the compressive strength as the concentration of Dal HSM was increased in the PCM-gypsum specimens. Tests were also performed to analyze the impact of increasing the PCM concentration on the flexural strength of PCM-gypsum composite.

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