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Article

Mechanical Property Comparison of Geopolymer Brick Dried by Electrical and Passive Solar Devices with Phase Change Material (Paraffin Wax)

by
Jeevan Ashok Kumar
1,
Sattanathan Muthuvel
1,*,
Rajay Vedaraj Issac Selvaraj
2,
Monsuru Ramoni
3,
Ragavanantham Shanmugam
4 and
Ranjitharamasamy Sudhakara Pandian
2,*
1
Department of Mechanical Engineering, Kalasalingam Academy of Research and Education, Srivilliputhur 626126, India
2
Vellore Institute of Technology, School of Mechanical Engineering, Vellore 632014, India
3
School of Engineering, Math and Technology, Navajo Technical University, Crown Point, NM 87313, USA
4
Department of Engineering Technology, Fairmont State University, Fairmont, WV 26554, USA
*
Authors to whom correspondence should be addressed.
Processes 2024, 12(1), 28; https://doi.org/10.3390/pr12010028
Submission received: 25 October 2023 / Revised: 21 November 2023 / Accepted: 22 November 2023 / Published: 21 December 2023
Browse Figures
Versions Notes

Abstract

:
In geopolymer bricks (GPBs), fly ash content, which is waste from power plants, is converted into bricks by chemical treatment. GPBs can be dried by using appropriate curing methods. Conventionally, electric oven curing is one of the prominent methods. Using a solar dryer instead of an electric oven provides the added advantage of saving high-grade electrical energy. So, in this work, a solar dryer with the phase change material (PCM) paraffin wax and without a PCM is used for curing applications. GPBs gain an added advantage when compared to conventional bricks like cement and sand bricks in terms of strength. A GPB has been taken as a specimen for comparing the compressive strength, tensile split strength, and flexural strength of electrical-energy-based curing and solar-energy-based curing. It has been experimentally observed that solar-energy-based curing with and without a PCM exhibits higher compressive strength, higher tensile split strength, and flexural strength when compared to electrical-energy-based curing. Solar curing with a PCM shows higher compressive strength, higher tensile split strength, and higher flexural strength when compared to solar curing without a PCM. Open solar curing is a traditional technique, but nowadays, aggressive climatic conditions can lead to severe damage to geopolymers. The novelty of this work is the study of the effect of PCMs like paraffin wax in solar drying on the curing time and the mechanical properties of GPBs.

Graphical Abstract

1. Introduction

Solar energy stands as an excellent alternate source of energy when compared to other forms of energy in thermal applications, especially in areas like drying and heating [1]. The recent progress in the use of solar energy has sparked broad interest in a variety of applications, such as drying, heating, cooling, and purifying. Solar energy applications can be divided into two categories: electrical and thermal applications. Solar thermal systems have traditionally been used in agriculture to preserve vegetables, fruits, cereals, and other products. They are considered inexpensive and widely known among farmers, yet they are utilized significantly less frequently in the manufacturing sector [2]. Removing moisture from a substance is generally termed drying, which finds applications in construction, food processing, agro-industries, and other industries [3]. Also, it can be employed in preserving agricultural food products like pepper and pumpkin seeds [4,5]. Usually, hot air between 45 °C and 60 °C will remove moisture content kept inside a solar thermal system for the drying of grapes [6]. Conventional drying methods like direct exposure to the sun are simpler methods for drying agricultural food products; for example, they are used for the preservation of kiwifruit and the preparation of dry grapes in farmyards [7,8]. The drying method of open exposure to the sun is a greenhouse energy method free from technological aspects and is economical when compared to other methods of drying [9]. Under unexpectedly severe climatic conditions, the open drying process may result in some damage to food and vegetable products being dried, which is evident in agricultural industries [10,11]. Open exposure to sun drying introduces certain risk factors like a slow rate of drying time, the development of microbial activities, and the weather forecast [12]. The risk factors of open-sun drying can be eliminated by thermal power, which is free from fuel usage [13]. As thermal-based solar drying uses natural convection, it does not pose any threat to the ecosystem [14]. Thermal-based solar dryers do not alter the color or texture of the products and are hence more feasible for drying than open drying [15]. In thermal-based solar dryers, buoyancy-based pressure, which is the result of natural convection, consumes some time for the completion of drying. Also, forced-convection-based thermal solar dryers can be employed, in which a fan is used to force the air for drying, which is charged by electric current, solar energy, or fuels [16]. Geopolymer was developed by Davidovits in 1978 and is produced by activating high-alumina silica-rich materials in an alkaline solution (consisting of sodium or potassium silicate and sodium or potassium hydroxide). It is similar to ceramic composites, with a link between alumina and silica. Geopolymer-based concrete based on fly ash has the potential to replace ordinary Portland cement (OPC)-based concrete with comparable structural qualities in the construction industry. Also, GPBs exhibit an amorphous nature at elevated temperatures [17]. Compared with concrete bricks, GPBs offer economy and eco-friendliness [18]. Hao Shi et al. investigated the effect of microwave curing on the mechanical strength and microstructure of metakaolin geopolymers with quartz sand, shortening the curing time [19,20]. Mohammed Rihan Maaze and Sandeep Shrivastava recommended a curing temperature between 40 and 60 °C for the efficient curing and good physical and mechanical properties of GPBs. A solar dryer was used as an alternative and compared with conventional electric convective drying [21]; it was shown that solar drying consumes less curing time when compared to conventional electric drying. Various advancements in fiber polymer composites are emerging because of their increased use in a myriad of applications, like polymer in bricks for construction applications [22,23]. Phase change materials are used to store latent heat during phase shifts at a controlled temperature within a certain range [24]. Low-cost, non-corrosive, and chemically stable below 500 °C, paraffin melts with a small volume difference [25]. As a thermal energy storage structure, PCMs like paraffin wax may sustain a greater temperature than the surrounding area for at least five hours following active sunlight hours, which reduces the absolute drying time of the crops [26]. A PCM charges with solar energy for around 8 h during the day and releases the stored energy at night [27]. A PCM achieves its melting point when the ambient temperature rises; as a result of the endothermic process, the PCM absorbs energy, melts, and transitions from a solid to a liquid state, which is a charging process. The PCM solidifies, converting from liquid to solid, which is a discharging process, and releases energy during the exothermic process [28]. When compared to open-sun-dried products, solar-dried products show good quality [29]. With the use of a sun dryer, the product’s drying time was significantly reduced [30,31]. Research studies have reported on many drying systems that use solar energy to improve crop drying efficiency. The primary goal of this research is to minimize absolute drying time and lengthen drying during off-sun hours, as well as to reduce staff engagement and incorrect drying during the winter. According to studies, using solar energy for drying is more cost-effective and compelling as a sustainable drying solution. The current investigation attempts to apply paraffin wax, a phase change substance, in a solar dryer for drying seedless grapes. The drying properties and quality of PCM-dried items were compared and evaluated. The suggested framework provides a feasible method of integrating energy utilization and lowering the carbon footprint in the drying process. The current design of the solar dryer with a PCM is relatively simple and inexpensive. It can be utilized by rural farmers because the materials are widely available and unique in preventing food spoilage and storing agricultural commodities for an extended period of time without a loss of quality. Solar dryers have a wide range of applications, including drying agricultural products such as shredded cabbage, granulated mashed potato, tomato, grapes, apple, coconut, chili, banana, lady finger, and mango pulp; drying marine products such as small fish and prawn; textiles; wood; food processing; paper; and pharmaceuticals. The limitations of traditional open-sun drying can be overcome by selecting an efficient drying system. The requirement for high fuel or power to run a drying system has encouraged sunlight-based drying systems. Here, a solar dryer that works on the principle of natural convection is employed for the process of curing GPBs. Buoyancy-driven air pressure is used to dry a GPB kept inside the chamber. Phase change materials are gaining an advantage in many areas of engineering as storage systems for thermal energy in the form of latent heat between states due to vaporization and condensation. APCM is charged using solar energy during the daytime and discharges the stored energy during the night, and this behavior can be employed in construction sectors for the curing of GPBs. PCMs like paraffin wax as thermal energy storage in solar dryers can maintain a higher temperature than surrounding air for several hours even if there is a sudden reduction in temperature, which decreases the drying time of GPBs.
The current work deals with GPB drying in the open sun, drying in an electric oven, solar drying with a PCM (paraffin wax), and solar drying without a PCM. The time taken for drying using all four methodologies has been compared. Also, mechanical properties like the compressive strength, tensile split strength, and flexural strength of the GPB have been compared for the above-stated four curing methods. Also, this study predicts the effect of PCMs like paraffin wax in solar drying applications on parameters like curing time and mechanical properties, which forms the novelty of this work.

2. Materials and Methods

At Kalasalingam Academy of Research and Education (9.5747° N, 77.6798° E), Tamil Nadu (India), a solar dryer (700 mm × 300 mm × 300 mm) was created and installed. The arrangement containing the drying chamber is supported by an iron stand. It is made of double-layered polycarbonate sheets that have been UV-coated. To focus and absorb the solar energy that is received inside the drying chamber, the polycarbonate sheet is bent in the shape of a parabola. Better thermal insulation is provided by the polycarbonate sheet, which is 60% more effective than glass. To protect the underlying material from damaging radiation, the UV coating is essential. The parabolic polycarbonate sheet is supported and attached by aluminum framing. A Cudappah black stone slab (700 mm × 300 mm) is set at the bottom of the polycarbonate sheet. The transfer of heat energy from PCM across the base of the stand was constrained by the Cudappah stone. The stand includes four nylon wheels at the bottom that may be easily utilized to load and unload GPBs as well as move the drying chamber. At one end of the drying chamber, a solar-powered exhaust fan is permanently installed. The electrical energy needed to run the fan is provided by a solar photovoltaic (PV) panel that is attached to the fan. The drying chamber’s saturated air is removed using the exhaust fan, which then lets fresh air from the atmosphere into the space. Based on temperatures inside the drying chamber, the exhaust fan is automatically turned on. The PCM employed in the study as a thermal storage medium was paraffin wax, which was set on the Cudappah stone and coated with a stainless steel sheet. Natural paraffin wax is in a solid state and has a melting temperature of 58 °C, as shown in Table 1. Also, other properties like density, specific heat, thermal conductivity, and latent heat of fusion are listed below in Table 1. It is an organic PCM that was purchased from Spectrum Reagents and Chemicals Private Ltd., Ernakulum, Kerala, India.
The experimental preparation of GPB and the GPB raw material composition and chemical composition are shown in Figure 1, Table 2 and Table 3. The particle size distribution for fly ash was 45 µm, and the particle size distribution for ground granulated blast furnace slag was 13.8 µm. The loss on ignition for ground granulated blast furnace slag was 0.72%. The loss on ignition for fly ash was 0.70%. The alkaline activator was prepared by mixing sodium hydroxide (>98% purity) with distilled water and a sodium silicate solution. The concentration of sodium hydroxide (SH) was 12 M for all mixtures. The chemical composition of fly ash and ground granulated blast furnace slag is shown above, as they are precursors of the GPBs. Figure 1 shows the ingredients of the GPBs. Sodium hydroxide (NaOH) was mixed with water and kept aside for 1 day. After 24 h, sodium silicate (Na2SiO3) was added to the above mixture in the bowl. After one hour, ground granulated blast furnace slag and fly ash mixed with coarse aggregate and fine aggregate sand were added in appropriate quantities to the bowl containing NaOH and Na2SiO3. M sand is an artificial type of sand formed by crushing large, hard stones, mainly rocks. It is used as a substitute for river sand, mainly for creating concrete or mortar mix. The alkali metal sodium is the primary activator bringing about a binding nature in the GPB polymerization. The SiO2/Al2O3 ratio plays a vital role in forming the microstructure. The total mixture is shown in Figure 2. Figure 2 shows the status after all the ingredients of GPBs are mixed. This is the raw material composition and the process for making GPBs. The prepared brick specimen was kept in an electric oven and a solar dryer, as shown in Figure 3 and Figure 4, respectively. The technique captures solar energy and converts it into heat energy inside the drying chamber. Convection and radiation are used to transfer energy. Convection is the major route of heat transport, while radiation is the passive mode. The 6 mm thick double-layered UV-coated polycarbonate sheet shown in Figure 4 allowed solar energy to travel through the drying chamber but prevented it from leaving. The black Cudappah stone (Figure 4) was placed above the iron stand, which served as the room’s basement, and the sides and edges of the chamber were densely packed. The paraffin wax (PCM in the study) was placed on the Cudappah stone in an insulated stainless steel tray. Throughout the drying process, the charging and discharging phases of the PCM occurred concurrently. An accurate balancing machine was used to determine the mass of the dried items. The trials were carried out in the chamber with a PCM (400 g of paraffin wax) and without a PCM. The PCM paraffin wax was in a solid state and underwent a phase change into liquid during the curing of GPBs. When there was a reduction in temperature, naturally, PCM reversed its phase to a solid nature. Of course, when there were oscillations in the surrounding ambient, the phase change material changed by itself to maintain a uniform curing nature inside the solar dryer. For the measurement of mechanical properties, the specimens were of standard geometry: a cubic (10 cm × 10 cm × 10 cm) sample for the compressive strength test, a cylindrical (L = 20 cm and D = 10 cm) sample for the tensile split strength test, and a rectangular (50 cm × 10 cm × 10 cm) prismatic sample for the flexural strength test, as shown in Figure 5 and Figure 6. The number of samples for each test was two. For all four methods of curing, the following standards were used: ASTM E9-19 Standard Test Method of Compression Testing of Metallic Materials at Room Temperature ASTM C496-96, Standard Test Method for Splitting Tensile Strength of Cylindrical Concrete Specimen ASTM D790-17, and Standard Test Methods for Flexural Properties of Unreinforced and Reinforced Plastics and Electrical Insulating Materials.

2.1. Electric Oven Drying

The LTMHOS-6 electric oven model with 3500 Watts with 220/230 V AC 50 Hz was used for curing moisture content. The GPB was kept in the oven, and it took 24 h to cure the moisture content. Here, we used the simple rule of weighing for the GPB to assess the moisture content. In the initial stages of curing the moisture content, the GPB showed variations in weight, and when the weight stabilized, it indicated that the moisture content had been cured. This same rule was used for all the four mentioned curing methods. GPBs were kept at ambient room temperature for 28 days for further curing in order to develop sufficient strength. After 28 days, bricks were taken for a compression strength test, a tensile split strength test, and a flexural strength test, as shown in Figure 5 and Figure 6. We used a cubic sample for measuring compression strength, a cylindrical sample for measuring tensile split strength, and a rectangular prismatic sample for measuring flexural strength to ensure proper clamping conditions so that property values would not be affected.

2.2. Solar Drying without a PCM

The curing of GPB moisture content took 24 h.

2.3. Solar Drying with a PCM

The curing of GPB moisture content took 22 h.

2.4. Open-Sun Drying

The curing of GPB moisture content took 24 h.

3. Results

This section interprets the results that have been obtained in this research study. The average values of the compressive strength, tensile split strength, and flexural strength test results are shown in Table 4. The following has been inferred from the test results: Electric oven drying is more uniform in nature when compared to solar drying. The electric oven drying temperature was around 65 °C throughout the curing process. Solar drying operates at around 60 °C, but fluctuations depend on the outer ambient. It is evident from Figure 7 that solar drying with a PCM requires 2 h less curing time when compared to all other methods.
As per modified guidelines for geopolymer concrete mix design using Indian standards, the target compressive strength is around 30 MPa [2,3], but the experimental result obtained was 38.50 MPa in solar drying with a PCM, as shown in Figure 8 and Table 4. For geopolymers, tensile split strength of 4.9 MPa was obtained in solar drying with a PCM, as shown in Figure 9 and Table 4. A flexural strength of 6.2 MPa was obtained in solar drying with a PCM, as shown in Figure 10 and Table 4.
Experimentally, it is evident from Table 4 that solar-dried bricks with a PCM and without a PCM exhibit 7.84% and 1.7% higher compressive strength, 34.2% and 12.3% higher tensile split strength, and 25.25% and 15.15% higher flexural strength when compared to electric-oven-dried bricks, respectively. Also, solar drying with a PCM shows 6.1% higher compressive strength, 19.5% higher tensile split strength, and 8.1% higher flexural strength when compared to solar drying without a PCM. At the same time, open-sun drying shows 1.8%, 8%, and 9.8% higher compressive strength;14.3%, 36.5%, and 53.4% higher tensile split strength; and 8.1%, 17.5%, 35.35% higher flexural strength properties when compared to solar drying with a PCM, solar drying without a PCM, and electrical drying, respectively.
In this work, as solar energy is used, which is free from fossil fuels for drying, the economic condition is also met, and there is a safe climatic atmosphere, so the sustainability goals are met, as shown in Table 5 below.

4. Discussion

Solar drying with a PCM consumes 2 h less curing time when compared to all other methods, which is in accordance with [21]. This is due to the effect of the PCM which captures more heat flux in the form of heat storage, giving rise to a hotter and more uniform atmosphereinside the solar dryer when compared to the solar dryer without a PCM. Experimentally, it is evident from Table 4 that solar-dried bricks with a PCM and without a PCM exhibit higher compressive strength, tensile split strength, and flexural strength when compared to electric-oven-dried bricks. This could be due to the effect of the ambient, which is hotter when compared to that for electric drying, which occurs inside a room. This is also evident from [21], which predicts that solar drying is more efficient and economical when compared to electric drying. Also, solar drying with a PCM shows higher compressive strength, tensile split strength, and flexural strength when compared to solar drying without a PCM, which is due to the higher heat storage capacity of the PCM and the fact that changes in the atmospheric temperature are well absorbed by the PCM, which gives rise to rough, tough, and dry conditions in the brick. Open-sun drying shows higher compressive strength, tensile split strength, and flexural strength properties when compared to all other methods due to the brick surfaces being exposed to very high sun temperatures in the summer. Also, waste management of products like fly ash from power plants is sustained by converting them into useful GPBs, which have proven properties [2], as shown in Figure 8, Figure 9 and Figure 10.
As solar drying is economical and shows better mechanical properties when compared to electrical drying, this study suggests that a solar dryer is a potential candidate for curing GPBs for construction applications. Also, a solar dryer is eco-friendly when compared to an electrical dryer, which satisfies the goals of SDGs 7, 8, and 13. A simple economic analysis for 100 bricks for four modes of drying is shown below in Figure 11. Electrical curing requires 3500 Watts of power consumption, which results in the usage of 0.4375 units of power supply. One unit in India costs INR8, and therefore, the cost for 0.4375 units is INR3.5, whereas solar drying does not consume any electric power for curing. Assuming 100 GPBs are dried per day, the total cost of electric curing would be 30 × 100 × 3.5 = INR10,500 per month, whereas solar drying does not need any electric power. Considering the cost of the PCM paraffin wax is INR500, the construction cost for the solar dryer prototype is INR4000 without a PCM and INR4500 with a PCM. A solar dryer requires only an initial cost and no running cost. Above all, electrical energy is called high-grade energy because of its availability when compared to thermal energy, which has lesser availability when compared to electrical energy. Converting electrical energy into thermal energy in electric oven curing to simply remove moisture content is not recommended from an energy point of view. So, on a large-scale basis like in construction industries, the curing of bricks by solar drying would be a more economical method when compared to electric oven drying.

5. Conclusions

➢
GPBs constructed from fly ash waste and other ingredients undergo full curing in all four methods.
➢
A solar dryer with a PCM consumes 2 h less curing time when compared to all other methods [21].
➢
As per modified guidelines for geopolymer concrete mix design using Indian standards, the target compressive strength is around 30 MPa [2,3], but the experimental result obtained was 38.50 MPa for solar-dried brick with a PCM.
➢
Solar-dried bricks with a PCM and without a PCM exhibit 7.84% and 1.7% higher compressive strength, 34.2% and 12.3% higher tensile split strength, and 25.25% and 15.15% higher flexural strength when compared to electric-oven-dried bricks, respectively.
➢
Solar drying with a PCM shows 6.1% higher compressive strength, 19.5% higher tensile split strength, and 8.1% higher flexural strength when compared to solar drying without a PCM.
➢
Open-sun drying shows 1.8%, 8%, and 9.8% higher compressive strength;14.3%, 36.5%, and 53.4% higher tensile split strength; and 8.1%, 17.5%, and 35.35% higher flexural strength properties when compared to solar drying with a PCM, solar drying without a PCM, and electrical drying, respectively.
➢
Open-sun drying may cause the degradation of materials in GPBs, which may lead to extremely dry conditions inside GPBs that may not be suitable from an application point of view.
➢
The use of PCMs like paraffin wax in solar dryers has a pronounced effect on the curing time and mechanical properties of GPBs.
➢
When sustainability goals are concerned, solar energy is a better performer when compared to electrical energy. From this research work, we conclude that by using solar energy in drying applications, we can save high-grade electrical energy from an energy and economic point of view.
➢
GPBs are finding applications in construction sectors as their properties are in accordance with concrete design standards.
➢
Newer PCMs (organic or inorganic) may be tested inside a solar dryer for the curing of GPBs, which forms the scope for future work. Along with that, the way in which PCMs influence the mechanical properties of GPBs can be studied. Also, a thermal degradation study of PCMs is suggested as a scope for future studies aiming to understand the entropy changes occurring inside PCMs so that a correlation between degradation and the life of PCMs for solar dryer applications can be established.

Author Contributions

Conceptualization, J.A.K. and S.M.; methodology, J.A.K. and S.M.; software, R.S.P.; validation, J.A.K. and S.M.; formal analysis, R.V.I.S. and R.S.P.; investigation, J.A.K.; resources, J.A.K.; data curation, J.A.K.; writing original draft preparation, S.M.; writing—review and editing, R.S.P.; visualization, R.S. and M.R.; supervision, S.M.; project administration, R.S.; funding acquisition, M.R. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by Navajo Technical University, Crown Point, New Mexico, USA.

Data Availability Statement

Any data related to this research study can be obtained from the corresponding authors upon request.

Acknowledgments

The authors are grateful for the support given by “Navajo Technical University, New Mexico, USA” for conducting the research and publication work.

Conflicts of Interest

The authors declare no conflicts of interest.

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Processes 12 00028 g001
Figure 1. Mixture of ingredients of GPB.
Figure 1. Mixture of ingredients of GPB.
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Figure 2. Final mixture after mixing all ingredients.
Figure 2. Final mixture after mixing all ingredients.
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Figure 3. GPB kept in electric oven.
Figure 3. GPB kept in electric oven.
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Figure 4. GPB kept in solar dryer.
Figure 4. GPB kept in solar dryer.
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Figure 5. GPB in compression and tension split test.
Figure 5. GPB in compression and tension split test.
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Figure 6. GPB in flexural test.
Figure 6. GPB in flexural test.
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Figure 7. GPB curing time comparison of all four methods.
Figure 7. GPB curing time comparison of all four methods.
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Figure 8. GPB compressive strength comparison of all four methods of curing.
Figure 8. GPB compressive strength comparison of all four methods of curing.
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Figure 9. GPB tensile split strength comparison of all four methods of curing.
Figure 9. GPB tensile split strength comparison of all four methods of curing.
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Figure 10. GPB flexural strength comparison of all four methods of curing.
Figure 10. GPB flexural strength comparison of all four methods of curing.
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Figure 11. Economicanalysis for 4 drying modes.
Figure 11. Economicanalysis for 4 drying modes.
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Table 1. Properties of paraffin wax.
Table 1. Properties of paraffin wax.
PCMMelting Temperature (°C)Density (kg/m3)Specific Heat (J/Kgk)Thermal Conductivity (W/mK)Latent Heat of Fusion (kJ/kg)
SolidLiquidSolidLiquidSolidLiquid
Paraffin wax58910810200021000.2280.25204
Table 2. Raw material composition of GPB.
Table 2. Raw material composition of GPB.
MaterialWeight in kg/m3
Fly ash385
GGBS—ground granulated blast furnace slag165
M sand579.64
Coarse aggregate 20 mm864.12
AAS—alkaline activated solution335.5
SSS—sodium silicate solution Na2SiO3239.64
NaOH95.86
NaOH molarity12
Alkaline/binder ratio0.61
Table 3. Chemical composition of GPB.
Table 3. Chemical composition of GPB.
PrecursorSiO2Al2O3 CaOMgOK2OFe2O3TiO2Na2OSO3
Fly Ash53263971.560.850.70.55
Ground granulated blast furnace slag36133770.550.40.70.21.75
Table 4. Mechanical properties (average values of two specimens) and curing time of GPBs obtained using 4 curing methods.
Table 4. Mechanical properties (average values of two specimens) and curing time of GPBs obtained using 4 curing methods.
Drying MethodCuring Time (Hours)Compressive Strength (MPa)Tensile Split Strength (MPa)Flexural Strength (MPa)
Electrical drying2435.703.654.95
Solar drying with a PCM2238.504.906.20
Solar drying without a PCM2436.304.105.70
Open-sun drying2439.205.606.70
Table 5. Sustainable Development Goals (SDGs).
Table 5. Sustainable Development Goals (SDGs).
Sustainable Development GoalDescription
SDG 7Clean and affordable energy—usage of solar energy
SDG 8Economic growth—cheaper than electric energy
SDG 13Climate action and its impact—free from fossil fuels and emissions
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MDPI and ACS Style

Ashok Kumar, J.; Muthuvel, S.; Issac Selvaraj, R.V.; Ramoni, M.; Shanmugam, R.; Pandian, R.S. Mechanical Property Comparison of Geopolymer Brick Dried by Electrical and Passive Solar Devices with Phase Change Material (Paraffin Wax). Processes 2024, 12, 28. https://doi.org/10.3390/pr12010028

AMA Style

Ashok Kumar J, Muthuvel S, Issac Selvaraj RV, Ramoni M, Shanmugam R, Pandian RS. Mechanical Property Comparison of Geopolymer Brick Dried by Electrical and Passive Solar Devices with Phase Change Material (Paraffin Wax). Processes. 2024; 12(1):28. https://doi.org/10.3390/pr12010028

Chicago/Turabian Style

Ashok Kumar, Jeevan, Sattanathan Muthuvel, Rajay Vedaraj Issac Selvaraj, Monsuru Ramoni, Ragavanantham Shanmugam, and Ranjitharamasamy Sudhakara Pandian. 2024. "Mechanical Property Comparison of Geopolymer Brick Dried by Electrical and Passive Solar Devices with Phase Change Material (Paraffin Wax)" Processes 12, no. 1: 28. https://doi.org/10.3390/pr12010028

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