1. Introduction
The global resource crisis is intensifying and irreplaceable resources are being depleted. Solar energy is becoming increasingly popular as a renewable resource. Since roads cover a significant part of the earth's surface, they are an ideal place to collect and use solar energy. Solar pavements and asphalt pavements are two of the most common uses of solar energy. Solar conversion is one of the most adaptive strategies to meet future energy needs. Phase change materials (PCMs) use their latent heat to allow the bitumen to absorb or release large amounts of heat even when the surrounding conditions remain constant. The development of solar pavements and asphalt pavements illustrates the fundamentals of solar energy production and heat utilization. History of materials used in asphalt pavements and future predictions for solar pavements.
The advantages of solar energy, such as cleanliness, environmental protection, and high energy density, have won the favour of most experts with the continuous development of technology. As a renewable energy source, solar energy is a key link in solving problems such as pollution caused by traditional fossil fuels and the depletion of natural resources. On the one hand, solar energy collected the temperature from asphalt roads with generate outlet electricity can be used to power buildings or other uses. It reduces the use of traditional energy sources and contributes greatly to solving the energy crisis. Therefore, the use of renewable green energy can help reduce the urban heat island effect by reducing carbon dioxide emissions and other forms of pollution. Change can happen in public institutions simply by considering the close connection between the 17 Sustainable Development Goals (SDGs).
1.1. Transformations to Achieve the Sustainable Development Goals (SDG)
Both the Sustainable Development Goals (SDGs) and the Paris Agreement on climate change require major changes in all countries. To achieve this change, governments, civil society, academia and business need to work together and act in concert. Based on previous work by The World in 2050 initiative, six (6) SDG transitions were introduced as modular elements to achieve the SDGs: (1) education, gender and inequality; (2) health, welfare and demographics; (3) Energy decarbonization and sustainable industries; (4) sustainable food, land, water and oceans; (5) sustainable cities and communities; (6) Digital revolution for sustainable development [
1]. Each transformation identifies priority investments and regulatory problems, which necessitates action on the part of well-defined government agencies working in conjunction with business and civil society [
1].
The development of Artificial Intelligence (AI) is having an impact on an increasing number of business sectors. It is projected that AI will have both short-term and long-term implications on a variety of sectors, including global productivity, equality and inclusion, environmental outcomes, and others [
2]. There have been reports of both good and negative possible repercussions that artificial intelligence may have on sustainable development. Presentation and discussion of the potential consequences of how artificial intelligence can either help or harmed attempts to meet the 17 goals and 169 targets defined in the 2030 Agenda for Sustainable Development. The aforementioned approaches were used to define the relationships, and these methodologies can be summed up as a consensus-based expert elicitation procedure that was meant to map the interlinkages between the Sustainable Development Goals [
3].
In order to achieve SDGs 7 (Affordable and Clean Energy) and 11 (Quality Education), Artificial Intelligence (AI) can enable smart and low-carbon cities with a wide range of interconnected technology, including electrical autonomous vehicles and smart appliances (Sustainable Cities and Communities). By allowing smart grids to partially match energy usage to periods when the sun and wind are shining, AI can also aid in the integration of variable renewables [
4].
The last group of SDGs, i.e., the one related to Environment, is analyzed three goals to do with climate change, underwater life, and life on land (SDGs 13, 14, and 15). One benefit of artificial intelligence could be the ability to look at large, connected databases to find ways to work together to protect the environment [
5]. Taking SDG 13 on climate action into account, there is evidence that progress in AI will make it easier to understand climate change and model its possible effects. Furthermore, AI will make it possible for low-carbon energy systems with a lot of renewable energy and energy efficiency, all of which are needed to fight climate change.
1.2. Solar Paver Technologies for the Advancement of Environmental Sustainability in Malaysia
The previous researcher’s study was conducted in Malaysia to investigate the challenges and potentials of implementing solar farm technology. The report is based on the opinions of those with an interest in the Malaysian construction industry. Broadly speaking, solar installation technology is a solar panel that can be placed on existing roads like concrete pavers, generating clean energy from the sun's exposed surface. If solar cell technology works, it could power road systems such as streetlights and traffic lights without relying on a centralized national power system. In addition, solar pavers can be used on roads where both cars and people travel. This technique is still very new in the construction industry.
Pavements are essential to the supply of roads and walking paths. There are different kinds of pavements based on the materials they are made of and how they are put together. As an example, there are three types of asphalt pavements: hot-mix, stone-mastic, and cold-mix. Other common types of pavements are made of concrete or a mixture of materials (with or without steel reinforcement). It is thought that building and maintaining pavements are responsible for 10% of the carbon emissions made by the transportation sector [
6]. This shows how important pavements are for developing in a way that is good for the environment and making transportation better. There are environmental effects and emissions that come from getting resources, processing them, building pavements, keeping them in good shape, and getting rid of them when they are done.
Solar Paver technology is a panel of photovoltaic cells that can be used as concrete pavers on existing road networks to make renewable energy by taking advantage of sunny, open surfaces. Solar pavers can be used on roads for both cars and people. Even though this technology is new, some of the first research has been done on how it can be used and adapted. The study came to the conclusion that solar pavers could be used as an alternative way to use land by generating off-grid power for road infrastructure like streetlights and reducing carbon emissions from generators that use fossil fuels [
7]. Solar pavers, on the other hand, were not as useful as rooftop solar panels because they did not produce as much power and did not work as well in bad weather. Even though this preliminary research gives us important information, the potential of the technology makes it necessary to learn more about how it will be made and how people will react to it. To analyses and use solar paver technology correctly, it is necessary to know more about the structure, business models, road design elements, and stakeholder operational strategies of the construction industry.
1.3. Pavement Energy Harvesting Technologies
With rising global energy demand, scientists are constantly looking for novel ways to gather power. Pavement engineers can make use of energy from the sun and car weight. Semi-transparent solar cells (photovoltaic highways) enable these systems to convert sunlight into electricity, while solar thermal systems can convert solar energy into heat. Heat pipes, thermoelectric generators, and heat-transfer fluids (like water) pushed through a medium can all take advantage of the temperature gradient of the pavement (asphalt solar collectors, porous layer, or air conduits). Use of piezoelectric materials allows the vehicle's weight to be transformed into an electric charge.
1.3.1. Asphalt Solar Collector
The asphalt's surface temperature can rise to around 70°C when exposed to sunlight, speeding up the rutting (permanent deformation of pavements) and oxidation of asphalt (causing changes in viscosity, component separation, embrittlement, and loss of cohesion) [
8]. Solar collectors made from asphalt are a practical means of lowering pavement temperatures and making the most of available solar energy. They are made up of pipes that are surgically implanted in asphalt and can extract heat energy via a fluid (i.e., water). To compensate for the fluid's lower temperature, heat is transmitted from the asphalt. Therefore, a cool fluid is introduced while a hot fluid is removed from the system.
The energy balance of an asphalt solar collector includes the following materials and environments: i) asphalt pavement, ii) pipes, iii) atmosphere, and iv) fluids flowing through the pipe network [
9]. In terms of heat exchange mechanisms, the energy is initially balanced across the entire pavement-atmosphere contact in terms of heat exchange mechanisms. The asphalt absorbs heat from the sun, transfers some of that heat to the surrounding air by convection and emits some of its own heat into space. Because of the change in temperature brought on by the heat flow, the road's surface heats up before its interior, a process known as conduction. First, conduction occurs at the asphalt-pipe junction, and then convection takes place at the asphalt-fluid contact.
1.3.2. Air-Powered Energy Harvesting Pavement
Solar collectors need a thermal fluid to extract energy from the asphalt. Pipe leaks can cause road surface deterioration. However, the presence of cracks in the pipes can endanger the entire system, release fluids and risk damage to the coating to imbed into the pavement a series of conduits, using the air as heat fluid [
10]. Reported by the other researchers, air conduits are connected to upward and downward chimneys, and due to the temperature difference between the environment and the asphalt, a pressure difference is created between the end of the chimney and the entrance to the pavement. This results in a steady breeze that can reduce the asphalt temperature by up to 10 percent in the summer and raise it by the same amount in the winter [
11]. The system's viability was confirmed by early results from a laboratory prototype, which highlighted the following:
- i.
When the pipes are laid out in a single row beneath the pavement wearing course, the air velocity is maximised and the surface temperature is reduced.
- i.
ii. Concrete corrugations can be used instead of the pipes, but they reduce the amount of energy that can be collected.
According to the literature research, the available studies paid scant attention to the effectiveness of pipe arrangement in heat dynamics and PSC performance. As a result, the current work includes an experimental and numerical analysis to analyse this crucial technical specification on the thermal performance of the built PSC based on the temperature measured in Malaysia. An experimental test setup was conceived and built to achieve this purpose. In addition, a numerical model was created and verified using the experimental data to optimise the embedded pipe arrangement using different types of piping material, numerous configurations were constructed and analysed by the validated numerical model to discover the best pipe layout.
With a purpose to comprehend intention-behaviour gap about acceptance of solar energy road pavement, the research gap arises from the literature review based on previous researcher. The comparison of pipe material, pipe depth, pipe spacing, pipe arrangement, output temperature, and flow rate for maximum thermal energy extraction were not clearly stated. Thus, in this paper, the optimum thermal energy harvesting road pavement using sustainable conductive material either stainless steel, copper or aluminium in Malaysia will be present in the outcome with the supporting from piping inserted into asphalt pavement.
4. Conclusions
The pipe material tested in this research are copper, stainless steel, and aluminium because of these pipes is categorized as sustainable conductive piping. The pipes are inserted with water stagnant flow in the various depth which are 30mm, 40mm, 50mm, 60mm, 70mm, and 80mm from the surface pavement. The pipe spacing between center-to-center were also tested at various spacing which are 70mm, 80mm, 100mm, 130mm, and 150mm. In conclusion, the pipe material chosen is copper, pipe depth at 50mm from surface pavement with the pipe arrangement is serpentine, pipe spacing is 80mm and water flow rate is 1.562m/s. The velocity flow rate from optimized thermal energy extraction of water reticulation landed residential houses was 1.562m/s by the outlet temperature was 327.36K (54.21oC) for solar pavement types was serpentine copper pipe inserted at the middle of the research prototype depth. The velocity is depending on the water flow rate set at inlet pipe as 0.0409 m/s for peak flow water demand.
Figure 1.
Process of flow optimization of thermal energy harvesting.
Figure 1.
Process of flow optimization of thermal energy harvesting.
Figure 2.
Serpentine pipe and the piping material replaced by stainless steel, copper, and aluminium.
Figure 2.
Serpentine pipe and the piping material replaced by stainless steel, copper, and aluminium.
Figure 3.
Serpentine pipe and the piping material replaced by stainless steel, copper, and aluminium.
Figure 3.
Serpentine pipe and the piping material replaced by stainless steel, copper, and aluminium.
Figure 4.
Serpentine pipe.
Figure 4.
Serpentine pipe.
Figure 5.
Meshing model for inserted serpentine piping.
Figure 5.
Meshing model for inserted serpentine piping.
Figure 7.
Meshing model for inserted series piping.
Figure 7.
Meshing model for inserted series piping.
Figure 13.
Various serpentine copper piping depth from the pavement surface: (a) 30mm, (b) 40mm, (c) 50mm, (d) 60mm, (e) 70mm, and (f) 80mm.
Figure 13.
Various serpentine copper piping depth from the pavement surface: (a) 30mm, (b) 40mm, (c) 50mm, (d) 60mm, (e) 70mm, and (f) 80mm.
Figure 14.
Various serpentine stainless steel piping depth from the pavement surface: (a) 30mm, (b) 40mm, (c) 50mm, (d) 60mm, (e) 70mm, and (f) 80mm.
Figure 14.
Various serpentine stainless steel piping depth from the pavement surface: (a) 30mm, (b) 40mm, (c) 50mm, (d) 60mm, (e) 70mm, and (f) 80mm.
Figure 15.
Various serpentine aluminium piping depth from the pavement surface: (a) 30mm, (b) 40mm, (c) 50mm, (d) 60mm, (e) 70mm, and (f) 80mm.
Figure 15.
Various serpentine aluminium piping depth from the pavement surface: (a) 30mm, (b) 40mm, (c) 50mm, (d) 60mm, (e) 70mm, and (f) 80mm.
Figure 16.
Serpentine pipe temperature outlet for various materials versus different piping depths.
Figure 16.
Serpentine pipe temperature outlet for various materials versus different piping depths.
Figure 17.
Serpentine pipe heat efficiency versus piping depth.
Figure 17.
Serpentine pipe heat efficiency versus piping depth.
Figure 18.
Various series copper piping depth from the pavement surface: (a) 30mm, (b) 40mm, (c) 50mm, (d) 60mm, (e) 70mm, and (f) 80mm.
Figure 18.
Various series copper piping depth from the pavement surface: (a) 30mm, (b) 40mm, (c) 50mm, (d) 60mm, (e) 70mm, and (f) 80mm.
Figure 19.
Various series stainless steel piping depth from the pavement surface: (a) 30mm, (b) 40mm, (c) 50mm, (d) 60mm, (e) 70mm, and (f) 80mm.
Figure 19.
Various series stainless steel piping depth from the pavement surface: (a) 30mm, (b) 40mm, (c) 50mm, (d) 60mm, (e) 70mm, and (f) 80mm.
Figure 20.
Various series aluminium piping depth from the pavement surface: (a) 30mm, (b) 40mm, (c) 50mm, (d) 60mm, (e) 70mm, and (f) 80mm.
Figure 20.
Various series aluminium piping depth from the pavement surface: (a) 30mm, (b) 40mm, (c) 50mm, (d) 60mm, (e) 70mm, and (f) 80mm.
Figure 21.
Series pipe temperature outlet for various materials versus different piping depths.
Figure 21.
Series pipe temperature outlet for various materials versus different piping depths.
Figure 22.
Temperature outlet versus piping spacing for serpentine piping.
Figure 22.
Temperature outlet versus piping spacing for serpentine piping.
Figure 23.
The comparison of temperature outlet for copper pipe.
Figure 23.
The comparison of temperature outlet for copper pipe.
Figure 24.
The comparison of temperature outlet for stainless steel pipe.
Figure 24.
The comparison of temperature outlet for stainless steel pipe.
Figure 25.
The comparison of temperature outlet for aluminium pipe.
Figure 25.
The comparison of temperature outlet for aluminium pipe.
Figure 26.
The comparison maximum values of temperature outlet.
Figure 26.
The comparison maximum values of temperature outlet.
Figure 27.
Uniform flow rate.
Figure 27.
Uniform flow rate.
Table 1.
Inlet Temperature for all piping material.
Table 1.
Inlet Temperature for all piping material.
Piping Material |
Inlet Temperature, K (oC) |
Copper |
314.15 (41.00) |
Stainless Steel |
317.35 (44.20) |
Aluminium |
42.90 (316.05) |
Table 2.
Thermal properties of asphalt concrete [
12].
Table 2.
Thermal properties of asphalt concrete [
12].
Bulk Density (kg/m3) |
Thermal Conductivity (W/m.K) |
Specific Heat Capacity (J/kg/K) |
2297.17 |
2.19 |
782.04 |
Table 3.
Velocity of domestic flow [
13].
Table 3.
Velocity of domestic flow [
13].
Types of Flow |
Velocity (m/s) |
Normal flow |
0.0205 |
Peak flow |
0.0409 |
Table 4.
Outlet temperature against piping depth.
Table 4.
Outlet temperature against piping depth.
Table 5.
Outlet temperature against piping depth.
Table 5.
Outlet temperature against piping depth.
Table 6.
Outlet temperature against piping depth.
Table 6.
Outlet temperature against piping depth.
Table 7.
Various materials with outlet temperature for different piping depths.
Table 7.
Various materials with outlet temperature for different piping depths.
Table 8.
Heat efficiency for various materials at different piping depths.
Table 8.
Heat efficiency for various materials at different piping depths.
Table 9.
Outlet temperature against piping depth.
Table 9.
Outlet temperature against piping depth.
Table 10.
Temperature outlet for difference piping spacing.
Table 10.
Temperature outlet for difference piping spacing.
Table 11.
Typical pipe velocities.
Table 11.
Typical pipe velocities.