1. Introduction
Global warming represents the most significant threat to human societies and global ecosystems in the coming years [
1]. Excessive energy consumption is a primary contributor to global warming [
2]. Since cities account for approximately 78% of global energy use and 60% of global greenhouse gas (GHG) emissions, they represent the primary battleground for reducing energy consumption and carbon emissions [
3]. The mitigation of excessive urban carbon emissions requires a sustained effort to develop renewable energy sources. Solar energy is an efficient and renewable energy source that can be effectively integrated into buildings and widely adopted in urban areas [
4,
5]. The PVSITES initiative in Europe aims to promote the deployment of solar energy in urban areas by accurately quantifying the available solar energy potential in cities [
6]. Similarly, China has committed to peak its carbon emissions by 2030 or earlier to achieve energy conservation and emission reduction, with plans to increase non-fossil energy usage to 20%, with photovoltaic energy being a key focus [
7,
8,
9,
10]. As such, enhancing the utilization of solar energy resources is crucial for Chinese urban areas to achieve low-carbon advancement [
11].
The extensive adoption of solar energy in industrial buildings located within urban areas offers tremendous potential and numerous advantages [
12,
13,
14]. Industrial buildings generally have substantial underutilized roofs and facades, providing ideal locations for solar energy development. The flat external surfaces of these structures are well-suited for installing PV panels. At the same time, as industrial buildings have a relatively high energy consumption level, they can maximize the consumption of PV generation, which helps to reduce the losses incurred by surplus electricity going online and mitigate the impact on the national grid [
15]. Consequently, research aimed at harnessing solar energy resources within industrial blocks in urban areas represents a promising approach to achieving the objective of urban carbon reduction.
A crucial prerequisite for implementing solar energy in urban areas is a comprehensive and accurate assessment of its potential [
16]. The continuous advancement of technology, specialized software such as geographic information systems (GISs), neural networks, and Grasshopper have been utilized to evaluate solar energy potential in various scenarios and scales with high calculation accuracy [
17,
18]. In a solar energy potential assessment conducted by Yaning An et al. [
19] for the Shenzhen region of China, GIS and Grasshopper were employed to compute the solar radiation values of roofs and vertical facades in four representative areas of Shenzhen. The findings revealed that the buildings’ total PV generation potential could exceed 88% of the local electricity demand. Furthermore, in a solar potential assessment study using the sun solar radiation model, the solar potential of the area was evaluated in conjunction with urban GIS data from the city of Baldejov in eastern Slovakia, and the study results confirmed that the PV potential of the region could cover two-thirds of the electricity consumption [
20]. This demonstrates the impressive potential for solar energy development in cities, which can fulfill most energy requirements, and therefore warrants further in-depth research.
The urban form is crucial in determining the potential for solar energy development in urban areas [
21]. Highly populated cities may suffer from mutual shading of buildings, reducing the capacity to harness solar energy. The typology of cities, including layout, height, orientation, and other indicators [
22] of buildings within a block, can affect the potential for solar energy development. Ming Lu et al. [
23] analyzed the impact of high-rise building layout forms on solar energy potential. They found that plot ratio, building density, and building height are the leading morphological indicators affecting solar energy potential. Research on solar potential in eight types of urban blocks showed that the U-shape has the highest average annual PV utilization potential of 143 kWh/m
2 and should be prioritized for PV panel placement [
24]. A prediction study of solar radiation potential by K.H. Poon et al. [
25] concluded that the average height of buildings within a block and height difference indicators could significantly impact solar potential. Furthermore, indicators describing the intensity of urban construction, such as building density and volume ratio, can reflect the degree of mutual shading and the relationship between buildings, and are closely associated with solar potential [
26,
27]. These indicators are widely used to assess solar potential in various urban blocks and show differences in different blocks and cities. For instance, a study of solar potential in residential blocks in Wuhan, China found that an increase in floor area ratio leads to an increase in solar potential [
28]. In contrast, another study of solar potential in a mixed neighborhood in Adelaide revealed that floor area ratio decreases solar potential [
29]. Overall, the urban form significantly influences solar potential, and further analytical studies are necessary to examine the relationship between urban form indicators and solar potential in different types and regions of urban blocks.
Physical properties of PV materials directly affect solar power generation [
30,
31]. Silicon-based crystalline PV technology is the most prevalent technology currently available, mainly due to silicon materials’ ready availability and environmental friendliness [
32]. Other types of PV include thin-film technologies such as amorphous silicon, cadmium telluride (CdTe), and copper–indium–gallium–selenide (CIGS), as well as emerging technologies like organic photovoltaic (OPV) [
33], perovskite photovoltaic (PPV), and dye-sensitized solar cells (DSSCs) [
34]. In practical PV applications, environmental factors such as sunlight intensity [
35,
36], temperature [
37], dust [
38], and wind speed [
39] can affect power generation efficiency [
40]. Dust adhering to PV panels affected PV generation by hindering the interaction between the panels and the incident light [
41,
42]. Some studies [
43] compared the effect of dust on the light transmittance of samples of PV panels with different placements under 120 days of uncleaned conditions. It was found that the light transmission decreased by 17.48%, 7.94%, and 14.13% for samples placed horizontally, vertically, and tilted, respectively. In addition, the operating temperature of the PV module was likewise a significant factor affecting the conversion of solar energy into electricity. Usually, manufacturers of PV devices stated the value of the power temperature coefficient for PV modules on the labels of PV products, which usually ranged from 0.3 to 0.5%/°C. This meant that for every 10 °C increase in temperature, the PV module temperature would be reduced to 0.5%/°C, which was the same as that of the PV module. That meant that for every 10 °C increase in temperature, the efficiency of PV modules decreased by 3 to 5% [
44]. Moreover, the variability in materials among different PV panels leads to their varying responses to environmental factors [
45,
46]. A review study conducted by Martin A. Green et al. [
47] on relevant articles up to 2020 summarized the performance of various PV materials under different environmental conditions. The distinct characteristics of each PV module type make them suitable for different scenarios of solar power generation, thereby emphasizing the importance of considering the kind of PV panels in researching the potential of solar energy resource exploitation.
Significant conversion efficiency and cost differences exist among various types of PV materials. Furthermore, different PV materials exhibit distinct power generation patterns under varying building configurations and solar radiation conditions. Consequently, when integrating PV panels with buildings, selecting appropriate PV panels is crucial to align with the distribution properties of solar radiation. This selection process is essential to maximize solar resource exploitation and increase user revenue.
However, previous studies have primarily focused on evaluating the potential for solar energy resource exploitation based on either block typology or PV material alone, whereas few studies have combined both block typology and PV material to determine the installation rate and power generation issues that arise when different PV materials are applied to different types of blocks or building surfaces. Therefore, to guide the design and planning of urban blocks for sustainable cities and the precise installation of PV equipment, it is crucial to summarize and explore the variations in power generation by different PV materials in various types of blocks.
This study, therefore, examines the impact of industrial block typology and PV material efficiency on the utilization of solar resources and provides recommendations for selecting appropriate PV materials based on different industrial block types. The ultimate objective is to offer guidance for designing industrial blocks and selecting PV materials to maximize solar resource utilization. To achieve this objective, the study would focus on the following aspects:
- (1)
What are the differences between the distribution of solar radiation and the radiation potential of building facades in different layouts of industrial blocks?
- (2)
What are the PV installation rates on the exterior surfaces of industrial blocks with different layouts when different materials are selected for PV equipment?
- (3)
How will the PV equipment match different layouts of industrial blocks to obtain the best exploitation of solar resources?
4. Conclusions
By analyzing the impact of urban block typology and PV material performance on solar energy utilization, this study provides important insights for planning and designing urban industrial blocks and installing PV panels in different types of blocks. The research findings of this study have significant implications for adopting sustainable energy practices and reducing carbon emissions in urban areas. Three main findings were established as follows:
- (1)
Among all types of blocks, single-story industrial blocks have the highest radiation potential, and the roofs have a very high solar resource development value; the solar resource potential can be further improved by increasing the area share of roofs in the block.
- (2)
Under the consideration of threshold conditions, there is a difference in the effect of PV material performance on the installation rate of different building surfaces, and the installation rate is affected by PV material from the largest to the smallest degree according to west > east > south > roof.
- (3)
From the perspective of power generation, Mono-Si has a higher power generation level in all types of blocks, where different PV materials can lead to a maximum of 59.2% difference in power generation. Poly-Si and Mono-Si should be considered for higher power generation for single-story industrial blocks with a higher percentage of roof area, while for multi-story and high-rise industrial blocks with a higher percentage of facade areas, a-Si and CIGS can be considered for higher cost performance.
The quantitative analysis of the impact of urban block typology and PV material performance on solar energy utilization, as presented in this study, have produced the following findings: The design recommendations for the early stages of urban planning and building design, as well as for guidance for proprietors of industrial blocks on selecting and installing PV panels can aid in optimizing solar energy utilization and promote energy and carbon emissions reduction in urban areas. The research findings also offer a valuable contribution to the literature on solar energy resource utilization in industrial blocks and can inform future studies in this area.
It was important to note that the study had certain limitations. Firstly, the issue of the mounting inclination of the PV panels had yet to be considered in the study. The tilt angle of PV was a crucial factor that affected PV generation. Since the study focused on the impact of block morphology on solar energy utilization, the PV mounting tilt angle was treated as a fixed value in the study setup. Future studies would delve further into the effect of the tilt angle of PV panels on the power generation in different building parts. Secondly, the energy consumption of the industrial block was a critical factor that affected how PV power generation was utilized. As the study focused on the potential of PV generation, the matter of energy consumption in industrial blocks still requires attention. The allocation of power generated by PV should be examined in conjunction with building energy consumption to maximize the benefits of PV generation. Lastly, during the study, it was discovered that within industrial blocks, a large number of spaces were suitable for the installation of PV panels, showing high potential for solar energy utilization. This could further increase the solar power generation capacity of the industrial blocks. However, the study had yet to cover power generation from these spaces. The effective utilization of these spaces would be comprehensively discussed in subsequent studies.