Journal of Energy and Environment Technology of Graduate School Siam Technology College

EFFECTS OF HYDRAULIC RETENTION TIME AND PH FOR THERMAL EFFICIENCY IN BIOGAS PRODUCTS FROM FOOD WASTE VIA ANAEROBIC DIGESTION METHOD

Thanyamai Samhirun — 2026-06-30

This study explores the influence of hydraulic retention time (HRT) and pH on the efficiency of biogas production and methane (CH₄) concentration in anaerobic digestion systems. Findings indicate that extending HRT enhances biogas output and improves methane purity, while simultaneously reducing levels of carbon dioxide (CO₂), oxygen (O₂), and nitrogen (N₂), reflecting more effective methanogenic activity. As HRT increases from 10 to 30 days, biogas yield improves from 0.6 to 1.0 m³/kg.VS, and CH₄ concentration rises from 54.71% to 65.92%. The decline in CO₂ content from 37.89% to 31.38% further supports the development of more stable anaerobic conditions. Despite these benefits, extended HRTs require larger digester capacities and raise operational expenses, underlining the necessity of identifying an economically viable operational window. At an HRT of 30 days, pH variation shows that methane levels grow from 63.78% at pH 6.0 to a peak of 73.46% at pH 9.0, with optimal methanogenesis observed between pH 7.0 and 8.5. The study also observes significant reductions in chemical oxygen demand (COD) within the first 10 days, indicating rapid breakdown of organic substrates. Alkaline conditions appear to mitigate the inhibitory effects of volatile fatty acids, thereby enhancing methane quality, calorific value, and thermal efficiency. Overall, the result showed that emphasize the critical role of fine-tuning both HRT and pH to maximize biogas yield, improve energy recovery, and promote more sustainable anaerobic digestion system performance.

FUTURE SCENARIOS AND FORESIGHTS OF ENVIRONMENTAL MANAGEMENT FOR ASTRONOMY AND SPACE LEARNING CENTERS IN THAILAND

Chaloemchon Wannathong — 2026-06-30

This research aims to analyze and forecast future scenarios regarding the environmental management of astronomy and space learning centers in Thailand over the next decade. As the initial phase of a broader mixed-methods study, this article adopts a qualitative approach utilizing the Ethnographic Delphi Futures Research (EDFR) technique. A panel of 24 key experts was purposively selected; notably, 75% of the informants hold doctoral degrees, while 54.2% possess more than 16 years of professional experience. Data collection was conducted through in-depth inquiries, followed by rigorous content analysis.

The Phase 1 qualitative findings, extracted from in-depth inquiries, establish three distinct future scenarios. First, the worst-case scenario underscores impending crises driven by urban expansion, physical structures obstructing astronomical visibility, environmental negligence, and a disproportionate focus on research that consequently marginalizes public service. Second, the desirable scenario portrays the successful integration of Sustainable Development Goals (SDGs), net-zero carbon policies, responsible tourism, and the advancement of citizen science. Third, the most probable scenario reflects a pragmatic adaptation characterized by the concurrent use of technology and nature conservation, the establishment of collaborative networks, and workforce development designed to accommodate the emerging space economy. Ultimately, these findings provide a strategic empirical foundation for elevating Thailand’s astronomical learning facilities toward long-term sustainability.

ASSESSMENT OF ORGANIZATIONAL CARBON FOOTPRINT AND TRANSITION RISKS TOWARD CARBON NEUTRALITY: A CASE STUDY OF A COMPRESSOR MANUFACTURING PLANT

Aritsanocha Pennoo — 2026-06-30

This research aims to assess the organizational carbon footprint (CFO) and analyze transition risks toward carbon neutrality in a case study of a compressor manufacturing plant. The study applies both quantitative and qualitative research methods using the McKinsey 7S framework, PESTEL analysis, and risk assessment in accordance with the Task Force on Climate-related Financial Disclosures (TCFD) framework.

The results indicate that the organization’s total greenhouse gas (GHG) emissions amount to 32,268 tCO₂e per year. The largest proportion of emissions originates from Scope 3 (other indirect emissions), accounting for 59.46%, primarily due to embedded carbon in raw materials such as steel and copper. This is followed by Scope 2 emissions (electricity consumption) at 23.68% and Scope 1 emissions (direct emissions) at 16.85%. The transition risk assessment identifies 11 high-risk issues, particularly policy and regulatory risks related to the Carbon Border Adjustment Mechanism (CBAM) and carbon taxation, as well as technological risks associated with the use of R-22 refrigerant. The study proposes management approaches including the implementation of green procurement policies, investment in high-efficiency technologies, and the integration of greenhouse gas (GHG) performance indicators into corporate strategy. These measures are intended to enhance competitiveness and support the organization’s transition toward a Carbon Neutrality.

COMPARISON OF ILLUMINANCE MEASUREMENTS BETWEEN A STANDARD LUX METER AND A SMARTPHONE APPLICATION: A CASE STUDY OF A SMALL-SCALE GARMENT FACTORY IN PHAYAO PROVINCE

Nutthaphong Mated — 2026-06-30

This cross-sectional descriptive study aimed to assess illuminance levels in a small-scale garment factory and compare the performance of a standard light meter with a smartphone application to develop contour map for safety management. A total of 24 measurement points were assessed using a grid-based sampling method. The results revealed that the mean illuminance recorded by the standard light meter was 441.04 ± 296.65 lux, whereas the smartphone application recorded significantly lower values of 111.43 ± 64.95 lux (p < .001). The application exhibited a high mean percentage error of 74.74% and significantly underestimated the actual light intensity. Furthermore, Bland-Altman analysis confirmed a systematic bias, with a mean bias of 329.61 lux and a trend showing increased deviation at higher illuminance levels. Consequently, the illuminance map generated by the application lacked spatial accuracy and distribution precision, failing to reflect actual conditions. This study concludes that smartphone applications currently lack the sufficient precision to replace standard, legally mandated industrial hygiene instruments for safety certification. Their use should be restricted to preliminary surveys only, in order to prevent inaccurate risk assessments that could adversely affect workers' ocular health in the long term.

A STUDY ON THE EFFECT OF CASSAVA BINDER RATIO ON THE HEATING VALUE AND THERMAL EFFICIENCY OF BIOMASS AND COCONUT SHELL FUEL BRIQUETTES

Yuttachai Jarujitr — 2026-06-30

The objective of this study was to investigate the properties and thermal efficiency of biomass fuel briquettes using cassava starch as a binder, with biomass and coconut shell charcoal as primary components. The experiment involved varying the mixing ratios of Binder : Biomass : Coconut Shell Charcoal, and setting the Binder-to-Water (B:W) concentration ratios at 90:10 and 80:20. The heating values were analyzed using an Oxygen Bomb Calorimeter in accordance with ASTM standards, and thermal efficiency was evaluated through water boiling tests. The results indicated that both heating value and thermal efficiency were directly correlated with the quantity of biomass. Furthermore, the B:W ratio of 90:10 consistently yielded higher performance compared to the 80:20 ratio across all mixing proportions. The optimal mixing ratio was found to be 1.5 : 6 : 1 (Binder : Biomass : Coconut Shell Charcoal) with a B:W ratio of 90:10. This formulation provided the maximum heating value of 21.43 MJ/kg and the highest thermal efficiency of 30.55%. These findings demonstrate that the proportion of ingredients significantly affects thermal properties, and the identified formula shows potential for development as a high-efficiency biomass fuel briquette.

GEOSPATIAL MODELING MAP CHARTS FOR ASSESSING PM2.5 CONCENTRATION LEVELS IN THAILAND

Jaturon Kantathong — 2026-06-30

This research aimed to comparatively analyze the differences in mean PM2.5 concentrations during peak critical days between 2025 and 2026, and to assess spatial distribution patterns utilizing geospatial modeling (Map Charts). The methodology entailed a secondary data analysis encompassing all 77 provinces across Thailand. Statistical analyses included descriptive statistics, Paired Samples t-tests, One-way Analysis of Variance (ANOVA), and Two-way Repeated Measures ANOVA. The findings revealed that the highest mean PM2.5 concentration occurred in January 2025 ( = 51.52 µg/m³, S.D. = 22.14 µg/m³), with the maximum provincial concentration reaching a level of 103.63 µg/m³. Temporal comparisons indicated that PM2.5 pollution levels in 2025 were significantly more severe than in 2026 during January and February
(p < .01). Concurrently, geographical analysis demonstrated that the Central Region and the Bangkok Metropolitan Region exhibited significantly higher pollutant concentrations compared to other regions during the early months of the year. These results align with advanced statistical evidence confirming a significant interaction effect between the "month" and "year" factors (F = 8.14, p < .01). Such findings suggest that PM2.5 variation patterns are driven by year-specific conditions rather than relying solely on seasonal factors. This phenomenon is further substantiated by the geospatial models, which identified critical PM2.5 hotspots densely clustered in zones of high economic activity. In conclusion, the integration of rigorous statistical analysis with geospatial modeling facilitates the precise identification of significant environmental shifts. This integrated approach effectively supports evidence-based policy decision-making, environmental health management, and public health surveillance in Thailand.

ASSESSMENT AND MANAGEMENT OF ORGANIZATIONAL CARBON FOOTPRINT FOR SUSTAINABLE GREENHOUSE GAS EMISSION REDUCTION IN THE CHEMICAL INDUSTRY: A CASE STUDY OF A CHEMICAL COMPANY IN BANGKOK, THAILAND

Supakorn suwannapan — 2026-06-30

This research aimed to 1) assess and identify the major sources of greenhouse gas (GHG) emissions, 2) propose approaches for reducing GHG emissions, and 3) recommend environmental management strategies for the chemical industry through a case study of a chemical company located in Bangkok, Thailand. The study employed an applied case study approach by collecting data on energy consumption, raw materials, transportation, and waste management from internal organizational records, together with interviews with relevant personnel. The collected data were used to assess the organization’s Carbon Footprint for Organization (CFO) in accordance with ISO 14064-1 and the GHG Protocol. The assessment covered both direct and indirect greenhouse gas emissions under Scope 1, Scope 2, and Scope 3, using emission factors provided by the Thailand Greenhouse Gas Management Organization (Public Organization) and reference databases consistent with the GHG Protocol guidelines.

The results revealed that the organization generated a total of 236,518 tCO₂eq per year. Other indirect emissions (Scope 3) accounted for the largest proportion at 99.18%, followed by indirect emissions from purchased electricity (Scope 2) at 0.59%, direct emissions from fuel combustion (Scope 1) at 0.19%, and other emission sources at 0.06%. The findings indicated that the major sources of greenhouse gas emissions originated primarily from supply chain activities, including raw material procurement, transportation, packaging utilization, and activities associated with business partners. Appropriate emission reduction measures include green procurement, logistics optimization, packaging reduction, energy conservation, the adoption of renewable energy, replacement of fossil fuel-based equipment, and waste management based on circular economy principles. In addition, the establishment of environmental performance indicators and continuous monitoring and evaluation are essential to enhance systematic greenhouse gas emission management at the organizational level.

A DESIGN ANALYSIS OF MOLDED PHOTOVOLTAIC PANEL LAYOUT FOR INTEGRATION ONTO THE BODY OF A SOLAR-POWERED VEHICLE FOR THE BRIDGESTONE WORLD SOLAR CHALLENGE 2027

Sarayut Rohitsathian — 2026-06-30

This study presents the design and development of a solar panel system installed on the hood of an electric vehicle, with the objective of evaluating its energy generation performance under real environmental conditions. The system comprises a total of 182 photovoltaic cells arranged into six series-connected modules. Modules 1 and 6 each consist of 27 cells, generating 13.5 V per module, while modules 2, 3, 4, and 5 each consist of 32 cells, generating 16 V per module. To assess system performance, measurement instruments including a solar irradiance meter, a relative humidity sensor, and a wattmeter were integrated into the experimental setup. Data were collected at 10 minute intervals between 09:00 and 15:00 throughout December 2025. The experimental results demonstrate that increased solar irradiance has a direct positive effect on the photovoltaic system, leading to higher power output and improved efficiency. In contrast, elevated relative humidity negatively impacts system performance, as atmospheric moisture can cause light scattering and refraction, thereby reducing the effective solar radiation incident on the panel surface and decreasing power generation.

Development of an Intelligent Condenser Fan Control System with Water-Assisted Discharge Line Cooling

Songkran Parakul — 2026-06-30

split-type air conditioners are the highest energy-consuming appliances in residential buildings, particularly due to the compressor and the condenser fan within the condensing unit. Concurrently, air conditioning systems continuously generate condensate water from the evaporator unit. This condensate water maintains a low average temperature of 15–20°C and is typically discarded. This research proposes an approach to enhance energy efficiency by utilizing this waste condensate water for water-assisted cooling of the compressor discharge line prior to entering the condenser, integrated with an automatic condenser fan speed control system to reduce the overall electrical energy consumption.The developed system operates by using the evaporator condensate water to lower the temperature of the compressor discharge line through heat absorption. Temperature sensors detect the temperature differences to transmit signals to a controller, which subsequently modulates and decreases the condenser fan speed corresponding to the real-time water-assisted cooling efficiency. Based on experimental testing on a 9,000 BTU wall-mounted split-type air conditioner installed in an actual residential building, the power consumption of the condensing unit was 980 Watts before system installation. Following the implementation of the compressor discharge line cooling device combined with the fan speed control system, the power consumption decreased to 930 Watts. This demonstrates that the system can achieve an electrical energy reduction of up to 5%. In addition to energy-saving efficiency, the continuous reduction of the thermal load substantially extends the operational lifespan of both the compressor and the air conditioning system.

SMOKE CAPTURE USING MICRO-NANO BUBBLE TECHNOLOGY FOR REDUCING ENVIRONMENTAL POLLUTION

Paitoon Laodee — 2026-06-30

This research aimed to investigate the smoke capture behavior of Micro/Nano Bubble (MNB) technology combined with ozone for reducing pollutants generated from coconut shell combustion. Smoke produced from the combustion process was drawn into a tunnel system by an exhaust fan and treated through a high-pressure spraying nozzle. The working fluid consisted of Micro/Nano Bubbles combined with ozone (MNBs + Ozone). The experimental results indicated that MNBs + Ozone significantly influenced pollutant removal efficiency. For carbon dioxide (CO₂), increasing the spray pressure from 10 to 50 bar resulted in a substantial reduction of treated gas concentrations compared with the untreated exhaust gas, with average removal efficiencies of 81.76% and 84.58%, respectively. In terms of nitrogen oxide (NO) removal, the treated gas concentrations were lower than those of the exhaust gas, achieving average removal efficiencies of 45.43% and 62.50%, respectively. Similarly, carbon monoxide (CO) concentrations decreased after treatment, with average removal efficiencies of 57.27% and 72.60%, respectively. The findings demonstrate that the MNBs + Ozone working fluid possesses effective pollutant absorption and removal capabilities, contributing to the reduction of emissions generated from biomass combustion. Furthermore, the working fluid is environmentally friendly and shows potential for application in air pollution control systems.

A Study on the Installation of a Rooftop Solar Photovoltaic System for Energy Efficiency Improvement and Electricity Cost Reduction at Thaisin Metal Industries Co., Ltd.

Tanaroj Pongkittiisara — 2026-06-30

This research aimed to: (1) study the efficiency of electricity generation from a solar rooftop system; (2) compare electricity consumption before and after the installation of the solar rooftop system; (3) analyze the reduction in electricity costs; and (4) evaluate the economic returns of solar power generation. The study involved the installation of a 974.40-kilowatt solar rooftop system to reduce dependence on electricity supplied by the Provincial Electricity Authority (PEA). A mixed-methods research approach was employed. Quantitative data were collected through questionnaires from a sample of 411 companies, while qualitative data were obtained through in-depth interviews with 11 experts and key informants, including executives, managers, and representatives from government agencies. Data were analyzed using descriptive statistics, including frequency, percentage, mean, and standard deviation.

The results of the study revealed that the solar rooftop photovoltaic (PV) system was capable of generating an average of approximately 1,470,000 kWh of electricity per year. This generation capacity contributed to a reduction in electricity consumption from the utility grid by approximately 19–27% of the factory’s total electricity demand. Consequently, the system enabled annual energy cost savings of approximately THB 6.1 million, with an estimated payback period of 5–7 years. These findings demonstrate that the expansion of rooftop solar power generation systems is an effective approach to reducing energy costs while supporting sustainable business operations and environmental responsibility.

A SYSTEMATIC LITERATURE REVIEW OF ENERGY TECHNOLOGIES FOR GREENHOUSE GAS REDUCTION AND CARBON NEUTRALITY IN THAILAND

Manee Kiewcharoen — 2026-06-30

This study employs a Systematic Literature Review (SLR), and the article selection process follows the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) framework to analyze energy technologies and approaches for reducing greenhouse gas emissions toward Carbon Neutrality. Research articles were collected from the ScienceDirect, Springer Nature, and Gale OneFile databases, covering the period from 2023 to 2025, based on systematically defined inclusion and exclusion criteria. A total of 4,704 articles were initially identified, including 596 from ScienceDirect, 2,643 from Springer Nature and 1,465 from Gale OneFile. These articles were screened based on titles and abstracts, followed by a full-text assessment according to the established criteria, resulting in 42 articles selected for in-depth analysis. The findings indicate that the key approaches can be categorized into four main groups (1) Policy Measures and Carbon Market mechanisms, (2) Smart Grid systems and Virtual Power Plants (VPP), (3) Renewable Energy integration; and (4) Waste Management and the Circular Economy. Renewable Energy and Energy Efficiency Improvements show high potential in the short term, whereas advanced technologies such as Hydrogen and Carbon Capture are more suitable for long-term development. This study proposes policy recommendations and energy system development pathways tailored to the Thai context to support the achievement of Carbon Neutrality by 2050 and Net Zero Emissions by the year 2065.