https://sure.su.ac.th/xmlui/handle/123456789/14264 2026-09-13T18:14:01Z 2026-09-13T18:14:01Z สุนิษา แขกฮู้ https://sure.su.ac.th/xmlui/handle/123456789/28473 2024-05-15T20:11:33Z 0004-01-01T00:00:00Z

Development of a model for calculating global spectral solar irradiance under all-sky conditions in Thailand; การพัฒนาแบบจำลองสำหรับคำนวณหาสเปกตรัมรังสีรวมจากดวงอาทิตย์ภายใต้สภาพท้องฟ้าทั่วไปในประเทศไทย สุนิษา แขกฮู้ This thesis presents a model for computing global spectral solar irradiance under all-sky conditions in Thailand. The model expresses the global spectral irradiance under all- sky conditions as a multiplication of two functions, namely a function of global spectral irradiance under clear sky conditions and a cloud modification function. To create the model, global spectral solar irradiance was measured at four stations in main regions of Thailand, namely Chiang Mai (18.77˚ N, 98.97˚ E) in the northern region of Thailand, Ubon Ratchathani (15.25˚ N, 104.87˚ E) in the north-eastern region of the country, Nakhon Pathom (13.82˚ N, 100.04˚ E) in the central region of this country, and Songkhla (7.18˚ N, 100.60˚ E) in the southern region of Thailand. The spectral data from these stations were collected and then separated into two groups. The first group (January, 2017- December, 2020) was employed for modeling and the second group (January- December, 2021) for validating the model. The first function was constructed using the first group of data. Clear sky conditions were identified by using sky images obtained from a sky camera installed at each station. To build the second function, satellite-derived cloud index obtained from Himawari-8 image data at the stations was used. To validate the model of the global spectral solar irradiance under all-sky conditions, the model was used to compute the global spectral solar irradiance at the four stations for the year 2021 and the result was compared to the global spectral solar irradiance obtained from measurements at the four stations. It was found that the spectral irradiance calculated from the model agreed well with those obtained from the measurements with the discrepancy in terms of root mean square difference relative to the mean measured value (RMSD) of 9.48%. We concluded that the model performed well in calculating global spectral solar irradiance.; -

0004-01-01T00:00:00Z ปรารถนา ไหลวารินทร์ https://sure.su.ac.th/xmlui/handle/123456789/28462 2024-05-15T20:11:10Z 0004-01-01T00:00:00Z

Development of monthly average hourly maps of vitamin D weighted solar ultraviolet radiation for Thailand using an empirical model from ground- and satellite-based data; การพัฒนาแผนที่รายชั่วโมงเฉลี่ยต่อเดือนของความเข้มรังสีอัลตราไวโอเลตจากดวงอาทิตย์ที่ช่วยสร้างวิตามินดีของมนุษย์สำหรับประเทศไทยโดยใช้แบบจำลองเอมไพริคัลจากข้อมูลภาคพื้นดินและข้อมูลดาวเทียม ปรารถนา ไหลวารินทร์ This thesis presents the development of maps of monthly average hourly vitamin D weighted solar ultraviolet radiation (DUV) for Thailand using an empirical model from ground- and satellite-based data. Spectral solar ultraviolet radiation measured by a spectrophotometer model DMc150 of Bentham Instruments installed at a roof top of Science building at Silpakorn University, Nakhon Pathom (13.82 oN, 100.04 oE) in years 2014 and 2016 were used to find a relationship between DUV and erythemal solar ultraviolet radiation (EUV). Broadband radiometers model 501A of Solar Light company installed at four stations namely, Chiang Mai (18.78 oN, 98.98 oE), Ubon Ratchathani (15.25 oN, 104.87 oE), Nakhon Pathom (13.82 oN, 100.04 oE), and Songkhla (7.20 oN, 100.60 oE) were used to measure EUV and then these values were converted to DUV using the relationship between DUV and EUV producted from the data at Nakhon Pathom station. The DUV data obtained from the radiometers at the four stations during 2014-2018 were used for modelling and validation processes. Another ground-based input data is visibility obtained from observation at 125 meteorological stations in Thailand. The visibility data was converted to aerosol optical depth. Satellite-based input data used in this thesis consist of a satellite-derived cloud index from MTSAT-2 and Himawari-8 satellites, and total ozone column from OMI/AURA satellite. In addition, solar zenith angle, air mass, and extraterrestrial DUV irradiance were also calculated. These input data were collected during 2012-2021, and were interpolated to obtain the data as grids covering the region of Thailand. An empirical model for estimating monthly average hourly DUV irradiance using the data from the four UV monitoring stations during 2014-2016 was developed as a function of aerosol, cloud index,  ozone, solar zenith angle, air mass, and extraterrestrial DUV irradiance. The model was validated by calculating DUV irradiance using the proposed model and compared the values obtained from this model with those obtained from the ground-based measurement during 2017-2018. The difference between DUV irradiances estimated from the proposed model and those obtained from the measurement was presented in terms of root mean square difference (RMSD) and mean bias difference (MBD). The RMSD and MBD were found to be 12.7% and -0.2%, respectively. Afterward, this model was used to estimate monthly average hourly DUV irradiance covering the region of Thailand during 2012-2021. The result was presented as maps and these maps show diurnal, seasonal and geographical variations of DUV irradiance.; -

0004-01-01T00:00:00Z https://sure.su.ac.th/xmlui/handle/123456789/28124 2024-05-14T20:07:21Z 0004-01-01T00:00:00Z

PERFORMANCE AND MODELING OF SOLAR VAPOR COMPRESSION REFRIGERATION SYSTEMS FOR COOLING FRUITS, VEGETABLES, AND BEVERAGES UNDER A THAI ENVIRONMENT; สมรรถนะและการจำลองแบบของระบบทำความเย็นแบบอัดไอพลังงานแสงอาทิตย์สำหรับการทำความเย็นผลไม้ ผัก และเครื่องดื่ม ภายใต้สภาวะแวดล้อมหนึ่งในประเทศไทย In this research work, performances of an Auto-Regressive with eXogeneous variables (ARX) and Artificial Neural Network (ANN) were compared. It was found that the ARX outperformed the ANN in predicting load temperature of the solar vapor compression refrigeration system. In the second part, a commercial solar cooling system was experimented. The system consists of a vapor compression refrigeration unit with the capacity of 169 liters, two 300 W solar modules, two 12 V batteries with the capacity of 200 Ah (each), and a charge controller. It was found that the system technically performed well but it is too small for applications in Thailand. Finally, an existing solar refrigeration system with capacity of 789 liters, 550 Watt from electricity gird in Thailand was modified to be a 12 V PV solar refrigeration system. The modified system was experimented and it was found that the load temperatures were reduced to 10 °C – 12 °C within 12 hours for most cases. The experimental results were also employed to model the modified system using the ARX approach. It was also found that the model predict well the load temperature. Additionally, the economic evaluation of the modified system was conducted. Based on the evaluate, the payback period of the modified system was 11.21 years.; -

0004-01-01T00:00:00Z https://sure.su.ac.th/xmlui/handle/123456789/26957 2023-12-27T20:07:19Z 0001-01-01T00:00:00Z

A study of clouds in Thailand using ground and satellite based data; การศึกษาเมฆจากข้อมูลภาคพื้นดินและข้อมูลดาวเทียมในประเทศไทย This research can be divided into three parts. The first part is to investigate the optical thickness of low cloud at Nakhon Pathom station (13.82°N, 100.04°E), Thailand during 2019-2020. A method for determining the physical properties of cloud from a spectroradiometer with a radiative transfer model (LibRadtran) was carried out.  According to the method, cloud optical thickness (COT) for ultraviolet, visible and near-infrared radiation were determined under an overcast sky. It was found that the COT in the UV and visible wavelengths are approximately similar and the COT increases in the near-infared wavelengths. These observation results correspond to the theory.  The second part of the research is a mapping of COT and cloud effective radius (re) over Thailand using satellite data. In this work, the COT and re have been derived using a radiative transfer model (SBDART) together with data from Himawari-8 satellite during 2016-2020. The maps of monthly average values of COT and re were generated, and the characteristics of COT and re were analyzed. The maps show the seasonal variations of COT and re. In the final part, maps of total cloud amount over Thailand using satellite data were generated. In this study, a model relating cloud cover obtained from ground-based measurement (Skyviews, model PSV-100) and cloud index retrieved from MTSAT-1R satellite data at four stations in Thailand during 2009-2016 was developed. This model was used to estimate cloud cover at four sites. The result of the model validation in terms of root mean square difference (RMSD) and mean bias difference (MBD) were found to be 12.9% and 3.5%, respectively. After the validation, the model was used to estimate cloud amount over Thailand and the results are shown as monthly and yearly maps.; -

0001-01-01T00:00:00Z