Effect Of Solar Radiation Intensity Research Articles

Predictive thermal performance analysis of T-wall based adsorption thermal battery for solar building heating

Moisture-based adsorption thermal battery (ATB) holds great potential for addressing energy storage and utilization challenges. In this work, a proof-of-concept solar harvesting building envelope using the Trombe-wall (T-wall) based ATB design is proposed and investigated, featuring a developed composite sorbent as the porous wall for effective heat storage and utilization. To demonstrate the feasibility of employing the ATB-based building envelope for day-and-night space heating, a 3-dimensional simulation model of the ATB wall is meticulously designed and comprehensively studied. Parametric analyses of various working conditions, including examining the effects of solar radiation intensity, air temperature, air humidity, and airflow velocity on the heat charging and discharging performances of the ATB wall, are conducted using the numerical model. Simulation results indicate that, under a solar irradiance level of 700 W m−2 during the daytime, an average output air temperature of 42.4 °C and an average heating power density of 2.5 kW m−3 are achieved. Extending the heat charging time to 8 h and 12 h significantly improves the desorption efficiency, which is able to reach 47.2% and 75.0%, respectively. In terms of heat discharging performances, various working conditions investigated in the ATB wall model will lead to different thermal output performances.

Comparative study on the performance of a solar photocatalytic Trombe wall with different types of collectors: Copper/Thermoelectric/PV plate

Solar photocatalytic Trombe wall (SPTW) is a technology that can help to improve the indoor environmental quality and simultaneously enhance solar energy utilization, which receives lots of attention recently. Nevertheless, current research predominantly emphasizes the heat and mass transfer analysis of a single envelope system, with limited exploration of energy and performance comparison of multi-physics systems. For this, flow, heat and mass transfer analysis of SPTW with four different types of collectors: SPTW with copper plate, SPTW with photovoltaic plate (PV-SPTW), SPTW with thermoelectric plate (TE-SPTW) and SPTW with hybrid PV-TE plate (PV-TE-SPTW), are theoretically proposed to reveal the energy flow distributions among these systems. Based on the coupled analysis, parameter characteristics have been conducted to investigate the effects of solar radiation intensity, system channel width and system channel height together with ambient temperature on the heating Q, purification CADR and power generation Z performance of various SPTWs. Furthermore, a comparison of the energy and exergy performance among these four systems is clarified through the energy, exergy flow and equivalent energy saving. From the obtained results, it can be indicated that the reverse flow has a strong impact on the performance of natural ventilation and further varies the indexes of Q, CADR and Z when the solar radiation intensity is inferior to a threshold value from 100 to 300 W/m2. With the changing channel height and width, the maximum Q and CADR are both appears in TE-SPTW system, respectively reaching by 4.64 MJ/h and 136.56 m3/h as the structure of 0.05 m channel width and 3.0 m channel height, which show 39.7 % and 5.9 % respectively compared to the SPTW model. Conducting energy and exergy analyses on the four systems reveal their remarkable potential, sacrificing a minimal 0.032 MJ or less in purification performance in exchange for substantial energy savings of at least 0.314 MJ. This work will establish a foundational contribution to advancing energy-efficient building technologies.

Integrated life cycle assessment and emergy analysis of liquid dehumidification absorption refrigeration driven by solar energy

The cascade utilization of solar energy is significant in alleviating energy and environmental problems. A novel solar-driven liquid dehumidification cascade absorption refrigeration (SLDAR) system applied to hot summer and cold winter areas of China is proposed in this paper. In order to evaluate the environmental and economic sustainability of the system, an integrating life cycle assessment and emergy analysis (LCA-EmA) method is developed. Parameter sensitivity analysis is conducted to determine the effects of solar radiation intensity, air temperature and relative humidity on the sustainability of the system. The results reveal that the total potential environmental impact of the system is 7.29E+03, of which the construction stage accounted for the most part of 65.36%. The total emergy input of the system is 1.61E+17 sej/yr, the operation stage accounted for the highest proportion of 73.29%. According to the integrated LCA-EmA, the emergy sustainability index of the system is 3.89, which reduces by 29.01% than the result of the emergy analysis. The parameter sensitivity analysis states that the system has higher resource use efficiency and emergy yield ratio in higher solar radiation intensity. And the emergy sustainability index of the system increases first and then decreases as the air temperature increases. The environmental load rate increases by 15.19% and the emergy sustainability index decreases by 44.50% as the increase of relative humidity. This study proves the feasibility and sustainability of the solar-driven cascade system.

Emergy evaluation of a solar-powered cascade system for dehumidification, cooling and heating in hot summer and cold winter areas of China

A solar-powered cascade system is proposed for dehumidification, cooling and heating in hot summer and cold winter areas of China. To evaluate the energy, environmental and economic sustainability of the system, the emergy evaluation of the proposed system is analyzed and compared with different energy sources. The effects of solar radiation intensity, air temperature and relative humidity on the emergy performance of the system are discussed. The results show that the input total emergy and transformity of the proposed system are 9.88 × 1016 sej/y and 4.75 × 105 sej/J, which are lower than that of the systems powered by other energy. The environmental load ratio and emergy sustainability index are the highest when the system is powered by solar energy, with the value reaching 1.33 and 1.66, respectively. According to parameter sensitivity analysis, the total emergy input decreases by 6.31% and the emergy saving ratio increases by 29.09% as the increase of solar radiation intensity. The system has the best emergy performance at air temperature of 26.18 °C. The system has lower environmental load and higher sustainability in lower relative humidity climate. This work proves the viability and sustainability of the novel cascade system.

不同时间尺度下华北落叶松人工林冠层蒸腾与环境因子的关系

PDF HTML阅读 XML下载 导出引用 引用提醒 不同时间尺度下华北落叶松人工林冠层蒸腾与环境因子的关系 DOI: 10.5846/stxb202107151903 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 内蒙古自治区关键技术攻关计划项目(2021GG0033);内蒙古自治区林业和草原局科研能力提升项目;内蒙古自治区自然科学基金项目(2021MS03101) Relationship between canopy transpiration of larch plantation and environmental factors at different time scales Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:在半干旱区连续2年监测华北落叶松(Larix principis-rupprechtii)的树干液流、气象因子和土壤体积含水量,分析不同时间尺度下人工林冠层蒸腾与环境因子的关系。结果表明:不同时间尺度下,华北落叶松人工林冠层蒸腾的季节变化均呈单峰曲线,即先增大后减小的趋势;2016年、2017年日蒸腾量分别为1.58 mm/d和1.71 mm/d,生长季蒸腾总量分别为241.30 mm和260.97 mm。在日尺度下,气温、太阳辐射强度和饱和水汽压差是影响华北落叶松人工林冠层蒸腾主要环境因子;月尺度下,气温、风速、降水和土壤水分是冠层蒸腾的主要影响因子;冠层蒸腾与降水、大气相对湿度的相关关系由日尺度下的负相关到月尺度的正相关,相关性增强。总体来看,随时间尺度由小到大,气温、风速、大气相对湿度、降水、土壤水分对冠层蒸腾的影响作用增大,而太阳辐射强度、饱和水汽压差的作用减弱;在未来增温增雨趋势下,研究区生长季将延长,华北落叶松人工林冠层蒸腾量可能会加大。 Abstract:Canopy transpiration is a major part of forestland water balance and a fundamental datum in understanding the planted forest ecophysiology in dry regions. Quantitatively analyzing variation of canopy transpiration induced by the environmental factors is beneficial for a better estimation forestland water balance and prediction the plantation ecophysiology. But the response mechanism of canopy transpiration to environmental factors may be different in different time scales, so it needs to be further understood. This study was conducted in a 42-year-old Larix principis-Rupprechtii plantation (a density of 1933 trees/hm2) at the middle position of a north facing slope in the Inner Mongolian Daqingshan National Nature Reserve, a semi-arid region of China. Firstly, the sap flow velocity in ten healthy and dominant Larix principis-Rupprechtii trees, soil volumetric water content and meteorological factors including air temperature, precipitation, solar radiation intensity, air relative humidity and wind speed, were observed during two growing seasons (May 1 to September 30) in 2016 and 2017 which precipitation was 435.00 mm and 348.80 mm, respectively. Then, sap flow velocity values which was measured by the thermal diffusion method, were upscaled to the forest canopy level. Finally, the relationship between canopy transpiration and the environmental factors at different time scales was analyzed. The results showed that the seasonal changes of canopy transpiration showed a single peak curve under the different time scales, that was, the trend of increase first and then decrease. In 2016 and 2017, the average value of daily canopy-level transpiration was 1.58 mm/d and 1.71 mm/d, respectively, and the total transpiration in the growing season was 241.30 mm and 260.97 mm, respectively. On the daily scale, air temperature, solar radiation intensity and saturated vapor pressure deficit markedly affected canopy transpiration. At the monthly scale, air temperature, wind speed, precipitation and soil volumetric water content were the main influencing factors of canopy transpiration. The correlation between transpiration and precipitation and air relative humidity increased from negative correlation on the daily scale to positive correlation on the monthly scale. In general, with time scale from small to large, the effects of air temperature, wind speed, air relative humidity, precipitation and soil water content on canopy transpiration increase, while the effects of solar radiation intensity and saturated vapor pressure deficit decrease. With the trend of increasing temperature and rainfall in the future, the growing season of Larix principis-Rupprechtii in the study area will be prolonged, and the canopy transpiration may increase. 参考文献 相似文献 引证文献

Solar radiation spectral composition determination program

The article describes the work of a software product designed to process the results of analytical studies on the effect of solar radiation intensity on its spectrum by bigarmonic interpolation. As a result of the program, the processed analytical data is converted into three-dimensional surfaces showing the dependencies of studies on the effect of solar radiation intensity on its spectrum, the height of the sun and geographical coordinates. The program allows you to determine areas with a certain percentage of the spectrum from the height of the sun and is used in research organizations, educational institutions and design organizations of the electric power industry.

Numerical study on the effect of solar radiation intensity on the fresh water productivity of solar still equipped with Thermoelectric Cooling System (TEC) for hot and dry areas of Semnan

The fresh water crisis is one of the most important issues in the world and as a solution one of the most important methods of freshwater production is the evaporation of saline water by using of solar stills. Semnan province is one of the largest provinces in Iran. The province covers an area of 97,491 km 2 , which is 5.9% of the total area of the country. This province is the seventh largest province in Iran and is located almost in the central desert region of Iran. Due to its location on the solar belt, the desert areas of Semnan province are prone to the installation of solar cells, and according to the statistics of the General Meteorological Department of Semnan, this province has 325 sunny days in 365 days of the year. Therefore, this area is a great location for using clean solar energy. In this research, using the numerical method, the effect of the presence of the Thermoelectric Cooling System (TEC) on the performance of solar still, intensity and direction of solar radiation has been investigated to check their effect on the rate of freshwater production. The simulations were performed for Semnan city condition with the method of humid air in a three-dimensional, steady and laminar regime by solving the equations of continuity, Navier-Stokes, and water vapor concentration. The results show that there is a direct relationship between radiation intensity and water production rate and increasing radiation intensity increases the amount of produced freshwater. It was also observed that applying a TEC on a part of the glass can increase water production from 15% to 62%. The reason for this increase can be the increase in free convection due to the increase in the flow temperature gradient in designed solar still.

Evaluation of the performance parameters of a PVT system: Case study of composite environmental conditions for different Indian cities

The efficiency of the photovoltaic thermal (PVT) system is affected by the meteorological and climatic conditions. Studies based on mathematical modeling has been applied to optimize the PVT system using absorber shape factor (Z) and mass flow rate (m). Mathematical modeling of heat transfer coefficients and their simulation in MATLAB is presented in the current study using the meteorological data of three major cities (Ahmedabad, Delhi, and Pilani) of India. The scope of the present work is not only limited to finding the effect of solar radiation intensity and ambient temperature but also to establish the optimized value for Z and the best suitable shape for the absorber plate. The detailed analysis of results obtained shows higher values of m gives better total efficiency. For m = 0.02 kg/s but it is observed Z = 1.3 gives maximum efficiency, 48% at noon, in comparison to Z = 2 which is 43% for m = 0.1 kg/s. Hence curved grooved absorber plate is predicted to give better performance for various geographical locations.

Performance Analysis of a PV Powered Variable Speed DC Fridge Integrated with PCM for Weak/Off-Grid Setting Areas

This paper investigates the transient performance of a DC compressor fridge incorporated with Phase Change Material (PCM) for weak/off-grid setting regions. A photovoltaics (PV) module is directly connected to the DC compressor without use of batteries and inverter, in order to simplify the system and reduce its cost. The DC compressor speed can be adjusted according to the radiation intensity for an optimum match between PV output and the efficiency of refrigeration. During the daytime, the PCM is charged for cold storage by refrigeration; when solar radiation is weak or during the night, the PCM releases cooling to maintain the required cabinet temperature. A transient mathematical model is built for the whole system including PV module, DC compressor refrigeration system, fridge cabinet and PCM packs. The model is coded and solved in MATLAB while CFD method is used to produce some additional information. The simulations are conducted to evaluate the effect of solar radiation intensity, thermostat setting and the number of PCM packs on the fridge refrigeration performance. Moreover, the study aims to investigate and present benefits of incorporating PCM with a direct PV powered DC compressor fridge in weak/off-grid setting areas. When the fridge cabinet temperature varies between 4℃ and –2℃, the average COP of the fridge refrigeration system was found 1.7 for high solar radiation day due to the high rotation speed of the compressor, but for low solar radiation day, the average COP was calculated as 1.95. The analysis also shows that a variable speed DC compressor can keep the foods in the desired temperature range for two days of power outage by using 1 m² PV module and 3.6 kg of thin PCM packs.

Mass flow rate prediction of direct-expansion solar-assisted heat pump using R290 based on ANN model

A direct-expansion solar-assisted heat pump (DX-SAHP) system using R290 (propane) is studied experimentally. A Coriolis mass flow meter is employed to measure the R290 mass flow rate, and the artificial neural network (ANN) model is used to predict it. Based on numerous experiments, the 5 independent variables are chosen as the input parameters of the ANN model, including the ambient temperature, solar radiation intensity, electronic expansion valve (EEV) opening, compressor frequency and water temperature. The appropriate number of the hidden layer neurons is obtained. The results show that the Mean Relative Error (MRE), Root Mean Square Error (RMSE), and Standard Deviation (SD) of the ANN model are 0.0012, 0.4139 kg h−1 and 0.0447, respectively. Above 97% of prediction results agree well with experimental data within a maximum error of 10%. Furthermore, as the ambient temperature increases, the refrigerant mass flow rate increases. As the solar radiation intensity increases, the refrigerant mass flow rate increases on the whole, and the effect of solar radiation intensity is weakened with the increment of ambient temperature. At a higher level of compressor frequency, the variation in the refrigerant mass flow rate is approximately linear with the ambient temperature, solar radiation intensity, EEV opening or water temperature. With the proposed ANN prediction model, the refrigerant mass flow rate of the DX-SAHP system can be quickly got, which will be very useful in system efficient operation.

Harvesting solar thermal energy with a micro-gap thermionic-thermoelectric hybrid energy converter: Model development, energy exchange analysis, and performance optimization

We present a comprehensive analysis of a dual, micro-gap thermionic-thermoelectric hybrid energy converter by developing a detailed theoretical model of the system. The space-charge and near-field effects in thermionic conversion and the temperature-dependent effects in thermoelectric conversion are considered while studying the energy flow through the cascade system. The temperatures and energy exchange channels in the different parts of the system are quantified using a self-consistent iterative algorithm considering the energy balance condition. The model is deployed to simulate the hybrid system performance when energized by a constant heat flux source which could, for example, be concentrated solar irradiance. The effect of solar radiation intensity on the combined system efficiency, and the dependence of the thermoelectric generator performance on the waste heat released from the thermionic top stage, are illustrated with several examples. Based on these analyses, a performance optimization of the hybrid system is carried out. The findings presented in this work offer useful insights into the hybrid generator operation. Moreover, the model developed can be used as a design tool for the practical implementation of such a hybrid system, or for extracting material- and device-related parameters from experimental data.

Zonal evaluation for siting a solar power plant in Cross River State, Nigeria

An experimental survey was embarked upon to establish the effect of solar radiation intensity, the panel power output, current density and the efficiency of solar panels in three major geographical zones in Cross River State, Nigeria. The zones are Mangrove, University of Calabar, Tropical Rainforest, Nko - Yakurr and Guinea Savanna, Abakpa - Ogoja. The result from the investigation shows that the Guinea Savanna produced the highest current density of 8.20 A/cm 2 , power output of 152.3W, 36.5% efficiency and a solar radiation magnitude of 991.9 W/m 2 from a monocrystalline panel. However, polycrystalline panel generated better output for all the measured parameters thus: current density of 8.80 A/cm 2 , power output of 170.72 W, 39.9% efficiency range for the same solar radiation magnitude of 991.9W/m 2 . From the analysis of the survey performed across the three geographical zones. The Mangrove zone has shown greater potential to accommodate solar farms, hence generate good energy to bridge the vacuum created in the power generating sector. Keywords: Epileptic supply, mangrove zone, solar farm, output power, panels efficiency

The performance analysis of a novel hybrid solar gradient utilization photocatalytic-thermal-catalytic-Trombe wall system

This article proposes a novel hybrid solar gradient utilization photocatalytic-thermal-catalytic-Trombe (PTC-Trombe) wall, which can realize dual functions of air purification and space heating. Firstly, based on the previous studies on photocatalytic-Trombe (PC-Trombe) and thermal-catalytic-Trombe (TC-Trombe) walls, a thermal and mass model of PTC-Trombe wall is established. Secondly, the performance comparisons among three Trombe walls are conducted based on the experimental results in daytime. Thirdly, the effect of solar radiation intensity on the system performance of PTC-Trombe wall is discussed. Finally, the energy saving performance of three walls in Hefei is calculated. Results are: (1) PTC-Trombe wall behaves the best performance for formaldehyde degradation compared with other walls; (2) The effect of solar radiation intensity on the catalytic oxidation rate in PTC-Trombe wall can be divided into three regions with different catalytic oxidation mechanisms; (3) The total reduced heat loads for PC-Trombe wall, TC-Trombe wall and PTC-Trombe wall are 309.8, 204.7 and 296.1 MJ/m2, while the total generated volume of clean air is 4764.9, 6608.9 and 9482.2 m3/m2, respectively.

Solar radiation affects bloat potential of wheat forage

Frothy bloat is a serious digestive disorder in cattle (<em>Bos taurus</em> L.) grazing winter wheat (<em>Triticum aestivum</em> L.) pastures in the Southern Great Plains of the USA. Wheat plant metabolism may be one of the factors involved in bloat occurrence. In a series of experiments conducted during 2004–2007, we evaluated the effects of solar radiation intensity (ambient, 100% vs. reduced, 25%), a short-time (24 h vs. 48 h) exposure to solar radiation, and forage allowance (high, 18 kg vs. low, 6 kg DM/100 kg body weight) on seasonal concentration of phenolic compounds and foam strength (a measure of bloat potential) of wheat forage ‘Cutter’. Reduced solar radiation decreased total phenolic concentration and increased foam strength when compared to ambient solar radiation. Forage allowance interacted with solar radiation and short-term exposure treatments in determining phenolic concentrations; however, the effects were inconsistent during and among growing seasons. Concentration of phenolic compounds responded rapidly to sudden changes in weather patterns (passing cold fronts) that were usually associated with significant decrease in solar radiation intensity and temperature. Solar radiation intensity was positively correlated with total phenolic concentration and explained 62% to 72% of the variation in total phenolic concentration. Correlation between temperature and total phenolic concentration varied among growing seasons and explained 9–17% of the variation in total phenolic concentration. Results suggest that phenolic concentration in wheat forage is correlated with solar radiation. The decrease in phenolic concentration and resulting increase of bloat potential are especially pronounced during sudden changes in weather patterns during winter.

A 3d model of the effect of using heat spreader on the performance of photovoltaic panel (PV)

In the current study, three-dimensional theoretical model of the photovoltaic (PV) panel coupled with a heat spreader is carried out. A thermal model is constructed and solved mathematically by using ANSYS software. The effect of coupling the heat spreader with the PV and the heat spreader dimensions on the PV cooling and performance is studied. Also, the effect of solar radiation intensity and weather conditions (wind speed and ambient temperature) on the performance of PV with heat spreader system is considered. The model is validated with the previous results found in the literature. Moreover, the temperature distribution of the PV with the heat spreader is presented. The results show that the optimum thickness and cross sectional area of the heat spreader for PV dimensions of 125×125 mm are 10 mm and 0.3 m2. The cell temperature is decreased by 15 °C when the heat spreader is used with the PV. Also the average power output and efficiency of the PV module are increased by 9% when the heat spreader is used.

A new correlation between global solar radiation and the quality of sunshine duration in China

Accurate and reliable solar radiation models are important in the building energy conservation, solar thermal and photovoltaic utilization, agricultural production and ecological environment, in which the global solar radiation model based on sunshine percentage is the most common model. Sunshine duration only reflects the time accumulation of solar radiation, but cannot reflect its intensity accumulation. Therefore, it is difficult to improve the accuracy of such models. To solve this problem, a new quality of sunshine duration model (QSD model) is proposed, which takes into account both the influence of sunshine duration on solar radiation and the effect of solar radiation intensity on the accumulation of day. The QSD model is simplified from the energy balance equation which is established based on theoretical analysis of the heat transfer process among the Earth's surface layer, air layer and atmospheric layer. Then Meteorological data of 24 stations are utilized to analyze the accuracy of QSD model. The results show that the QSD model is more accurate, and the accuracy of QSD model is best during sunny days, followed by cloudy days, whereas overcast days provide the worst results. Meanwhile, a QSD model is obtained based on data from different regions. Statistical analysis shows that a QSD model has universal applicability in China, and the average value of correlation coefficient (R) is 0.929, Nash-Sutcliffe equation (NSE) is 0.864, and root mean squared error (RMSE) is 0.088.

Numerical Simulation of Heat and Mass Transfers During Solar Drying of Sewage Sludge: Solar Radiation Effect

The drying of sewage sludge is a current environmental problem, not sufficiently described in the literature. Hence, the aim of this work is a numerical study of heat and mass transfers during solar drying of residual sludge. This sludge is assimilated to a porous medium and exposed to a forced convection laminar flow within a horizontal channel. The transfers in the channel and the porous medium are respectively described by the classic equations of forced convection and the Darcy-Brinkman-Forchheimer model. The implicit finite difference method is used to discretize the governing differential equation system. The algebraic systems obtained are solved using the Gauss, Thomas and Gauss-Seidel algorithms. To determine the drying rate, we associate a drying kinetics model. We particularly studied the effects of solar radiation intensity on the space-time evolution of temperature, velocity and mass fraction at the porous medium-fluid interface. Moreover, the evolutions of the Nusselt numbers are represented to characterize the transfers at the sludge surface. This work is completed by a drying kinetics study. Indeed, we represent the effect of solar radiation on the space-time evolution of the drying rate.

Experimental and numerical analysis of solar enhanced natural draft dry cooling tower

Solar enhanced natural draft dry cooling tower(SENDDCT) is a new heat rejection device that uses solar energy to increase the cooling efficiency of natural draft dry cooling tower. In this paper, an experiment study was carried out t under natural conditions to investigate the effect of solar radiation intensity on the performance of SENDDCT. Meanwhile, a same-size CFD model was developed by using FLUENT to analyze the influence of ambient temperature on the cooling performance of SENDDCT. The results verified that SENNDCT can enhance heat transfer rate of natural draft dry cooling tower when ambient temperature was high at noon, solar radiation increased heat transfer rate by an average of 16.5% during the experiment. Air mass flow and heat transfer rate decreased with the increase of ambient temperature.

Sizing and performance analysis of standalone hybrid photovoltaic/battery/hydrogen storage technology power generation systems based on the energy hub concept

ABSTRACTIn this study, the optimal sizing and performance analysis of a standalone integrated solar power system equipped with different storage scenarios to supply the power demand of a household is presented. One of the main purposes when applying solar energy resource is to face the increasing environmental pollutions resulting from fossil fuel based electricity sector. To this end, and to compare and examine two energy storage technologies (battery and hydrogen storage technology), three storage scenarios including battery only, hydrogen storage technology only and hybrid storage options are evaluated. An optimization framework based on Energy Hub concept is used to determine the optimum sizes of equipment for the lowest net present cost (NPC) while maintaining the system reliability. It was determined that the most cost effective and reliable case is the system with hybrid storage technology. Also, the effects of solar radiation intensity, the abatement potential of CO2 emissions and converting excess power to hydrogen on the system’s performance and economics, were investigated and a few noticeable findings were obtained.

Evaluation of aging behavior of polypropylene in natural environment by principal component analysis

To evaluate the aging behavior of polypropylene (PP) under an aggressive environment, principal component analysis (PCA) was used to establish a non-dimensional expression Z from a data set of multiple properties of PP. In this study, PP specimens were subjected to natural exposure under the tropical environment on Xisha islands in China for different time periods. Chromatic aberration, gloss, tensile strength, elongation at break, flexural strength and impact strength were tested to evaluate the aging behavior of the PP. Principal component analysis (PCA) was then used to find a specific property to represent all properties of PP. The combined evaluation parameter Z of PP degradation showed no change for the initial two months of exposure. After a sharp increase, the value of Z increased gradually and finally leveled off for the last two months. Based on the Z values, the effect of solar radiation intensity on the degradation of PP is discussed.