scholarly journals Efisiensi Kompor Surya Parabola Berreflektor Cermin Untuk Menunjang Ketahanan Energi

2020 ◽  
Vol 4 (1) ◽  
Author(s):  
Abdul Haris Subarjo ◽  
Benedictus Mardwianta ◽  
Anugrah Budi Wicaksono
Keyword(s):  
Heat Transfer ◽  
Solar Radiation ◽  
Water Temperature ◽  
Environmental Conditions ◽  
Thermal Efficiency ◽  
Research Methodology ◽  
Single Point ◽  
Data Retrieval ◽  
Time Parameters ◽  
The Subject

Radiasi matahari menghasilkan kalor sebagai sumber energi yang dapat dikumpulkan menjadi satu titik sehingga mampu untuk memasak air menggunakan alat bernama Reflektor cermin parabolic. Untuk memperbesar perpindahan kalor menyeluruh (Qm) maka dipilih bahan reflector yang mudah memantulkan sinar matahari. Tujuan yang dilakukan pada penelitian ini adalah untuk mengetahui daya dan efisiensi termal kolektor pada kompor tenaga surya. Metodologi penelitian ini dengan cara pengambilan data dengan parameter waktu yang sudah ditentukan sesuai kondisi  lingkungan untuk memanaskan air 1000 gram. Subyek penelitian ini adalah parabolic solar cooker dengan diameter 84 cm. Hasil daya kompor yang diperoleh sebesar 36,59 Watt dan efisiensi termal kompor sebesar 6,18 %. Daya kompor dipengaruhi oleh selisih temperatur air setelah dipanaskan dengan temperatur air sebelum dipanaskan. Semakin besar temperatur air setelah dipanaskan maka akan memperbesar daya kompor tersebut. Semakin besar perpindahan kalor menyeluruh Qm dan semakin kecil intensitas radiasi matahari pada reflector yang menggunakan cermin maka efisiensi termal semakin besar.Kata kunci: kompor parabola tenaga surya, daya kompor, efisiensi termalABSTRACTSolar radiation generates the heat as a source of energy that can be collected into a single point so that it is able to cook water using a tool named mirror parabolic reflector. To enlarge the whole heat transfer (QM) then selected reflector material that easily reflects the sunlight. The purpose of this study is to find out the power and efficiency of thermal collectors on solar power stoves. This research methodology by means of data retrieval with specified time parameters according to environmental conditions to heat water 1000 grams. The subject of this study is the parabolic solar cooker with a diameter of 84 cm. Results of stove Power obtained at 36.59 Watt and thermal efficiency of the stove amounted to 6.18%. The cooker's power is influenced by the water temperature difference after heated with water temperature before heated. The larger the water temperature after heated it will enlarge the stove's power. The larger the overall heat transfer of the Qm and the smaller the intensity of the solar radiation on the reflector using the mirror hence the greater the thermal efficiency.

scholarly journals An analysis of temperature distribution in solar photovoltaic module under various environmental conditions

2018 ◽  
Vol 240 ◽  
pp. 04004 ◽  
Author(s):  
Marek Jaszczur ◽  
Qusay Hassan ◽  
Janusz Teneta ◽  
Ewelina Majewska ◽  
Marcin Zych
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Wind Speed ◽  
Solar Radiation ◽  
Environmental Conditions ◽  
Operating Temperature ◽  
Photovoltaic Module ◽  
Solar Photovoltaic ◽  
System Efficiency ◽  
Pv System

The operating temperature of the photovoltaic module is an important issue because it is directly linked with system efficiency. The objective of this work is to evaluate temperature distribution in the photovoltaic module under different environmental conditions. The results shown that photovoltaic module operating temperature depends not only on the ambient temperature or solar radiation dependent but also depends on wind speed and wind direction. It is presented that the mounting conditions which are not taken into consideration by most of the literature models also play a significant role in heat transfer. Depends on mounting type an increase in module operating temperature in the range 10-15oC was observed which cause further PV system efficiency decrease of about 3.8-6.5 %.

scholarly journals Tissue Hydrogen Peroxide Concentration Can Explain the Invasiveness of Aquatic Macrophytes: A Modeling Perspective

2021 ◽  
Vol 8 ◽  
Author(s):  
Takashi Asaeda ◽  
Md Harun Rashid ◽  
Jonas Schoelynck
Keyword(s):  
Hydrogen Peroxide ◽  
Environmental Factors ◽  
Solar Radiation ◽  
Water Temperature ◽  
Flow Velocity ◽  
Environmental Conditions ◽  
Native Species ◽  
Water Flow Velocity ◽  
High Solar Radiation ◽  
Japanese Rivers

In recent years, an invasive macrophyte, Egeria densa, has overwhelmingly colonized some midstream reaches of Japanese rivers. This study was designed to determine how E. densa has been able to colonize these areas and to assess the environmental conditions that limit or even prevent colonization. Invasive species (E. densa and Elodea nuttallii), and Japanese native species (Myriophyllum spicatum, Ceratophyllum demersum, and Potamogeton crispuss) were kept in experimental tanks and a flume with different environmental conditions. Tissue hydrogen peroxide (H2O2) concentrations were measured responding to either individual or multiple environmental factors of light intensity, water temperature, and water flow velocity. In addition, plants were sampled in rivers across Japan, and environmental conditions were measured. The H2O2 concentration increased in parallel to the increment of unpreferable levels of each abiotic factor, and the trend was independent of other factors. The total H2O2 concentration is provided by the sum of contribution of each factor. Under increased total H2O2 concentration, plants first started to decrease in chlorophyll concentration, then reduce their growth rate, and subsequently reduce their biomass. The H2O2 concentration threshold, beyond which degradation is initiated, was between 15 and 20 µmol/gFW regardless of the environmental factors. These results highlight the potential efficacy of total H2O2 concentration as a proxy for the overall environmental condition. In Japanese rivers, major environmental factors limiting macrophyte colonization were identified as water temperature, high solar radiation, and flow velocity. The relationship between the unpreferable levels of these factors and H2O2 concentration was empirically obtained for these species. Then a mathematical model was developed to predict the colonization area of these species with environmental conditions. The tissue H2O2 concentration decreases with increasing temperature for E. densa and increases for other species, including native species. Therefore, native species grow intensively in spring; however, they often deteriorate in summer. For E. densa, on the other hand, H2O2 concentration decreases with high water temperature in summer, allowing intensive growth. High solar radiation increases the H2O2 concentration, deteriorating the plant. Although the H2O2 concentration of E. densa increases with low water temperature in winter, it can survive in deep water with low H2O2 concentration due to diffused solar radiation. Currently, river rehabilitation has created a deep zone in the channel, which supports the growth and spreading of E. densa.

scholarly journals Experimental investigation on efficient heat collection of aboveground pipes

2020 ◽  
Vol 24 (2 Part B) ◽  
pp. 1445-1460
Author(s):  
Kaipeng Wang ◽  
Qimin Li ◽  
Ke Cheng ◽  
Jian Wang
Keyword(s):  
Heat Transfer ◽  
Solar Radiation ◽  
Water Temperature ◽  
Field Experiments ◽  
Great Influence ◽  
Spatial Position ◽  
Galvanized Steel ◽  
Outer Diameter ◽  
Plastic Film ◽  
Radiant Intensity

Prospects for low-cost utilization and storage of solar energy are promising. In this study, the change of shallow geo-temperature was monitored, and the influence of solar radiation on shallow geo-temperature was discussed. Three series of field experiments on heat transfer of aboveground pipes were designed, and the variations of water temperature in the aboveground pipes were also monitored. According to the experimental data, the relevant factors affecting the water temperature inside the pipe (such as solar radiant intensity, pipe?s material, pipe?s spatial location, heat-accumulating wall and so on) were analyzed. Based on the field test, a 3-D model of aboveground pipe heat transfer was established to verify and temperature prediction was carried out. The results show that the water temperature in the pipe is most significantly affected by solar radiation, and is also related to the color of the pipe and its spatial position. The water temperature of galvanized steel pipe wrapped with black plastic film is the highest under solar radiation, and the op?timum distance between the pipe and the heat-accumulating wall and the Earth?s surface is, respectively, 0.90~1.25 times of the outer diameter of the pipe. The way the pipe is covered has a great influence on the water temperature inside the pipe. When the black and polyethylene pipe covered with the white plastic film is in the best spatial position, the highest heat of the three series of tests is obtained, and the difference between the water temperature inside the pipe and the atmospheric temperature reaches 36.3?C.

scholarly journals Effects of Nanofluids in Improving the Efficiency of the Conical Concentrator System

Energies ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 28
Author(s):  
Alsalame Haedr Abdalha Mahmood ◽  
Muhammad Imtiaz Hussain ◽  
Gwi-Hyun Lee
Keyword(s):  
Heat Transfer ◽  
Solar Radiation ◽  
Thermal Efficiency ◽  
Fossil Fuels ◽  
Distilled Water ◽  
Flow Rates ◽  
Practical Applications ◽  
Heat Transfer Fluids ◽  
Significant Research ◽  
Collector Efficiency

Fossil fuels are being depleted, resulting in increasing environmental pollution due to greenhouse gases and, consequently, emerging detrimental environmental problems. Therefore, renewable energy is becoming more important; hence, significant research is in progress to increase efficient uses of solar energy. In this paper, the thermal performance of a conical concentrating system with different heat transfer fluids at varied flow rates was studied. The conical-shaped concentrator reflects the incoming solar radiation onto the absorber surface, which is located at the focal axis, where the collected heat is transported through heating mediums or heat transfer fluids. Distilled water and nanofluids (Al2O3, CuO) were used in this study as the heat transfer fluids and were circulated through the absorber and the heat storage tank in a closed loop by a pump to absorb the solar radiation. The efficiency of the conical concentrating system was measured during solar noon hours under a clear sky. The collector efficiency was analyzed at different flow rates of 2, 4, and 6 L/min. The thermal efficiency, calculated using different heat transfer fluids, were 72.5% for Al2O3, 65% for CuO, and 62.8% for distilled water. Comparing the thermal efficiency at different flow rates, Al2O3 at 6 L/min, CuO at 6 L/min, and distilled water at 4 L/min showed high efficiencies; these results indicate that the Al2O3 nanofluid is the better choice for use as a heating medium for practical applications.

Harrison Decoded

2020 ◽  
Keyword(s):  
Theoretical Approach ◽  
Environmental Conditions ◽  
Collaborative Research ◽  
Electronic Equipment ◽  
The Public ◽  
Royal Observatory ◽  
The Subject ◽  
Written Descriptions ◽  
Pendulum Clock

This volume centres on a clock, known as Clock B, built in the mid-1970s that achieved considerable acclaim after an extraordinary performance in a 2015 peer-reviewed public trial at the Royal Observatory, Greenwich. The clock was built according to an understanding of John Harrison’s unique theoretical approach to making precision pendulum clocks, which defies the standard approaches to making accurate clocks. The clock represents the culmination of over forty years of collaborative research into Harrison’s writing on the subject, which is scattered across a number of manuscripts and a book, printed shortly before his death. Ostensibly, Harrison set out to describe how to make his precision pendulum clock, but it is a mixture of his peripheral interests. Horological information is almost completely lost among vitriolic sentiments relating to his experiences with the Board of Longitude. However, as one reviewer surmised: ‘we are sorry to say that the public will be disappointed’ and another concluded that ‘it can only be excused by superannuated dotage’. The chapters provides contextual history and documentation of the analysis and decoding of the cryptic written descriptions. It presents this in parallel to the modern horological story of making, finishing, and adjusting Clock B; the process of testing, using electronic equipment to monitor the its performance and reaction to changes in environmental conditions, and, indeed, the mechanics behind the various compensating features of the design.

scholarly journals Lagged recovery of fish spatial distributions following a cold-water perturbation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. D. Robertson ◽  
J. Gao ◽  
P. M. Regular ◽  
M. J. Morgan ◽  
F. Zhang
Keyword(s):  
Water Temperature ◽  
Species Distribution ◽  
Environmental Conditions ◽  
Cold Water ◽  
Heat Waves ◽  
Rapid Change ◽  
Nonlinear Effects ◽  
Spatial Distributions ◽  
Spatiotemporal Model ◽  
Yellowtail Flounder

AbstractAnomalous local temperature and extreme events (e.g. heat-waves) can cause rapid change and gradual recovery of local environmental conditions. However, few studies have tested whether species distribution can recover following returning environmental conditions. Here, we tested for change and recovery of the spatial distributions of two flatfish populations, American plaice (Hippoglossoides platessoides) and yellowtail flounder (Limanda ferruginea), in response to consecutive decreasing and increasing water temperature on the Grand Bank off Newfoundland, Canada from 1985 to 2018. Using a Vector Autoregressive Spatiotemporal model, we found the distributions of both species shifted southwards following a period when anomalous cold water covered the northern sections of the Grand Bank. After accounting for density-dependent effects, we observed that yellowtail flounder re-distributed northwards when water temperature returned and exceeded levels recorded before the cold period, while the spatial distribution of American plaice has not recovered. Our study demonstrates nonlinear effects of an environmental factor on species distribution, implying the possibility of irreversible (or hard-to-reverse) changes of species distribution following a rapid change and gradual recovery of environmental conditions.

scholarly journals Evaluation and Recommendations for Improving the Accuracy of an Inexpensive Water Temperature Logger

2013 ◽  
Vol 30 (7) ◽  
pp. 1576-1582 ◽  
Author(s):  
S. J. Lentz ◽  
J. H. Churchill ◽  
C. Marquette ◽  
J. Smith
Keyword(s):  
Surface Layer ◽  
Solar Radiation ◽  
Water Temperature ◽  
Solar Heating ◽  
Bias Error ◽  
Mean Square ◽  
Temperature Logger ◽  
Accurate Temperature ◽  
Rms Error ◽  
Rms Errors

Abstract Onset's HOBO U22 Water Temp Pros are small, reliable, relatively inexpensive, self-contained temperature loggers that are widely used in studies of oceans, lakes, and streams. An in-house temperature bath calibration of 158 Temp Pros indicated root-mean-square (RMS) errors ranging from 0.01° to 0.14°C, with one value of 0.23°C, consistent with the factory specifications. Application of a quadratic calibration correction substantially reduced the RMS error to less than 0.009°C in all cases. The primary correction was a bias error typically between −0.1° and 0.15°C. Comparison of water temperature measurements from Temp Pros and more accurate temperature loggers during two oceanographic studies indicates that calibrated Temp Pros have an RMS error of ~0.02°C throughout the water column at night and beneath the surface layer influenced by penetrating solar radiation during the day. Larger RMS errors (up to 0.08°C) are observed near the surface during the day due to solar heating of the black Temp Pro housing. Errors due to solar heating are significantly reduced by wrapping the housing with white electrical tape.

Annual variations in body-size spectra of planktonic ciliate communities and their relationships to environmental conditions: a case study in Jiaozhou Bay, northern China

2012 ◽  
Vol 93 (1) ◽  
pp. 47-55 ◽  
Author(s):  
Henglong Xu ◽  
Yong Jiang ◽  
Wei Zhang ◽  
Mingzhuang Zhu ◽  
Khaled A. S. Al-Rasheid ◽  
...  
Keyword(s):  
Body Size ◽  
Water Temperature ◽  
Environmental Conditions ◽  
Jiaozhou Bay ◽  
Northern China ◽  
The Body ◽  
The Yellow Sea ◽  
Size Spectra ◽  
Annual Variations ◽  
Planktonic Ciliate

The annual variations in body-size spectra of planktonic ciliate communities and their relationships to environmental conditions were studied based on a 12-month dataset (June 2007 to May 2008) from Jiaozhou Bay on the Yellow Sea coast of northern China. Based on the dataset, the body sizes of the ciliates, expressed as equivalent spherical diameters, included five ranks: S1 (5–35 μm); S2 (35–55 μm); S3 (55–75 μm); S4 (75–100 μm); and S5 (100–350 μm). These body-size ranks showed a clear temporal succession of dominance in the order of S2 (January–April) → S1 (May–July) → S4 (August–September) → S3 (October–December). Multivariate analyses showed that the temporal variations in their body-size patterns were significantly correlated with changes in environmental conditions, especially water temperature, salinity, dissolved oxygen concentration (DO) and nutrients. In terms of abundance, rank S2 was significantly correlated with water temperature, DO and nutrients, whereas ranks S4 and S5 were correlated with the salinity and nutrients respectively (P < 0.05). These results suggest that the body-size patterns of planktonic ciliate communities showed a clear temporal pattern during an annual cycle and significantly associated with environmental conditions in marine ecosystems.

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