Large Collector Research Articles

Estimation and identification of cost reduction potential avenues for large aperture parabolic trough solar collector

Estimation and identification of cost reduction potential avenues for large aperture parabolic trough solar collector

Enhanced interfacial capture with an elliptical cylinder

Interfacial capture of particles and droplets is important in practical applications. Interfacial capture owing to the surface tension force occurs only when the target (particle or droplet) is close to the collector, leading to low efficiency with collector or collector arrays. An elliptical cylinder instead of a common circular cylinder is a method to enhance capture efficiency. We theoretically investigate this situation by modelling the motion of floating particles around a surface-piercing elliptical cylindrical collector at Reynolds numbers of 1–10. Results indicate that, despite a smaller capture width, elliptical cross-sections, especially with smaller aspect ratios, are more efficient in capturing owing to a much smaller contact line perimeter compared with circular cross-sections. The aligned orientation (the major axis is parallel to the flow) is better than the orthogonal orientation (the major axis is perpendicular to the flow) owing to a larger capture width. A larger collector is beneficial to capillary capture but a very large size is adverse. Smaller but heavier floating particles for smaller capillary numbers can be easily captured at lower Reynolds numbers. The aligned orientation has a greater advantage over the circular cross-section and the orthogonal orientation in the capillary capture. This provides a good method for enhancing the capture efficiency of floating particles in applications.

Rantai Pasok Kopra Di Desa Cio Gerong Kecamatan Morotai Selatan Barat Kabupaten Pulau Morotai

The purpose of this study was to analyze and describe the copra supply chain in Cio Gerong Village, South West Morotai District, Morotai Island Regency. The research was conducted for 3 months, from August to November 2023. The research was conducted in Cio Gerong Village, South West Morotai District, Morotai Island Regency. This research uses primary data taken by conducting surveys, interviews, questionnaires, and documentation to respondents directly. The secondary data were taken through relevant agencies, such as the Central Bureau of Statistics, literature books, literature, journals from the internet. Sampling of farmers was done purposively (purposive sampling), the number of samples selected was 10 samples from 50 copra farmers, while the sample for copra traders was 5 people from 10 copra collectors. The data analysis used is descriptive method to identify product flow, financial flow and information flow. The results showed that the supply chain in Cio Gerong Village, West South Morotai Subdistrict, Morotai Island Regency, based on the flow of products from upstream to downstream starting from copra farmers, small collectors, and large copra collectors. The financial flow from downstream to upstream starts from large collecting traders buying copra from small collecting traders with a cash payment system and small collecting traders buying copra from farmers with a cash payment system. The flow of information flows from two directions, namely the first direction of large collectors to small collectors then to farmers, the second direction is farmers to small collectors then to large collectors.

Analysis of Clove Supply in Jombang District Regency, East Java Province, Indonesia (Case Study CV Mega Tiga Anugrah)

Cloves are an agricultural commodity that has great potential. CV Mega Tiga Anugrah is a clove supplier located on Java Island, where the clove supply is obtained from farmers from various regions on Sulawesi Island. This research aims to analyze product flows, money flows and information flows as well as the supply chain actors’ activities. This research uses a descriptive qualitative method with a case study approach. The research results show that the clove supply chain mechanism starts from the flow of products from farmers, small collectors, medium collectors, large collectors, and CV companies. Mega Tiga Anugrah, until they reached the cigarette factory. The flow of information in the clove supply chain is well integrated between supply chain actors, while the flow of money occurs by the agreement of the supply chain actors. Supply chain activities consist of two actors in the supply chain, namely the main and supporting actors. The main actors are farmers, small, medium, and large collectors, and the CV Mega Tiga Anugrah company. Meanwhile, the supporting actors include transport workers, factory workers, and the Cigarette Factory Company PT Hanjaya Mandala Sampoerna Tbk.

Agent Behavior Collaborative Strategy in Cocoa Agroindustry in Central Java, Indonesia

Objective: This study aims to influence the behavior of agro-industry actors in meeting the demand for cocoa beans in Batang Regency, Central Java, Indonesia. Methods: From a similar synthesis of literature, 38 indicators of collaborative behavior were produced which were used to create a questionnaire, and the data was collected by directly observing cocoa agro-industry actors—farmers, village collectors, sub-district collectors, large collectors, and cocoa factories. Partial Least Square (PLS) is used in data processing to identify collaborative behavior and indicators that influence behavior, and the Fuzzy Analytical Hierarchy Process (FAHP) is used for weighting. Results: The PLS results explain that the behavior of "trust" greatly influences communication behavior. That is, communication goes well when the agro-industry actor's trust system is high. "Information-sharing" behavior has a large impact on collaboration and "collaborative" behavior has a large impact on "continuous improvement". FAHP results obtained weighting values, and the order of priority shows that behaviors with the highest weighting values are trust between members of the supply chain, continuous communication, information sharing, value relationships, collaboration, and continuous improvement. In this results, each of these things needs to be considered for the smooth flow of distribution at the microscopic level in supporting the performance improvement of the cocoa agro-industry, and for other agro-industry.

Pola Distribusi Perdagangan dan MPP (Margin Pengangkutan dan Perdagangan) Bawang Merah di Jawa Barat

The trade distribution pattern describes the distribution chain of a commodity from the producer to the final consumer in an area where trading activities occur. The distribution of shallot commodities from final consumers involves one to seven trading business actors. The seven business actors can be broken down into six distribution patterns. Every business actor gets a transportation and trade margin (MPP) in his trading business, the longer the distribution chain, the potential for price increases for consumers. Farmers know the sources of price information from large farmers, collectors, and wholesalers. The distribution pattern in West Java Province consists of six patterns carried out by seven subjects, namely collectors, distributors, sub-distributors, agents, wholesalers, retailers, and supermarkets/supermarkets. This study took samples from shallot production centers in West Java, which is one sub-district which has the largest area and largest production. The number of farmers who became respondents was 10 percent, with the category of having been trying to cultivate shallots for at least three years which was analyzed descriptively. Based on the survey results, the MPP of shallots in West Java Province is 31.37 percent where the increase in the price of shallots from farmers to final consumers in West Java Province is 31.37 percent.

Technical and Economic Performance of Four Solar Cooling and Power Co-Generated Systems Integrated With Facades in Chinese Climate Zones

Abstract There has been an increasing interest in solar-driven combined energy supply systems for low-temperate applications, particularly those based on the Organic Rankine Cycle (ORC), Kalina Cycle (KC), or Trilateral Cycle (TLC). However, systems based on these thermodynamic cycles usually employ large area collectors that stand alone or are placed on the roof, without considering integration with the building facade. This research presents a solution to large-scale photothermal utilization integrated with facades for co-generated systems. The current study is the first to conduct performance and economic assessment for four novel solar cooling and power (SCP) co-generated systems driven by evacuated tube solar collectors (ETCs) or semi-transparent photovoltaic (STPV) integrated into the building facades. The suggested systems were simulated using TRNSYS to forecast their performance metrics when used in four Chinese cities with various climate zones. As indicators, a solar fraction (SF) and unit energy cost (UEC) were used to evaluate the technical and financial aspects of each system. The STPV-vapor compression cycle (VCC) system had the highest SF (100%, except Haikou), as well as the lowest UEC (0.211$/kWh on average) among the four cities, according to the results. Among the three solar–thermal co-generation systems, ETC–ORC–VCC had the best performance (SF,37.9%; UEC,0.597$/kWh on average).

Analysis of the Areca Nut Agroindustry Value Chain in Padang Pariaman Regency

There are two chain structures consisting of main actors and supporting actors. The structure of the first chain is Farmers → Small Collectors, → Large Collectors → Exporters. At the same time, the second chain structure is: Farmers, → Home Industry, → Collecting agents. Areca farmers get an added value of IDR 1,647.12/kilogram with an added value ratio of 71.80%. Small collectors get an added IDR 994.46/kilogram with an added value ratio of 22.10%. Prominent collectors get an added value of IDR 702.67/kg with a value-added ratio of 13.01%. The home industry obtains an added value of IDR 16,634.07/kilogram with an added value ratio of 79.21%. Farmers get a marketing margin of IDR 1,794.19/kilogram. Small collectors earn a marketing margin of IDR 1,500/kg. Collector traders earn a large marketing margin of IDR 900/kg. The home industry earns a marketing margin of IDR 18,000/kilogram.

The Effective and Exergy Efficiency of Multi-Pass Solar Air Collector with Longitudinal Fins: Analysis and Optimization

The present work investigates the exergy and effective efficiency of the multi-pass solar air collector with longitudinal fins by analysis approach and multi-objective optimization. The effect of 0.01-0.02 kg/s air flow rate, 15-35 mm collector depth, 1-3 m collector length, and 24.21-30.67 mm fin pitch was considered. The optimization was analyzed by the Preference Selection Index (PSI) method, with three maximum criteria: thermal efficiency, effective efficiency, and exergy efficiency. Mathematical models were solved by EES software. Results indicated that the multi-pass (TPLF and DPLF) type was better than the SPWF type by three criteria. The highest exergy efficiency of the TPLF and DPLF types was 6.696% and 5.636%. The greatest effective efficiency of the TPLF and DPLF types was 69.09% and 66.17%. Furthermore, the optimization results indicated that the three efficiency criteria of the DPLF type were 58.38%, 58.22%, and 4.491% for the best case; the three efficiency criteria of the TPLF type were 60.97%, 60.85%, and 5.439% for the best case. The worst configuration was the model with a short collector length, large collector depth, and large fin pitch. The collector efficiency decreased with decreased fin pitch for the configuration with the large collector length, short collector depth, and high mass flow rate.

Water harvesting through fog collectors: a review of conceptual, experimental and operational aspects

Abstract In water-scarce regions where fog is abundant, the population can rely on this resource to obtain fresh water. The potential to harvest fog is confirmed by Large Fog Collector projects worldwide, which are reviewed. Mostly maintenance issues due to environmental and complex social factors compromise the sustainability of such projects. The researchers endeavour to resolve these issues by developing enhanced materials, while others use biomimetic design, hence creating innovative collectors. The objective of this paper is to survey and review the state of the art and develop a framework of different types of innovative fog collectors, including conceptual, experimental and operational aspects.

Performance of a novel solar driven ventilation of smoke from moxibustion therapy

In this paper, a novel solar driven smoke ventilation system was proposed for the moxibustion therapy. A mathematical model is developed based on heat balance and fluid flow, and the performance of the ventilation system is studied. Sensitivity analyses of solar radiation intensity from 100 to 1000 W/m 2 , collector length from 1 to 10 m, solar system width from 0.5 to 3 m, and chimney width from 0.1 to 0.3 m, and chimney height from 0.5 to 3 m are also performed. For stronger solar radiation, larger collector or higher chimney, the effective heat flux of the solar system increases and the flow rate increases. For the solar radiation of larger than 210 W/m 2 , the velocity at the smoke pipe entrance is larger than the critical velocity of 0.5 m/s. Higher chimney also leads to the increase of the driving force besides receiving more solar radiation. For reaching the pipe entrance velocity of larger than the critical velocity, a solar radiation of larger than 210 W/m 2 , a chimney height of higher than 0.89 m, a collector length of larger than 1.9 m, or a collector width of larger than 0.198 m is needed. The conclusions are obtained under the absent parametric values: the solar radiation intensity of 600 W/m 2 , the chimney height of 2 m, the solar collector length of 8 m, and the widths of solar collector and chimney of 0.25 m. This work lays a solid foundation for application of this solar driven smoke ventilation system to the moxibustion therapy.

Analisis Penerimaan Petani Penyadap Getah Pinus Di Hutan Kemasyarakatan Sipatuo Lembang Pa’tengko Kecamatan Mengkendek Kabupaten Tana Toraja

This study aims to analyze how much pine resin tapping farmers receive and describe the marketing channels of pine resin tapping farmers in the Sipatuo Community Forest, Lembang Pa'tengko, Mengkendek District, Tana Toraja Regency. The variables to be observed in this study are pine resin production, tapper farmers' revenue, socio-economic factors, management of Sipatuo HKm, and marketing channels. The data collection method was carried out through surveys and distributing questionnaires to pine resin tappers as many as 40 respondents. Data is analyzed descriptively and revenue is calculated based on the Total Revenue equation. The results showed that the Sipatuo HKm was a limited production forest managed by the Lembang Pa'tengko community, the tree stands that were managed were a government reforestation program in 1976-1978. Furthermore, the results of the analysis of the average tapper acceptance of Rp6,300,450 thus the reception of tappers at HKm Sipatuo is sufficient to meet household needs because the average acceptance of tappers exceeds the UMP of South Sulawesi. Marketing of pine resin in HKm is carried out on average once a month, with a selling price of pine resin, which is Rp. 9,500.00 where the pine resin is sold to partners as one intermediary, then the pine resin is sent to CV.Pindo Indonesia in Makassar as a large collector.

Innovative flotation separation considering pores blocking to facilitate residual carbon recovery from coal gasification fine slag

The conventional flotation of coal gasification fine slag has the dilemma of large collector dosage and low carbon recovery due to the developed porosity of the residual carbon. In this study, an innovative method to enhance the flotation recovery of residual carbon was proposed by pores blocking with pulverized coal. Flotation experiments were carried out to verify the effect of pore blocking on the recovery of residual carbon, and scanning electron microscope, X-ray photoelectron spectroscopy, and mercury intrusion porosimetry were used for mechanism analysis. The results showed that the addition of pulverized coal did play a role in pores blocking in the novel flotation, and its carbon recovery rate was improved by 14.11% (absolute value) compared to that of conventional flotation at the same ash content of the concentrates. On the one hand, the pulverized coal adheres on the pore openings on the residual carbon surface, thus preventing the collector adsorption into the pore channels; on the other hand, the adhesion of pulverized coal to the residual carbon surface increases the adsorption sites for collector. Therefore, pores blocking is beneficial for more adsorption of the collector on the outer surface of the residual carbon and thus improving its flotation recovery. This paper provides significant inspiration for efficient flotation of coal gasification fine slag.

Thermal and thermodynamic optimization of the performance of a large aperture width parabolic trough solar collector using gaseous and supercritical CO2 as heat transfer fluids

• A coupled optical-thermal-fluid model of a parabolic trough collector is developed. • sCO 2 exhibits better thermal and thermodynamic performance compared to gaseous CO 2. • sCO 2 has comparable thermal performance relative to Therminol-VP1 above 80 bar. • Flow rates above 300 m 3 /h give receiver temperature gradients lower than 50°C. • New correlations for optimal thermal and thermodynamic performance are presented. The degradation of thermal-oil-based working fluids in parabolic trough solar collectors (PTSCs) systems at temperatures above 400 °C has accelerated the search for cost-effective and efficient heat transfer fluids (HTFs) for high-temperature applications. Carbon dioxide is abundant and has the potential to be used as a working fluid in PTSCs. In this work, the performance of a larger aperture width PTSC with CO 2 as the working fluid (either in gaseous or supercritical phase) is investigated. In this study, a PTSC system with an aperture width of 9 m (geometric concentration ratio of 113) was considered. The operating pressure is in the range of 40−100 bar, the HTF inlet temperatures are between 650 and 1000 K, and the flow rate varies from 32.6 to 653 m 3 /h. A thoroughly verified and validated computational model using a combination of Monte-Carlo ray tracing and computational fluid dynamics was used for the numerical study. In addition, the Realizable k- ε model was used for turbulence modeling. The results show that CO 2 at 80 bar has comparable thermal performance relative to current thermal oil-based HTFs. Results further show that supercritical CO 2 (sCO 2 ) has the best thermal performance compared to gaseous CO 2 . In addition, the entropy generation minimization method was used to determine the Reynolds number that minimizes the irreversibilities at a given operating pressure. At low pressures, much higher flow rates are required to achieve high heat transfer rates and reduce temperature gradients in the absorber tube. Furthermore, correlations have been developed for the optimal Reynolds numbers at which the entropy generation rate is minimum and the collector efficiency is maximum.

Temperature homogenization control of parabolic trough solar collector field

The collector fields of large-scale commercial trough solar power stations often face inhomogeneities in environmental parameters and resistance to flow in the pipe network. Aiming at dealing with the problem of uneven distribution of hydraulic parameters and radiation in large collector fields, this study establishes a heat transfer model and a hydraulic model of the collector field and proposes a control strategy for the heat transfer fluid (HTF) flow in the parabolic trough collector (PTC) loops. Based on the proposed hydraulic model, the loop valve opening is directly calculated and fast control of the loop HTF flow is achieved. Simulation results show that the scheme significantly reduces the differences in HTF temperature at the outlet of the PTC loops.

Issues in rice marketing system: a case of central terai

This study was conducted to understand the challenges and prospects of ricemarketing by taking case of central Nepal. Two focus group discussionsalong with eight key informants’ interviewswere conductedinBara and Parsa districts of Nepal.Also, secondary information was collected by reviewing the related literatures.The study revealed that the consumer price of rice is almost double than the farm gate price, possibly due to the presence of several intermediaries in different nodes of the supply chain.Key market actors like large collectors, millers and wholesalers have a dominating role in price negotiation and supply of rice in the market. The rice value chain is not strong enough, which might be due to poor vertical and horizontal as well as backward and forward linkages among the key players. The demand of fine and aromatic rice is gradually increasing due to changing food habits of the consumers and their access to purchasing capacity as well.The high yielding short duration varieties of fine and aromatic rice need to be identified and developed to meet the growing demand of consumers.In addition, to boost productivity and profitability of rice, a better investment climate, risk sharing mechanism and strengthened value chain with efficient research and extension services are required.

Daylighting of road tunnels through external ground-based light-pipes and complex reflective geometry

The transfer of solar light to the interior of tunnels to complement electrical lighting during daytime, contributes to save energy and decrease the number of installed projectors. The solutions traditionally implemented, based on light-pipes hanging from the vault, seemed reasonable because the leakages of light-pipes can emit luminous flux like projectors, but had the disadvantage of needing higher clearance gauges with the consequent costs in drilling, building materials, works and maintenance. Furthermore, these hanging light-pipes cannot be installed in working tunnels if they were not foreseen in the initial project. In this article, a new concept of light injection and distribution in tunnels is proposed. It consists of the coupling of three main elements: collectors, light-pipes, and one reflecting vault whose design is optimized to ensure the photometric requirements on the pavement. The proposed system can collect more than 1.5 Mlm of solar flux with not excessively large collectors installed on the ground of the road shoulder, and project them to the vault that finally distributes the light towards the pavement. With this flux, average illuminances of 3478 lx and uniformities of 0.73 can be achieved, which means pavement luminance around 350–400 cd/m2, in good agreement with the requirements during daytime. The savings can be higher than 40 %. Besides these savings, this system can be easily implemented in existing tunnels. The proposal and some estimations are discussed.

Technical and economic performance analysis of large flat plate solar collector coupled air source heat pump heating system

In rural areas of China, clean energy heating in winter is important for coal replacement. Winter temperatures in northwest China are usually below 0°Celsius and the heating season lasts for a long time, which is a huge expense for local residents. Solar energy, air source heat pumps(ASHP), and other energy-saving technologies are known to be effective in reducing heating expenses. However, due to the intermittent and unstable nature of solar energy itself, relying on solar heating is difficult to ensure stable heating and is certainly not economical. ASHP adds a financial burden to local residents due to the relatively high cost of winter heating. In response to the above problems, a new idea of ASHP coupled with solar energy for stable heating is proposed, and a large flat plate solar collector-air source heat pump(LFPSC-ASHP) heating system was established in Green Village, Lanzhou City. Experimental and simulation studies were conducted for this system to reveal the performance and economic benefits of the system for the heating season in three modes: solar collector heating, solar heat pump heating, and air source heat pump heating. The results show that the ASHP-assisted solar heating system is a great technical and economical improvement over the use of solar collectors or ASHP heating throughout the heating season. The LFPSC-ASHP system can continuously and stably heat the target building and has excellent economic and environmental benefits. In the operation of the whole heating season, the average collector efficiency of LFPSC is 0.42, the average COP of solar heat pump heating season is 3.75, and the average COP of ASHP heating season is 2.94. The solar fraction of the system in the whole heating season is 31.8 %, and the system energy efficiency ratio is 3.08. The system can save 7,690.5 CNY by running the whole heating season with a dynamic payback period of 6.58 years. ​Sensitivity analysis of the dynamic payback period shows that lower coal prices extend the dynamic payback period, while lower electricity prices and system costs reduce it. The primary energy saving rate of the system in the whole heating season is 67.5 %. The system can conserve 4,700.06 kg of standard coal in a whole heating season, which is equivalent to a reduction of 12,323.55 kg of CO2.

The Diversity of Warehouse Pests on Areca Nuts in the West Sumatera, Indonesia

Areca nut is one of Indonesia’s leading export commodities that must adhere to certain phytosanitary requirements, including being pest-free. It is infested by several types of insect pests during the storage process. Therefore, this study aims to determine the diversity of warehouse pests that infest areca nuts. It was conducted using a survey method at three warehouses of large collectors and exporters of areca nut in the Padang city and the Padang Pariaman regency. The purposive sampling method was adopted to collect samples from three traders' warehouses. Furthermore, the nut was taken diagonally in a pile, namely the corner and center of 1 kg each, and repeated 4 times. The identification key was used to identify 15 insect types from 10 families and 3 orders. The Cryptolestes pusillus, C. ferugineus, and Carpophilus sp. were found with the highest number of individuals in each warehouse. The diversity index of the three warehouses is 1.78, 2.14, and 1.90 indicating a moderate level. Additionally, the similarity index between warehouses shows a high and very high level of species similarity.

Analisis Efisiensi Saluran Tataniaga Biji Pinang Kering di Kecamatan Kuala Kabupaten Nagan Raya

The purpose of this study was to determine the pattern of commerce and efficiency of the business channel of dried betel nut in Kuala District, Nagan Raya Regency. Data were collected by conducting direct interviews with farmers, small collector traders (PPK), and large collector traders (PPB). Data analysis uses Structure, Conduct, and Performance approaches. The overall market structure in the betel nut business process in Kuala District tends to lead to a monopsony market structure. Seeing that the number of sellers and buyers is not balanced, the betel nut business system in Kuala District is inefficient, because it refers to the monopsony market structure. Of the three commercial channels, the most efficient commercial channel is channel I because it has the lowest margin value and the highest farmer's share so that from the farmer's side, the share of prices received by farmers is quite large.