Comparison between double slope solar still and fourfold slope solar still: energy, exergy, exergoeconomic, and enviroeconomic evaluation

This paper proposes a single basin fourfold slope solar still, which includes a fourfold slope glass cover plate used for solar heat collection and steam condensation. In order to show the efficiency of fourfold slope solar still, comparative experiments are conducted under the winter climate conditions in Hangzhou for testing the operational performance of double slope type solar still (DOSS) and fourfold slope still (FOSS), so as to make a comparative analysis between them. Results show that the productivity of fourfold slope still is 19.51% higher than that of double slope still, and fourfold slope solar still enhances the average hourly energy efficiency by 31.11%. According to the energy method, the energy payback time values of fourfold slope solar still and double slope solar still are 64.88 months and 75.42 months respectively. According to the environmental parameter method, FOSS and DOSS reduce 5.47 tons and 4.58 tons of CO2 respectively. The corresponding values based on the exergy environment parameters are 0.21 and 0.18 tons of CO2, respectively. The fourfold slope solar still has more obvious emission reduction function than the double slope solar still. The cost of distilled water of fourfold slope solar still is 0.28 RMB/kg, and the cost of double slope solar still is 0.30 RMB/kg. In addition, the environmental and economic parameters of fourfold slope still and double slope still are 79.29$ (561.37RMB) and 66.35$ (469.76RMB), respectively. While, the corresponding values based on the exergoenvironmental parameter are 3.05$ (21.59RMB) and 2.56$ (18.12RMB), respectively. From the analysis of exergoeconomic and exergoenvironmental parameters, fourfold slope single basin solar still appears to be more effective.

Enhancing the renewable energy payback period of a photovoltaic power generation system by water flow cooling

A photovoltaic system which enjoys water flow cooling to enhance the performance is considered, and the impact of water flow rate variation on energy payback period is investigated. The investigation is done by developing a mathematical model to describe the heat transfer and fluid flow. A poly crytalline PV module with the nomical capacity of 150 W that is located in city Tehran, Iran, is chosen as the case study. The results show that by incresing water flow rate, EPBP declines first linearly, from the inlet water flow rate of 0 to 0.015 kg.s-1, and then, EPBP approaches a constant value. When there is no water flow cooling, EPBP is 8.88, while by applying the water flow rate of 0.015 kg.s-1, EPBP reaches 6.26 years. However, only 0.28 further years decreament in EPBP is observed when the inlet water mass flow rate becomes 0.015 kg.s-1. Consequently, an optimum limit for the inlet water mass flow rate could be defined, which is the point the linear trend turns into approaching a constant value. For this case, as indicated, this value is 0.015 kg.s-1.

Experimental study of a solar water treatment device with dome structure cover in winter: performance evaluation and comparative analysis

In this paper, a dome slope single basin solar still for water treatment and desalination is presented. This new solar still device is based on installing a dome slope cover on the walls of the solar still. The main objective of such still is to concentrate more sunrays at the still's bottom basin, through the increased area of dome glass cover. Experiments are conducted under the climate conditions in Hangzhou city, China, for testing the operational performance of dome slope type solar still and the fourfold slope still, so as to make a comparative analysis between them. Assessment of the dome slope still's feasibility is performed based on energy, exergy, exergoeconomic, and enviroeconomic methodologies, as well as energy payback time. Results show that the productivity of dome slope still is 36% higher than that of fourfold slope still, and dome slope solar still enhances the average hourly energy efficiency by 34%. Due to the higher energy and exergy outputs of dome slope solar still throughout its lifetime, the novel solar still proposed in this study mitigates more CO2 compared to the fourfold slope still. Overall, incorporation dome slope cover with the still is found promising in terms of freshwater yield, cost, and energy payback time compared to conventional one. The dome slope single basin solar still appears to be effective from exergoeconomic, exergoenvironmental parameters analysis.

Experimental Study of Solar Energy Based Water Purifier (SEBWP) of Single Slope Type by Incorporating N Similar Evacuated Tubular Collectors (ETCs) having Series Connection

This research paper deals with the experimental investigation of solar energy based water purifier (SEBWP) of single slope type by incorporating N similar evacuated tubular collectors (ETCs) having series connection. Experimental investigation has been done for a year from August 2018 to July 2019. MATLAB has been used for evaluating performance parameters of the system followed by the validation of these results with their experimental values. A fair agreement has been found between theoretical and experimental values. Values of correlation coefficients for condensing glass temperature, water temperature and water yield have been found to be 0.9932, 0.9928 and 0.9951 respectively. Further, energy metrics, productivity, cost of producing one kg of fresh water, exergoeconomic and enviroeconomic parameters have been evaluated. Values of energy payback time, per kg cost of producing fresh water and exergy loss per unit Rs. have been evaluated to be 1.72 years, Rs. 0.95/kg and 0.128 kWh/Rs. respectively.

Application of LCA to Determine Environmental Impact of Concentrated Photovoltaic Solar Panels—State-of-the-Art

Photovoltaic systems represent a leading part of the market in the renewable energies sector. Contemporary technology offers possibilities to improve systems converting sun energy, especially for the efficiency of modules. The paper focuses on current concentrated photovoltaic (CPV) technologies, presenting data for solar cells and modules working under lab conditions as well as in a real environment. In this paper, we consider up-to-date solutions for two types of concentrating photovoltaic systems: high-concentration photovoltaics (HCPV) and low-concentration photovoltaics (LCPV). The current status of CPV solar modules was complemented by the preliminary results of new hybrid photovoltaic technology achieving records in efficiency. Compared to traditional Si-PV panels, CPV modules achieve greater conversion efficiency as a result of the concentrator optics applied. Specific CPV technologies were described in terms of efficiency, new approaches of a multijunction solar cell, a tracking system, and durability. The results of the analysis prove intensive development in the field of CPV modules and the potential of achieving record system efficiency. The paper also presents methods for the determination of the environmental impact of CPV during the entire life cycle by life cycle assessment (LCA) analysis and possible waste management scenarios. Environmental performance is generally assessed based on standard indicators, such as energy payback time, CO2 footprint, or GHG emission.

Improved Stability of Organic Photovotlaic Devices With FeCl3 Intercalated Graphene Electrodes

In this paper, we present the first organic photovoltaic (OPV) devices fabricated with FeCl3 intercalated few layer graphene (i-FLG) electrodes. i-FLG electrodes were first fabricated and characterized by electrical and spectroscopic means, showing enhanced conductive properties compared to pristine graphene. These electrodes were then used in the fabrication of OPV devices and tested against devices made with commercially available Indium Tin Oxide (ITO) electrodes. Both types of device achieved similar efficiencies, while the i-FLG based device exhibited superior charge transport properties due to the increase in work function characterizing i-FLG. Both types of device underwent a stability study using both periodic and continuous illumination measurements, which revealed i-FLG based OPVs to be significantly more stable than those based on ITO. These improvements are expected to translate to increased device lifetimes and a greater total energy payback from i-FLG based photovoltaic devices. These results highlight the potential benefits of using intercalated graphene materials as an alternative to ITO in photovoltaic devices.

An IoT-Based Life Cycle Assessment Platform of Wind Turbines

Life cycle assessment (LCA) is conducive to the change in the wind power industry management model and is beneficial to the green design of products. Nowadays, none of the LCA systems are for wind turbines and the concept of Internet of Things (IoT) in LCA is quite a new idea. In this paper, a four-layer LCA platform of wind turbines based on IoT architecture is designed and discussed. In the data transmission layer, intelligent sensing of wind turbines can be achieved and their status and location can be monitored. In the data transmission layer, the LCA platform can be effectively integrated with enterprise information systems through the object name service (ONS) and directory service (DS). In the platform layer, a model based on IMPACT 2002+ is developed, and four management modules are designed. In the application layer, different from other systems, energy payback time (EPBT) is selected as an important evaluation index for wind turbines. Compared with the existing LCA systems, the proposed system is specifically for wind turbines and can collect data in real-time, leading to improved accuracy and response time.

Application of organic photovoltaic materials (OPV) as greenhouse roof structures: A review

Organic Photovoltaic (OPV), as a third-generation PV technology, is becoming an appropriate substance used for greenhouse roofing structures. Semi-transparent OPV has a variety of merits such as low weight, flexibility, low environment impact and short energy payback time. Besides, it can harness larger amounts of sunlight as means of a very strong light absorbent material. This study shares some of the latest research which examines the feasibility of using semi-transparent, flexible organic photovoltaic (OPV) modules as greenhouse shading material. By using such modules, it may be possible to utilize the existing greenhouse-based agricultural areas for electricity production. The concept projects OPV modules to shade greenhouses and reduces excess solar energy which may result in reducing internal surrounding heat thus helps to mitigate the control environment. This will furthermore control plant heat stress which is one of the most important factors for plant growth. Some conclusion on the quality and quantity of plants with respect to the energy consumption in the greenhouse are also discussed.