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Solar Power Successes and Failures
Published in Anco S. Blazev, Solar Technologies for the 21st Century, 2021
Solyndra’s biggest problem was its tubular thin film technology which had a number of serious flaws. The thin films in the glass tubes were close to the bottom of the competitors’ efficiencies table.The tubes were spaced so that only 50% of the module’s top was struck by sunlight—50% more inefficient in most cases.The bottom part of the tubes was not accessible, would not allow proper cleaning, would get dirty, reduce total output, and eventually stop working.The glass tubes and their fused glass/metal connections (weldment) were quite fragile. Shifting of the frame during transport, installation and operation caused them to stress and crack, thus losing integrity (vacuum) and allowing moisture and the elements to penetrate the tube.The modules could not be used in general purpose and large-scale power installations because they required white background to reflect some of the sunlight as needed to activate the bottom of the modules. This alone limited the market to a very narrow niche, contributing to slow sales and an unsustainable situation.The glass encapsulated thin films tubes required specially designed, custom made, and expensive to purchase, modify and operate processing equipment, engineering and labor.The materials costs were very high as well. The product was more expensive than the competition.
Instrumentation and Controls
Published in Siddhartha Mukherjee, Process Engineering and Plant Design, 2021
While the cost of rotameters is low, they provide good accuracies at low and medium flowrates. However, with opaque fluids, the float may not be visible. Further, glass tube types are subject to breakage. As a result, rotameters find limited applications in large process units like refineries or petrochemicals industries.
Comparison of ozone-based AOPs on the removal of organic matter from the secondary biochemical effluent of coking wastewater
Published in Environmental Technology, 2023
Yuxian Ji, Chunrong Wang, Lei He, Xiaoya Chen, Jianbing Wang, Xian Zhang, Qingbang Du
The reactions of organic matter degradation and mineralisation were performed in a 2L borosilicate glass reactor, which contained almost 1 L of actual coking wastewater, as shown in Figure 1. It can be seen that the oxygen cylinder provides the gas source which pressure does not exceed 0.03 MPa. The oxygen is dried and purified with silica gel before entering the ozone generator. The oxygen generates a mixture of ozone and oxygen through high-voltage discharge in the ozone generator (VMUS-ASE, AZCO INDUSTIES LTD, CANADA), and then enters the reactor after being adjusted by a flow metre. There are 10 gears on the ozone generator that are used to determine its power. The ozone concentration into the reactor is adjusted by changing the gas flow rate and the power of the ozone generator. The mixed composition of ozone and oxygen enters the reactor from the bottom of the reaction device (h = 1250 cm, Ф = 6 cm), and there is a sand core aeration plate of size 1.5-2.5μm at the bottom of the device to diffuse bubbles. The outer glass of the reactor is high borosilicate glass, which is resistant to ozone oxidation, and the inside is a quartz glass tube, which is used to install ultraviolet lamps. To avoid ozone pollution, the reacted gas is discharged into the ozone quenching in the fume hood.
Heat transfer and friction factor characteristics of annuli formed by the smooth inner tube and corrugated outer tube – An experimental study
Published in Experimental Heat Transfer, 2020
Saurabh Yadav, Santosh K. Sahu
Figure 1a and 1b shows the schematic diagram of test facility used to estimate the heat transfer and friction factor characteristics of flow through annuli formed by the smooth inner tube and corrugated outer tube in counterflow conditions and schematic of test specimen, respectively. Figure 1c shows a cut section of the test specimen. The test facility includes the test specimen, water flow system and airflow system, and instrumentation scheme. The test specimen is a DPHE formed by smooth inner tube and corrugated outer tube. The corrugation height (e) is kept 2.5 mm for all the test specimens. Detail of the test specimen is provided in Table 2. Twelve test specimens are used (TS1–TS12) in the investigation. Here, TS1, TS2, and TS3 denote the DPHE made of smooth inner and smooth outer tubes. While TS4 to TS12 denote the DPHE with smooth inner and corrugated outer tube of three different corrugated pitches and three different diameter ratios. The inner tube is made of copper material, while the outer tube is made of borosilicate glass material for each test specimen. Purpose of using borosilicate glass (as corrugated outer tube) is easy manufacturing of corrugation on glass tube. The specimens are prepared using the glassblowing lathe machine.
Evaluation and optimisation of receiver height in a compound parabolic collector with low acceptance angle
Published in International Journal of Ambient Energy, 2019
Sainath A. Waghmare, Nitin P. Gulhane
The parabolic shape of the collector is made up of highly reflective glass strips to construct it economically (Gudekar et al. 2013; Jadhav et al. 2013). The working fluid used is pure water, circulated by a centrifugal pump and stored in the water tank. Rotameter ensures the metered quantity of water flows through the receiver. Two thermocouples are placed on either side of the receiver to measure the inlet and outlet water temperature. An albedometer and a shaded pyranometer are used to measure global and diffuse radiation. The beam radiation was calculated by subtracting diffuse radiation from the global radiation. The U-bolts are capable of holding receiver pipe at the desired position. The heat energy received at different receiver height would be different. It results in a variation in a temperature rise of water, which is sensed by the thermocouples at the ends. The tubular receiver is covered with borosilicate glass tube to minimise the convection heat losses. It is supported by silicon O-rings at the ends. The receiver tube is supported by U-bolts and its height are adjusted very precisely by using vernier caliper with 0.1 mm least count. There are 8 no. of U-bolts attached at the ends of the collector frame to avoid bending of receiver pipe as shown in Figure 4.