Recent content by The Fez

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    Net metering - hybrid solar inverter system question

    I don't think you are going to find what you are looking for. Even in large wind farms, where the turbines in the nacelles produce AC power, it is then converted to DC before being fed to in inverter to connect to the grid.
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    Do engineers working on high-tech applications make approximations?

    There will always bee approximations in any engineering application, no matter how "high tech" it is. For instance, starting with the material you are working with, whether simple mass-produced steel beams, to aluminum, to titanium to some exotic nickel super alloy, you can't even know the...
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    Using Hydrogen in natural gas pipelines

    At the end of the day, I don't see much viability for the green hydrogen industry outside some niche applications. The round trip energy efficiency is horrid (about 30%) and storage is a problem. We did a study for one of our power plants, currently generates about 600 MW. I calculated it...
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    Using Hydrogen in natural gas pipelines

    You are correct that normal cellulose SMAW electrodes generate high hydrogen, but normal pipeline is still welded that way, since the majority of the hydrogen is diffused out when the weld cools. If you are welding on a pipeline such as hot tapping, where the pipeline is in service and the weld...
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    Using Hydrogen in natural gas pipelines

    Actually that isn't true. LNG is used to transport natural gas overseas, but the vast majority within the country is transported in it's gaseous state. Per DOE website: "While the majority of natural gas is delivered in its gaseous form via pipeline in the United States, the growth in the...
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    B Comparing energy released to the energy needed to compress a gas (game design scenario)

    Reading the reddit thread, there is no way to calculate this at all, based on the amount of power we're dealing with (about 3 billion times the total power consumed by everyone on earth in a year), compressed into such a small area (at least fusion level temperatures, probably greater than CERN...
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    Validating "NET Power's" use of the Allam-Fetvedt cycle

    My company CEO was very interested in this technology to support our zero carbon goal, so he sent two of our engineers out to La Porte to get a tour of the "fully functional" 50 MW plant, per the manufacturer. When they got out there, all the "Well, actually.." started coming out. Well...
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    B Doubts about the definition of a linear system

    F=ma is not a valid equation if m isn't constant. 2nd law of motion states "The rate of change of momentum of a body is directly proportional to the applied force..." In other words, F=d(mv)/dt. only if m is constant can you pull it out of the derivative, so F=d(mv)/dt = m(dv/dt) = ma.
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    B Validating Darts Tournament Skill Levels: A Non-Intrusive Approach

    Yes, darts stats for games like Cricket are usually marks per round (MPR), so number of scores per 3 darts.
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    Challenge Math Challenge - June 2023

    What am I missing on Question 1? It would be easy to construct a line through the centroids of both shapes, which should bisect each one. Centroid of a rectangle is the intersection of the diagonals, and triangle is intersection of the three medians.
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    How much air pressure is needed to push water up a column?

    If you have water flowing, you can always use a hydraulic ram. It takes flowing water and diverts a portion to a higher elevation. Readily available online. https://en.wikipedia.org/wiki/Hydraulic_ram
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    I Relative humidity question (cooling the air in a room)

    What you need is known as a "psycrometric chart." The answer will vary somewhat based on your elevation, but there are charts for many different elevations and some correction factors for stuff inbetween. Long story short, without removing any water from the air (looks about 8g H2O/kg dry...
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    B Strange Relationships of the Circle

    There are many basic arithmetic errors in your charts. The [S/L]/R column should always be 1/2, for instance.
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    Potential Energy Storage: Investigating the Mechanics of a Heavy Weight Drop

    There are people working on this concept, with pressurized water lifting a huge weight up and down, and then running through a turbine, similar to pumped hydro, but without the large footprint/ecological concerns: https://heindl-energy.com/ I think what you guys had calculated is in the...
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    Challenge Math Challenge - July 2021

    And I can't read either. I had F(0) = 0. With the actual stated problem C1 = 1, C2 = 0, and C3 = 1. So $$F(x) = e^{-x} + xe^x$$
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