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Re: Request hot-seat critique: Pumping cycle

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  • Doug
    The pumping cycle versus continuous rotation: Efficiency: reduced Capacity factor: impaired Intermittency: increased Speed to drive generator: too low
    Message 1 of 20 , Jun 3 6:34 AM
      The pumping cycle versus continuous rotation:
      Efficiency: reduced
      Capacity factor: impaired
      Intermittency: increased
      Speed to drive generator: too low
      Continuous output: no
      motive force: thrust
      native speed for generation: too slow
      overspeed protection: no
      unattended launch: no
      unattended operation: no
      storm survival: no
      Solution to noncontinuous output and weak performance:
      "laddermill" concept introduced by me in the 1970's
      Better solution: rotating propellers driving generators as practiced by the multi-billion-dollar wind energy industry.
      - Doug Selsam
      'bye again...


      --- In AirborneWindEnergy@yahoogroups.com, "Joe Faust" <joefaust333@...> wrote:
      >
      > Request hot-seat critique: Pumping cycleWhat say you?
      > Trial text for glossary is up on hot seat for peer critique:
      > ============pumping cycle HighWind tutorial
      > <http://homes.esat.kuleuven.be/~highwind/?p=36> | Note: By use of
      > loop, a system may rotate continuously in one direction; in such, a
      > return sector of the loop is phased to low resistance; such loop tactic
      > hides the pumping cycle by continuous powering that is reduced by the
      > continuous cost of the residual resistance in the return-low-resistance
      > sector of the loop. ~JpF, June 2, 2012.=====================
    • blturner3
      Cool. I have a new favorite. They re actually making stuff. They are doing the simulations. They are doing three(multiple) kites on one generator. They are
      Message 2 of 20 , Jun 4 6:27 AM
        Cool. I have a new favorite. They're actually making stuff. They are doing the simulations. They are doing three(multiple) kites on one generator. They are looking at both high and low L/D. They are working on the other details that these systems entail. All the stuff I would do If I were actually doing it.

        I will take up Doug's rebuttal inline below.

        Brian

        --- In AirborneWindEnergy@yahoogroups.com, "Doug" <doug@...> wrote:
        >
        > The pumping cycle versus continuous rotation:
        > Efficiency: reduced

        Yes, A pumping system looses 1/2 to 1/4 of it's production time to reel-in. It also has to put power back in. Vs. a traditional turbine that has 90% of it's material in the mast, hub, and inner part of the blade.

        > Capacity factor: impaired

        No, Higher altitude has better capacity factor.

        > Intermittency: increased

        A multi-kite system makes this a non-issue

        > Speed to drive generator: too low

        Yes, Same as a regular turbine.

        > Continuous output: no

        Yes, In a multikite system or farm.

        > motive force: thrust

        I may not understand your point here but the good systems are largely the same as a regular turbine.

        > native speed for generation: too slow

        Same as a regular turbine.

        > overspeed protection: no

        Not yet

        > unattended launch: no

        Not yet

        > unattended operation: no

        Not yet

        > storm survival: no

        Not yet

        > Solution to noncontinuous output and weak performance:
        > "laddermill" concept introduced by me in the 1970's
        > Better solution: rotating propellers driving generators as practiced by the multi-billion-dollar wind energy industry.
        > - Doug Selsam
        > 'bye again...
        >
        >
        > --- In AirborneWindEnergy@yahoogroups.com, "Joe Faust" <joefaust333@> wrote:
        > >
        > > Request hot-seat critique: Pumping cycleWhat say you?
        > > Trial text for glossary is up on hot seat for peer critique:
        > > ============pumping cycle HighWind tutorial
        > > <http://homes.esat.kuleuven.be/~highwind/?p=36> | Note: By use of
        > > loop, a system may rotate continuously in one direction; in such, a
        > > return sector of the loop is phased to low resistance; such loop tactic
        > > hides the pumping cycle by continuous powering that is reduced by the
        > > continuous cost of the residual resistance in the return-low-resistance
        > > sector of the loop. ~JpF, June 2, 2012.=====================
        >
      • Pierre Benhaiem
        ... Not yet Yes by slowing or stopping crosswind kite motion. PierreB ... doing the simulations. They are doing three(multiple) kites on one generator. They
        Message 3 of 20 , Jun 4 9:26 AM
          "
          > overspeed protection: no

          Not yet"

          Yes by slowing or stopping crosswind kite motion.

          PierreB

          --- In AirborneWindEnergy@yahoogroups.com, "blturner3" <yahoo2@...>
          wrote:
          >
          > Cool. I have a new favorite. They're actually making stuff. They are
          doing the simulations. They are doing three(multiple) kites on one
          generator. They are looking at both high and low L/D. They are working
          on the other details that these systems entail. All the stuff I would do
          If I were actually doing it.
          >
          > I will take up Doug's rebuttal inline below.
          >
          > Brian
          >
          > --- In AirborneWindEnergy@yahoogroups.com, "Doug" doug@ wrote:
          > >
          > > The pumping cycle versus continuous rotation:
          > > Efficiency: reduced
          >
          > Yes, A pumping system looses 1/2 to 1/4 of it's production time to
          reel-in. It also has to put power back in. Vs. a traditional turbine
          that has 90% of it's material in the mast, hub, and inner part of the
          blade.
          >
          > > Capacity factor: impaired
          >
          > No, Higher altitude has better capacity factor.
          >
          > > Intermittency: increased
          >
          > A multi-kite system makes this a non-issue
          >
          > > Speed to drive generator: too low
          >
          > Yes, Same as a regular turbine.
          >
          > > Continuous output: no
          >
          > Yes, In a multikite system or farm.
          >
          > > motive force: thrust
          >
          > I may not understand your point here but the good systems are largely
          the same as a regular turbine.
          >
          > > native speed for generation: too slow
          >
          > Same as a regular turbine.
          >
          > > overspeed protection: no
          >
          > Not yet
          >
          > > unattended launch: no
          >
          > Not yet
          >
          > > unattended operation: no
          >
          > Not yet
          >
          > > storm survival: no
          >
          > Not yet
          >
          > > Solution to noncontinuous output and weak performance:
          > > "laddermill" concept introduced by me in the 1970's
          > > Better solution: rotating propellers driving generators as practiced
          by the multi-billion-dollar wind energy industry.
          > > - Doug Selsam
          > > 'bye again...
          > >
          > >
          > > --- In AirborneWindEnergy@yahoogroups.com, "Joe Faust"
          <joefaust333@> wrote:
          > > >
          > > > Request hot-seat critique: Pumping cycleWhat say you?
          > > > Trial text for glossary is up on hot seat for peer critique:
          > > > ============pumping cycle HighWind tutorial
          > > > <http://homes.esat.kuleuven.be/~highwind/?p=36> | Note: By use of
          > > > loop, a system may rotate continuously in one direction; in such,
          a
          > > > return sector of the loop is phased to low resistance; such loop
          tactic
          > > > hides the pumping cycle by continuous powering that is reduced by
          the
          > > > continuous cost of the residual resistance in the
          return-low-resistance
          > > > sector of the loop. ~JpF, June 2, 2012.=====================
          > >
          >
        • roderickjosephread
          Correct me if I m wrong,...Overspeed protection is about saving your generator / alternator windings from burning up because they can t hold back the blades,
          Message 4 of 20 , Jun 4 12:54 PM
            Correct me if I'm wrong,...Overspeed protection is about saving your generator / alternator windings from burning up because they can't hold back the blades, that's covered by shunt engagement of extra windings at higher speeds and setting outside kite lines on bungee to give loose leach response spilling gusts. lift kites pulling the generator to the side or down would do too. A cooled braking system will cause a ring set to twist downward (almost like that elastic hose we saw) as rings wind together (tethers joining at less than 1 ring diameter)
            sorted.
          • roderickjosephread
            Storm survival. Pack it away. storms are highly predictable. keep an inner hard working core set of lines to prevent fly away in prolonged damaging gusts. Self
            Message 5 of 20 , Jun 4 1:00 PM
              Storm survival.
              Pack it away. storms are highly predictable. keep an inner hard working core set of lines to prevent fly away in prolonged damaging gusts.

              Self launching
              LEI surf kites self launch.
              progressing scale (lobster tail) small kite lifts first in lightest wind aiding larger and larger lifters.
              Done on the water surface your worry is no wind when the kites will go more with the tides. patrol tug boat keeps the top line tight in direction of next most likely downwind.

              Unattended. I don't want any unattended machine. Humans need jobs.
            • Doug
              Brian: Your response indicates you do not know the definition of the term capacity factor . It refers to the fraction of energy contained in the wind you can
              Message 6 of 20 , Jun 5 7:36 AM
                Brian:
                Your response indicates you do not know the definition of the term "capacity factor". It refers to the fraction of energy contained in the wind you can capture based on your swept area, wherever that swept area may be. Most windfarm turbines hope for 30-40%
                The "intermittency" for any working surface (single kite?) (blade?) is not improved by multiple kites (blades). Intermittency for the generator, yes, but the rest of the system must be redundant, which multiplies costs for the same power output. If I showed you a wind turbine that needed 3 times as much blade and drivetrain to do the same job is that an improvement? It all comes down to economics.

                Thought experiment:
                1) Take 3 General Electric 1.5 Megawatt turbines.
                2) Remove the generators and gearboxes and let the rotors spin freely.
                3) Place the turbines on rails so the can slide upwind/downwind
                4) engineer a redundant winch system so all 3 General Electric turbines are sliding alternately upwind and downwind on their rails, pulling on the winches while other winches are powering a retraction cycle, together powering rotation of a shaft with whatever energy is left over...
                5) attach a generator to the shaft
                6) or do we need 3 separate generators?
                7) and a lot of electronics and programming?
                8) At what point do you admit you've created a "clusterflux" situation?
                9) Compare your output to a single G.E. 1.5 Megawatt turbine operating as designed.
                10) Run the numbers and see how economical this engineering solution turns out to be
                11) address and solve all reliability issues
                12) Now make it fly. :)
                13) repeat steps 1-12


                --- In AirborneWindEnergy@yahoogroups.com, "blturner3" <yahoo2@...> wrote:
                >
                > Cool. I have a new favorite. They're actually making stuff. They are doing the simulations. They are doing three(multiple) kites on one generator. They are looking at both high and low L/D. They are working on the other details that these systems entail. All the stuff I would do If I were actually doing it.
                >
                > I will take up Doug's rebuttal inline below.
                >
                > Brian
                >
                > --- In AirborneWindEnergy@yahoogroups.com, "Doug" <doug@> wrote:
                > >
                > > The pumping cycle versus continuous rotation:
                > > Efficiency: reduced
                >
                > Yes, A pumping system looses 1/2 to 1/4 of it's production time to reel-in. It also has to put power back in. Vs. a traditional turbine that has 90% of it's material in the mast, hub, and inner part of the blade.
                >
                > > Capacity factor: impaired
                >
                > No, Higher altitude has better capacity factor.
                >
                > > Intermittency: increased
                >
                > A multi-kite system makes this a non-issue
                >
                > > Speed to drive generator: too low
                >
                > Yes, Same as a regular turbine.
                >
                > > Continuous output: no
                >
                > Yes, In a multikite system or farm.
                >
                > > motive force: thrust
                >
                > I may not understand your point here but the good systems are largely the same as a regular turbine.
                >
                > > native speed for generation: too slow
                >
                > Same as a regular turbine.
                >
                > > overspeed protection: no
                >
                > Not yet
                >
                > > unattended launch: no
                >
                > Not yet
                >
                > > unattended operation: no
                >
                > Not yet
                >
                > > storm survival: no
                >
                > Not yet
                >
                > > Solution to noncontinuous output and weak performance:
                > > "laddermill" concept introduced by me in the 1970's
                > > Better solution: rotating propellers driving generators as practiced by the multi-billion-dollar wind energy industry.
                > > - Doug Selsam
                > > 'bye again...
                > >
                > >
                > > --- In AirborneWindEnergy@yahoogroups.com, "Joe Faust" <joefaust333@> wrote:
                > > >
                > > > Request hot-seat critique: Pumping cycleWhat say you?
                > > > Trial text for glossary is up on hot seat for peer critique:
                > > > ============pumping cycle HighWind tutorial
                > > > <http://homes.esat.kuleuven.be/~highwind/?p=36> | Note: By use of
                > > > loop, a system may rotate continuously in one direction; in such, a
                > > > return sector of the loop is phased to low resistance; such loop tactic
                > > > hides the pumping cycle by continuous powering that is reduced by the
                > > > continuous cost of the residual resistance in the return-low-resistance
                > > > sector of the loop. ~JpF, June 2, 2012.=====================
                > >
                >
              • Doug
                As always, the idle musings of someone with ZERO familiarity with the real world of wind energy. Idiots have been claiming their contraption need not address
                Message 7 of 20 , Jun 5 7:49 AM
                  As always, the idle musings of someone with ZERO familiarity with the real world of wind energy.
                  Idiots have been claiming their contraption need not address overspeed from day 1. "I'll just shut it down! - Storms are "highly predictable"! -
                  Famous last words.
                  Once again, it's "groundhog day".
                  They go to the store and come back to find their machine destroyed or burned out, scratch their heads and ask "what happened"?

                  Here's what happened:
                  You went to the store to buy some bread. It got windy in the half-hour you were away.
                  Hey Roderick, why not go convince the wind energy industry to start ignoring its main challenge for the last 1000 years, overspeed protection?
                  Let's see, how are wind turbines classified?
                  By their method of overspeed protection!
                  Therefore it must be insignificant!
                  Insignificant in the mind of someone who has never had the problem of making too much power - one with no experience in wind energy.
                  I know, I know, this is all way "over your head"...
                  Sorry about that.

                  Overspeed protection is not the main thing.
                  It's the ONLY thing in wind turbine design.
                  Making power is easy - not a mystery - follow the formula.
                  Controlling that power, or not, is when failure begins.
                  It all starts when it gets windy. And windier. And windier.
                  The exact windpseed is not predictable.
                  So a solution to shut down the system when strong winds approach will result in a further reduction in capacity factor.
                  Because you will not be able to shut down your system once the strong winds have already started, so you will have to keep it on the ground whenever there is any chance of strong winds.
                  So while real wind energy people are counting the dollars harvested, you will be saying "maybe not today..."

                  --- In AirborneWindEnergy@yahoogroups.com, "roderickjosephread" <rod.read@...> wrote:
                  >
                  > Storm survival.
                  > Pack it away. storms are highly predictable. keep an inner hard working core set of lines to prevent fly away in prolonged damaging gusts.
                  >
                  > Self launching
                  > LEI surf kites self launch.
                  > progressing scale (lobster tail) small kite lifts first in lightest wind aiding larger and larger lifters.
                  > Done on the water surface your worry is no wind when the kites will go more with the tides. patrol tug boat keeps the top line tight in direction of next most likely downwind.
                  >
                  > Unattended. I don't want any unattended machine. Humans need jobs.
                  >
                • roderickjosephread
                  Overspeed protection is not the main thing. ... Not in the UK Doug. Maybe in happy land USA. Had you bothered to read or try to understand (I don t think you
                  Message 8 of 20 , Jun 6 3:34 AM
                    Overspeed protection is not the main thing.
                    > It's the ONLY thing in wind turbine design.

                    Not in the UK Doug. Maybe in happy land USA. Had you bothered to read or try to understand (I don't think you have yet) my description of fail safe modes through to to collapse, continuing generation through out of spec wind speeds ... you may have seen that there is more involvement. see below. Read it this time. Re-read what you missed. Now, do you want to share anything useful? like say gyroscopic effects modelling on the long shaft generator? New CFD results? anything constructive please.

                    Specific design considerations will be required in respect of:
                    • manufacturer's turbine certification;
                    • manufacturer's operations manual and maintenance instructions;
                    • results of factory acceptance testing;
                    • provision of assembly instructions, drawings and design information for the construction phase;
                    • assembly criteria and workmanship standards to be achieved;
                    • inspection, test and commissioning criteria and documentation;
                    • interfaces between turbine mechanical, LV and HV activities;
                    • safe isolation of mechanical and electrical equipment for maintenance, e.g. locking-off devices,
                    clamping of rotating parts;
                    • fail-to-safe modes, e.g. to ensure all critical component failures fail to a safe condition and prevent
                    additional runaway failure events;
                    • earthing and protection;
                    • safe remote control/operation, e.g. preventing remote control when a machine is being maintained;
                    • in-service condition monitoring systems, devices and components;
                    • insulation of electrical equipment and cables;
                    • guarding of dangerous parts of machinery;
                    • turbine overspeed control;
                    • controls, e.g. for starting or changing operating conditions, stopping, emergency stop;
                    • provision of clear and unambiguous markings and warnings;
                    • provision of safe working access, e.g. striving to minimise the risks associated with vertical ladders
                    by way of safety harness anchor points, providing rest platforms, powered personnel hoists, lighting,
                    including emergency lighting;
                    • the selection of work equipment for work at height must:
                    - be suitable and sufficient, and be of adequate strength for its intended use;August 2010 Guidelines for Health & Safety in the Wind Energy Industry Sector 38
                    - be appropriate to the nature of the work to be performed and the foreseeable loadings on it;
                    - allow passage without risk for the duration and frequency of use;
                    - offer collective protection over personal protection;
                    • provision of safe work areas;
                    • preventing unauthorised access and control of the equipment, e.g. security and passwords, only
                    allowing control by personnel in the nacelle during maintenance;
                    • practicality of access by helicopter;
                    • the need for fire detection/protection;
                    • provision of a safe means of escape;
                    • provision of accommodation and emergency rations;
                    • occurrences of incidents and near events as collated and reported on the RenewableUK Health and
                    Safety Database, including all safety alerts issued;
                    • emergency response arrangements for the evacuation and removal of injured personnel from the
                    turbine and treatment of injured personnel in remote locations;
                    • PPE;
                    • avoidance of or minimising the need for working on, near or over water;
                    • provision of appropriate navigation aids, i.e. lights and foghorn;
                    • access to navigation aids for maintenance;
                    • access onto turbines and other offshore structures;
                    • potential damage, wear and corrosion from waves and weather;
                    • potential damage from ship collisions;
                    • specific implications of fire at an offshore installation;
                    • access to the base of the wind turbines from a vessel, whether by mooring alongside a landing stage
                    or via a personnel transfer system, to take account of tidal range and tidal streams; this must also be
                    considered for met mast locations;
                    • provision and storage for survival suits, buoyancy aids and PLBs;
                    • provision of appropriate systems for communication between personnel located on offshore
                    structures and the attendant vessels, vessels and the shore-based control centres, and emergency
                    services;
                    • the need to undertake subsea remotely operated vehicle (ROV) operations during the construction or
                    operational phases (in preference to diving);
                    • the need to undertake unavoidable diving operations, either during the construction or operational
                    phases;
                    • Provision of suitable first aid as part of the risk assesment
                    • the need to remotely stop turbine blades in the appropriate formation to allow for access by
                    helicopter; and
                    • emergency response arrangements, including the provision of first aid equipment, rations and
                    equipment in the event of stranding.
                    In putting into effect these design issues, direct reference should be made to the relevant regulations,
                    codes of practice, standards and guidance that may apply

                    Not bored yet... try these http://www.legislation.gov.uk/uksi/2007/320/contents/made

                    I bake my own bread by the way.
                  • Doug
                    Come to think of it I think I explained Capacity Factor wrong. Sure there is a capacity factor related to total awept area, but the term is more usually
                    Message 9 of 20 , Jun 6 5:19 AM
                      Come to think of it I think I explained Capacity Factor wrong. Sure there is a capacity factor related to total awept area, but the term is more usually applied to the total energy output over time, of a turbine installed at a particular site, as a numerator in a fraction where the denominator is the nameplate power rating of the turbine multiplied by the number of hours measured. And it's more of a measure of the site combined with the way the turbine was rated, than a measure of a turbine per se. (In fact it is meaningless to talk of a capacity factor of just a turbine model without it being installed at a particular site.) Therefore a "10 kW" (nameplate rated power) turbine measured over 24 hours would have a capacity factor equal to its total energy output divided by 240 kWh over those 24 hours.
                      On-paper tricks to raise the capacity factor: Add more rotor compared to the amount of generator (creating a "low windspeed turbine"), and/or rate the power at a lower windspeed, and your turbine will then enjoy "a higher capacity factor".
                      Which way you rate your machine, as usual, comes down to buyer mentality and incentives: if you're getting a rebate based on installed nameplate capacity, rate it at the highest windspeed possible. (That was how one company shut down the whole California small wind rebate system. The gatekeepers were clueless about any of these facts, as it turned out.) Similarly to impress the buyer with a high power rating. Wind energy veterans protest, citing reliability above all, and total energy capture over time in all windpseeds. Rating your turbine at a lower windspeed is also useful for coming under the bar in getting a permit for putting up your machine or not even needing one.
                      :)

                      --- In AirborneWindEnergy@yahoogroups.com, "Doug" <doug@...> wrote:
                      >
                      > Brian:
                      > Your response indicates you do not know the definition of the term "capacity factor". It refers to the fraction of energy contained in the wind you can capture based on your swept area, wherever that swept area may be. Most windfarm turbines hope for 30-40%
                      > The "intermittency" for any working surface (single kite?) (blade?) is not improved by multiple kites (blades). Intermittency for the generator, yes, but the rest of the system must be redundant, which multiplies costs for the same power output. If I showed you a wind turbine that needed 3 times as much blade and drivetrain to do the same job is that an improvement? It all comes down to economics.
                      >
                      > Thought experiment:
                      > 1) Take 3 General Electric 1.5 Megawatt turbines.
                      > 2) Remove the generators and gearboxes and let the rotors spin freely.
                      > 3) Place the turbines on rails so the can slide upwind/downwind
                      > 4) engineer a redundant winch system so all 3 General Electric turbines are sliding alternately upwind and downwind on their rails, pulling on the winches while other winches are powering a retraction cycle, together powering rotation of a shaft with whatever energy is left over...
                      > 5) attach a generator to the shaft
                      > 6) or do we need 3 separate generators?
                      > 7) and a lot of electronics and programming?
                      > 8) At what point do you admit you've created a "clusterflux" situation?
                      > 9) Compare your output to a single G.E. 1.5 Megawatt turbine operating as designed.
                      > 10) Run the numbers and see how economical this engineering solution turns out to be
                      > 11) address and solve all reliability issues
                      > 12) Now make it fly. :)
                      > 13) repeat steps 1-12
                      >
                      >
                      > --- In AirborneWindEnergy@yahoogroups.com, "blturner3" <yahoo2@> wrote:
                      > >
                      > > Cool. I have a new favorite. They're actually making stuff. They are doing the simulations. They are doing three(multiple) kites on one generator. They are looking at both high and low L/D. They are working on the other details that these systems entail. All the stuff I would do If I were actually doing it.
                      > >
                      > > I will take up Doug's rebuttal inline below.
                      > >
                      > > Brian
                      > >
                      > > --- In AirborneWindEnergy@yahoogroups.com, "Doug" <doug@> wrote:
                      > > >
                      > > > The pumping cycle versus continuous rotation:
                      > > > Efficiency: reduced
                      > >
                      > > Yes, A pumping system looses 1/2 to 1/4 of it's production time to reel-in. It also has to put power back in. Vs. a traditional turbine that has 90% of it's material in the mast, hub, and inner part of the blade.
                      > >
                      > > > Capacity factor: impaired
                      > >
                      > > No, Higher altitude has better capacity factor.
                      > >
                      > > > Intermittency: increased
                      > >
                      > > A multi-kite system makes this a non-issue
                      > >
                      > > > Speed to drive generator: too low
                      > >
                      > > Yes, Same as a regular turbine.
                      > >
                      > > > Continuous output: no
                      > >
                      > > Yes, In a multikite system or farm.
                      > >
                      > > > motive force: thrust
                      > >
                      > > I may not understand your point here but the good systems are largely the same as a regular turbine.
                      > >
                      > > > native speed for generation: too slow
                      > >
                      > > Same as a regular turbine.
                      > >
                      > > > overspeed protection: no
                      > >
                      > > Not yet
                      > >
                      > > > unattended launch: no
                      > >
                      > > Not yet
                      > >
                      > > > unattended operation: no
                      > >
                      > > Not yet
                      > >
                      > > > storm survival: no
                      > >
                      > > Not yet
                      > >
                      > > > Solution to noncontinuous output and weak performance:
                      > > > "laddermill" concept introduced by me in the 1970's
                      > > > Better solution: rotating propellers driving generators as practiced by the multi-billion-dollar wind energy industry.
                      > > > - Doug Selsam
                      > > > 'bye again...
                      > > >
                      > > >
                      > > > --- In AirborneWindEnergy@yahoogroups.com, "Joe Faust" <joefaust333@> wrote:
                      > > > >
                      > > > > Request hot-seat critique: Pumping cycleWhat say you?
                      > > > > Trial text for glossary is up on hot seat for peer critique:
                      > > > > ============pumping cycle HighWind tutorial
                      > > > > <http://homes.esat.kuleuven.be/~highwind/?p=36> | Note: By use of
                      > > > > loop, a system may rotate continuously in one direction; in such, a
                      > > > > return sector of the loop is phased to low resistance; such loop tactic
                      > > > > hides the pumping cycle by continuous powering that is reduced by the
                      > > > > continuous cost of the residual resistance in the return-low-resistance
                      > > > > sector of the loop. ~JpF, June 2, 2012.=====================
                      > > >
                      > >
                      >
                    • blturner3
                      Yes, On the capacity factor and intermittency issues we were misunderstanding each other. The main cause of reduced capacity factor in wind turbines is the
                      Message 10 of 20 , Jun 6 6:43 AM
                        Yes, On the capacity factor and intermittency issues we were misunderstanding each other.

                        The main cause of reduced capacity factor in wind turbines is the intermittency of the wind itself, So I thought that when you said intermittency right after capacity factor you were referring to the in-out cycle intermittence rather than some tendency of the kites not to perform in all the same wind conditions that a regular turbine can.

                        Higher altitude winds are more powerful and consistent. This helps capacity factor.

                        Yes, most the current kite designs we discuss here would be conditions limited and suffer from reduced capacity factor as a result. But I put that in the category of "not yet". For example, the designs that have a hard wing and a tail can change their pitch much the same as a traditional turbine.

                        I like your thought experiment. It heads toward the basic difference in how we see this. A wind turbine translates the lift of the wing into torque with just one basic step. An equivalent kite system has 2 basic steps and many other steps to support the process that complicate the matter. Yes this is clearly a big disadvantage and stands as one of the big challenges to this whole endeavor.

                        You also seem to imply that the translation through those 2 basic steps of pulling on the tether and turning a generator are somehow dramatically less efficient. I think we disagree here. I should come up with a rebuttal thought experiment but alas I don't have time. Sorry.

                        Good critique.

                        Brian



                        --- In AirborneWindEnergy@yahoogroups.com, "Doug" <doug@...> wrote:
                        >
                        > Come to think of it I think I explained Capacity Factor wrong. Sure there is a capacity factor related to total awept area, but the term is more usually applied to the total energy output over time, of a turbine installed at a particular site, as a numerator in a fraction where the denominator is the nameplate power rating of the turbine multiplied by the number of hours measured. And it's more of a measure of the site combined with the way the turbine was rated, than a measure of a turbine per se. (In fact it is meaningless to talk of a capacity factor of just a turbine model without it being installed at a particular site.) Therefore a "10 kW" (nameplate rated power) turbine measured over 24 hours would have a capacity factor equal to its total energy output divided by 240 kWh over those 24 hours.
                        > On-paper tricks to raise the capacity factor: Add more rotor compared to the amount of generator (creating a "low windspeed turbine"), and/or rate the power at a lower windspeed, and your turbine will then enjoy "a higher capacity factor".
                        > Which way you rate your machine, as usual, comes down to buyer mentality and incentives: if you're getting a rebate based on installed nameplate capacity, rate it at the highest windspeed possible. (That was how one company shut down the whole California small wind rebate system. The gatekeepers were clueless about any of these facts, as it turned out.) Similarly to impress the buyer with a high power rating. Wind energy veterans protest, citing reliability above all, and total energy capture over time in all windpseeds. Rating your turbine at a lower windspeed is also useful for coming under the bar in getting a permit for putting up your machine or not even needing one.
                        > :)
                        >
                        > --- In AirborneWindEnergy@yahoogroups.com, "Doug" <doug@> wrote:
                        > >
                        > > Brian:
                        > > Your response indicates you do not know the definition of the term "capacity factor". It refers to the fraction of energy contained in the wind you can capture based on your swept area, wherever that swept area may be. Most windfarm turbines hope for 30-40%
                        > > The "intermittency" for any working surface (single kite?) (blade?) is not improved by multiple kites (blades). Intermittency for the generator, yes, but the rest of the system must be redundant, which multiplies costs for the same power output. If I showed you a wind turbine that needed 3 times as much blade and drivetrain to do the same job is that an improvement? It all comes down to economics.
                        > >
                        > > Thought experiment:
                        > > 1) Take 3 General Electric 1.5 Megawatt turbines.
                        > > 2) Remove the generators and gearboxes and let the rotors spin freely.
                        > > 3) Place the turbines on rails so the can slide upwind/downwind
                        > > 4) engineer a redundant winch system so all 3 General Electric turbines are sliding alternately upwind and downwind on their rails, pulling on the winches while other winches are powering a retraction cycle, together powering rotation of a shaft with whatever energy is left over...
                        > > 5) attach a generator to the shaft
                        > > 6) or do we need 3 separate generators?
                        > > 7) and a lot of electronics and programming?
                        > > 8) At what point do you admit you've created a "clusterflux" situation?
                        > > 9) Compare your output to a single G.E. 1.5 Megawatt turbine operating as designed.
                        > > 10) Run the numbers and see how economical this engineering solution turns out to be
                        > > 11) address and solve all reliability issues
                        > > 12) Now make it fly. :)
                        > > 13) repeat steps 1-12
                        > >
                        > >
                        > > --- In AirborneWindEnergy@yahoogroups.com, "blturner3" <yahoo2@> wrote:
                        > > >
                        > > > Cool. I have a new favorite. They're actually making stuff. They are doing the simulations. They are doing three(multiple) kites on one generator. They are looking at both high and low L/D. They are working on the other details that these systems entail. All the stuff I would do If I were actually doing it.
                        > > >
                        > > > I will take up Doug's rebuttal inline below.
                        > > >
                        > > > Brian
                        > > >
                        > > > --- In AirborneWindEnergy@yahoogroups.com, "Doug" <doug@> wrote:
                        > > > >
                        > > > > The pumping cycle versus continuous rotation:
                        > > > > Efficiency: reduced
                        > > >
                        > > > Yes, A pumping system looses 1/2 to 1/4 of it's production time to reel-in. It also has to put power back in. Vs. a traditional turbine that has 90% of it's material in the mast, hub, and inner part of the blade.
                        > > >
                        > > > > Capacity factor: impaired
                        > > >
                        > > > No, Higher altitude has better capacity factor.
                        > > >
                        > > > > Intermittency: increased
                        > > >
                        > > > A multi-kite system makes this a non-issue
                        > > >
                        > > > > Speed to drive generator: too low
                        > > >
                        > > > Yes, Same as a regular turbine.
                        > > >
                        > > > > Continuous output: no
                        > > >
                        > > > Yes, In a multikite system or farm.
                        > > >
                        > > > > motive force: thrust
                        > > >
                        > > > I may not understand your point here but the good systems are largely the same as a regular turbine.
                        > > >
                        > > > > native speed for generation: too slow
                        > > >
                        > > > Same as a regular turbine.
                        > > >
                        > > > > overspeed protection: no
                        > > >
                        > > > Not yet
                        > > >
                        > > > > unattended launch: no
                        > > >
                        > > > Not yet
                        > > >
                        > > > > unattended operation: no
                        > > >
                        > > > Not yet
                        > > >
                        > > > > storm survival: no
                        > > >
                        > > > Not yet
                        > > >
                        > > > > Solution to noncontinuous output and weak performance:
                        > > > > "laddermill" concept introduced by me in the 1970's
                        > > > > Better solution: rotating propellers driving generators as practiced by the multi-billion-dollar wind energy industry.
                        > > > > - Doug Selsam
                        > > > > 'bye again...
                        > > > >
                        > > > >
                        > > > > --- In AirborneWindEnergy@yahoogroups.com, "Joe Faust" <joefaust333@> wrote:
                        > > > > >
                        > > > > > Request hot-seat critique: Pumping cycleWhat say you?
                        > > > > > Trial text for glossary is up on hot seat for peer critique:
                        > > > > > ============pumping cycle HighWind tutorial
                        > > > > > <http://homes.esat.kuleuven.be/~highwind/?p=36> | Note: By use of
                        > > > > > loop, a system may rotate continuously in one direction; in such, a
                        > > > > > return sector of the loop is phased to low resistance; such loop tactic
                        > > > > > hides the pumping cycle by continuous powering that is reduced by the
                        > > > > > continuous cost of the residual resistance in the return-low-resistance
                        > > > > > sector of the loop. ~JpF, June 2, 2012.=====================
                        > > > >
                        > > >
                        > >
                        >
                      • dave santos
                        Few issues are so misunderstood as AWES Pumping Physics. Efficiency potential is very high in the case of high Q elastic return. This is why so many biological
                        Message 11 of 20 , Jun 6 10:28 AM
                          Few issues are so misunderstood as AWES Pumping Physics. Efficiency potential is very high in the case of high Q elastic return. This is why so many biological systems use reciprocating motion with elastic materials like resilin, with no necessity for rotation. The output is smoothed, with high overall efficiency preserved.

                          We must also put Rotation in the "hot-seat". In fact, only one major instance of biorotary actuation exists, the microscopic flagellum motor. Above this scale the penalty of scaling torque drives grows drastically such that the great structural engineering writer, Gordon, proclaimed- "Nature abhors torsion".

                          Not just Nature, but engineering as well is so constrained. That is why long-shaft rotary drives are mostly small, or else far too massive to fly as aircraft, as AWES. Even at small scales the advantages are decisive. Our cars are still dominated by reciprocating pistons (with gearboxes to boot). Cars are small and do not fly, so they can employ short drive shafts effectively. By contrast, 1000ft rotating carbon towers in the form of SuperTurbines hardly seem practical or affordable. Let Doug try to do rotating AWES to even 200ft without excess weight or hockling defeating him. Doug has never faced that AWES is not just windpower but also aviation, and that power-to-weight is the dominant flight design parameter. "Overspeed" in the conventional HAWT sense is a lesser issue, with new operational means to tame it.

                          Another aspect most folks overlook is the fantastic potential to drive UHMWPE with high frequency pulses,  given the super high (diamond-like) internal speed-of-sound. For the same fundamental reasons that AC power is so effective, reciprocating mechanical power can get the job done.

                          Given +90% efficiency spring returns, we will beat rotary-drive systems by flying higher into better wind. Rotary drives will be limited to small AWES, and continuous-loop transmissions.

                          Likely the best systems will be a hybrid of pumping and rotation, like a human on a bike.


                          PS AlexM should not exchange the amazing superconducting efficiencies of high-tech rope-driving for electrical conductors/generators aloft. For some reason he chose a Savonius Rotor to test, and its poor performance (by weight or power) is predictable. Putting a generator and conducting tether on this rotor would only make tings even worse. Selecting a better power-to-weight turbine, like a traction-rotor HAWT, would be a better solution.

                        • roderickjosephread
                          The obvious mix is a car piston and crank in reverse. fly a mesh of kites as a wide rotatable array. between the nodes from up to downwind, tie spinning ring
                          Message 12 of 20 , Jun 6 2:30 PM
                            The obvious mix is a car piston and crank in reverse.

                            fly a mesh of kites as a wide rotatable array.

                            between the nodes from up to downwind, tie spinning ring sets.
                            operate a crank on the downwind, upwind or both sides tied bellow    of the spinner.

                            Car engine run backwards basically.
                            kickstarter.

                            --- In AirborneWindEnergy@yahoogroups.com, dave santos <santos137@...> wrote:
                            >
                            > Few issues are so misunderstood as AWES Pumping Physics. Efficiency potential is very high in the case of high Q elastic return. This is why so many biological systems use reciprocating motion with elastic materials like resilin, with no necessity for rotation. The output is smoothed, with high overall efficiency preserved.
                            >
                            >
                            > We must also put Rotation in the "hot-seat". In fact, only one major instance of biorotary actuation exists, the microscopic flagellum motor. Above this scale the penalty of scaling torque drives grows drastically such that the great structural engineering writer, Gordon, proclaimed- "Nature abhors torsion".
                            >
                            > Not just Nature, but engineering as well is so constrained. That is why long-shaft rotary drives are mostly small, or else far too massive to fly as aircraft, as AWES. Even at small scales the advantages are decisive. Our cars are still dominated by reciprocating pistons (with gearboxes to boot). Cars are small and do not fly, so they can employ short drive shafts effectively. By contrast, 1000ft rotating carbon towers in the form of SuperTurbines hardly seem practical or affordable. Let Doug try to do rotating AWES to even 200ft without excess weight or hockling defeating him.Doug has never faced that AWES is not just windpower but also aviation, and that power-to-weight is the dominant flight design parameter. "Overspeed" in the conventional HAWT sense is a lesser issue, with new operational means to tame it.
                            >
                            >
                            > Another aspect most folks overlook is the fantastic potential to drive UHMWPE with high frequency pulses,  given the super high (diamond-like) internal speed-of-sound. For the same fundamental reasons that AC power is so effective, reciprocating mechanical power can get the job done.
                            >
                            >
                            > Given +90% efficiency spring returns, we will beat rotary-drive systems by flying higher into better wind. Rotary drives will be limited to small AWES, and continuous-loop transmissions.
                            >
                            > Likely the best systems will be a hybrid of pumping and rotation, like a human on a bike.
                            >
                            >
                            >
                            > PS AlexM should not exchange the amazing superconducting efficiencies of high-tech rope-driving for electrical conductors/generators aloft. For some reason he chose a Savonius Rotor to test, and its poor performance (by weight or power) is predictable. Putting a generator and conducting tether on this rotor would only make tings even worse. Selecting a better power-to-weight turbine, like a traction-rotor HAWT, would be a better solution.
                            >
                          • roderickjosephread
                            The other good point about doing it this way... the rings can be thin and stable into wind like x-zylo s as they are held high but horizontal instead of in a
                            Message 13 of 20 , Jun 6 2:32 PM
                              The other good point about doing it this way... the rings can be thin and stable into wind like x-zylo's as they are held high but horizontal instead of in a long chain.


                              --- In AirborneWindEnergy@yahoogroups.com, "roderickjosephread" <rod.read@...> wrote:
                              >
                              > The obvious mix is a car piston and crank in reverse.
                              > fly a mesh of kites as a wide rotatable array.
                              > between the nodes from up to downwind, tie spinning ring sets.operate a
                              > crank on the downwind, upwind or both sides tied bellow of the
                              > spinner.
                              > Car engine run backwards basically.kickstarter.
                              > --- In AirborneWindEnergy@yahoogroups.com, dave santos <santos137@>
                              > wrote:
                              > >
                              > > Few issues are so misunderstood as AWES Pumping Physics. Efficiency
                              > potential is very high in the case of high Q elastic return. This is why
                              > so many biological systems use reciprocating motion with elastic
                              > materials like resilin, with no necessity for rotation. The output is
                              > smoothed, with high overall efficiency preserved.
                              > >
                              > >
                              > > We must also put Rotation in the "hot-seat". In fact, only one major
                              > instance of biorotary actuation exists, the microscopic flagellum motor.
                              > Above this scale the penalty of scaling torque drives grows drastically
                              > such that the great structural engineering writer, Gordon, proclaimed-
                              > "Nature abhors torsion".
                              > >
                              > > Not just Nature, but engineering as well is so constrained. That is
                              > why long-shaft rotary drives are mostly small, or else far too massive
                              > to fly as aircraft, as AWES. Even at small scales the advantages are
                              > decisive. Our cars are still dominated by reciprocating pistons (with
                              > gearboxes to boot). Cars are small and do not fly, so they can employ
                              > short drive shafts effectively. By contrast, 1000ft rotating carbon
                              > towers in the form of SuperTurbines hardly seem practical or affordable.
                              > Let Doug try to do rotating AWES to even 200ft without excess weight or
                              > hockling defeating him.Doug has never faced that AWES is not just
                              > windpower but also aviation, and that power-to-weight is the dominant
                              > flight design parameter. "Overspeed" in the conventional HAWT sense is a
                              > lesser issue, with new operational means to tame it.
                              > >
                              > >
                              > > Another aspect most folks overlook is the fantastic potential to drive
                              > UHMWPE with high frequency pulses, given the super high (diamond-like)
                              > internal speed-of-sound. For the same fundamental reasons that AC power
                              > is so effective, reciprocating mechanical power can get the job done.
                              > >
                              > >
                              > > Given +90% efficiency spring returns, we will beat rotary-drive
                              > systems by flying higher into better wind. Rotary drives will be limited
                              > to small AWES, and continuous-loop transmissions.
                              > >
                              > > Likely the best systems will be a hybrid of pumping and rotation, like
                              > a human on a bike.
                              > >
                              > >
                              > >
                              > > PS AlexM should not exchange the amazing superconducting efficiencies
                              > of high-tech rope-driving for electrical conductors/generators aloft.
                              > For some reason he chose a Savonius Rotor to test, and its poor
                              > performance (by weight or power) is predictable. Putting a generator and
                              > conducting tether on this rotor would only make tings even worse.
                              > Selecting a better power-to-weight turbine, like a traction-rotor HAWT,
                              > would be a better solution.
                              > >
                              >
                            • blturner3
                              This thread was comparing traditional turbines vs the pumping cycle that many AWESs are using today. If you want to discuss Super Turbine vs Diamond like
                              Message 14 of 20 , Jun 7 5:11 AM
                                This thread was comparing traditional turbines vs the pumping cycle that many AWESs are using today.
                                If you want to discuss Super Turbine vs "Diamond like internal speed of sound" or any of the other off topic ongoing debates. I believe it would be best if you started a new thread.

                                Brian

                                --- In AirborneWindEnergy@yahoogroups.com, dave santos <santos137@...> wrote:
                                >
                                > Few issues are so misunderstood as AWES Pumping Physics. Efficiency potential is very high in the case of high Q elastic return. This is why so many biological systems use reciprocating motion with elastic materials like resilin, with no necessity for rotation. The output is smoothed, with high overall efficiency preserved.
                                >
                                >
                                > We must also put Rotation in the "hot-seat". In fact, only one major instance of biorotary actuation exists, the microscopic flagellum motor. Above this scale the penalty of scaling torque drives grows drastically such that the great structural engineering writer, Gordon, proclaimed- "Nature abhors torsion".
                                >
                                > Not just Nature, but engineering as well is so constrained. That is why long-shaft rotary drives are mostly small, or else far too massive to fly as aircraft, as AWES. Even at small scales the advantages are decisive. Our cars are still dominated by reciprocating pistons (with gearboxes to boot). Cars are small and do not fly, so they can employ short drive shafts effectively. By contrast, 1000ft rotating carbon towers in the form of SuperTurbines hardly seem practical or affordable. Let Doug try to do rotating AWES to even 200ft without excess weight or hockling defeating him.Doug has never faced that AWES is not just windpower but also aviation, and that power-to-weight is the dominant flight design parameter. "Overspeed" in the conventional HAWT sense is a lesser issue, with new operational means to tame it.
                                >
                                >
                                > Another aspect most folks overlook is the fantastic potential to drive UHMWPE with high frequency pulses,  given the super high (diamond-like) internal speed-of-sound. For the same fundamental reasons that AC power is so effective, reciprocating mechanical power can get the job done.
                                >
                                >
                                > Given +90% efficiency spring returns, we will beat rotary-drive systems by flying higher into better wind. Rotary drives will be limited to small AWES, and continuous-loop transmissions.
                                >
                                > Likely the best systems will be a hybrid of pumping and rotation, like a human on a bike.
                                >
                                >
                                >
                                > PS AlexM should not exchange the amazing superconducting efficiencies of high-tech rope-driving for electrical conductors/generators aloft. For some reason he chose a Savonius Rotor to test, and its poor performance (by weight or power) is predictable. Putting a generator and conducting tether on this rotor would only make tings even worse. Selecting a better power-to-weight turbine, like a traction-rotor HAWT, would be a better solution.
                                >
                              • Doug
                                Sorry Roderick I am way too busy to wade through so many (probably meaningless) words. If you have a prototype that makes decent power I would make time to
                                Message 15 of 20 , Jun 7 12:08 PM
                                  Sorry Roderick I am way too busy to wade through so many (probably meaningless) words. If you have a prototype that makes decent power I would make time to watch a video with instrumentation showing output. (The wind acts pretty much the same in every country.)
                                  ***problem: too many words take up your whole day for nothing***
                                  :)


                                  --- In AirborneWindEnergy@yahoogroups.com, "roderickjosephread" <rod.read@...> wrote:
                                  >
                                  > Overspeed protection is not the main thing.
                                  > > It's the ONLY thing in wind turbine design.
                                  >
                                  > Not in the UK Doug. Maybe in happy land USA. Had you bothered to read or try to understand (I don't think you have yet) my description of fail safe modes through to to collapse, continuing generation through out of spec wind speeds ... you may have seen that there is more involvement. see below. Read it this time. Re-read what you missed. Now, do you want to share anything useful? like say gyroscopic effects modelling on the long shaft generator? New CFD results? anything constructive please.
                                  >
                                  > Specific design considerations will be required in respect of:
                                  > � manufacturer's turbine certification;
                                  > � manufacturer's operations manual and maintenance instructions;
                                  > � results of factory acceptance testing;
                                  > � provision of assembly instructions, drawings and design information for the construction phase;
                                  > � assembly criteria and workmanship standards to be achieved;
                                  > � inspection, test and commissioning criteria and documentation;
                                  > � interfaces between turbine mechanical, LV and HV activities;
                                  > � safe isolation of mechanical and electrical equipment for maintenance, e.g. locking-off devices,
                                  > clamping of rotating parts;
                                  > � fail-to-safe modes, e.g. to ensure all critical component failures fail to a safe condition and prevent
                                  > additional runaway failure events;
                                  > � earthing and protection;
                                  > � safe remote control/operation, e.g. preventing remote control when a machine is being maintained;
                                  > � in-service condition monitoring systems, devices and components;
                                  > � insulation of electrical equipment and cables;
                                  > � guarding of dangerous parts of machinery;
                                  > � turbine overspeed control;
                                  > � controls, e.g. for starting or changing operating conditions, stopping, emergency stop;
                                  > � provision of clear and unambiguous markings and warnings;
                                  > � provision of safe working access, e.g. striving to minimise the risks associated with vertical ladders
                                  > by way of safety harness anchor points, providing rest platforms, powered personnel hoists, lighting,
                                  > including emergency lighting;
                                  > � the selection of work equipment for work at height must:
                                  > - be suitable and sufficient, and be of adequate strength for its intended use;August 2010 Guidelines for Health & Safety in the Wind Energy Industry Sector 38
                                  > - be appropriate to the nature of the work to be performed and the foreseeable loadings on it;
                                  > - allow passage without risk for the duration and frequency of use;
                                  > - offer collective protection over personal protection;
                                  > � provision of safe work areas;
                                  > � preventing unauthorised access and control of the equipment, e.g. security and passwords, only
                                  > allowing control by personnel in the nacelle during maintenance;
                                  > � practicality of access by helicopter;
                                  > � the need for fire detection/protection;
                                  > � provision of a safe means of escape;
                                  > � provision of accommodation and emergency rations;
                                  > � occurrences of incidents and near events as collated and reported on the RenewableUK Health and
                                  > Safety Database, including all safety alerts issued;
                                  > � emergency response arrangements for the evacuation and removal of injured personnel from the
                                  > turbine and treatment of injured personnel in remote locations;
                                  > � PPE;
                                  > � avoidance of or minimising the need for working on, near or over water;
                                  > � provision of appropriate navigation aids, i.e. lights and foghorn;
                                  > � access to navigation aids for maintenance;
                                  > � access onto turbines and other offshore structures;
                                  > � potential damage, wear and corrosion from waves and weather;
                                  > � potential damage from ship collisions;
                                  > � specific implications of fire at an offshore installation;
                                  > � access to the base of the wind turbines from a vessel, whether by mooring alongside a landing stage
                                  > or via a personnel transfer system, to take account of tidal range and tidal streams; this must also be
                                  > considered for met mast locations;
                                  > � provision and storage for survival suits, buoyancy aids and PLBs;
                                  > � provision of appropriate systems for communication between personnel located on offshore
                                  > structures and the attendant vessels, vessels and the shore-based control centres, and emergency
                                  > services;
                                  > � the need to undertake subsea remotely operated vehicle (ROV) operations during the construction or
                                  > operational phases (in preference to diving);
                                  > � the need to undertake unavoidable diving operations, either during the construction or operational
                                  > phases;
                                  > � Provision of suitable first aid as part of the risk assesment
                                  > � the need to remotely stop turbine blades in the appropriate formation to allow for access by
                                  > helicopter; and
                                  > � emergency response arrangements, including the provision of first aid equipment, rations and
                                  > equipment in the event of stranding.
                                  > In putting into effect these design issues, direct reference should be made to the relevant regulations,
                                  > codes of practice, standards and guidance that may apply
                                  >
                                  > Not bored yet... try these http://www.legislation.gov.uk/uksi/2007/320/contents/made
                                  >
                                  > I bake my own bread by the way.
                                  >
                                • Doug
                                  Hi Brian: Thanks for a good critique of my good critique. Rather than another thought experiment , I suggest someone with engineering skills, who thinks it s
                                  Message 16 of 20 , Jun 7 12:22 PM
                                    Hi Brian:
                                    Thanks for a good critique of my good critique. Rather than another "thought experiment", I suggest someone with engineering skills, who thinks it's worth the time, can easily run the numbers:
                                    1) start with the thrust force of a G.E wind turbine, at a given windspeed, say 25 MPH. Easily calculated based on swept area, using common tables or formulae used in wind energy
                                    2) Modify (lower) that thrust rating for a turbine traveling on rails downwind
                                    3) Subtract the force needed to move the upwind-traveling turbine against the wind, though its blades may be feathered.
                                    4) calculate the resulting power, which is energy per unit time, with energy being force x distance
                                    5) see where you stand compared to the 1.5 MegaWatts any single one of these turbines could be making if left to operate as intended by the educated wind turbine designers.

                                    Compare the cost, including all modifications, with output.
                                    Know why wind energy works? Because it can compete with natural gas-fired power plants. If your power costs more than what you can get out of the wall, forget it. If your power costs more than what the electric company normally pays for power, you will still not be able to get a power purchase agreement, normally required for serious producers of wind energy.

                                    If there's any lesson we learn building turbines and fixing them when they break, it is keep it simple and keep it beefy. Every potential added system or component introduces more failure modes.

                                    And, never assume a turbine can handle high winds without overspeed protection.

                                    --- In AirborneWindEnergy@yahoogroups.com, "blturner3" <yahoo2@...> wrote:
                                    You also seem to imply that the translation through those 2 basic steps of pulling on the tether and turning a generator are somehow dramatically less efficient. I think we disagree here. I should come up with a rebuttal thought experiment but alas I don't have time. Sorry.
                                    >
                                    > Good critique.
                                    >
                                    > Brian
                                  • Doug
                                    ... *** You are funny! Yeah Professor , I think you are the only one who understands it... (he he he)*** This is why so many biological systems use
                                    Message 17 of 20 , Jun 7 12:43 PM
                                      --- In AirborneWindEnergy@yahoogroups.com, dave santos <santos137@...> wrote:
                                      >
                                      > Few issues are so misunderstood as AWES Pumping Physics.

                                      *** You are funny! Yeah "Professor", I think you are the only one who "understands" it... (he he he)***

                                      This is why so many biological systems use reciprocating motion with elastic materials like resilin, with no necessity for rotation. The output is smoothed, with high overall efficiency preserved.

                                      ***interesting - and I always assumed animals don't have wheels because blood vessels would not be able to connect from the axle to the tire. Hey give evolution another billion years and maybe animals will have wheels!"***
                                      >
                                      > We must also put Rotation in the "hot-seat".

                                      ***Yeah, you should contact machinery designers and the American Wind Energy Association and put them on notice that you are about to make rotation obsolete! (hope they don't laugh)***

                                      In fact, only one major instance of biorotary actuation exists, the microscopic flagellum motor. Above this scale the penalty of scaling torque drives grows drastically such that the great structural engineering writer, Gordon, proclaimed- "Nature abhors torsion".

                                      ***Wow you know some big words. Yeah, I'd forget about using anything that rotates... (insert laugh track here)***

                                      > Not just Nature, but engineering as well is so constrained. That is why long-shaft rotary drives are mostly small, or else far too massive to fly as aircraft, as AWES. Even at small scales the advantages are decisive.

                                      ***Sure Dave, keep fixating on that "torque tube", as though I don't have many other ways that also work well***

                                      >Our cars are still dominated by reciprocating pistons (with gearboxes to boot). Cars are small and do not fly, so they can employ short drive shafts effectively. By contrast, 1000ft rotating carbon towers in the form of SuperTurbines hardly seem practical or affordable.

                                      ***The professor has spoken - "hardly seem"is really convincing!***

                                      - that Let Doug try to do rotating AWES to even 200ft without excess weight or hockling defeating him.Doug has never faced that AWES is not just windpower but also aviation, and that power-to-weight is the dominant flight design parameter.

                                      ***Yeah I've never faced it. That's it. If I "faced it" I'd be flying reciprocating kites...***

                                      "Overspeed" in the conventional HAWT sense is a lesser issue, with new operational means to tame it.

                                      ***Dave your delusion is matched only by your focus on somehow rebutting every idea I have ever introduced. Yes, overspeed protection is not a factor at all for people who only imagine they are working in wind energy***

                                      > Another aspect most folks overlook is the fantastic potential to drive UHMWPE with high frequency pulses,� given the super high (diamond-like) internal speed-of-sound. For the same fundamental reasons that AC power is so effective, reciprocating mechanical power can get the job done.

                                      ***Once again, professor, you speak with such authority - let's see an example lest we begin to doubt your veracity...***

                                      > Given +90% efficiency spring returns, we will beat rotary-drive systems by flying higher into better wind. Rotary drives will be limited to small AWES, and continuous-loop transmissions.

                                      ***There is nothing so laughable in wind energy as people who cannot produce ANY wind energy whatsoever, despite years of attempts, endlessly deriding all that IS, in lieu of all they promise to create. One thing we notice though is the statements of superiority always refer to future activities. They kick and scream for years, and always end up sulking away with tail between legs and head hung low, with the attitude of "What are you still bringing that up for?"***

                                      > Likely the best systems will be a hybrid of pumping and rotation, like a human on a bike.
                                      ***Yeah "likely this" and "likely that" - Dave, unknown to you, you are one of the greatest comedy routines to ever besmirch wind energy. Really, thanks for endless laughs! You have me rolling around on the ground almost every day! :)))***
                                      >
                                      Doug Selsam
                                    • dave santos
                                      Me, previously: For the same fundamental [dynamics] that AC power is so effective, reciprocating mechanical power can get the job done. Doug: ***Once again,
                                      Message 18 of 20 , Jun 8 12:52 PM
                                        Me, previously: "For the same fundamental [dynamics] that AC power is so effective, reciprocating mechanical power can get the job done."

                                        Doug: ***Once again, professor, you speak with such authority - let's see an example lest we begin to doubt your veracity...***

                                        Me: A wonderful reciprocating-power "get the job done" example for you is your own pumping heart. An example of extreme reciprocating cycling efficiency is the transmigration of hummingbirds across vast stretches of the Gulf of Mexico, pumping those wings on just a dab of fat! This is an amazing pumping world, and the invention of wheels and turbines just add to it.

                                        Doug: "One thing we notice though is the statements of superiority always refer to future activities."

                                        Me:  I hope some of my many direct flight experiments in past decades were superior for their time. The hummingbird case at least is a done deal.

                                        Re: another of your playful jibes, its not true that KiteLab's many small demonstrators make "no power"; they make "scale power" consistent with expectations. Let other teams with similar ideas hold the early AWE Peak Power records by flying larger AWES. They pay by reduced engineering agility.  As i work through personal foundational study, scaling up will follow. Superiority is by the numbers, not marketing hype. Let's soon do "system fly-offs" to help settle claims.

                                        Based on critical path analysis of AWES R&D as a whole , the general conclusion is that hybrid AWES systems are currently favored, with reciprocating methods offering unique design advantages in many specific contexts of interest. The fraction of "rotary only" schemes do not hold any power records, nor do they seem to easily reach the best winds estimated between 500-2000m altitude.
                                      • Robert Copcutt
                                        ... Efficiency is of tiny consequence. What matters is cost of energy. Costs are very hard to predict but my bets are on pumping cycle systems. ... Again, of
                                        Message 19 of 20 , Jun 8 5:43 PM
                                          On Sun, 2012-06-03 at 13:34 +0000, Doug wrote:
                                          >
                                          > The pumping cycle versus continuous rotation:
                                          > Efficiency: reduced

                                          Efficiency is of tiny consequence. What matters is cost of energy. Costs
                                          are very hard to predict but my bets are on pumping cycle systems.

                                          > Capacity factor: impaired

                                          Again, of tiny importance compared to cost of energy.

                                          > Intermittency: increased

                                          As I have pointed out before nearly all AWES will be connected to the
                                          grid or batteries so intermittency is of no problem.

                                          > Speed to drive generator: too low

                                          With groundgen systems the gearbox, or chain drive, can be built bulky
                                          enough to be reliable.

                                          > Continuous output: no

                                          Does not matter.

                                          > motive force: thrust

                                          It is tension which is by far the most cost effective.

                                          > native speed for generation: too slow

                                          Can be speeded up.

                                          > overspeed protection: no

                                          It can be done in many ways.
                                          1) Change kites to suit conditions.
                                          2) Change flight altitude.
                                          3) Change angle of attack of kite.
                                          4) Put a torque limiting clutch between the reels and generator

                                          > unattended launch: no

                                          Skysails have already demonstrated an automated system.

                                          > unattended operation: no

                                          It will come as confidence in the computer algorithms grows.

                                          > storm survival: no

                                          Simply reel the kite in to its docking station.

                                          Robert.
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