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  1. #14
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    We all know that inverters are more efficient but that comes at a price. There may be markets where that price in unacceptable for many and where their usage patterns can't make up for the initial hit in price outlay.

    My mini market survey suggests that an inverter a/c unit regardless of compressor type costs at least 50-60% more than a basic recip. Many people around the world want A/c but can't afford that difference. In addition, if they only use it for cooling at night to sleep (like I do) then the efficiency difference may never be realised in savings in electricity.

    I'm hoping that my innovation will provide the efficiency gains of a 2 stage or digital scroll - not the gains of an inverter- but also be cheaper than everything except a basic recip.

    So you are correct if talking about first world markets where inverters will dominate but there are very different price sensitivities on other markets.

  2. #15
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    I tend to think that most variable speed units are not so expensive just because of the inverter technology because minisplits are available for $400 - $800 up to 2 tons and they are decently reliable. I think that with an inverter drive reciprocating compressor you could achieve good efficiency and durability for a low price if that was your aim. I think most oems are not trying yet.
    I think the current cost of variable speed equipment is driven by design cost and market placement not manufacturing cost.


    Sent in a state of increasing entropy using Tapatalk

  3. #16
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    Quote Originally Posted by R600a View Post
    I tend to think that most variable speed units are not so expensive just because of the inverter technology because minisplits are available for $400 - $800 up to 2 tons and they are decently reliable. I think that with an inverter drive reciprocating compressor you could achieve good efficiency and durability for a low price if that was your aim. I think most oems are not trying yet.
    I think the current cost of variable speed equipment is driven by design cost and market placement not manufacturing cost.


    Sent in a state of increasing entropy using Tapatalk
    I think Danfoss have been selling inverter based recips for a long time-mostly for the RV, boat and off grid markets as fridge/freezers. They are widely regarded as expensive but that may be because of the size of the market i.e. lower volumes vs residential a/c.

    I don't see a place for my own innovation with an inverter. They are really alternatives to each other and dialing down rpm as well as piston stroke would be overkill for most applications and probably too expensive.

    I will beaver on with what I have and so how I go. Thanks for your insights.

  4. #17
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    I definitely agree I wouldn't think putting inverter tech on your design is a good idea.
    Just curious without giving away too much information have you been able to build a working model?
    Quote Originally Posted by Dreyfus View Post
    I think Danfoss have been selling inverter based recips for a long time-mostly for the RV, boat and off grid markets as fridge/freezers. They are widely regarded as expensive but that may be because of the size of the market i.e. lower volumes vs residential a/c.

    I don't see a place for my own innovation with an inverter. They are really alternatives to each other and dialing down rpm as well as piston stroke would be overkill for most applications and probably too expensive.

    I will beaver on with what I have and so how I go. Thanks for your insights.
    Sent from mars using Tapatalk

  5. #18
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    Quote Originally Posted by R600a View Post
    I definitely agree I wouldn't think putting inverter tech on your design is a good idea.
    Just curious without giving away too much information have you been able to build a working model?

    Sent from mars using Tapatalk
    I have built a large scale model of the crank system and powered it using 2 battery drills just to test the feasibility of control. Obviously one simulates the compressor motor and the other the controller. It works well enough although the level of vibration at large piston strokes is alarming. That is one reason I applied it to A/C compressors since these are typically damped using springs and noise suppression is more feasible with various materials and enclosures.

    I haven't looked in detail at the infiniti variable compression engine design but its limited range of variation in vibration would I imagine be controlled with a flywheel. I think any internal combustion application of my concept would be very challenged by vibration due to the extreme variation in crank trajectory,

    In a sense this concept is closer to variable displacement than variable compression due to the range of variation. Other methods of variable displacement such as turning off cylinders or skip firing or varying the combustion chamber volume structurally, don't involve this kind of variation in rotating mass.

    I have yet to build anything that actually compresses gas in a cylinder but in practice that should be straightforward. The challenge is that most manufacturers will want to see something that looks like a compressor actually compressing. That probably means I will have to adapt parts from old units as best I can into something not too frankenstein.

    Once again I don't see this as being worthwhile in the developed world where purchase price is less sensitive. However there are many parts of the world where the extra purchase price of an inverter will never be recouped in efficiencies because the units just aren't run long enough because people can't afford the power. For example, I rarely use an a/c in the day but rely on it at night for sleeping in humid conditions.

    I imagine filipinos for example could afford a more efficient and slightly more expensive recip and maybe recoup that cost in their usage level, but an inverter is out of their reach just in intial purchase price and the difference will not be recouped due to limited run times. But I could be wrong.

    Anyway, we shall see. Thanks again

  6. #19
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    While having no real idea what your system looks like I am sure it could be balanced at least to a degree. Sounds like an interesting idea.
    Does the piston always come to the top of the cylinder or does the compression vary with capacity?
    Quote Originally Posted by Dreyfus View Post
    I have built a large scale model of the crank system and powered it using 2 battery drills just to test the feasibility of control. Obviously one simulates the compressor motor and the other the controller. It works well enough although the level of vibration at large piston strokes is alarming. That is one reason I applied it to A/C compressors since these are typically damped using springs and noise suppression is more feasible with various materials and enclosures.

    I haven't looked in detail at the infiniti variable compression engine design but its limited range of variation in vibration would I imagine be controlled with a flywheel. I think any internal combustion application of my concept would be very challenged by vibration due to the extreme variation in crank trajectory,

    In a sense this concept is closer to variable displacement than variable compression due to the range of variation. Other methods of variable displacement such as turning off cylinders or skip firing or varying the combustion chamber volume structurally, don't involve this kind of variation in rotating mass.

    I have yet to build anything that actually compresses gas in a cylinder but in practice that should be straightforward. The challenge is that most manufacturers will want to see something that looks like a compressor actually compressing. That probably means I will have to adapt parts from old units as best I can into something not too frankenstein.

    Once again I don't see this as being worthwhile in the developed world where purchase price is less sensitive. However there are many parts of the world where the extra purchase price of an inverter will never be recouped in efficiencies because the units just aren't run long enough because people can't afford the power. For example, I rarely use an a/c in the day but rely on it at night for sleeping in humid conditions.

    I imagine filipinos for example could afford a more efficient and slightly more expensive recip and maybe recoup that cost in their usage level, but an inverter is out of their reach just in intial purchase price and the difference will not be recouped due to limited run times. But I could be wrong.

    Anyway, we shall see. Thanks again
    Sent from mars using Tapatalk

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