Otis Elevator's 75% More Efficient Design: What's Behind the Savings?

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Discussion Overview

The discussion centers around the energy efficiency of Otis Elevator's new design, which is claimed to be 75% more efficient than conventional elevators. Participants explore the mechanisms behind this efficiency, including regenerative braking, reduced friction, and the implications of control system energy consumption. The conversation touches on theoretical and practical aspects of elevator technology and energy savings.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants discuss the role of regenerative braking in energy savings, noting that it is primarily used for slowing the elevator at stops.
  • There is speculation about the contributions of reduced friction in cables and improvements in lighting, such as the use of LEDs, to overall efficiency.
  • Participants express curiosity about the proportion of energy savings attributed to different factors, particularly the control systems, which some note have increased energy consumption.
  • Some argue that the efficiency of power electronics may not follow Moore's law, suggesting that improvements in this area could be a significant avenue for future research.
  • There is a humorous suggestion about energy-saving practices, such as walking up stairs instead of using elevators, which some participants support as a health benefit.
  • One participant reflects on their experience with high-power electronics, indicating that there may be additional factors in control systems that require significant power.

Areas of Agreement / Disagreement

Participants express a mix of agreement and differing views on the factors contributing to energy efficiency in elevators. While there is consensus on the potential benefits of regenerative braking and the need for further exploration of power electronics, the discussion remains unresolved regarding the specific contributions of various elements to overall energy savings.

Contextual Notes

Some participants note the variability in energy consumption based on the number of passengers in the elevator, indicating that this factor complicates the analysis of energy efficiency. There are also references to the limitations of current control systems and the need for further investigation into their energy demands.

anorlunda
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There has been much talk about regerative braking on PF lately. With that in mind, this article in today's Washington Post caught my eye. It talks about Otis Elevator's newest design which the article claims is 75% more efficient than conventional elevators.

http://www.washingtonpost.com/sf/br...energy-efficient-elevators-are-imperative/#!/

How did they do it? The (non technical) article says via improvements in lighting (I guess LEDs), less friction in the cables due to cable design, and regenerative braking. I would love to learn what fraction of the savings came from reduced friction, but the article doesn't say.

Note that this reganerative braking scheme has all the advantages. The motors, and the drive electronics are needed anyhow, and the load to be served by regenerative power is within the building. The energy does not need to be stored, nor negotiated for sale to a third party.

Most interesting is a bar graph showing where the energy was spent in the newest elevators compared to conventional ones. The savings in lighting and drive power are obviouis. But control systems dissipation actually increased, and now appears to account for 2/3 of the energy consumption. I smirk at the irony, because that opens the door to future critics who might attack the wasteful smart control systems as energy hogs. You and I know that this is a good thing, but politics does not follow logic.

What about Moore's law? Be careful. The smart microchips will not be dissipating all that energy, it must be the high power electronics. I don't think Moore's law applies to power electronics. However, improving the efficiency of power elecctronics might be a fruitful field of reasearch in coming decades.
 
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anorlunda said:
What about Moore's law? Be careful. The smart microchips will not be dissipating all that energy, it must be the high power electronics. I don't think Moore's law applies to power electronics. However, improving the efficiency of power elecctronics might be a fruitful field of reasearch in coming decades.
I agree. I would expect that every CPU that is still in production has enough computing power for escalators and elevators, and the simple ones do not need 100 W (-> 1000 kWh/year control systems). There has to be something else in the control system that needs more power.

Should we use the elevator or escalator to go down now to save energy?
 
mfb said:
I agree. I would expect that every CPU that is still in production has enough computing power for escalators and elevators, and the simple ones do not need 100 W (-> 1000 kWh/year control systems). There has to be something else in the control system that needs more power.

Years ago, I worked at ASEA in Sweden. We made SCRs the size of large pizzas. Those babies could dissipate quite a few watts.

mfb said:
Should we use the elevator or escalator to go down now to save energy?

Outstanding, walk up - ride down. Improve your health while you're saving the world. Will that become the new social meme?
 
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anorlunda said:
Outstanding, walk up - ride down. Improve your health while you're saving the world
mfb said:
Should we use the elevator or escalator to go down now to save energy?

Sorry.
The regenerative is only for braking - braking to slow to a stop at a floor either going up, or going down.
Still, using the stairs is a good workout.

The counterweight is chosen for balance, so the motor uses as much ( wasteful ) energy to accelerate the car up or down.
People load in the car does have an affect but that is variable.
In which case, the elevator should only be used when it is full for maximum savings.
With only one person inside - now that is just like driving on the road as the single lone occupant..