How much extra power for one person to ride a chairlift?
- Thread starter milk_man
- Start date
jellomellow
Member
kinetic energy is 1/2mv^2 and potential is mgh. not sure if this helps or not. just find the answer then convert it into whatever
topic:milk_man said:
It's definetly possible and it can be estimated quite simply. The issue arises when you have to decide what variables you will have to use or take into account. Then it's just a matter of plugging in the numbers.
You would need to know the change in height and the overall weight of the chairlift to calculate the work done. Then you'd have to factor in any mechanical "loss" of energy. Then you'd probably have to worry about tension and some friction because it is not a perfect system.
Once you have those variables it's just a matter of finding the amount of work done, and the amount of energy inefficieny of the chairlift. Then you'll have an answer.
GrapeHunter
Active member
Id say about 4 by my calculations.
daannnnieel
Active member
13770268:Lonely said:
wouldn't you also need to know the angle of the line between the towers...? I'm super rusty on this but if the towers are all steep it's not going to be as easy as if they weren't. I don't think it's something you can just factor out or estimate really.
finding the tension you would need to know all the angles for the entire system more or less
in math, everything depends on variables. this question just has a lot of shitty useless ones we can leave to the magicians at poma or whatever the fuck that chairlift company is.
13770295:daannnnieel said:
I was actually thinking about that; I just left it out because I was unsure of it.
I'm trying to conceptialize this by thinking about pedaling a bike. Does it take more energy if the gears are places vertically rather than horizontally like they traditionally are?
I believe it would be the same for the lifts. Or at least close to the same. The chair itself will be pulling down with the same amount of force for a flat lift, and a lift that is at a forty five degree angle. There may be an increase in tension on the cable when it is at a forty five degree angle, but that should be negligible when compared to a flat lift. Given that the chairs can pivot and are not static.
The chair on the flat lif would pull down at a ninety degree angle, whereas the lift at a forty five degree angle would have the chair pulling down at a one hundred and thirty five degree angle. This would increase the angular tension, which in turn would increase friction. But I still think that it would be negligible.
skierman
Active member
It doesn't fucking matter. The initial power output from the lift is enough to keep the lift moving at the same pace whether no one is riding the lift or 50 fat fucks from Texas with guts filled with rodeo burgers that can barely zip up their Cowboys jackets.
God you people are stupid.
God you people are stupid.
Daph
Active member
13770550:skierman said:
Actually the motor load is significantly more with a full line than all empty chairs. Every lift should have a gauge that shows percent load on the motor and drive system. With a full line of chairs a lift typically only sees a 80% load on the motor, any more than that and you start to see drive faults and motor failure especially when the lift is trying to ramp up after a slow or stop.
Like many people have already said, there are lots of variables to consider and they differ from lift to lift. Say you have a high speed quad with a bottom drive, each chair weighs about 500 lbs, there are 30 towers, 5 of which are depressions. That will take much more power to run than a fixed grip 2 seater with a top drive and only 14 towers.
13770782:intifada said:
What? Something like gravity is a constant. They are variables. They change the equation depending on what number you put in. If anything the electric motor would be a constant. It is the one of the only things constant between the lift having a person or not.
Lol
intifada
Member
13770823:Lonely said:
Chairlifts and their electric motors already give you enough information to determine energy usage. You can determine how much it takes to run an empty line just by starting it. Since this is the case everything you listed is not a variable. It's exactly the same for an empty line and a line as it is with one person on it. the variable is that the difference in energy consumption is going to change for every lift.
milk_man
Active member
13770787:intifada said:
I agree, very negligible. I was thinking maybe an extra 100-200 watts but that's a crazy guess based on absolutely 0 information
that's why I want someone to try to figure it out, using specs of their choice.The chairlift at the small ski area I go to is 75 hp I believe
intifada
Member
I guess I was thinking about this in regards to a single lift.
Length, weight, and steepness of a lift compared to the size of its electric motor will definately give you different results, but again these differences are nothing you need to calculate as they will show up in the information the electric motor gives you.
Then again I believe electric motors get more mechanically efficient at a higher load so maybe that 150 pound person is saving you power.
Length, weight, and steepness of a lift compared to the size of its electric motor will definately give you different results, but again these differences are nothing you need to calculate as they will show up in the information the electric motor gives you.
Then again I believe electric motors get more mechanically efficient at a higher load so maybe that 150 pound person is saving you power.
TVRNTVPOOP
Member
ask borty he knows all
Scotty_B
Member
depends on the weight of the chairlift.
energy going up or down is potential and is defined as mgZ
(Mass*Gravity*Height)
Assuming an empty 4 person chairlift weighs 500 lbs
and a loaded one with little OP weighs 650 lbs
MgZ of empty
Mgz of loaded
they are going the same distance up the hill so z's cancel
so this becomes
Mg empty = 500*32 = 16000 ftlbf/s
Mg loaded = 650*32 = 20800 ftlbf/s
divide the above by 550 (this is conversion for HP)
we arrive at...
_______________________________________________________
Empty chair uses 29.09HP
OP's Chair uses 37.81HP
________________________________________________________
OP you use around 9 HP more than the empty chair and use about 30% more energy.
________________________________________________________
energy going up or down is potential and is defined as mgZ
(Mass*Gravity*Height)
Assuming an empty 4 person chairlift weighs 500 lbs
and a loaded one with little OP weighs 650 lbs
MgZ of empty
Mgz of loaded
they are going the same distance up the hill so z's cancel
so this becomes
Mg empty = 500*32 = 16000 ftlbf/s
Mg loaded = 650*32 = 20800 ftlbf/s
divide the above by 550 (this is conversion for HP)
we arrive at...
_______________________________________________________
Empty chair uses 29.09HP
OP's Chair uses 37.81HP
________________________________________________________
OP you use around 9 HP more than the empty chair and use about 30% more energy.
________________________________________________________
Scotty_B
Member
13771127:milk_man said:
Yea I fucked it up hard my bad.
I reworked the problem though so you're good.
-500lbf
-1ft vertical
-3 seconds
((500*1) / 3s ) = 166 lbf*ft/s
((650*1) / 3s ) = 216 lbf*ft/s
166/550 = 0.30 HP
216/550 = 0.39 HP
You use about 30% more energy.
I love units.
_______________________________________________________
TACO-DOG.exe
Active member
hah nerds. go read a book or something.
corona
Active member
13771164:Scotty_B said:
This is flawed. You can't use the weight of the chairs in the calculation since assuming there are an equal number going up the lift as down then it should theoretically cancel. Then you need a whole bunch of other variables.
Then you need the chairlift speed. 3 m/s is about right for fixed chair lift. So a 60kg object moving vertically would require 60*(9.8+3) N m/s. Which is 0.77 kW. Then say it's at a 20 deg angle which means it would be sin20(0.77) which is 0.26 kW. This is assuming no friction. that would mean a fully loaded 100 chair quad lift would need a 140hp engine if it's a fixed grip going rather slow and being 100% efficient up a 20 degree slope.
I dunno what the efficiency is, but if its 75% and they want the lift to be running at 80% capacity when it's loaded then a slow lift that size should be about 240hp I guess.
corona
Active member
13775075:milk_man said:
given a 100% efficient system with no air resistance moving at 3 m/s up a 20 degree incline, then I think that's correct.
You could assume that if the lift is already running and you don't care to figure out how much energy it's using running empty then adding 1 person of 60 kg would amount to roughly 0.26 kw extra load on the motor.
keep in mind that's a small person (130 lb). but if you average out with children that might be correct.
So then the fun stuff is how much more money it costs to run a full lift vs empty lift.
So if it's a quad with 100 chairs (so 50 chairs full) then that would add 52 kw. the average price in the US is 12 cents per kwh, so running the chairlift full would cost $6.24 an hour more than empty.
and just for fun. If this chairlift over the season averages 50% capacity and runs 8 hours a day for 4 months, that's $3000 in electricity for the extra weight of riders.
