I’m wondering what the alternatives are to having a gas or diesel generator to provided emergency power to by building’s sole elevator (five story building). As I understand it, the sole purpose is not even continual power, but just to return the elevator to the main floor, open the doors, and stop. I.e., people in the elevator won’t be trapped but nobody else can use the elevator until the power outage is over. I’ve been looking around for batteries that would be able to do this, but I’ve had a hard time finding much about this. Are they allowed, affordable, reasonable?
We have only 26 units in the building (elevator serves four floors and a basement with units and its own side exit to the street). I’d hate to spend close to six figures removing and replacing the old diesel generator. Seems a more eco-friendly solution is possible.
Thoughts?
Thanks!
(Note: I thought I posted this question before, but cannot find it or maybe I forgot my old user name…but still couldn’t find the topic using the advanced search…sorry if I posted it and lost it.)
Elevators, like much industrial equipment, use AC induction motors. Induction motors cannot run on DC, which a battery would provide, so now you need very high power inverters to convert the DC power to 3-phase AC.
On the other hand, an engine spinning a generator will generate 3-phase AC directly.
does this thing run all that frequently?
ETA: nevermind the fact that if your cobbled-together battery-powered solution fails when pressed into service, it’ll be your arse on the line.
The generator runs for 20 minutes each weekend for “exercise.” Not sure if that is really needed that often. Power outages seem to happen every other or third year (after storms).
Ideally, we wouldn’t cobble together anything, it would be a system some business sells for this purpose. I just haven’t found anything (maybe a couple sites in Germany). Maybe your answer on AC and DC explains why.
Diesel fuel has a limited storage life, so it has to be consumed eventually; further engines don’t care for sitting unused for long periods so starting them periodically and getting them up to operating temp for a while is advisable.
worrying about the “environmental impact” of something used so infrequently is IMO a misplaced priority.
Using biodiesel with a diesel generator might satisfy the eco-friendly requirement, depending on your own personal definition of that. The big drawback of biodiesel in vehicles is that even moderately cool weather leads to gelling, but in a backup generator your fuel supply is inside so it isn’t an issue.
Check with your elevator service company. It may be possible to retrofit the elevator with a dedicated battery backup, or configure it to return to the ground or next lowest floor by gravity.
5 story building? then probably your elevator is a cable traction elevator. Gravity will not return it to ground but to the top of the shaft. convertng your elevator over to direct battery operation will probably cost more than just replacing them.
If you ellimiate your emergency generator you are going to also have other problems. You need emergency lighting. Enough lighting lighting for people to safely “egress” the building.
If you want to eliminate the generator you can consider a UPS. They make them big enough to provide 3 phase power for the time that you determine will be necessary. Going to be big with a lot of batteries and room. And the elevators can be modified easily so when they are on the UPS without utility power they will return to 1st floor and the doors will open and the elevators will shut down.
I worked in a building that had Otis elevators with battery backup for power outages. In a power outage the batteries would run the elevators for 30 minutes. Because of low power supplied they only ran at slow speed. The only company that would service them was Otis, and they did not want to work on them. They batteries had to be changed every year. I think each elevator had 20 or 40 batteries. The cost of operating those elevators over 20 years could have paid for a new engine driven generator.