I have a local health care clinic(doctor offices) that called and is looking for a way to supply power to a refrigerator and a freezer in the event of a power outage. They are used to store vacines and related medical products. What would be the best way to do this? A generator? Would I then need to consider all three branches of emergency power? Or some type of UPS system? Any thoughts would be appreciated.
Uniteruptable power supplies.
- Thread starter arnettda
- Start date
- Status
I'd have a preference for a UPS system.
No moving parts, no noise, and no exhaust to deal with.
ceb58
Senior Member
- Location
- Raeford, NC
I would prefer a UPS also but you get into the amount of time it will hold the load. If the location is where an extended amount of outage time is expected due to storms and such a small generator may be the only way to go.
I agree with the both of you. I will have to see how large the load actually is and do a calc on them. I do know they are both small. No large chest or upright sizes. They are all say dorm room sizes. Would any one know if a UPS system would power these loads for say two days? No one will be there during a outage so it is not like they will be opened and closed muliple times.
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
UPS backup times are measured in minutes and hours. For days you will need a automatic generator system.
This application would fall under the NEC 'optional standby' requirements. If this facility fell into the 'required standby' requirements, a backup system would already be installed.
What you have described are likely to be intermittent loads. A UPS inverter stage would need to be rated to deal with the actual loading that will occur from time to time. The battery has to support the average load which might be quite a lot less than short term loading.
Yes, continuously at rated load. This application isn't likely to be continuously at rated load.
And a generator also has a limit on autonomy - it won't have an infinite fuel tank.
kbsparky
Senior Member
- Location
- Delmarva, USA
In some cases, you can connect a generator to a natural gas line, or large LP gas tank. In the case of the municipal natural gas, it can indeed be "unlimited" --
In the case of an LP tank, a large tank can offer weeks of standby capacity.
brian john
Senior Member
- Location
- Leesburg, VA
Generator, hands down.
UPS?s have VERY limited battery life, long slow discharges are harmful to lead acid batteries. Batteries have a limited life span 3-5 years for sealed in an area with regular extended outages. Higher maintenance cost for a UPS. No one checking the batteries regularly. High battery replacement cost.
Needing to size the UPS for motor load requiring a much larger UPS than required to handle just the motor running load. And while this applies to generators as well, the cost would escalate more with the UPS. A properly maintained generator will last 10-15 years, a UPS service life is typically 5-10, mainly due to availability of parts.
Generators can be filled fairly easy in the middle of an outage, a UPS with a dead battery in the middle of an outage is well, not a UPS.
UPS?s have VERY limited battery life, long slow discharges are harmful to lead acid batteries. Batteries have a limited life span 3-5 years for sealed in an area with regular extended outages. Higher maintenance cost for a UPS. No one checking the batteries regularly. High battery replacement cost.
Needing to size the UPS for motor load requiring a much larger UPS than required to handle just the motor running load. And while this applies to generators as well, the cost would escalate more with the UPS. A properly maintained generator will last 10-15 years, a UPS service life is typically 5-10, mainly due to availability of parts.
Generators can be filled fairly easy in the middle of an outage, a UPS with a dead battery in the middle of an outage is well, not a UPS.
Most of the UPS systems we supply have 10-year life Yuasa VRLA cells.
The UPS has no moving parts that require maintenance. A generator set has.....well, quite a few.
Most, if not all of the UPS systems I have dealt with recently have pretty comprehensive diagnostics and comms facilities that give remote access to the status.
Agreed. If and when you have to replace it. I don't how durable a generator would be it was given the same duty as a true on-line UPS.
As I noted above, the UPS system has no moving parts that require maintenance. Batteries are usually VRLA which are also maintenance free.
Maybe we're looking at different ends of the market here. We are mostly dealing with the upper end of the commercial and industrial segments.
I agree that there are horses for courses. A pumping station that needs half a MW for a few hours is an obvious candidate for a Diesel generator.
The emergency lighting in a place of entertainment like an opera house or cinema complex will often use an on-line UPS. In UK, the Cinematic Code of Practice requires three hours autonomy but typically the UPS required is only in the 20-40 kVA range.
- Status