Quieting generator for neighbors? 1

[LMF5000]

Because of the way the world is going, I just bought a portable generator for emergency power. It's a Chinese clone of the Honda eu2000i . I measured about 70dBa from two car lengths away.

I will be running this to power my ground-floor apartment but I'm concerned about the annoyance it will cause the neighbors. Running it in the backyard the noise is very obvious and I'm sure it travels up to where all the neighbors are (there's 5 floors of apartments above mine).

I have a small brick outhouse in the yard (small meaning 1m wide, 1.8m long and 2m high - about the floor area of three washing machines). I've considered locking the generator in there and plumbing the exhaust outside, but I'm concerned that it will overheat since there's no ventilation and the walls are 20cm concrete block. The door is aluminium with glass panes, about 90cm wide and 1.9m high. Is this room too small to passively handle the heat from a 2kW generator?

Another option I considered is a quiet box. I previously built one for my dad's generator (a 4kw open-frame non inverter). We used plywood lined with foam and put two intake and two exhaust baffles, plus a centrifugal blower for forced ventilation. It reduced the noise of that generator from 77dBA to about 67dBA, but the box is massive and weighs about as much as the generator (30kg). Is there some way to construct a quiet box that's also lightweight and cheap? The generator cost €500 so I'd rather not spend $1200 on a professional quiet box.

Last option I've considered is running it in my garage that forms part of the underlying garage complex, but then it would be running relatively unattended, and the fumes and noise would be getting dumped into the common parts of the garage complex which might cause more problems.

Thoughts?

 

[LMF5000]

TugboatEng - thanks for reminding me. From Dyno tests we did on engines during my university days I recall for a petrol engine the energy flows were about 33% mechanical energy out the flywheel, 33% heat energy out the radiator and 33% out the exhaust. In my mind heat energy was power output x3 but I forgot that the flywheel component won't actually go into the room since it's the useful electrical energy, so you're right, net heat into room is power output x2, and if I can install a good insulated exhaust hose it becomes power output x1, so 2kW max. I suppose I can simulate this with space heaters and see what kind of temperature I get in the room. Thanks for the inspiration.

Wayne, I am too. If I open my own small engine factory I might be able to provide one by making the world's smallest liquid-cooled, turbocharged engine. Might go for a boxer design (horizontally opposed) to have near perfect balance with minimal counterweighting on the crankshaft. I have no intention to try that, but if I do you will be the first to know . I still am not sure why nobody tries. I suspect it's because the Chinese just clone Honda, and Honda are content being cautious and aiming for absolute reliability rather than cutting-edge performance. I find the older I get and the more experience I get of how the average user treats the product in the field, the more I realize why some carmakers design cars that will keep running without an oil change in 10-years...

If we ever have mainstream fuel cells that can run on natural gas or straight gasoline, it might be a possibility to achieve those specs by going that route (and bonus points for being silent) - the FC provides the immense compact energy that only liquid fuels can store, and a LFP battery provides surge power capability. A 5-10kW inverter doesn't take that much space and weight, powering it for 5 hours is the only issue.

 

[TugboatEng]

In the motorcycle world manufacturers have decided balance is unimportant. My last motorcycle had an online 4 engine with a cross-plane crankshaft arrangement. This creates a rocking motion along the length of the crankshaft. A counterbalance shaft manages this easily. The venerable Detroit Diesel 71 series is the earliest example of an engine with a counterbalance shaft as the 2-stroke cycle in an inline configuration requires such.

 

[Ethnan]

@LMF5000

So sorry about your experience in Europe. We have been used to this all our life in Africa. Adults and Children alike scream for joy when the power company supplies power suddenly. The normal is power outage. The abnormal is power availability. Perhaps, the situation in Europe will compel global bodies to listen and evaluate various claims about the invention of non-fossil power machines other than solar, wind and others.

Let me know if you do not have a solution of a non-fossil silent power generator(other than solar, wind etc) by last quarter of 2022.

All the best.