Posted by Hoomin Bean on 01/12/2008 06:50
Thanks for your replies. I've got pics for later today when I sit back down re: the first assembly quandry and its solution, but I'll respond to the electrical stuff.
When I am with my coffee truck, which will be most of the time since I'm be roasting at weekend shows as the main thing, and one Wednesday market for sure, I have a 50 amp generator on board, muffled exhaust, and though I'm running a several hot items - drip coffee, espresso machine, granita machine, refrigeration, and hot water tank for hand wash sink I can juggle my load. Occasionally we've had to leave the espresso machine off while making several airpots of coffee, but often the facility can provide a single 20 amp circuit, which means I can run everything. We do 3 urban festivals in Harrisburg where we can just list our needs and they give us unlimited amperage from subpanels spaced regularly in their Riverfront Park. Yep, the park is wired for parties! At those affairs, we've run all the above plus a convection oven for fresh baked cookies, and never turned our generator on.
The single farmers market I'll be at (for now) is an organic, local producers market located at a historic grain mill and they have power available.
When I started this business, I was a little overwrought about how to run a energy intensive concesssion in situations where there was limited or no local power. As it turned out, the generator has never been a problem, because when they are allowed, everybody else has a louder one, when they are not there is usually power available. And if no power and no generators allowed, well, no Hobo Ed's Espresso either! Draw a 100 mile circle around your hometown and you will find so many things going on you won't know how to choose between them. Anyway, the point of mentioning my early anxiety is that I did a ton of work on small scale solar and wind until the math forced me to understand that just to supply the high cycling element in the espresso machine I would end up with a trailer full of batteries for the amp hours demanded, which could not be reasonably recharged in a typical Pennsylvania environment between the Saturday of the show and the Sunday. Or, even if they could, it would require one bank of batteries charging while the other worked.
But in fact, the roasting operation solo stands the chance of being supported by a reasonable solar array to recharge a battery or two with inverter as Rick mentions. Speculating from an armchair without looking anything up, I'll presume that the cooling will require more amphours than the drum motor. We do a couple zero-waste energy fest events where the generator is mildly problematic, but not so much that everyone won't ignore it because they want their coffee! Solar roasting at any kind of alt-fest should be a definate door opener for the vendor committee!