Re: [RE-wrenches] Gen preheat in cold climates

[Allan Sindelar]

I too have an off grid customer with a Quad Stack, who has plumbed his Onan 20kW (industrial) unit as a heat source to his home's hydronic system. We installed his system in 2005; later he became the CEO of Solar Logic, the state-of-the-art solar-hydronic controls developer, so it's no surprise that he did this. The clear report is that it works very well (he runs three Wattsun trackers for the array, so PV production fluctuates widely between summer and winter, so he depends on his generator during winter) and was worth the effort. I'd also like to contribute a related idea to this discussion. I haven't tried this, as New Mexico just isn't that brutally cold. If fuel vaporization isn't an issue, but cranking ability is, a battery heater might be a good solution. it would demand fewer watts, we all know how batteries respond to extremely cold temperatures, and a gennie starting battery could be easily insulated to reduce the runtime of a battery heater. Has nyone done this and can report on the results? Allan Allan Sindelar al...@sindelarsolar.com NABCEP Certified PV Installation Professional NABCEP Certified Technical Sales Professional New Mexico EE98J Journeyman Electrician Founder (Retired), Positive Energy, Inc. 505 780-2738 cell   On 4/3/2015 9:56 AM, d...@foxfire-energy.com wrote: OBTW, I do have one off grid customer that has the water jacket from his diesel genny plumbed into his heating system. So no only can he dump heat from the engine into his thermal storage tank, he can also treat the engine as a zone and heat it from the wood furnace. db Dan Brown Foxfire Energy Corp. Renewable Energy Systems (802)-483-2564 www.Foxfire-Energy.com NABCEP #092907-44 -------- Original Message -------- Subject: Re: [RE-wrenches] Gen preheat in cold climates From: drake.chamber...@redwoodalliance.org Date: Fri, April 03, 2015 10:32 am To: "RE-wrenches" <re-wrenches@lists.re-wrenches.org> We are dealing with a generator that absolutely won't start when cold, so I was considering a block heater. Below 20 deg F it has proven worthless, and we can see -20 F on occasion. My concern is using power from a low battery on a cold cloudy day to heat a generator. How long does it take to make a difference? Has this method proven 100% reliable? Thanks, Drake > Hi Gary, > > We have implemented a preheat strategy that has really worked well at a > site using dual sunny islands. They have a load shed function built in > with the control relays. We are using that function to add the block > heater load. When a generator start is likely (~50% SOC) it triggers a > relay that energized the block heater. The generator start is then > programmed at a lower SOC (~30% SOC). It takes some guesswork to know how > many watt hours its going to take to get the block heated up, but we > conservatively chose and have fiddled with it. I imagine this can be done > with either the Radian or the XW, and you could trigger with voltage > instead of SOC, but SOC is a superior way to do it. > > Another way is to use a propane block heater. This will work well, but > they use quite a bit of propane, and are very expensive (~$1500). > > Good luck > > On Thu, Apr 2, 2015 at 8:47 PM, Gary Higbee <g...@windstreamsolar.com> > wrote: > >> Wrenches, >> >> I'm curious what strategies you use to preheat a propane gen in cold >> climates. This is a large off-grid design in a sub-zero winter climate >> and >> ideal would be to turn on a block heater an hour or two in advance, then >> run the gen cycle. We plan to use either a Schneider XW or Outback >> Radian >> configuration (still very interested in which you'd use and why). We >> could >> set up a logic/relay system to first send the gen request to the heater >> for >> a while and then turn off and initiate a gen cycle but that would >> eliminate >> the ability for autostart on short notice. I've read of heat lamps on a >> thermostat, just wondering if you have seen other solutions. >> >> Thanks! >> >> Gary >> _______________________________________________ >> List sponsored by Redwood Alliance >> >> List Address: RE-wrenches@lists.re-wrenches.org >> >> Change listserver email address & settings: >> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org >> >> List-Archive: >> http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html >> >> List rules & etiquette: >> www.re-wrenches.org/etiquette.htm >> >> Check out or update participant bios: >> www.members.re-wrenches.org >> >> > > > -- > > > > Mac Lewis > > *"Yo solo sé que no sé nada." -Sócrates* > _______________________________________________ > List sponsored by Redwood Alliance > > List Address: RE-wrenches@lists.re-wrenches.org > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > www.members.re-wrenches.org > > _______________________________________________ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org _______________________________________________ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org

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