[RE-wrenches] Gen preheat in cold climates

[Chris Mason]

Heating the regulator won't help if the propane is not vapourizing. You
would need to heat the tank.
However, you do not need to heat it very much, just enough to let it
vapourize. Think about putting it somewhere with a little heat, or burying
it.

On Fri, Apr 3, 2015 at 1:51 PM, Larry <larry at starlightsolar.com> wrote:

>  About the carb heat idea...LP is a liquid at -44°F. The liquid does not
> combust, it must be vaporized. As the ambient temperature drops closer to
> the LP liquid temperature, there would be a reduction in how fast liquid is
> vaporizing and therefor a reduction in volume. What you need in cold
> weather is enough volume to maintain at least 11" wc while cranking or
> running the engine. You can test the vapor pressure with a manometer while
> cranking to verify if this is the problem.
>
> If this is the reason the engine does not run, my thoughts are that
> heating the LP regulator would be much more economical from an energy
> standpoint, than heating the whole engine block. Perhaps an insulated
> enclosure with silicone heaters appropriately attached would work. They are
> available in many DC or AC and at various voltages.
>
> Larry Crutcher
> Starlight Solar Power Systems
>
> On 4/2/15 10:34 PM, Allan Sindelar wrote:
>
> Gary,
> Mac's approach is intelligent and will work well, as an automated system
> with the right hardware. We took a quite different approach on a somewhat
> similar scenario in 2009.
>
> This was a Kohler 8.5REZ, with the electric carb heater and AC charter for
> the starting battery. No block heater, but that could have been handled the
> same way. The inverter was a Magnum MS4024PAE, but that doesn't matter
> here. When we ran the bundle of gennie output conductors, we added a
> separate load circuit conductor, on its own breaker in the system E-Panel.
> Here's an excerpt from the original proposal description about our approach:
>
>  The unit uses an electronic generator controller with modest (estimated
> at 200-700 mA, depending on state of operation) draw on the starting
> battery. This controller drops to minimal “sleep” draw automatically after
> 48 hours of non-operation. This generator does not have a starting battery
> charging coil, but rather uses a separate AC battery trickle charger to
> maintain the battery. I will install a 20W PV module and small charge
> controller on the generator to keep the starting battery charged. I will
> also install the AC charger to operate whenever the generator is running.
> While this combined setup has worked successfully for other installers with
> whom I have spoken, if this proves insufficient I can later add a switch
> and relay to allow the charger to also operate off of inverter AC if ever
> needed.
>
>
>
> The unit also requires a built-in carburetor heater to operate during cold
> weather. This heater is normally controlled by a thermostat to
> conservatively come on at or below 40°F, which would mean that it would
> operate nearly continuously during Taos’ winter months, draining the PV
> system. My solution is to put the carburetor heater on a manual mechanical
> one-hour time switch located at the generator; you will activate the heater
> through this switch 15-30 minutes before starting the generator.
>
> This may not work for you. This is a modern doublewide serving as a
> seasonal family meeting place, rather than a full time residence. With our
> usual sunny winters, we figure that if nobody is there, loads are minimal,
> and we don't want automatic (unattended) generator operation. I think we
> used a DG WP box inside the generator enclosure, with a mechanical timer
> (maybe one-hour) controlling a GFCI receptacle, with carb heater and
> battery charger plugged in.
>
> I hope that gives you some ideas you can use.
>
>  *Allan Sindelar*
> allan at 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 <505%20780-2738> cell*
>
>
>
>
>
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-- 
Chris Mason
NABCEP Certified Solar PV Installer™
Solar Design Engineer
Generac Generators Industrial technician

www.cometsolar.com <http://www.cometenergysystems.com>
264.235.5670
869.662.5670
Skype: netconcepts
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