Diesel engine with radiant heat co-gen

 

Hello all,

    I've had the idea for a few years to use a diesel engine to drive
one or more DC generators for charging a battery bank (as an auxiliary
DC source), running on biodiesel.

    I have since expanded the idea to include using the heat generated
from the engine to heat my home when necessary. Up until today, I
figured I would look into plumbing my existing radiator system into the
engine's cooling system.

    However, as I was looking in the back of my newly-arrived PopSci
today, I came across a link to a company that sells radiant heating
supplies. That started the gears working ...

    Unfortunately, I have little to no grasp of thermodynamics, and as
such, have no idea exactly how much waste heat would be generated by
the diesel engine, and utilized for heat cogen. I have no specific
engine size in mind, as the entire concept resides solely 'on paper' at
the moment. About the only thing that I *do* know is that the main
function of the engine will be for the generation of electricity, with
the heating being a secondary consideration.

    Although there certainly will be sidereal issues pertaining to the
electricity generating aspect of the idea, I would like to limit this
particular discussion to the heating aspect, if at all possible.

    That being said, would anyone have example figures of BTU/hr versus
engine displacement? My idea is to use a solenoid valve to divert the
hot fluid between radiant PEX tubing and an outside radiator, according
to the desired temperature. The solenoid valve will be controlled by a
PIC and/or PC, in a hysteresis loop scenario.

    In a perfect world, I would also use any excess/unused heat to help
in the biodiesel conversion process, although I doubt that there would
be any excess heat in most cases.

    I welcome any comments on the topic.

    Thank you,
    Jeremiah D. Seitz
    http://www.omegatechare.net

PS - I will soon be posting a PDF of my ideal HP setup to my web page,
and would welcome any criticism or pointers.

 

You need to think of your engine as a heat generator, with electric as a
nice side product. Radiant floor heating uses low grade heat, perfect
for a coolant heat exchanger engine powered system.

Steve Spence
Dir., Green Trust
http://www.green-trust.org

Contributing Editor
http://www.off-grid.net
http://www.rebelwolf.com/essn.html

Narrff wrote:

 


Note though, that most heat escapes as hot exhaust gas.

i

 

Which is a good thing for us, as the generator is in the greenhouse, and
that hot pipe helps provide heat for the plants in cold weather.

Steve Spence
Dir., Green Trust
http://www.green-trust.org

Contributing Editor
http://www.off-grid.net
http://www.rebelwolf.com/essn.html

Ignoramus8965 wrote:

 


Do you exhaust gas right into the greenhouse? If so, I am curious, is
there any issue of the exhaust contaminating plants in the greenhouse?
Also, how can you enter the greenhouse without being exposed to CO?

And if you pipe the exhaust through some heat exchangers, is your
backpressure ok?

i


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