Trigenerator and system plan

[mobile_bob]

my plan is for an  offgrid installation
and will basically be serviced by 3 different sized units to drive the load, depending on season
and the size of the load.

the main unit is based on the changfa 195 IDI engine, rated at 12hp continuous and 13.2 hp one hour rating
it direct drives an ST7.5 for 120/240 60hz loads, it also drives two alternators one being a prestolite 110-555jho
and the other an alternator i will refer to as "project X", the remaining driven component is a sanden A/C compressor
(the alternators and compressor are twin AA belt driven, the belts are hexagonal allowing them to run in a serpentine drive)

now of course the engine cannot pull all the driven components at full capacity at the same time, it can however drive the
ST to full  capacity by itself, it can drive both alternators to capacity by themselves, and drive the A/C compressor to capacity
and also run other driven components at reduced capacity.

there is both coolant heat exchanger and an exhaust heat exchanger (my design) and i am able to reach over 75% recovery of the
heat typically lost in gensets.

the coolant exchanger will be used for space heating and the exhaust exchanger for domestic hot water production. getting exhaust leakage into my drinking water is much preferrable to antifreeze getting into it.

the idea behind the system is to provide the following for a superinsulated and small by today's standards house of approx 800 sq/ft
1. all of the domestic hot water
2. a significant portion of the space heating load during moderate cool/cold months
3. provide battery charging for a 48 volt battery bank
4. provide for my refrigeration need year round and also my cooling needs during the hot months
5. provide for my heavy 120/240 scheduled loads

the goal is to limit runtime to approx 2 hours per day, and while the engine is running keep it loaded to near 100% capacity
and harvest all the heat for use in the home. overall efficiency target of 75% should be attainable in my opinion and with some
optimizing perhaps as high as 80-85% overall efficiency is possible.

in order to control this system there will have to be a certain amount of automation and planning/scheduling on my part.
the level of which i can achieve will have a large impact on the overall efficiency of the system.

finally i plan on burying the exhaust not so much for noise abatement but to reclaim the last bits of heat and the exhaust byproducts
to offset fertilizer needs of a garden,
if that works as planned let the epa come sniff the exhaust!

of course i will be running my 2 hours per day in two runs of one hour each, one from 5-6am and the other from 6-7pm
the thinking here is nobody at the epa comes in that early or stays that late? 

i plan on useing a water tank of approx 500-750 gallons for thermal storage and from there pump it into a pex woven concrete slab
floor as needed to temper the interior climate.

the exhaust exchanger in testing has proven to make approx 50 gallons of 130 degree water per/hour of run time, thats enough for
the two of us for showers and other hot water needs.

sort of an overview of the plan, tons of details of course have been left out to keep it short

bob g

[Curbie]

I'm interested in the part of your plan where you're running multiple loads off a single engine, in thinking about this idea for myself I came up with the thought of driving a single hydraulic pump with a quick disconnects for multiple hydraulic motors mated to various devices (DC or AA generators, compressor, screw-press, ...).

It would seem on the face of it that the hydraulic idea would be more reliable and less maintenance than a belt plan, but I don't know what the efficiency differences would be, although I presume the belt plan would be more efficient?

Any thoughts???

Thanks,

Curbie

[lowspeedlife]

Hi again Curbie,
you are correct in your assumption that belts would be more efficient, hydraulics, to my understanding, is one of the most in-efficient means of driving a load. if i'm wrong about this i'm sure some one with better knowlege about it will chime in.

  Scott R.