Cogeneration oil for workshop

[emlaurent]

Hello,

For the project of workshop / associative laboratory (see my signature), I plan to heat the room that will host the workshop with an oil jar. The idea is that the sale of electricity or conso on the spot will offset some of the cost of oil (well, it takes the basic principle of the cogé).

I paint a picture:
250m² to be heated for 25000 kWh / year (it corresponds to an average building isolated with non-permanent use). This is the average surface that I aim at knowing that I do not have this room yet.

With 50Cv car engine (37kW) rotating 2.2h / day (max) on 6 month / year, and with a buffer storage on the day in 3m ^ 3 water, ca can cover the heating requirements . It corresponds to about 14000 kWh of electricity produced per year (on 6 month in fact, since the heat will only turn on the heating period). I do not have much idea if it will correspond to the conso elec of the workshop ...

All this is an estimate that could be refined, moreover a less powerful engine might be enough to run it longer per day.

The difficulty is that to simplify the injection of elec on the network and the contracts with EDF, it would be necessary to be able to consecuate the elec and pull on the network if the engine does not run. Since electricity produced by co-op or biomass is not bought more expensive than that consumed, there is no interest in selling.

In case of self-consumption, it will be necessary to regulate the motor according to the demand.
I have some doubts about how to regulate a cog oil?

Is it possible to regulate the consumption of fuel but at constant speed while varying the load of the generator?
Or, should the rotational speed be varied at the same time as the load?

In fact, how do you make the generators to regulate according to the load? Listening to the generators (yes, it's better than opera ), I do not feel that there is a change of regime ...

I need some clarification!

Thank you

[Alain G]

Hello emlaurent!

The small generators use a three-phase generator with a capacitor rectifier and an integrated inverter which is more stable at the operation frequencies in 50 or 60 hz depending on the country of use.

The simplest way would be to buy one or two generators sold on the market and to mate them on the car engine that is cooled to the liquid so you can recover the calories for heating, the excess electricity can also serve to heat the storage tank.
A battery bank and inverter can also be used in periods when heating is not required.

[emlaurent]

Hello emlaurent!

The small generators use a three-phase generator with a capacitor rectifier and an integrated inverter which is more stable at the operation frequencies in 50 or 60 hz depending on the country of use.

The simplest way would be to buy one or two generators sold on the market and to mate them on the car engine that is cooled to the liquid so you can recover the calories for heating, the excess electricity can also serve to heat the storage tank.

Hello Alain!

Are you sure that the inverters of small generators are not just used to compensate for short variations between need and production and to avoid micro-cuts ??

In addition, it's a shame to have a three-phase generator (very useful for powering machine tools!) And turn it into 12V ...
to then do the opposite!

In my case, to store a day of electric production of 50cv's engine, it would take more than 2 tons of lead-acid battery (and again without taking into account all the charge / discharge efficiencies) !!
Well, ok, there is a way to reduce the amount of battery by running the engine several times in the day instead of once.

On the other hand, the idea of ​​regulating by converting surplus electricity into hot water with an electrical resistance is interesting. I had vaguely thought about it and it's simple to implement!

I searched on the net but I can not find information on cogé regulation schemes when there is self-consumption.
Help

[Forhorse]

A group engine always runs at the same speed (which must be 1500 revolutions / minutes) because most of the groups are based on a synchronous generator, it is the engine speed that determines the frequency of the current produced.

There are 2 regulations:
- A mechanic, at the engine, so that it always runs at the same speed whatever the load applied to it, it guarantees the frequency of the current
- An electric, which acts on the excitation of the generator, in order to stabilize the output voltage

It is true that in the very small group, the incorporation of an inverter seems to be generalized. But this is not the case on what exceeds the 2KVA

In this kind of project find the generator is always the problem ... after that also depends on the budget. Because it can very well be bought at any manufacturer of electric motor. Now, if it's to get there, maybe the price of the generator plus all the hacks that must be added will cost no more expensive than a good diesel generator set.

[jonule]

hi autonoman! =)

on a diesel engine, with the oil of recovery (gratos) you can roll it, even in intermittence (like a boiler), several techniques are possible, starting 100% on oil or small volume gas oil before 100% oil in buckle , in short feed it on the recovery! frying oil ...
then you recover the heat: just connect your cast iron radiators instead of the car radiator!
you will recover a lot of heat. you even have the small cockpit blower of the car, finally you choose cast iron inertia or fins radiator alu on blower.
you can also recover calories on the muffler.

then for electricity: you keep the alternator and the battery!
you can use any 12V, comem for camper. Low lighting conso 12V CFL (energy store sweet com, I just enc ommander the cons of 5W 40W for lighting, small room for I do not find on this site apart from the LED bulbs), in short you have all the comfort possible! fridge, etc ...
nothing prevents you to connect an inverter, recovery as to do: like those found on the net cheap because abtterie HS: you connect then a good battery, solar as long as do, finally slow discharge (electric chair style, etc ...).

do you want +? and of course on your engine you connect another alternator, another battery etc! each alternator has its regulator. they are synchronous: you do not need a fixed speed to charge, and we take DC, not AC (which is made for long distances).

in winter, super you warm a room with the engine, which devellope watts, in the form of heat. well, in summer it may be less profitable, but in 2 cases you can also couple to your hot water production (hot water tank for shower, washing machine etc).

a turbo diesel engine alone, pump bosch (to start on 100% of vegetable oil) is minting from 300 €!


then long live the autonomy accessible, and realistic!

[Forhorse]

Yeah finally, on a 37Kw engine, only use alternators 1Kw it's not really profitable, hello mechanical losses! ...
It's a bit like using a mass to drive a nail.
Finally I have not found a more suitable metaphor, but you get the picture

[emlaurent]

Thanks Forhorse for the explanations on the regulation of the cogés, I understand better!

Good idea to use a diesel generator directly instead of adapting a car engine and make a regulation (I should have started there, by the way).
I checked, we find plenty of opportunity (agricultural equipment and construction sites). There are already enough work to run the engine oil and adjust the heat recovery from the exhaust and coolant for not longer care to control a motor car.

With that, I'll be able to actually be in self-consumption and choose a smaller engine to make it run longer in the day. The water storage tank for heating will be just a buffer tank of a few hundred liters.

I will review my dimensioning.

Jonule, it's nice all your ideas but hey, I do not try to be autonomous at all! I am trying to heat a associative workshop at a reasonable cost and for that the joint is very interesting. And then, running a roommate in summer, it makes no sense as well from the economic point of view as from the ecological point of view!
In addition, this workshop will be equipped with machine tools that will require three-phase, so the 12V is good for lighting but for the rest ...

Emmanuel

[Forhorse]

If you do not find your happiness among the groups of occasion, I invite you to consult the catalog of a very large French company specialized in generating sets.
They certainly have the group that will suit your application.

(I ogled the side of their model 6KVA, diesel, automatic startup, completely soundproof, the engine already a liquid cooling system ... only the price a little elevé over my use m ' had braked, depending on your budget, sometimes it's worth looking at the new side, if only to have a reference price)

[Alain G]

emlaurent

If this is the phase that interests you is the very different, you can use a big alternator phase motor with some capacitors for your powered tools, a simple already existing cruise control on the engine you recover you will regulate the phase that you can manage using a frequency indicator.

You will thus be able to recover the heat of the coolant and with an exchanger made using 2 pipes of different dimension.

All this will cost you some trifles but a lot of time to implement.

[Forhorse]

This is a solution that is only valid for supplying resistive loads. To power inductive loads, which consume reactive power, one must be able to vary the capacity of the capacitors across the generator.
This is feasible with capacitor batteries dimmer (kind rectivar), but the purchase price of this kind of equipment immediately makes the solution less interesting. As well buy directly a synchronous generator.