Blockheizkraftwerk mit 1,9 Liter TDI Motor | Posts 16+

Hello everyone,

Looking at the boat engine section, it doesn't seem any better, in my opinion. To me, these are car engines that have probably been adapted to different conditions (more continuous operation under load, different movements of the engine).

It also seems unsuitable for a CHP system that needs to operate 24/7.

Wie funktioniert das mit den Oelwechseln usw. eogentlich bei grossen Stationaerdieseln, die wirklich viele Wochen Dauerbetrieb laufen? Nebenstromfilter? Or something completely different?

Best regards,

Jan.

@christian

It was exactly that kind of van, but as a pickup truck! It was a lot of fun to drive. I don't remember the exact details about what the engine could do. I was just fascinated by the fact that it had 600,000 km on it, and with just a press of the starter, the diesel engine would come to life.

@Jan

Okay, they can't deny that the boat engines are very similar to the engines from the T4. But believe me, these components are about to initiate a near-revolution in shipbuilding (not just from VW, although they started it...). Take a look at a Perkins or Faryman boat diesel engine. They're bringing back the old Deutz era. Sure, they're practically indestructible, but with 800 kg of weight in the boat for so little power, the fun stops there. And the amount of fuel they consume is unbelievable.
"Personally, I often crew on a 48-foot sailboat, and it has a TDI 100-5 engine (which is an expensive special feature), and it's truly excellent – quiet, fuel-efficient, and incredibly powerful. This is also because it's a performance class that is rarely found in sailboats."

Sure, here's the translation:

"For example, oil changes on the massive diesel engines of large ships are performed while the ship is in operation. This is partly achieved through bypass filters, where "used" oil is drained and new oil is added. These huge engines don't even need 200 hours of new oil, which I also find to be quite tight for VW engines, but it's probably a consequence of the power output and their origin in passenger car engines."
VW has also made quite a few changes. I'm not sure what the current configuration is regarding bearings and such. However, it has two oil pumps, a dry sump, a water-cooled variable geometry turbocharger, and NO EGR system! ...and so on.

[Translating...]http://www.mtu-diesel.de
http://www.mtu-diesel.de/de/pr/prdiep5c.htm

Hi,
I'm not a sailor, but I'm sure 200 hours on a sailboat that's mostly drifting would be easier to endure than on a sports boat that, for example, pulls water skiers for 8 hours a day, or on a large ocean yacht.

Yes, that's probably true, but also remember that you need electricity. This device works perfectly well as a wind deflector. However, it's unfortunately much too expensive for that purpose.
And for motorboating, you need...MORE POWER. Those speedboat enthusiasts seem to be into more of a thrill...I prefer sailing!

@gremlin

The really thick ones have... http://www.manbw.com/web/viewers/news/SubjectViewer.aspx?id=77

With a capacity of 70,000 kW, the energy supplier could potentially shut down.

...

With 70,000 kW, the energy provider could then shut down!

Hi,

Such an engine also requires 7.5-11 kg of OIL per 24 hours per cylinder for lubrication.

On the other hand, a TDI...

Greetings.

Eike.

...well, nothing is free.
...don't forget the heating aspect; the engine is overheating at full throttle...
...and it doesn't need premium diesel, it eats almost anything, as long as there's plenty of it.

It doesn't really matter if my son happens to pee in the tank sometimes. *g*

Best regards, WarLord.

a completely different objection.
If I understand correctly, you want to control the frequency based on the motor speed. That's complete nonsense; you'll never achieve a stable frequency that way, making it impossible to feed power into the public grid. Furthermore, not only the frequency, but also the phase relationship must be correct, otherwise there will be a short circuit.
This is typically done with electronic inverters via a DC intermediate circuit. And then it doesn't matter what comes out of the generator beforehand.

Regarding synchronous generators: This problem does not occur with proper control, and proper control can be achieved with relatively simple electronic means.

The only potentially tricky situation is before connecting to the grid, but even that is not a problem thanks to the electronic phase angle comparison. Once the generator is synchronized, very little can go wrong.

Why? It's quite simple: When feeding into a large interconnected grid, you have the advantage that you can design the feed-in as a constant power feed-in, at most up to the upper tolerance limit of the grid voltage, which rarely occurs. A constant power feed-in means that the excitation current of the generator is always adjusted in such a way that - regardless of the instantaneous voltage of the grid within the tolerance limits - a constant electrical power is always fed into the grid. Since the excitation current can be electronically adjusted in near real-time in response to grid voltage fluctuations, the generator continuously requires a constant torque. (the speed is, after all, constant). Load changes practically do not exist.

Regarding the phase angle, a synchronous generator, under constant load and within a specific torque range, has a 'locking range' where it remains phase-locked independently. Why? The higher the torque of the prime mover, the more the generator phase wants to lead the grid phase. However, leading the grid phase introduces an additional braking torque because it causes loss-inducing reactive currents to flow.

Within narrow torque limits, a synchronous generator synchronized to an external grid can be driven, even with a constant load, without any drive motor control. Of course, control is better for reducing reactive currents, and also to compensate for potential load changes or fluctuations in the drive torque.

something off-topic:

How would one go about sizing such a CHP system?
So that the heat generated is always sufficient for heating, and any excess electricity is fed back into the power grid? Or so that the electrical energy plus waste heat corresponds to the maximum heat demand, and electricity can also be used for heating when needed?

Greetings.

Eike.

"This is certainly a question that needs to be tailored to each specific need. So, if you put my ASZ (air-to-water heat pump) in the basement and run it, the heat from the cooling water will likely only be sufficient for a room of about 8 square meters, as is probably the case with most TDI engines. You can't extract an unlimited amount of heat from it... on one side, it's 90°C, and on the other, only 30°C when it re-enters the engine. I think that would completely shut down the engine. Of course, with a suitable generator, you will certainly produce plenty of energy, which is enough for everything in a private household. However, as we've already discussed, the problem here is the too-small flywheel and the tiny displacement of our TDI engines."
Turn on the heated rear window, lights, and ventilation at the same time while the engine is idling, and you'll notice the engine speed drops slightly. Now, imagine that happening with a generator that's running idle. Suddenly (because you have to consider everything), all the vacuum cleaners, drills, and model trains in the town are switched on... it would get really dark.

That's why there's a good reason to use a really powerful, purpose-built engine for such applications.

And if you only need electricity and heat for your home, I'd like to know how a combined heat and power (CHP) system would be cost-effective.

'Regarding Matthias: Unlike a car, with a CHP (Combined Heat and Power) system, ideally, the entire exhaust heat is utilized. This results in roughly double the heating capacity compared to simply using the cooling water. Furthermore, as you already mentioned, the cooling water must have a minimum return temperature. This does not apply to the exhaust heat exchanger.'

Using only the cooling water means, in terms of heating, that you're heating the outside air. The exhaust gases contain at least 30% of the total waste heat. Therefore, the exhaust gases are passed through a large heat exchanger. There's usually enough space for that.

An extreme solution is to use the engine to power a heat pump (e.g., a former air conditioning compressor) and to cool the exhaust gases down to 15°C. This would result in a 100% efficiency, including electricity generation. (Ideally, the room where the CHP system is located should also be considered a heated space, such as a garage or workshop.)

Here's a general rule: When a motor has an efficiency of 33%, you have twice the kW value available as heat (1/3 goes to the motor, 2/3 is converted to heat). If the motor operates with a mechanical power of 40 kW, you have 80 kW available for the house. This is enough for a large villa with 32 rooms, assuming 100% heat utilization (as mentioned above).

'In typical exhaust heat exchangers, the heating capacity is usually at least equal to the mechanical power output. It depends on the specific engine efficiency, but it rarely exceeds 40%.'

Regarding the fluctuating speed: As I mentioned earlier, this problem doesn't occur when feeding power into the grid and using proper regulation (constant power injection). In that case, you don't need a flywheel either.

There's also a simple and inexpensive solution: the asynchronous generator. When feeding power into the grid, practically nothing needs to be regulated. The output power is determined by the drive speed – that's it. An asynchronous generator is essentially an asynchronous three-phase motor that is driven beyond its rated speed by the external grid. It then becomes a generator. In this case, the grid provides the excitation power. However, for this reason, it is better suited for feeding power into a grid-connected system than for an isolated system. For an isolated system, it requires large capacitors for self-excitation, but there are significant control problems regarding voltage and frequency, because there is no excitation winding. Furthermore, it typically has a somewhat lower efficiency than a synchronous generator.

For an islanded solution (without a grid connection), a synchronous generator is the preferred choice.

Oops... I didn't think about the exhaust. THANK YOU! That was very silly of me, I'll be more careful from now on!

Hey, if that was meant sarcastically - I don't want anyone to hold back, nor do I want to 'lecture' anyone here. Everyone should feel free to share their thoughts in a forum. The more people who participate (meaningfully), the more valuable information others can find later in the thread.

Okay, don't hold back because of me, and just tell me what you think.

Sure, here is the translation of the text from German to English:

'Hello'

Quatsch, das war mein ernst, bin hier doch nicht beleidigt....das mit der Abgaswärme habe ich völlig vergessen obwohl ich mich gerade nach einem neuen Niedertemperaturkessel für die Old school Kellerheizung angesehen habe. Doof.

Well, I was just saying that I've already written enough about it, and you can kind of tell from all the responses that the motor will eventually fail if it's run for 24 hours straight!

Regarding lifespan: If you operate a car engine at only 1500 RPM and 30% of its rated power, and also use an oil regeneration system, it might be worthwhile. At least, if you can get the engine and a lot of spare parts cheaply. Ideally, you would have a complete assembly setup above the engine, with pneumatic impact wrenches hanging from the ceiling.

'The timing belt is indeed a problem. Perhaps a special device could be built for the timing belt replacement to minimize the effort involved. The advantage compared to passenger cars is that you have direct access to the timing belt in a CHP system. Ideally, the engine should be at an optimal working height of 90 cm.'