Co-generation for Vehicle Electrical System and Greenhouse Thermal

[Tyler Dean Wisconsin]

I am in the process of designing a system that does some co-generation of electricity and thermal energy like a lot of power plants do. The electricity will be used to charge the battery on a Nissan Leaf and the thermal energy will heat a greenhouse.

This is my personal plan, but I live in Wisconsin where a large generator manufacturer is located and also the most co-op farming organizations in the nation. At co-op farms everyone drives pretty nice Chevy trucks. I always wonder, "How are we going to retrofit vehicles for fuel economy?"

At ecomodder.com, people will add a toggle switch to their alternator and charge their batteries using a regular battery charger that plugs into the wall. The alternator is only 50% efficient at converting kinetic energy into electric energy because it has brushes and has to generate two opposing electromagnetic fields. Permanent magnet alternators require rare earth magnets, and are 100% more efficient, but they still drag on an internal combustion engine that is ~25% thermally efficient. So, by turning the alternator off and charging deep cycle batteries they can ADD horsepower AND eliminate the drag on the motor.

Imagine farmers at the co-op going to the shop and plugging their Chevy trucks in. They are charged off of generators that run on biofuels; biodiesel, ethanol, biomass, etc. Redundancy is good for fail safe, thermal efficiency(redundant generators are a hybrid system), fuel purchasing, etc. Those alternators are 100-140a! If they are only 50% efficient they are dragging on the engine with the force of 60hp, and if we eliminate the drag AND ADD the electricity to the batteries there is a net gain of 90hp!

15kw diesel generators are liquid cooled. It would take a little bit of engineering, but I would run that engine coolant into a tank and use it in PEX tubing for radiant heating in the greenhouse. I would expect to improve thermal efficiency of the generator by almost 100%.

So, this is a double, double. 100% better thermal efficiency on electric energy generation and 100% better thermal efficiency of the stationary internal combustion engine.

I will buy commercially available biofuel. I will even submit an offroad fuel refund for the cost of the road tax. I think the current state of road technology is over built for too many trucks and SUVs. I drive an electric car that I charge off grid and I use 50% of the energy from the biofuel to heat a greenhouse. I will use the refund to buy beer.

[Dave Schwartz]

There's one rather large erroneous assumption in your calculations... that the alternator is creating a constant drag on the engine. That is not true. If it were, you'd have to have a large dump load to keep from boiling the battery and frying all your electronics.

The 100-140A rating of an alternator is its maximum output (before bits start to melt). The alternator almost never puts this out. The biggest load on an alternator is to recharge the battery after the initial starting drain but this is completed quite quickly - its what starting batteries are designed to do. After that, the alternator is only supplying the running loads and the regulator throttles back the field winding current to keep the output voltage in check. That probably adds up to around 10A (less if you have LED DRLs). 10A at 14V is 140 watts or about 1/5 of a hp and at 50% would still not be large load on the engine.

Then all your users are going to have to get used to driving around all the time with their alternator light on. The computer expects to see nearly 15V from the alternator when the engine is running and when it sees only ~12.5V it will turn on the alternator light.

Plus, you're going to need some sort of monitoring system so that running the battery down significantly during a long trip (and automotive starting batteries hate this - it dramatically shortens their life) doesn't leave the owner stranded by not having enough charge to start the engine after turning it off somewhere it wasn't going to be recharged.

Many people think there's a great conspiracy by auto manufacturers and oil companies to make your cars have bad gas mileage. Its really not true and auto manufacturers fight tooth and nail to eek out tiny fractions of an MPG ('diesel emissions scandal' anyone?). Its also why most engines these days specify 5W or 0W oil - really thin, low drag stuff at operating temperatures.

[Tyler Dean Wisconsin]

There's one rather large erroneous assumption in your calculations... that the alternator is creating a constant drag on the engine. That is not true. If it were, you'd have to have a large dump load to keep from boiling the battery and frying all your electronics.
Many people think there's a great conspiracy by auto manufacturers and oil companies to make your cars have bad gas mileage. Its really not true and auto manufacturers fight tooth and nail to eek out tiny fractions of an MPG ('diesel emissions scandal' anyone?). Its also why most engines these days specify 5W or 0W oil - really thin, low drag stuff at operating temperatures.

While I appreciate that those ratings are "maximum" the burdon of proof for the 1/5hp claim is on you. I am eeking out MPG over short distance trips. So, even with your calculus I could see significant improvements. Your hyperbole about conspiracy theorist insists that people who believe in conspiracy theories(which I don't) are stupid and that auto manufactures participate in conspiracies. That is basically double talk

What if I co-generate electricity and thermal into a Prius? You recognize that I would be able to double a 10kw generator if I can regenerate 1/3 of the thermal energy it is wasting. I can't make that water go into the Prius?

Then, it is a 20kw generator. I know I can do this.

[Dave Schwartz]

The physical laws describing the generation, transmission, conversion and conservation of energy ('thermodynamics') are well established and need no further proving by anyone. No one has yet to avoid them or even suspend them temporarily.

I did not insist that anyone was stupid - do not attempt to mischaracterize my post. Self-deluded by insufficient understanding of the physics, maybe, but that does not necessarily imply a lack of intelligence.

You are correct that a generator deriving its mechanical input from combustion is wasting far more energy in waste heat than it is producing in electrical power, the internal combustion process being only about 30% efficient to start. However, the heat is a degraded form of energy (see entropy) and the great trick is to upgrade that energy to a more useful form. It can be done (e.g. turbochargers) but is not generally something that can be retrofitted (or, in a vehicle, would not eat up its own gains by having to move the extra weight around).

I don't understand what you're asking with the question "I can't make that water go into the Prius?" I hope that's not some recycled form of the "water carburetor".

Probably the best way to improve the MPG of a pickup is streamlining. Pickups are horrible aerodynamically - bricks are more streamlined. However, not many users would want their pickup to look like a GM EV1.

I look forward to the 10kW nameplate generator that can produce 20kW. I have one of those standby generators produced in your region in my backyard and would very much like to see a doubling of the price/performance ratio.

[Tyler Dean Wisconsin]

The physical laws describing the generation, transmission, conversion and conservation of energy ('thermodynamics') are well established and need no further proving by anyone. No one has yet to avoid them or even suspend them temporarily.

I did not insist that anyone was stupid - do not attempt to mischaracterize my post. Self-deluded by insufficient understanding of the physics, maybe, but that does not necessarily imply a lack of intelligence.

You are correct that a generator deriving its mechanical input from combustion is wasting far more energy in waste heat than it is producing in electrical power, the internal combustion process being only about 30% efficient to start. However, the heat is a degraded form of energy (see entropy) and the great trick is to upgrade that energy to a more useful form. It can be done (e.g. turbochargers) but is not generally something that can be retrofitted (or, in a vehicle, would not eat up its own gains by having to move the extra weight around).

The evidence for the specifications of alternators performance is likely documented. This is the information we are accusing each other of exaggerating.

I think the metric will be good. Vehicles made plug in hybrid:American homes.

It is getting colder here. If the Prius starts on battery in the morning, the coolant would be cold. The generator can heat the coolant and charge the battery. The car has all electric accessories. The water pump and fan will work when the car is off. So, you can heat the cab.

I have read that combustion efficiency is improved when the cylinder temp is 170°f. So, I would even use a block heater on the Prius. Electric would be kind of cool, but I think the exhaust from the generator would be awesome.

[Tyler Dean Wisconsin]

Everyone who wants to work on this project is equal. Except if you called someone stupid on the first day you are demoted.

With redundant generators, we can off load systems that are succumbing to entropy.

I say we put a couple generators in a pick up truck.

I can actually add a single generator to the truck and use the PTO to add brushless (****), air compressor, hydraulic pumps, the PTO is a nice prime mover, but the truck should shut off too, right?

Maybe add some SLA? A water heater?

It would be sick to have three or four Priuses. And at the end of the day put the left over thermal in the shop.

Hypermilling the potential of the four or five vehicles. They would be constrained by the timing of the system. So, they would have to choose meet up locations, periodically.

Turning the engines off prevents thermal losses.

It is a virtual micro-grid. If the shop has solar panels. Probably a generator. Maybe something more experimental. That runs on biomass. Domes would be cool but everyone uses barns.

I will get the coil pickling people on the phone. For a water heater thermal exchanger.

The shop should have a wellness center with a gym and showers.

The frequency of the periods would be determined by ambient temperature

We could probably get a good deal on insurance but I vote we avoid taxes as much as possible.

The Prius should have an empty battery and coolant at a target temperature. It's two stage thermal. So, the battery charges and the generator brings the thermal energy up from the Prius into the water heater tank at a higher tperature for an efficient capture. This is from the biofuel.

See why it is off road? That water is like 75% of the energy. + Prius energy.

If we save hot water, there is always heat for the morning. What are we doing with out lives?

See why I want to charge the lead acid batteries?

Virtual micro-grid. 100% renewable. High efficiency co-generation

I can make that like 500% efficient.

Epic should get yaxis like that.

Co-op farming would have heat for some hella green house.

And be warm, for growing delicious veggies and weed fish chickens and chia. Fruit trees.

15% of what is recaptured from the vehicles is 15% ethanol. The biodiesel generators make a high efficiency capture by co-generation. 1994 Geo-metros get like 60mpg with this techn:idea: ecomodder.com

Why don't cars put their coolant in at work? Wages should be better and I want to put my coolant into you.

I quit driving 10 years ago and I have road my bike to dozens of Walmarts and libraries. Now, I work on the Walmart supply chain and intralibrary delivery.

That high efficiency capture is important. I am competing with natural gas for heating efficiency. Natural Gas can invite auto coolant. Natural Gas is super efficient efficient for heating. So, I like co-generation.

I think natural gas could beat biodiesel on efficiency at generating electricity. The ratio would be more electricity then heat. Plus, the natural gas could do hybrid thermal generation to beat the biofuel by two margins.

A good way to make a big burn load is to make electric lithium ion blowers that come from Walmart. Use at your own risk.

In case charging lead acid batteries is stupid. Tesla says lead is competitive with lion in energy conversion. NiMH is inherently 67%

If a Geo Metro is 90hp and it goes from 35mpg to 51.667mpg it is 30% more mileage per tank of gas, but to describe it in terms of improvement in thermal efficiency would require taking into account the amount of energy added to the system from thermally efficient co-generation. The thermally efficiency of the energy added has significant factors of improvement. So, if 0.200ml of biodiesel goes in it is like 1l of gas. Or 2l of gas if it the improvement is against the alternator, right? Throw a little engine coolant in there to fudge my numbers?

I need a few Geo metros and a generator. Do two control and one modified. Then two modified using the same generator.

I am interested to know the average temperature of the engine coolant during the trip. Will the coolant be 18.5% cooler or 33% cooler? How hot is the engine spark? Can I make it hotter for better combustion?

They make similar 45mi trips two ways everyday. They all fill up at the same time.

Those things waste 270hp/h or something like that. So, the improvement in thermal efficiency there requires understanding that average coolant temperature and then figuring how how many hp you you recaptured. It will be way smaller. I think adding electricity and adding heat will is going to be like adding gas. 100% renewable gas.

It would be sweet to get a swarm drone class of entries to "The 24hr $500 Lemon Race."

I've heard of guys who flip the fuel pump off and the alternator on in their metros. So, they charge the battery when they coast. If I had a lithium ion blowers, I could regenerate 50 of the energy from that blower when coasting.

[Dave Schwartz]

Wow... just WOW!!

Mark Twain once said 'never argue with an *****, the casual observer may not be able to tell the difference'.

[Ralph Day]

Please Rob...save us!

[Rob Beckers]

I think we're done with this thread...