fasteddie313

good idea... header wrap?

67King

What that is, is physically IMPOSSIBLE. Ammonia boils at -33C. And that is at atmospheric pressure. It will be at a higher temperature under pressure, and your system will certainly be operating under pressure. Your system, no matter HOW efficient or massive, will never have the ability to cool temperatures to below the temperature of your refrigerant.

You simply CANNOT just extrapolate.

Was trying to show the challenges you would face with pulling heat out of the exhaust. You also have problems with pulling heat out of the air charge. Now, the heat capacity of ammonia is about twice what the heat capacity of air is, meaning to get your air charge to drop to hte midway point between where the factory intercooler is and the boiling point of ammonia, your ammonia side will need to only carry half the mass as the intake side. But then again, your intake side is boosted, so volume wise, it is a wash.

So now, you are taking a system that is already package constrianed, adding a second intercooler to it, and now making that system twice as big as the first, plus you have to have it sealed. It is getting not only big, but enormous. And that is just the "cold" side.

Again, go run the numbers. But you need to learn a whole lot more about heat transfer and physical chemistry before you start spending any money on this.

Voith

Look at the mobile truck/train cooling systems. Almost all of them are powered by separate diesel engine and only need to cool the amount of air that average car consumes in minutes.

If -68C would be so easy to reach, food transport companies would definitely use it and save a lot of money.

http://en.wikipedia.org/wiki/Refrigerator_car

fasteddie313

a quote from (American Society of Mechanical Engineers) on absorption refrigeration,

refrigeration temperatures as low as 205 K being achievable.. that's kelvin

205 K = -90.67 F = -68.15 C

so yes your right we are not going to see - 68 C intake temps..... I was wrong to extrapolate like that..

but those numbers are still greatly in favor if it working and being of use.. just further solidifies it as far as im concerned...

for the goal of 0 C intake temps the input to output ratios and capability to chill to chill that much air down to that tempature with the available waste energy in engine exhaust is very easily achieveable..

if a 2 sq ft intercooler can reduce temps from 150 C to 25 C with ambient temp air on the other side
then why couldn't an intercooler of the same size with -60 C ammonia on the other side do it too???
it will...


the math is solid, the numbers work, an absorption system is well capable of doing as much and more than I am asking of it.... period...

so.. it all comes down to packaging.. if the system required to do this amount of work is too massive/big to be packaged into a performance car then it is a bust...

I am greatly more than satisfied with the math that says yes we can... next I have to find out if it can be made to fit under the hood...

as far as im concerned if it can do this work and weigh less than 150lbs give or take than its a go..

these cool entire shopping malls, power plants, colleges, government buildings... they produce huge amounts of cooling...

the only question left is how big the system has to be to do how much work...

size to work capability ratio... and I haven't found it yet...

usually these things have there own buildings.. most information is for industrial air con... not much diy info out there...

fasteddie313

good thinking... obviously another industry that could benefit from this concept...

Voith

The air will heat amonia as it cools the air. You need A LOT of cold amonia for cooler to stay cold if it is heated by thousands of liters of hot air.

On the contrary on a regular intercoler, you will never heat up the atmosphere since there is A LOT of colder air that is used as cooling media, specially at high speed.

Take a hot air gun and propane freezer(at ambient temp), turn the gun to 100°C and freezer to -18 and see what happens. Even at relatively small amount of hot air, freezer does not stand a chance.

Since you could maybe run only few freezers on heat from exhaust, those few freezers could never be efficient charge air coolant system. I doubt they would cool even one single °C.

fasteddie313

these systems are put to use when there is waste heat free for the taking or when the cost of propane/fuel is cheaper than the cost of electricity to run a compression system or when electricity is just plain unavailable like in RV's witch all use these systems, they just fire with propane and not exhaust..

usually electricity is cheaper to convert into cooling than a heat fuel source but nothing beats free waste heat because its free

so if food companies had access to plenty of free waste heat they would most definitely be using this system and I would bet good money that there are examples of food companies that currently ARE using some absorption refrigeration system...

$100 bucks? any takers?

Dougs951S

Dude, ill say it again that I love your creativity, but you need to know when to go back to the drawing board, that is a hallmark of a good engineer. Both myself and harry have "run the numbers" for you in an attempt to show you why this is not really feasible for this application. We just sont want you wasting your time, money, and energy. Keep the ideas coming though.

specsalot

Interesting Thread - Great Comments - For sure there may be other potential applications outside of automotive for this concept. Almost all of the cycle efficiency improvements to Power Engineering systems come from recycling / recovering lost energy. I work at a CHP (combined heat & power) utility plant. We operate at efficiency levels ~ double traditional grid values. Its all about recovering / using waste energy. Internally our gas turbine recovers ~ 500 DEG F of exhaust heat (1200 DEG F). Externally our steam topping cycle recovers another 480 DEG F from the turbine exhaust stream. Our overall heat rate is ~4500 to 4800 BTU/kW (equivalent). Recycling energy works.

Recovering energy at an automotive scale - not so easy - but for sure something which is actively being pursued by all automotive engine designers. A lot of work is being done to alter / improve engine warm up times. Start / Stop systems which reduce idling and hybrid power help trim periods of inefficient operation to improve fuel economy. Porsche is putting start / stop systems in some of their line and has committed to offering a hybrid in all platforms within the next 4-5 years. Hybrids power helps extend peak power for a given piston displacement. Most car drivers only need full engine power for limited time periods. The Jetta Hybrid I drive is a perfect example of where these concepts work well. It's years ahead of Prius in terms of being fun to drive, while also delivering fuel economy numbers which justify the purchase price.

The biggest challenge (outside of size / scale / feasibility) for this intake cooling scheme is how the system will function during part load operation when waste thermal input is reduced. This is where some kind of thermal storage possibly on both sides (cooling and waste energy) of the system. Everything discussed adds weight / complexity / cost to the final solution.

All innovations begin by tackling problems others said couldn't be done. For example gas turbine manufactures for years had very poor results with recuperator heat exchanges to recover exhaust heat. There were no successful designs in any manufacturer's current portfolio. The big issue was engine reliability problems due to thermal expansion causing recuperator leaks. The gas turbine at work utilizes a recuperator whose design was funded $1M through a DOE grant. The design effort was successful enough that the engine / recuperator combo became part of the manufacturers engine portfolio. We've accumulated over 45,000 operating hours at full thermal limit on our unit with no recuperator issues.

Solving complex problems are always resource driven affairs which begin as novel ideas. I do have to agree with Doug951S above in that the numbers don't look promising.

fasteddie313

ok ill stop tryin to convince anybody sense that obviously isn't working.. I don't want to **** anyone off or make too much of an *** out of myself because I do have a Porsche that I will need guys like you's help with so I better not mess that up too bad..

but don't you think this would work on a stationare engine application like those giant cat diesel engines bigger than trucks in natural gas pump stations that push screw compressors, pressurize gas lines....

there whatever size the absorbtion system turns out to be wouldn't matter...

im going to finish gathering as much of the math as I can, write up a clear concice report/presentation of my findings, and then go present it to the head of the engineering department, jim coughlin, at my local community college, northern Michigan community college NMC in traverse city and see what he says....

I have talked with him a few times before when I was planning on getting an engineering degree and he seemed to have no problem taking a few minutes out of his day for me, seemed like a very reasonable guy, and they build a rally car and race it every year at that school, his son drives pro rally too...

I have pretty much decided not to go to college... pretty much everything I try to do is complicated because I have a bit of a criminal history that really puts me at a disadvantage.. I applied again this spring there and they said my app had to go before the board and I never heard back from them...

just a few alcohol related charges with the worst of them being a DUI and attempted resisting arrest really has put a huge damper in what options are available to me... especially in the automotive field... UTI even says it would hurt a lot trying to get into any of there advanced programs and im not going if I cant get into advanced because I refuse to be just another normal person...

odurandina

header wrapping is not a good idea for your T engines.

already enough heat at the exhaust ports.

fasteddie313

header wrap around the charge piping to reduce heat soak it what was meant...

not on the header

specsalot

Hey fasteddie313 - Be careful with the conclusions you are drawing about yourself, your potential, and your acceptability to academia. There is nothing about a disciplinary history that should disqualify you from seeking higher education. The best way to understand the commentary you are receiving is in recognizing that most "advanced programs" tend to be selective because they both have to be selective due to size limits of their program. DO NOT SELL YOURSELF SHORT.

I think you would be surprised at the number of folks who post here who have engineering degrees. There have been some good comments made regarding the numbers. Even for civil and mechanical engineers, translating that understanding into the specific discipline of automotive engineering is harder than it looks from a distance. It's no coincidence that all of us here are enamored with German cars. Germany continues to produce some of the best engineers in the world (especially in automotive / electrical engineering).

Your inspiration comes from an ability to "connect dots" which others miss. That is why we all think your concept is interesting. An engineering degree will give you the knowledge and discipline to build a framework around your ideas to determine if they can be made real. As Doug951S has pointed out, it is the discipline of the profession that informs whether an idea will pass muster in the real world or not. Whether its time to refine a design or just start over. Most engineering problems are bounded by boxes dimensioned by "cost" and "time". If the solution can't be fit into the box, the default action is to start over.

If you feel a real passion for pursuing this work, you need to respect that and follow up on it. As someone with an engineering degree (marine engineering), I can tell you that an engineering education is a difficult major. But it is also rewarding in that it provides a very practical understanding of the world which can serve you well for the rest of your life. Many people these days seem to want to be engineers. The profession offers great pay and easy job placement for graduates. But many seem to go through the motions without really feeling a passion for the work. I graduated engineering school 35 years ago. I attended a specialized school that was very difficult to get into. About 50% of my entering class washed out over the ensuing 4 years. We all took upwards of 150 credits and attended classes 10 1/2 months a year. Few schools push as hard as the one I attended these days, but engineering degrees are still very difficult to obtain.

specsalot

Believe it or not, one of the emerging area's given the global emergence of "frac" gas has been the development of large scale otto cycle (spark ignition) RICE (reciprocating internal combustion engines) units. Wartsilla is a leader in this development area. The principal advantage of Wartsilla engines is their ability to maintain relatively high thermal efficiency through a wide turn down in output power.

The other truth in this landscape is that exhaust emission levels (and how to mitigate emissions) tends to be one of the major differentiating factors in engine selection. The number one factor is still thermal efficiency over the intended operating range of the plant. One of the most promising areas for the adoption of efficiency enhancing technologies is the area of CHP (combined heat & power) plants. Here's a link you might find interesting:

http://www.wartsila.com/en/power-pla...ons/chp-plants

Utility rates are expected to double over the next 15 years. CHP plants are few and far between in the US right now, but there will be many more built (in targeted locations) because they provide $ that cannot be matched by traditional utility models.

ptuomov

"Wärtsilä" with a single "L."

I agree with everything else.