On Radiators

So, I’ve been thinking a lot about radiators lately. When you’re driving in a very low car, sometimes all you see of the vehicle behind you is the big chrome grille designed to let air through to reach the radiator. Even cars with excellent aerodynamics are forced to have this component that, by its very nature, requires wind resistance to operate. There is even a fan to expend more energy to make sure that air is passing over the radiator at all times. If there was a way to get rid of the radiator, fuel efficiency in vehicles would be increased. Maybe not a lot, but a measurable amount that would certainly add up.

The only catch is that the radiator is really important. Owners of old air-cooled Volkswagens can testify to that; those engines had no radiators and were not terribly reliable — plus, they paid the same aerodynamic price to have the air pass through the engine compartment.

Internal combustion engines produce a lot of heat; in fact, thermodynamics says that the hotter they burn, the more efficient they are. My clever nephew Gerald, when presented with the Radiator Conundrum, realized immediately that one solution is simply to embrace the heat rather than get rid of it. If one builds the engine out of materials that can withstand much higher heat than modern engines, then you can let that sucker get really, really hot and actually burn more efficiently at the same time. It’s win-win! I know that there are experimental ceramic engines built around this principle, and it’s about time to get them into production vehicles.

Superhot engines may be good, but superhot engine compartments are not. There’s still going to be some waste heat to manage, if only for safety. My thoughts turned to ways to take at least some of the waste heat and make use of it. By converting the heat energy into some other form of energy, say, electricity, we can simultaneously cool the engine and reclaim some of the waste. Perhaps we could even do away with the alternator, which costs a typical car a couple of horsepower. By reducing the load on the engine once again we can increase efficiency.

Unfortunately, that’s easier said than done (or it would be done already). However, with a really hot ceramic engine, I think it would be possible to use the thermoelectric effect. All you need to do is embed series of different metals along the heat gradient within the engine to create thermopiles. (More modern thermopiles are used to power deep-space probes.) Thermopiles can supply large amounts of current, but only at low voltages. With enough of them, however, you would have a cooling system that simultaneously recharged the car’s battery. If the system worked really well, you could even use surplus current to power a small electric helper motor.

So, anyone up for investing in Jer’s Radiatorless Engine? If it works, we’d make a fortune!


17 thoughts on “On Radiators

  1. Yay! A G-P-Q entry. Always like those.

    I remember reading about porcelain engines in Popular Science magazine decades ago. Makes you wonder about the obstacles that seemingly brilliant ideas encounter. That is the nature of life, I guess, and points to the inherent wisdom of naming this category Get Poor quick rather than Rich

    Another great idea we’ve been hearing about since like, gah, forever, is geothermal energy. It was in Pop Sci Mag, of course, but also any Los Alamos brat circa 1970s heard all about LANL’s Hot dry rock experiment, probably even went on a field trip up into the Jemez mountains. Why is this going nowhere? What are the obstacles? I think it would be illuminating. I know of one problem…recently attended the PhD defense of a geology student in my department. His work was analyszing the semi-disasterous results of an attempt to drill for a hot dry rock geothermal electric plant in a town in Switzerland. The drilling triggered…you guessed it…earthquakes. Citizenry of this fine alpine town are NOT happy.

    But back to those porcelain engines. Didn’t somebody get as far as cylinder sleeves? Maybe it’s like the hybrid cars. For whatever reason, they cost at least $2000 more to buy at a loss than the all gasoline base model. So I’m only investing in Jer’s radiatorless engine if I can sell it at a loss for $2000 (hey it’s called get-poor-quick, and I’m loyal to the category).

  2. I have been waiting for someone with greater knowledge of thermodynamics than mine to point out that the efficiency of the internal combustion engine depends on the DIFFERENCE of the temperature between the exploding gas and the final exhaust gas. Hence the effort made to keep the engine block relatively cool. As I am sure you remember, the 3 laws of thermodynamics are
    1) you can’t win;
    2) you can’t break even;
    3) you can’t get out of the game.

    Using the heat of the exhaust gas in a second (and third!) cyclic engine is commonly done in marine steam engines. Since the size of the cylinder gets larger as the temperature gets lower, those engines get rather bulky – not as much of a problem on a ship as in a car. Whatever energy you extract from the hot gas, you always have to have some way to keep the final temperature low.

    That heat exchanger out front, called a “radiator,” actually depends on convection instead of radiation to transfer heat. It HAS to have moving air, and it wants to slow the air down enough so that it is heated it as it passes through. I think that is the kernel of your argument. How about replacing the “radiator” with a real radiator — large black fins, parallel to the airflow, shaded from the sun? That works well in space, where convection is not practical, but I don’t know if anyone has tried it down here. I suspect the frontal area of the fins would be as bad as the radiator core.

    A final thought, as I was about to close – if you want to generate electricity, how about foregoing internal combustion altogether? Either light a fire under your thermoelectric device, or … fuel cells!

  3. I should have said that it was high temperature in the cylinder that helped efficiency. One of my later designs was to apply a Russian Lamp Thermopile along the length of the exhaust system. It got rid of the alternator (with a more reliable substitute), but didn’t solve the radiator problem. If exhaust gas is cooled past a certain point, condensing water provides yet more heat to play with.

    Getting rid of the internal combustion entirely is an attractive proposition, as well.

  4. Hot dry rock, as I recall, hit some location snags. One thing I remember was that they drilled into a giant chamber, so when they pumped water down, nothing came back up. Attempts to fill the chamber with concrete failed miserably. There may have been other issues as well (besides just funding cuts) that discouraged the group from trying the same project in another location.

  5. Diesel engines get efficiency from pressure. And fusion energy research tries to achieve a whole lot of heat AND pressure. So, all you need to do is make a reality out of the “Back to the Future” (something like) “Mr. Fusion” engine.

    By the time you had that technology perfected, you could also have a car smart enough to gather its own fuel material. Whenever you weren’t driving, you could just turn the car out to pasture to graze … or use it as a lawnmower/mulcher … or run a feed line from your trash compactor.

  6. Isn’t that technology known as … oxen?

    You take 10 kilograms of plant protein plus the accompanying cellulose and other stuff, convert it to 1 kilogram of animal protein, and also produce massive quantities of methane and manure, and some energy output in the form of motive power and heat.

    As for geothermal energy … the entire country of Iceland runs on it, but that’s dealing with hot rocks that already have water in the system. There’s a company down near Deming that’s pumping water down into hot dry rocks to get geothermal energy — so far, they’ve been successful, but only on a very small scale.

  7. Speaking of radiators, does anyone know why the temp for a 92 XJ with a 4.0L HO would drop from 210+-10 at idle to 160+-10 at highway speed, with ambient temps running from 60 to 90?

  8. To put Squirrely Joe’s answer into complete sentences, the radiator is really a convector, and requires a steady flow of air. I am developing a thermocouple design that is so crazy it just might work.

  9. I once had a car whose owner’s manual even warned that the engine might get hot if the car wasn’t moving very fast — the manual said that it was OK if the engine temperature needle went into the red zone briefly, but that if the needle went into the red zone for a longer period of time, the solution was to drive faster so more air would pass through the radiator.

    I wonder what the owner of the car was supposed to do in a California traffic jam?

  10. But the temp for the jeep is supposed to be within the 200 to 220 range. I’m thinking that the thermostat maybe off.

  11. Possible but not likely. Thermostats typically fail but due to being mechanical devices, they don’t go out of spec.

    Have you taken a look at the little bugger?

    Anywho, it’s not a situation that I would call a problem. But then again squirrels and cars do not typically mix.

  12. So I really like those pre-packaged ice cream cones, sold in places like 7/11 or Circle K, that come with monikers like Nutty Buddy or Drumstick. An interesting feature that makes this treat even yummier is that they line the sugar cone with chocolate. Now I suspect, but don’t know, that they didn’t do this just to enhance our lip smacking pleasure, but rather to solve a real, industrial manufacturing, problem; maybe the ice cream soaked thru the sugar cone making it yucky on the shelf; or maybe the ice cream was melting too easily in transit and needed more insulation.
    Whatever the case, the cure is definately a plus in my book, and illustrates how important creativity is to solving problems. I think a smaller radiator and a hotter occupant cabin can simply be solved by lining the interior of the car in chocolate. And who could object!

  13. The drumsticks that this squirrel gets from his local 7-11 are not choco-lined but do have the plug of chocolate at the bottom (tip) of the cone. S’pposed to prevent the dreaded ice cream dip but I like to bite off the cocoa nipple and let it drip as the good lord intended.

    /I’m just a rodent but I know what I like

  14. The 12 Sept 2008 issue of SCIENCE magazine has a review article on recovery of waste heat via thermoelectric systems (vol. 321, pp1457-1461). The technology is further along than I realized.
    Also, as a result of GE buying Carrier, they have now developed a “reverse air conditioner” that can generate electricity from water with a temperature as low as 73C.

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