TERS : Thermal Energy Recovery System

[Randolph Toom]

The FIA has recently set goals for fuel economy of Formula 1 cars. The intention is to reach this goal in two steps: The first is 20% fuel economy in 2011 (compared with today) and the second is to reach 50% fuel economy in 2015. The FIA asks the teams to make proposals for new regulations and gives them three months time for this. Fuel economy has to be achieved while at the same time Formula 1 has to keep its attractiveness for the public with excitingly fast driving.

One of the technologies already known to contribute to this goal is the KERS. Today I would like to talk with you about TERS. This is a new term and stands for Thermal Energy Recovery System. In other words, it is a system capable of Waste Heat Regeneration or "WHR" in short.

On a Formula 1 engine a major part of the power is lost as heat through the exhaust and through the cooling system. The power lost through the exhaust is actually quite impressive and can be as high as 190% of crankshaft power. This power is at high temperature which enables recovery of a part of it and regeneration into a useful form of power : torque or mechanical power. That is what in the end is driving the wheels.

TERS is not a new approach and several systems are currently being worked on at various engine developers (not restricted to F1). You will find more information about TERS or about WHR on the website of a french company (http://www.heat2power.net) that is promoting WHR in Formula 1, but as well in the Le Mans Series, the automotive industry, trucks, power generation, in fact in all sectors where combustion engines are used.

Heat2power also develops its own TERS. This one was initially thought for mass production in the automotive industry and therefor made simple and cost effective (Target cost price on a road car around 400 Euro for at least 10 kW regenerated). The "Benchmark" page on the website gives several other examples of WHR.

You will find an interesting article about WHR in Formula 1 that just appeared in the latest "Race Engine Technology" on the page "heat2power in the press". I can recommend reading this article. It deals with KERS and "TERS" (though not named as such yet) and gives orders of magnitude of the powerflows that can be regenerated as well as the amount of regenerated energy on a lap.

I hope you will find this information useful.

Best regards,

Randolph Toom

[Scotracer]

Yep. HERS/TERS will be incorporated into the regulations in the future but for now it's just KERS. It is definetely viable for the sport. Problem is, to reduce fuel consumption by 20% they will have to reduce the ICE therefore heat output will be lower. Still, it will be useful.

[flynfrog]

They want all of this extra stuff but ban turbos?

[mx_tifoso]

They want all of this extra stuff but ban turbos?

If and when TERS is incorporated, a turbocharged ICE would most likely be the way to go for the FIA (or whoever comes up with the regs by then).

IIRC, there has already been talk of decreasing the cylinder count and displacement, so a V6 of less than 2 litres would be the end result.

A turbo V6 would definately be more efficient than the current NA V8, so with KERS and TERS I don't see why a 50% reduction in fuel economy would be difficult to accomplish by 2015.

And thank you for the news Randolph, very much appreciated.

EDIT: How do you recover heat energy from the cooling systems?

[heosat]

The simplest way to recover electricity from heat is via a thermocouple which could then charge the battery/capacitor in a KERS. However, the amount of electricity produced for the weight would probably be very low.

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

[Belatti]

Where it says: "You will find more information about TERS or about WHR on the website of a french company" it should say "You will find more information about TERS or about WHR on the website of MY french company"

BTW Randolph, a nice way to have some feedback from petrolheads arround the globe and let me add the quality of the web page (info and how it is presented) is excellent =D>

IIRC this page url was posted somewhere in other threads like this:
viewtopic.php?f=4&t=3619&start=230
and this:
viewtopic.php?f=4&t=4876&start=30

[Randolph Toom]

Dear all,

Besides the fact that it is my company and that we try to get into F1, I also wish to raise the awareness of the potential of WHR in general. It is still generally just not well understood yet what can be done with waste power flows and how much this can influence fuel economy. That is why I put a benchmark page with lots of information on other concepts as well. In total I identified more than 40 technologies to regenerate waste heat and there are quite some diffences between them. That is in terms of efficiency, cost, specific power, complexity, environmental impact, safety and so on.

The term TERS did not exist before my article and I wanted to put some term in place that is easy to pronounce which is not the case with WHR. As KERS is already a common term, TERS was the most logical to pick.

I truely believe that there is a big future for TERS, both in racing and in road applications and powergeneration. BMW has already presented the Turbosteamer concept and a good article about it has just appeared in MTZ (Motor Technisches Zeitschrift) of July 2008. It shows the distribution of waste heat flows between exhaust and cooling system for a gasoline engine on a 3-series and also the amount of added power generated by the TERS. It is the order of 12 to 15% over the major part of the RPM and torque range which in my opinion is a very good performance.

Of all the technologies for fuel economy that I have looked into I believe that TERS, downsizing (turbocharging), variable compression ratio and overexpansion (Gomecsys for example) are the most effective ones, and combinations are of course possible. For part load the VCR and downsizing are very good. For "only full load" or "binary driving style" as in F1 the VCR brings nothing though. Overexpansion does however and I see a good potential for a combination of this with TERS as there will always be lots of power available in the exhaust. As or turbocharging we all know it is going to bring a few percent fuel economy and we will quite probably see this coming back to F1.

Increasing the speed of combustion is in my opinion also something that can help improving fuel economy as less fuel would be wasted by blowing it away through the exhaust. (remember why we put catalyst converters in the exhaust?). Hydrogen addition to improve combustion (also in lean mixtures for part load applications) has been worked on in the past and positive results have been shown by Prof Eran Sher of Ben Gurion University and by Prof Radu Chiriac of University of Bucurest. Only small amounts of Hydrogen are actually needed to improve fuel economy and the effect relies on the higher flame speed of hydrogen (8 times as fast as gasoline) to bring the full chamber of gasoline to combustion. The results I have seen are for RPM ranges corresponding to road vehicles so I guess that the effect will be even more beneficial on high-revving Formula 1 engines.

Then there is organometallic combustion that seems to improve fuel economy by increased flamespeed. I don't know what the effect of the added metals in the fuel are on the environment but the idea to integrate a combustion catalyst in the fuel itself does not sound odd. I have however quite little scientific information about this that I can share with you. Please forgive me.

Another method to improve efficiency I have read about is copper coating (Journal of applied sciences 7, 2007, pages 1633 and on) but the test basically were done at low RPM (around 1600 RPM) so I cannot estimate the effect at high RPM. I suggest you Google for "Krishnamoorthy and Chandrasekaran copper" to find the paper.

Apart from regenerating the waste heat you can also try to reduce it to the max. "Adiabatic engines" are what you optimally would like to have. It seems that the Shell people applied this approach in the Fuel economy record of 376.59 MPG in 1973 with a modified Opel. This was listed in the Guiness book of records at the time and I can recommend reading "Fuel Economy of the Gasoline Engine" (ISBN 0-470-99132-1) that was published by John Wiley & Sons, New York, in 1977 (written by the same Shell people). Material and lubricant properties in general keep you from applying the adiabatic principle because of too high temperatures. But times are changing and materials get better and better...

There are a few main rules to retain when you want to achieve fuel economy:
- For good thermodynamic efficiency you need high compression ratio.
- Have all the fuel burn exactly when you want it (that is what Diesotto-HCCI is doing).
- Know where the heat losses are and work on reducing them or on regenerating them (huge potential)
- Minimize mechanical losses (=friction); F1 is already quite good in this.
- Minimize oil churning losses (dry sump)
- Optimize engine internal aerodynamics

And finally...
be educated and creative.



Best regards,

Randolph Toom

[Conceptual]

Why worry about the displacement drop of the ICE in regards to heat output?

The brake calipers reach 300C+ JUST TO OPERATE!

If you were to place 6 Peltier Devices on each caliper, you could generate 12V and 3312W of energy.... Off a piece of equipment that is already used, and will forever generate heat.

Chris

[flynfrog]

Why worry about the displacement drop of the ICE in regards to heat output?

The brake calipers reach 300C+ JUST TO OPERATE!

If you were to place 6 Peltier Devices on each caliper, you could generate 12V and 3312W of energy.... Off a piece of equipment that is already used, and will forever generate heat.

Chris

Do you ever think these ideas through?

3kw its such a small amount of power.

Not to mention the complexity of such a system. And the losses in power transmission

[PlatinumZealot]

All i know is that and easy way to recover thermal energy is with a Turbine. Obviously not to make the engine more powerful (you will use more fuel) but maybe reconnected to the crankshaft with gear box or attached to a generator.

There also the use of thermo-electrics.

My 2 cents that.

[Robbobnob]

Anybody know how efficient the Engines are currently with KERS in its current form? what are the energy efficiencies of the engines compared to 2008 today?

[Belatti]

what are the energy efficiencies of the engines compared to 2008 today?

The same...

[WhiteBlue]

We have been over that issue in a dedicated thread and found that engines were likely to be less than 29% effective before KERS. KERS in terms of extra power recuperated from kinetic waste energy is very small. It would raise the efficiency by less than one percent.

But the new turbo engines which will have kinetic and heat energy recovery will be a big step up from 29%. If I remember correctly it was higher thirties figures. Just have a search on F1 efficiency and you will probably find the thread. It was sometime before December 2010 when the four cylinder engine was announced. The efficiency will go down a little (1-1.5%)for the 6-cylinder lay out though.

Another way to simply figure it out is applying the efficiency to the fuel cut. They will cut the fuel use by 33% while aiming at similar performance. At roughly 30% efficiency that will improve the efficiency by almost 10 points.

[xpensive]

What do we know so far of the TERS technology of choice WB, steam generation to turbine or what else is on the table?

Come to think of it, wasn't that a BMW development, but perhaps to cumbersome for F1?

[WhiteBlue]

What do we know so far of the TERS technology of choice WB, steam generation to turbine or what else is on the table?

The rules for 2014 are published. Heat is recovered by a single turbine that also drives the turbo compressor. The excess power not needed for the compressor will be generating electricity in a unit called MGUH. This electricity is immediately fed to the kinetic MGU that drives the rear wheels.