The majority of VO conversion components which are used to add heat to VO use "waste" engine heat by transferring it via shared interface surfaces from the hot coolant to the cooler VO fuel. I believe that this is a logical place to begin this discussion...and that electrical VO heating components should be discussed separately. A second technical discussion is provided for this.

The most commonly used coolant/VO fuel heat exchanger is probably the Flat Plate Heat Exchanger or FPHE. These are inexpensive, efficient, and very compact units commonly used in the HVAC industry for liquid to liquid heat transfer which are easily adapted to VO conversion use.

Other coolant heated components are Hose In Hose (HIH) and Hose On Hose (HOH) fuel line, Coolant Heated Fuel Filters (CHFF), Coolant Heated Fuel tank Outlets (CHFO), and Coolant Heated Fuel Tanks (CHFT).

I submit that for all of these components a single set of heat inputs can be used to standardize a test which will allow a uniform set of data to be produced. This data can then be used to allow basic comparison of the heat transfer abilities of ALL coolant heated VO conversion components rather than just those components that perform exactly the same function. Since VO conversions optimally integrate many of these components it makes great sense to me to use the same basic test for all of them.

I further submit that all tests should be as simple as possible to allow for ease of duplication by as many individuals as possible AND lessen the opportunity for error. Similarly these tests should use inexpensive  materials and instruments to allow as many individuals as possible to duplicate them.

IMO the more available we can make these tests to the general VO community the better. The more individuals that perform duplicate tests the less disputable the results become. Test results and data are only useful if they are demonstrably valid. 

Comments?

Sounds good...though I prefer to consider both the parameters and test equipment costs at the same time.

I submit that plain old hot tap water be used as the heat input medium. 

This choice allows any kitchen sink with hot water to then become a possible testing lab. Using tap water would allow very simple heat input and flow regulation for the test as well since tap pressure tends to be very steady.  Simply hooking up to a single faucet and having an adjustable (screw type) valve between the faucet outlet and the component inlet would allow the flow rate to be set prior to test commencement by measuring how long a half gallon container takes to fill.

For simplicity I submit that a standard flow rate of 1/2 gpm be adopted as the standard.  If in initial testing this proves unrealistically low we can adopt a higher flow rate standard.

Comments?

Although a gravity fuel feed is simple I do not believe the flow will remain constant. This may be critical for accuracy. I use a fairly inexpensive facet pump with a needle valve installed downstream to set the fuel flow rate. This  provides a very consistent fuel flow rate for the duration of even very long tests.

Tap water temp can be easily raised  by simply turning up the water heater thermostat an hour before the test. I think we can get a fairly long test from an average water heater if it is turned up to max and the (tap water) heat input is adjusted to remain at 150°F. 

Is there a specific reason we need a higher flow rate for the (tap water) heat input than 1/2 gpm? A flow rater 2 or 3 times that rate will limit the test length significantly..but maybe we will only need  a test under 10 minutes.

How about we initially run three tests at 1/2 gpm, 1gpm, and 1.5 gpm and see if there is any significant difference in the results?

Comments?

I think most are just watching for a bit and will chime in when they feel they have something to add. I encourage participation though. There are no stupid questions..and in technical discussions there are not even stupid ideas. Please don't be shy about posting.

How about two flow rates to begin with? Possibly 2.5 and 5 gph?

Depending on the initial results we can modify them later if needed.

Fine with me..how do we most easily achieve that? In most cases I think the VO will be at a warmer temp and so will need to be cooled.

I think that two separate containers might be easiest...but am open to suggestions on how the heated VO might be simply cooled and recycled. This would use less VO and so potentially lower the cost of the testing.

Do we need to designate a specific type of oil to use? Do different types of VO have significantly different heat absorption characteristics or can we simply specify non hydrogenated VO?

Ok..how about Canola?

Rapeseed oil is the standard used for VO fuel in Germany at this time and I suspect using it as a base oil for all testing (not just component testing) may allow some opportunity in the future for closer comparisons to this existing test data.

A recap of what is tentatively agreed upon so far is in order.

The tests will:

A. Use 150°F tap water as the heat input medium.

B. Three tests will be initially run with tap water set at .5, 1, and 1.5 GPM flow rates. The data gathered will be used to determine if any of those flow rates would suffice used alone.

C. The VO input temp will be 50°F.

D. Two sets of tests will be  run with VO input flow rates at 2.5 and 5 GPH.

E. The type of VO used will be food grade Canola/rapeseed oil.

All of this is subject to change and input/comments are encouraged.

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These tests essentially measure the heat transferred from the heat input medium (150°F tap water) to the VO fuel. Pretty simple stuff I think.

I believe that three temperatures need to be monitored.

1. The VO input temp. This must be maintained at 50°F ..which should be fairly easy IMO. I think a dial type thermometer is sufficient for monitoring this.

2. The heat input medium (150°F tap water) must be maintained at 150°F. Again..I think this should be relatively simple and that a dial type thermometer is sufficient for monitoring this.

3. The temp of the VO exiting the component must me monitored and logged.  For this I believe a digital thermometer should be used. This can then also be used to calibrate the other two thermometers before the test.

Is this reasonable? Comments? Suggestions?

The proposed VO flow rate is too low.

I estimate my return line flow rate at 20-30 lph at idle, and 50-60 lph at cruising speeds. 

It is very important to calibrate dial type thermometers. in my experience home brewing beer they can be as much as 10 deg. off.  but calibrating with a good digital or glass floating thermometer can easily fix this problem. however calibration should be done at the desired use temp., because the difference is not a stable number, but a percentage of the total temp.

Great discussion,

Che'

2. The heat input medium (150°F tap water) must be maintained at 150°F. Again..I think this should be relatively simple and that a dial type thermometer is sufficient for monitoring this.

3. The temp of the VO exiting the component must me monitored and logged.  For this I believe a digital thermometer should be used. This can then also be used to calibrate the other two thermometers before the test.

Is this reasonable? Comments? Suggestions?

Thank you for clarifying that.

I do not believe that a "universal" return flow can be established...it is highly variable even in unconverted vehicles. Some diesel engines have a nearly nonexistent return flow at highway speeds while others have return flow of several liters per minute at idle and nearly zero at WOT (Wide Open Throttle)

Very few VO conversions use a full return to tank configuration due to its extreme inefficiency. Most use a configuration that either routes all or the vast majority of return flow back to the IP.

With that in mind the previously proposed 2.5 and 5 GPH fuel flow rate represent a fuel use rate of approximately 28 and 14 mpg at 70 mph and I believe therefore are realistic fuel flow rates for the majority of private use vehicles commonly converted.

Since the vehicles I convert (large trucks) all have much higher flow rate I would be very happy to include a higher flow rate as these tests develop further.  But even these large engines only have a flow rater through the VO heating components of around 16 gph.  This will be approximately the proposed 1 liter per minute.