Topic: Barani pro passive shield

[jerryg]

Yes the chamber is the same but at the bottom where the air enters it is restricted by that disk shaped piece that i think shields the chamber from reflected heat and forms the vintura , spelled wrong, effect. That was how it was described in the patent application.

[CW2274]

Yes the chamber is the same but at the bottom where the air enters it is restricted by that disk shaped piece that i think shields the chamber from reflected heat and forms the vintura , spelled wrong, effect. That was how it was described in the patent application.

Yes, see what you're saying.
With that, and my common sense (for what it's worth), I am completely unconvinced that wind causes a high bias temp, certainly for any kind of continuity.

[jerryg]

I wonder how they determined it was the wind and not some other anomaly. The wind speed varies quite a bit so like you said i would think it would be in spurts and not a lot at that.

[hwcorder]

I would like to see more test showing the same results. Like others I a little dubious over their conclusion that the Davis fars runs too cool in light wind to calm conditions. It's difficult to get a thermometer to read on the cool side during the day.

[jgentry]

Thanks to Jerry & Randy, I pulled the trigger and bought the pro shield. I guess I’m now a part of the club. Lol

[jerryg]

Great i think you will be happy with it.

[ValentineWeather]

Both shields ended almost same .3 difference high temperature, few clouds in afternoon. The Fars was warmer until afternoon about .4F. Wind is at 2.5' above sensor level or 8'.

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[ValentineWeather]

Pro vs Standard, The 7714 was also 90.3 for a high so tied the PRO. Standard was warmest of 4 shields at 90.9°.  Max differential between the 4 shields .9 with a breeze. 
Even though the max temps were close in reality the Pro ran cooler for larger portion of day over all shields. Wasn't until almost 4:30 pm when FARS was slightly better or the same.
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[openvista]

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Are these graphs of the same shields? Appears to me that in the morning graph (top graph above running from about midnight to 2pm) there's about a 1 degree differential, but in the later graph (whose time scale somewhat overlaps the first) the two shields are neck and neck.

If anything, the morning graph should appear more compressed since the image is not as tall and it has a y-axis (temperature) with a larger scale (5 more degrees). But in fact, it's the graph showing more separation between shields.

My guess would be that the first graph shows a different shield comparison. The Barani standard vs pro?

[openvista]

Comparing the time-equivalent TEMP versus insolation numbers should provide a hint as to why things are happening as they are.

It would be helpful for you to quote whom you're addressing. I'm going to assume this was in response to my post immediately above yours.

Look more closely. The two graphs overlap in time somewhat (approx 10a - 2pm). At no point in the 2nd graph is there the separation we see in the 1st graph during the same period. This has nothing to do with insolation as that's a constant if you compare the same shields in the same time period.

[ValentineWeather]

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Are these graphs of the same shields? Appears to me that in the morning graph (top graph above running from midnight to noon) there's about a 1 degree differential, but in the later graph (whose time scale somewhat overlaps the first) the two shields are neck and neck.

If anything, the morning graph should appear more compressed since the image is not as tall and it has a y-axis (temperature) with a larger scale (5 more degrees). But in fact, it's the graph showing more separation between shields.

My guess would be that the first graph shows a different shield comparison. The Barani standard vs pro?

Yes the top graph scale is less and only went until 2:30, being less condensed so better view. The second is full day much more condensed not as clear on tracking.

[openvista]

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Are these graphs of the same shields? Appears to me that in the morning graph (top graph above running from midnight to noon) there's about a 1 degree differential, but in the later graph (whose time scale somewhat overlaps the first) the two shields are neck and neck.

If anything, the morning graph should appear more compressed since the image is not as tall and it has a y-axis (temperature) with a larger scale (5 more degrees). But in fact, it's the graph showing more separation between shields.

My guess would be that the first graph shows a different shield comparison. The Barani standard vs pro?

Yes the top graph scale is less and only went until 2:30, being less condensed so better view. The second is full day much more condensed not as clear on tracking.

Both graphs depict about 14 hours in time scale and 30-35 degrees in temperature scale. So if there's a 1 degree difference that appears nearly constantly in one graph, it should also appear in the 2nd graph since they overlap during the period of differential (which begins around 10AM). Their scale is the roughly same, just time shifted somewhat.

[ValentineWeather]

I wonder also now looking at it. I guess it's possible the first graph was different shield like standard by mistake.  I moved the transmitters around the fars previously was on standard  frequency so switched them and may have grabbed wrong shield. 
Also it was only .4 difference not 1°as depicted on graph.
Regardless the Pro ran below the Fars on average around .4 until late afternoon just wasn't as big of difference on first graph.

I was convinced even sent the graph to Barini I'll now need to send them email on this.
 
Apologize that happened everyone.

I'll leave the transmitter status at bottom of graph for now on so doesn't happen again .
TX-1 is Pro, Tx-3 Fars, TX-6 Standard

[openvista]

I wonder also now looking at it. I guess it's possible the first graph was different shield like standard by mistake.  I moved the transmitters around the fars previously was on standard  frequency so switched them and may have grabbed wrong shield. 
Also it was only .4 difference not 1°as depicted on graph.
Regardless the Pro ran below the Fars on average around .4 until late afternoon just wasn't as big of difference on first graph.

I was convinced even sent the graph to Barini I'll now need to send them email on this.
 
Apologize that happened everyone.

I'll leave the transmitter status at bottom of graph for now on so doesn't happen again .
TX-1 is Pro, Tx-3 Fars, TX-6 Standard

It's an easy mistake to make. I know because I've done stuff like that too. In the end all that matters is that we know that the later graph (~10a - midnight) is correct and can draw conclusions from that. Appreciate the clarification, Randy. 

[ValentineWeather]

A little better look of Pro vs Fars yesterday. Notice left TX status at bottom alone because of my screw up and lesson learned. 
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[openvista]

A little better look of Pro vs Fars yesterday. Notice left TX status at bottom alone because of my screw up and lesson learned. 

The slight separation between 4:30 - 5:00PM looks to correspond to a temporary slow down in wind speeds.

Wondering if the reason the Pro runs underneath for the majority of the daytime hours is due to heat radiation from the fan in the FARS. I'm splitting hairs here, of course, as we're inside the Davis spec for temp (+/- 0.5F). Just spitballing....

[ValentineWeather]

A little better look of Pro vs Fars yesterday. Notice left TX status at bottom alone because of my screw up and lesson learned. 
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Yes, on that plot, it's easy to see when the solar peak occurred (≈3:43 PM) and the temp differences "switched" places: 'TX1 < TX3-FARS' switched to 'TX3-FARS > TX1'.

Glad you can see that. I switched data logger back to 5 minutes those times are too close at 1 minute. Plus the data logger captures high and low in 5 minute block. 
Barani asked for 1 minute not realizing high and low were captured.

openvista
I may switch to Stock FARS today if I get more energy.

[dendrite]

If it was the fan, why are we only seeing it during higher insolation?

[openvista]

If it was the fan, why are we only seeing it during higher insolation?

Good point.

[openvista]

If it was the fan, why are we only seeing it during higher insolation?

My SWAG (Stupid Wild Ass Guess) is that it's the *latent* heat that's been *accumulated/stored/retained* within the radiation shield material that is slightly warming the cooler incoming air the fan sucks in.

Could be.

Randy, how old is the FARS shield? That plastic decays with time. When I replaced a top plate recently, the old one had grey discolorations all over it and it was yellowing pretty badly too. I'm guessing older plastic performs worse than newer plastic.

Again, we're splitting hairs here, so no worries either way.

[CW2274]

A little better look of Pro vs Fars yesterday. Notice left TX status at bottom alone because of my screw up and lesson learned. 

Wondering if the reason the Pro runs underneath for the majority of the daytime hours is due to heat radiation from the fan in the FARS.

No. That's why the fan is located above, not below the sensor. What little heat the motor does generate is blown out top by it's own fan.

[ValentineWeather]

A little better look of Pro vs Fars yesterday. Notice left TX status at bottom alone because of my screw up and lesson learned. 

Wondering if the reason the Pro runs underneath for the majority of the daytime hours is due to heat radiation from the fan in the FARS.

No. That's why the fan is located above, not below the sensor. What little heat the motor does generates is blow out top by it's own fan.

Yeah agree I still want to test the solar fan for awhile.
 

[CW2274]

A little better look of Pro vs Fars yesterday. Notice left TX status at bottom alone because of my screw up and lesson learned. 

Wondering if the reason the Pro runs underneath for the majority of the daytime hours is due to heat radiation from the fan in the FARS.

No. That's why the fan is located above, not below the sensor. What little heat the motor does generates is blow out top by it's own fan.

Yeah agree I still want to test the solar fan for awhile.

[jerryg]

It will be interesting to see your results, i tried that some time ago and the results were not very good. I thought the fan might help with airflow problems with light winds but i think all it did was draw the hot air in off the plates and up the temp quite a bit. The plates are most effective when they shade the fars tube and allow the air being drawn up the tubes to remove any heat from them so the center chamber stays at ambient air temp.

[ValentineWeather]

Well switched the Davis FARS to stock and within 2 minutes fan died (Batteries I'm sure dead)  and no sun for recharge so this will end any comparison test until tomorrow.