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Old 09-10-2015, 08:56   #376
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Re: Why no Residential Fridges?

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Actually don't need to have a boat float on mars to do that math once you have a specific weight defined by gravity on the surface of the earth at sea level. Mars is .38 earth gravity but I'm not going to mars anytime soon so doesn't matter to me. Now my tohatsu outboard uses 5 gph of gasoline so I know I can run it for 7.5 hours with the available fuel capacity on my boat. Don't care what it weighs .
Given just 5 gph as information, you can't show that it runs for 7.5 hours without adding more information. What you are likely doing is you know the volume contained in the tank. With a flow rate and volume in the tank, you can determine the time to drain the tank but you need both variables. The original assertion was you can determine the volume strictly based on the flow rate.

Ignore the weight as that was just a thought experiment to demonstrate that 1 gph of a fluid does not have a volume or weight. As you say, weight isn't typically of much interest in terms of fuel storage on boats.

For those still questioning the point, show me a tank marked with a capacity measured in GPH. Someone has already shown that electric meters for 12v systems show it in amp-hrs not amps.
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Old 09-10-2015, 09:06   #377
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Re: Why no Residential Fridges?

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Originally Posted by valhalla360 View Post
Given just 5 gph as information, you can't show that it runs for 7.5 hours without adding more information. What you are likely doing is you know the volume contained in the tank. With a flow rate and volume in the tank, you can determine the time to drain the tank but you need both variables. The original assertion was you can determine the volume strictly based on the flow rate.

Ignore the weight as that was just a thought experiment to demonstrate that 1 gph of a fluid does not have a volume or weight. As you say, weight isn't typically of much interest in terms of fuel storage on boats.

For those still questioning the point, show me a tank marked with a capacity measured in GPH. Someone has already shown that electric meters for 12v systems show it in amp-hrs not amps.
OK I noticed that my post had a minor issue it was supposed to be .5 id 1/2 gallon per hour with a run time of 15 hours using the available capacity. Not 7.5 hours. My bad the math it is easy and doesn't require any physics classes to do .5 gal per hour with a duration of 15 hours equals 7.5 gallon capacity.
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Old 09-10-2015, 09:18   #378
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Re: Why no Residential Fridges?

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But back to our recent discussion, I'm still waiting for a source that provides lists volume in GPH or can define weight based on GPH without providing a duration or other
Like I said before, you can't get volume from GPH, but you actually need volume to define GPH. That is how its actually works. As you said, if you have volume then you also have weight of flow.

I guess what I'm saying is GPH or amperes or coulombs do not exist with out other real physical properties.

Sort of like Al Einstein working out the photoelectric effect that defines how solar panels work. He had to understand the underlining quantum properties.


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Ignore the weight as that was just a thought experiment to demonstrate that 1 gph of a fluid does not have a volume or weight.
Yet the fluid does have weight and volume. Like I said you need to know volume of flow of the fluid to even calculate GPH. GPH is derived from volume of flow That is what I'm saying.
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Old 09-10-2015, 09:44   #379
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Re: Why no Residential Fridges?

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Like I said before, you can't get volume from GPH, but you actually need volume to define GPH. That is how its actually works. As you said, if you have volume then you also have weight of flow.

I guess what I'm saying is GPH or amperes or coulombs do not exist with out other real physical properties.

Sort of like Al Einstein working out the photoelectric effect that defines how solar panels work. He had to understand the underlining quantum properties.




Yet the fluid does have weight and volume. Like I said you need to know volume of flow of the fluid to even calculate GPH. GPH is derived from volume of flow That is what I'm saying.
To quote you:
- GPM IS a measurement of volume.
- How many GPH does a 20 liter jerrycan hold? Somewhere between 0 and 4.45 ish.
- The question was how many gph it can hold, not how fast you can fill it.
- A single GPH if it's cold water weights 8.33 pounds

The first one is wrong because it's a flow rate not a volume
The second is wrong because I guarantee, I can put a 1000 GPH into your jerrycan.
The third is wrong because GPH still isn't a volume
The fourth is wrong because because if you leave the hose running for 1000hrs it is 833 lbs.

But interestingly, you story is starting to change. Hopefully, you've learned something.
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Old 09-10-2015, 10:02   #380
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Re: Why no Residential Fridges?

Quote:
Originally Posted by valhalla360 View Post
To quote you:
- GPM IS a measurement of volume.
- How many GPH does a 20 liter jerrycan hold? Somewhere between 0 and 4.45 ish.
- The question was how many gph it can hold, not how fast you can fill it.
- A single GPH if it's cold water weights 8.33 pounds

The first one is wrong because it's a flow rate not a volume
The second is wrong because I guarantee, I can put a 1000 GPH into your jerrycan.
The third is wrong because GPH still isn't a volume
The fourth is wrong because because if you leave the hose running for 1000hrs it is 833 lbs.

1. Yet to get the flow rate you need the volume to define it

But interestingly, you story is starting to change. Hopefully, you've learned something.
1. You derive GPH from volume, so yes it has a volume. That you may not know what the volume is, is beside the point.
2. The question was not about the rate of fill, But how many GPH does a 20 liter can hold.
3. Yet a 20 liter jerry can does have volume.
4. And still, even for a 1000 hours, a single GPH, that is one gallon for one hour is 8.33 pounds.
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Old 09-10-2015, 10:09   #381
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Re: Why no Residential Fridges?

Quote:
Originally Posted by valhalla360 View Post
To quote you:
- GPM IS a measurement of volume.
- How many GPH does a 20 liter jerrycan hold? Somewhere between 0 and 4.45 ish.
- The question was how many gph it can hold, not how fast you can fill it.
- A single GPH if it's cold water weights 8.33 pounds

The first one is wrong because it's a flow rate not a volume
The second is wrong because I guarantee, I can put a 1000 GPH into your jerrycan.
The third is wrong because GPH still isn't a volume
The fourth is wrong because because if you leave the hose running for 1000hrs it is 833 lbs.

But interestingly, you story is starting to change. Hopefully, you've learned something.
Actually your math is wrong as well the fourth is to get 833 pounds at a flow rate of one gallon per hour would only require 100 hours.
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Old 09-10-2015, 11:23   #382
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Re: Why no Residential Fridges?

Sorry I start this drift with a simple analogy.
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Old 09-10-2015, 12:41   #383
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Re: Why no Residential Fridges?

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Sorry I start this drift with a simple analogy.
See where your thread drift lead. Actually it's been fun. Sort of the ultimate thread drift.
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Old 09-10-2015, 17:02   #384
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Re: Why no Residential Fridges?

I am almost as new as the guy with the original post about standard size refrigerators in boats. We are upgrading from our 35' center console to a sportfisher. We did bit of math and it was going to cost a small fortune to run one. Unfortunately, we do not sail. You mentioned powerboats running for hours a day! We can't do that and don't want to!

So, is it that uncommon to see powerboats that rely on solar for these type of things? I've been looking at options for solar and it doesn't seem to be too far fetched.

Thanks for any advice.
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Old 09-10-2015, 17:18   #385
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Re: Why no Residential Fridges?

If it's inboard engine(s) on a sportfisher, take a look at eutectic refrigeration with a compressor driven directly off your engine. It's a good match for that sort of operation. Search the forum for "eutectic", there are several appropriate threads.
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Old 09-10-2015, 18:23   #386
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Re: Why no Residential Fridges?

No wonder I have to keep fixing things that engineers desighn. And simple is normally better and more reliable

Sent from my D6653 using Cruisers Sailing Forum mobile app
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Old 09-10-2015, 22:54   #387
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Re: Why no Residential Fridges?

OK, absolutely, definitely, positively my last post in this thread on the sbuject (cross my heart and hope to die)!

I think I've summed our drift up here:

Amps v Amp hours v Amps/Hr - Cruisers & Sailing Forums

Let's take it there if you disagree with any of what I've said.
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