AuthorTopic: The DIY Thread  (Read 436 times)

Offline RE

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The DIY Thread
« on: February 16, 2017, 05:06:48 AM »
Kickoff for this official thread on DIY Projects is making a Walk-In Cooler from an Air Conditioner and a "Coolbot" temperature controller that mates to digitally controlled air conditioners.  As opposed to $5000  for a typical commercial unit, you can have your walk in fridge for $1500 or even less if you pick up your A/C unit used.

The guy doing this YouTube vid review is a Florist, and uses it to keep his flowers nice looking prior to sale.

Now, I know the criticism here, "RE, Air Conditioners use a lot of electricity!".  Which is true, but if you consider that so do refrigerators, what you do in your SUN☼ Community is have one of these for say about every 20 people (depends how big a room you insulate up) instead of a fridge for every 4 people, you're going to use less total juice.  So it is more for a community or for a small commercial operation that might be selling say Mangalitsa Pig Bacon.  ;)

<a href="http://www.youtube.com/v/NrqnzLuWMcc" target="_blank" class="new_win">http://www.youtube.com/v/NrqnzLuWMcc</a>

How big a solar array and batt storage system you would need to power it I am not sure.  It would depend on the BTUs of the A/C unit and the outside temps and how well you insulate your room/cooler.

Refrigeration is one of the last things you want to have to give up after TSHTF.  This is a great way to do large scale refrigeration at a low cost.

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Offline Eddie

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Re: The DIY Thread
« Reply #1 on: February 16, 2017, 05:23:12 AM »
I was aware of this gadget, and actually had a lecture (in my PDC course) from a farmer who is entirely off-grid, who uses this. One of the farmers crops was  cut flowers, which, of course, are in all the supermarkets these days. They do run the generator a lot to keep their batteries up.

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Offline RE

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Re: The DIY Thread
« Reply #2 on: February 16, 2017, 06:01:05 AM »
I was aware of this gadget, and actually had a lecture (in my PDC course) from a farmer who is entirely off-grid, who uses this. One of the farmers crops was  cut flowers, which, of course, are in all the supermarkets these days. They do run the generator a lot to keep their batteries up.

Yea, it's hard to see how you could run it on just solar/wind.

The question would be how much fuel is used to run the Genny each month, and can you make the fuel yourself, either Biodiesel or Alcohol or Methane digester?

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Offline David B.

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Re: The DIY Thread
« Reply #3 on: February 16, 2017, 10:20:10 AM »
Or charcoal...
If its important then try something, fail, disect, learn from it, try again, and again and again until it kills you or you succeed.

Offline RE

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Re: The DIY Thread
« Reply #4 on: February 16, 2017, 10:27:07 AM »
Or charcoal...

Sorry...forgot the charcoal.  LOL.

However, you could make wood alcohol out of the same log you make charcoal from, and then you gotta figure which is the more efficient conversion, AND is it useful in an engine to run a compressor?  Tough to run a compressor with charcoal, although you probably can figure a way to do it.  Steam engine obviously there, but I think the wood alcohol in an ICE engine would be more efficient.

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Offline Eddie

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Re: The DIY Thread
« Reply #5 on: February 16, 2017, 10:36:03 AM »
I think David is making wood GAS, just from charcoal as a starting material.

A wood gas generator is a gasification unit which converts timber or charcoal into wood gas, a syngas consisting of atmospheric nitrogen, carbon monoxide, hydrogen, traces of methane, and other gases, which - after cooling and filtering - can then be used to power an internal combustion engine or for other purposes.

https://en.wikipedia.org/wiki/Wood_gas_generator

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Offline David B.

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Re: The DIY Thread
« Reply #6 on: February 16, 2017, 10:45:57 AM »
Sorry boss man energy conversion for methanol runs about 12 percent conversion biomass to charcoal 25 percent and you get to use the waste heat for something else.  You would probably charge a battery via dc generator and run a standard ac unit through an inverter. You could customise it all but that gets expensive.  Boat guys have fancy rigs that turn an alternator and a compressor on one engine store the cold as ice but those are much expensive rigs...
If its important then try something, fail, disect, learn from it, try again, and again and again until it kills you or you succeed.

Offline RE

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Re: The DIY Thread
« Reply #7 on: February 16, 2017, 11:10:37 AM »
Sorry boss man energy conversion for methanol runs about 12 percent conversion biomass to charcoal 25 percent and you get to use the waste heat for something else.  You would probably charge a battery via dc generator and run a standard ac unit through an inverter. You could customise it all but that gets expensive.  Boat guys have fancy rigs that turn an alternator and a compressor on one engine store the cold as ice but those are much expensive rigs...

LOL. OK, wood gas out of charcoal more efficient than methanol. So this is how you go assuming you have a wood lot to make your charcoal from.

But now we are back to the fundamental question of how much wood would (another homonym!) it take to keep your cooler cool, assisted by how many solar panels?  How much total juice per day do you need to keep the internal temp of the walk in fridge to say 35F when the exterior temp is say 80F?

Would you also do better if instead of the wood lot you cut down the trees and grew sunflowers to make sunflower oil and biodiesel? ???  :icon_scratch:

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Offline David B.

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Re: The DIY Thread
« Reply #8 on: February 16, 2017, 11:50:51 AM »
I've never run the numbers for oil production versus wood production .  That could take several pages!  The idea of charcoal is marginal land that could never be field or pasture can be left as a forest and you can extract the energy equivalent of 30-40 gallons of gasoline per acre per year for engines plus another energy equivalent of 60-80 gallons as recoverable heat all while leaving the forest ecology intact...
Sorry I am a fanatic.  For your cooler project I think I would rejig it to be 3 or 4 chest freezers with a controllable thermostat placed side by side in an already cool room possible underground.  Our 9 cubic foot freezer uses 750 watts a day.  I installed a chest freezer with a modified thermostat for a client 5 years ago and he tells me it's running at 350 watts a day runing as a fridge.  At that kind of footprint I would have several of them and turn them on or off as the season required...
You might have noticed I have a lot of free time these days it's winter time...
Best regards, David Baillie
If its important then try something, fail, disect, learn from it, try again, and again and again until it kills you or you succeed.

Offline RE

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Re: The DIY Thread
« Reply #9 on: February 16, 2017, 12:12:54 PM »
I've never run the numbers for oil production versus wood production .  That could take several pages!  The idea of charcoal is marginal land that could never be field or pasture can be left as a forest and you can extract the energy equivalent of 30-40 gallons of gasoline per acre per year for engines plus another energy equivalent of 60-80 gallons as recoverable heat all while leaving the forest ecology intact...
Sorry I am a fanatic.  For your cooler project I think I would rejig it to be 3 or 4 chest freezers with a controllable thermostat placed side by side in an already cool room possible underground.  Our 9 cubic foot freezer uses 750 watts a day.  I installed a chest freezer with a modified thermostat for a client 5 years ago and he tells me it's running at 350 watts a day runing as a fridge.  At that kind of footprint I would have several of them and turn them on or off as the season required...
You might have noticed I have a lot of free time these days it's winter time...
Best regards, David Baillie

Well, you are definitely the Diner resident EXPERT on these topics, so your input is highly valued.  :icon_sunny:

You would really have to test it out directly, having one large room as a cooler vs using several smaller fridges all in an underground cellar.  Your cellar could in fact BE the walk-in cooler!

I still bet if you ran one large fridge as to several smaller ones, this would be more energy efficient.

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Offline David B.

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Re: The DIY Thread
« Reply #10 on: February 16, 2017, 12:24:55 PM »
As long as expert is not a way of saying smart as I'm good ;D quantitative proof would be required you are right.
If its important then try something, fail, disect, learn from it, try again, and again and again until it kills you or you succeed.

Offline Eddie

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Re: The DIY Thread
« Reply #11 on: February 20, 2017, 06:30:02 AM »
I spent a half hour yesterday afternoon looking at the spot where I've wanted to dam up the creek to make a new swimming hole. It looks to me like I might have enough head and flow these days to put in some kind of micro-hydro generator. These are very similar to wind generators, in that you have to worry about what happens when you have too much flow, and diversion loads are a necessary component of most hydro systems.

This low-head generator looks like the one I'd need.



<a href="http://www.youtube.com/v/Z0NXp8nU5AY&fs=1" target="_blank" class="new_win">http://www.youtube.com/v/Z0NXp8nU5AY&fs=1</a>

They sit in a box , on top of a draft tube that empties underneath, as depicted by the photo below. They are a vertical axis water wheel, called a Kaplan turbine. Good where you have a lot of flowing water, but not much vertical drop across your land. The most drop I'm likely to be able to get is about 2 meters....maybe not quite that much.



Each unit gives about 1500W, and you can design to scale up to multiple generators in one catchment box.

The advantage of hydro is that it is constant, 24/7, in the wet season, which is when panels give the least power.

These PowerSpout models (from the Land Down Under) go for about 2K apiece, which is not terrible. Old school low head generators like the Scott Cross Flow, start at about 4K, and require 20 ft of head, from what I gather.  The PS models are supposed to go ten years, and then be overhaul-able.



« Last Edit: February 20, 2017, 06:47:01 PM by Eddie »
What makes the desert beautiful is that somewhere it hides a well.

Offline RE

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Re: The DIY Thread
« Reply #12 on: February 20, 2017, 07:23:40 AM »
I spent a half hour yesterday afternoon looking at the spot where I've wanted to dam up the creek to make a new swimming hole. It looks to me like I might have enough head and flow these days to put in some kind of micro-hydro generator. These are very similar to wind generators, in that you have to worry about what happens when you have too much flow, and diversion loads are a necessary component of most hydro systems.

For Power Diversion, I would go with an electro-mechanical energy storage system.

Build a small tower with an electric motor that will take say a 2 ton bag of sand or gravel and gradually winch it up in height.  Then when the flow is low, you let the bag back down again, it drives the motor and this then produces electricity.

Also, when you engineer your mini-dam, make sure you do a good job on the spillways.  You don't want this happening to you.  :o


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Offline Eddie

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Re: The DIY Thread
« Reply #13 on: February 20, 2017, 07:30:30 AM »
Diversion loads usually power lights or hot water heating elements....or just heating coils that hear air and waste the excess electricity. A good part of the time they don't draw anything, but when you need them, you have to have them.

An interesting alternative might be to pump water up to storage tanks on the high ground, which would allow the power to be recovered by small turbines in the gravity fed water lines, coming back down. But it comes down to how much extra power you'd be generating. With one 1500W turbine, probably not enough to make such an energy system worthwhile.

It would be fun to play around with. Nobody around here has hydro. Nobody.
What makes the desert beautiful is that somewhere it hides a well.

Offline RE

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Re: The DIY Thread
« Reply #14 on: February 20, 2017, 07:35:52 AM »
Diversion loads usually power lights or hot water heating elements....or just heating coils that hear air and waste the excess electricity. A good part of the time they don't draw anything, but when you need them, you have to have them.

An interesting alternative might be to pump water up to storage tanks on the high ground, which would allow the power to be recovered by small turbines in the gravity fed water lines, coming back down. But it comes down to how much extra power you'd be generating. With one 1500W turbine, probably not enough to make such an energy system worthwhile.

It would be fun to play around with. Nobody around here has hydro. Nobody.

The problem with using water as your gravity driven storage system for energy is the internal resistance of the water lines up the hill.  The type of mechanical storage device I describe has much less internal resistance.  Way more efficient.

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« Last Edit: February 20, 2017, 08:02:15 AM by RE »
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