DIY Grid Tie

Well, finally finished my ebook on Do it Yourself Grid Tie.

This e-book will show you the following:

• How asynchronous grid tie works
  
• Make pulleys, any size you want out of plywood, super easy
• Make an automated Poor Man's Power Point Tracker (solar or wind)
• Homemade grid tie inverter - solar can grid tie with this!
• Use your windmill with an AC motor to "backfeed" the grid
• Charging batteries using grid tie (for emergency backup)
• Make a simple wind speed sensor to engage the grid tie at the right time

Richard

Worm Farm - Poor Man Style

Worm Farm - Poor Man Style

This is in response to Wretha in the previous' post comment. This is two 55 gallon blue plastic barrels per their idea. I didn't spend a lot of time on this but let me know if I forgot something.

Richard

Worm Farm Composter

I found this on http://www.wormfarm.com.au/domestic.php . It is a worm farm in a tank that you bury underground. It can take all of your houses sewage and grey water and there is a compost cap on top that sticks out of the ground. You can throw ALL kitchen waste, including meat, into it. You can also throw all paper and cardboard into it. It eliminates 75% of your garbage.The water that comes out the bottom is odorless and full of worm castings and great for the garden. This system is meant to replace or be used instead of a septic system.

Richard

Bubble Wrap Windows - super insulation

Some of you might have seen this done before but I found it interesting. The article I read said that this guy's house was really well insulated except the windows. He had upgraded some of the single paned windows to double glazing but it was expensive. He decided to test bubble wrap. The bubble side faced the window while the smooth side faced inside the house. On a cold day he put his hand on the 2 paned windows and it was way better than the single paned ones. But then he touched the single paned window with bubble wrap and it was worlds of difference from the double glazed window. Not even in the same ball park. He said he can do each window for about $2.

So, it looks like a great way to let light inside during the cold months but still retain that heat. I love the fact that it is cheap and easy and that it out performs the expensive alternative.

Richard

AC Grid Tie update

Well, good news. I successfully pumped 42 watts into the grid last night. As you can see, I'm just testing using a DC motor to drive an AC induction motor from a clothes dryer. The DC motor is on the left. It is geared at 3.5 to 1.5 or 2.33:1. Just a word about pulleys. I know that the pulley on the right is 1 inch, but the outside of the belt is the load carrying part. So, measure from the center of the pulley to the outer edge of the belt and then double.
Below, you can see a close up of the AC motor.
I can't find any numbers on it but I believe it is a 1/4 hp. But something to remember about dryer motors with centrifugal switches is that they have two sets of windings. They both start in parallel and once the speed is up to a certain point, then just one winding is used to maintain speed. So, a 1/4 hp motor is really closer to 1/2 hp when both windings are being used. But you can't run them both together once it gets up to speed due to the start winding being out of phase with the run winding. It will work but sound funny and be very inefficient. And if this were used in a windmill, then the wind would be a natural cooling. In the summer time that would mean a doubling of possible power and in the winter about 3 times the power can be expected. So, if you bypass the centrifugal switch and connect to just the run windings then you can expect .5 hp up to 3/4 hp as a max. So, 375 watts in the summer up to about 550 watts in the winter.

I also played around with using the centrifugal switch to connect to the grid once the speed was up. But just like I thought, it would stay connected even after the DC motor was turned off. So, I figure a simple trigger mechanism that triggers on at a certain windspeed and shuts off again once the wind slows down again.

Later today or tonight I'll measure amps and voltage going into the DC motor and compare the input power to the AC grid tie power to determine efficiency of this setup.

Also, I don't like using the V belt on that little tiny pulley on the AC motor. It means that the tension on the belt has to be quite high to keep it from slipping at the higher wattage. It also means the belt heats up quite a bit more due to the constant extreme bending around that tight radius. If I used a 3 inch pulley on the AC motor and used a 7 foot blade set turning a big homemade plywood pulley, it would have to be about 18 inches to start grid feeding at about 10 mph wind.

Richard

Super efficient fridge

I came across this awhile back. Some people were taking a chest freezer and running it like a fridge. It makes sense too. Cold air is heavier than warm air, so when you open up a regular fridge, then the cold air "falls" out to the ground. But in a chest freezer or fridge that doesn't happen, the cold air is trapped. That makes the chest freezer or fridge incredibly more efficient for its size than a stand up type.
The simple way to do it is to take a freezer and put an external thermometer nearby. The probe will go inside the freezer and sense when to turn it off or on. The power for the freezer goes through the external thermometer and literally turns the power off or on, just like plugging it in or unplugging it when it needs to. Here is what that device looks like.
This is what that thermometer looks like and here is a closer look.
A typical fridge may use 1.8 kwh per day or 1800 watt hours per day. Solar powered at 5 hours of effective full power sun a day would mean 1800/5 = 360 watts of solar panels or about $2500 just to run the fridge. Some examples with running a freezer like a fridge shows roughly 100 to 300 watt hours per day for about 16 cubic feet. So, worse case, 300/5 = 60 watt solar panel or about $400 instead of $2500. They make $2000 Sun Frost fridges meant for solar power, but this method is as low power as theirs and you can do it with a $200 freezer, not a $2,000 device. You can find this device here but you might could find it cheaper elsewhere as well.

Richard

Solar Powered Hot Tub

There are probably hundreds of ways to make a solar powered hot tub, but today I'll be just referring to my specific situation. For example, I know that if the hot tub were raised on a platform, then I could make a thermosiphon that would require no pump at all. But it would also mean that I would need to make an expensive platform and also I would need some way to shut down the thermosiphon when the temp gets too hot or too cold.

But, right now, I have the hot tub pump that shuts itself off when the thermostat says so. And hooking it up will be super simple. I will just separate the pump from the hot tub and tap into the pump output section and just run that through 50 feet of black garden hose.
The hose would be wrapped and secured on a 2 foot by 2 foot piece of plywood painted black. The plywood will be the back of a solar hot box and a piece of glass or other glazing on the front. It should raise the water in the hose up to 180 or a little more during the heat of the day. The hose wouldn't be under any pressure, so it won't burst. But I live in the pacific northwest. Living in the desert of the south west, things would be different. But even if it started to boil, then it would just expand back into the hot tub.

So, 4 square feet at about 50% efficiency is about 240 watts or about 800 BTUs per hour. The hose would have 1.1 gallons or 9.1 pounds of water inside. And 800 BTUs divided by 9.1 pounds = 88 degrees F. And 88 plus 105 F (starting temp of the water) would be 193. The solar box won't be that well made, because I will make it quickly and cheaply, so it may only peak at about 170F or so. If I get 5 hours of effective full power sun for the whole day, then that means 4000 BTUs per day. The hot tub holds 220 gallons or 1826 pounds of water. So, I could use the sun to recover 2.2 F per day. I could double that number by using a 3 foot by 3 foot solar box, but I would have to use 100 feet of hose, otherwise the water would be boiling in the hose. That 5 hours is based on solar photovoltaic panels. The early morning and late afternoon sun doesn't make much power and may not make enough to reach battery voltages, therefore can't charge. But in solar thermal applications, any heat is good. You just have to make up enough heat to overcome any losses in heat from you heat collector. So, 6 or 7 hours may be closer to a good estimate here.

So, let's say that the hot tub is at 105F and the thermostat shuts the pump down at 11am. From 11am to 12pm the temp drops to 104F and the pump kicks on again. At that point there is a 20 to 30 second insurge of 170F or so of water. That could scald if you are sitting up against a jet. So it is better to either turn on the jets 30 seconds before you get in and leave them on. Or, just turn the hot tub off when you get in.

I may make 2 or 3 of these hot boxes and just use one in the summer. When the weather starts getting cooler, I will add the second and then third boxes to the mix. Then, during the winter, just disconnect them and put them away until April or so.

My hot tub is already pretty energy efficient. It is a "softtub" and it has no heaters. The waste heat from the pump motor is captured and put into the water to heat the water up. Adding heat with solar will mean that I could easily run the hot tub from my small PV array and still have plenty of power left over.
Also, I'll have it on a timer so that it turns off at 6pm and comes back on in the morning at 9am. That way I don't hear the motor at night and also if it ran at night with this setup then the heat would escape through the hose.

Richard