Fun with the Sun

Today, I volunteered to help man the Alternate Technology Association (ATA) Solar Trailer at the yearly Djerriwarrah Festival here in Melton. The trailer is now looked after by the Ceres Community Environment Park, and is taken to shows and festivals all around Victoria. I had the pleasure of spending the day with Bruce McKenzie, who works for Ceres part time, and helps spread the word about wonders of renewable energy.

I arrived at 0900 to find the trailer like this.

It took Bruce and I about 40 minutes to make it look like this.

Here are some of the features of the trailer. First the wind turbine.

It is a 400 watt Air-X Marine 12 volt wind turbine. As it wasn’t very windy, we didn’t get to see it in all its glory. There was one time however that a big gust of wind whipped up, and the turbine started whirring. It scared half of the festival goers half to death, myself included. Even though it looked like it was spinning at a fair rate, it was only producing about 20 watts. Apparently, it has to be very windy for these turbines to produce their rated output. As it was only stuck on a 3 metre mast, and placed next to a building, it didn’t have a chance at getting up to speed. Bruce told me that in a windy position and on a 18 meter mast, this turbine was far better value for money than solar.

Next are the solar panels.

These three 75 watt, 17 volt panels were connected to the trailer, where the DC current was passed through a regulator, then into a 200Ah sealed lead acid battery. The energy from the battery was then fed into a 240v AC inverter, which produced enough current to work all of the displays in the trailer. There were also two other solar PV on the roof of the trailer, but I forgot to ask what these were rated at. The displays inside the trailer were focused on educating the public about energy efficiency. The first was about energy efficient lighting.

You can see by the photo, that there is a watt meter surrounded by 4 light switches. Each switch corresponded to a different type of light bulb. The incandescent sent the needle of the meter hard to the right, and the warm light CFL hardly moved the needle at all. I wish this sort of display was replicated at all lighting shops. Maybe the general public would then see the light about the energy that can be saved by installing CFL’s throughout their homes.

The regulator (little black box on the red panel) and Inverter (blue box) are pictured to the right. You can see my spare camera batteries charging in the power socket! The 200Ah battery is the big gray box sunken into the trailer. It has the red and blue caps on it. Above the Inverter are two amp meters that measure the current input from both the solar panels and the wind turbine. As it was a fairly cloudy day, we were producing on average about 100 watts (6 amps x 17 volts). Certainly enough to keep the battery charged throughout the day.

The other energy efficiency display demonstrated the power consumption of tools and appliances.

There was a power drill, blender, toaster and a cassette radio. The Toaster was the biggest consumer, and all the kids who visited the trailer loved to have a go at this one because it made the most noise!

One of the other displays that drew a lot of attention was the solar water pump.

Basically, this was two small solar PV panels connected to a bilge pump submersed in a bucket that fed back into itself via a tap. A closed system, just to demonstrate that you can use the sun to pump water. It would be useful on a farm to pump water from a tank to water troughs or some similar application. One person even told us that we were wasting water! We had to explain that it was a closed system.

Some of the other table displays were an evacuated solar hot water tube, that you fill up with water and it just about boils.

It is marketed as a Solar Billy, and you can take it camping and make a cuppa from the suns energy. Here is the thermometer showing that the water was at 56.6 degrees C. Pretty good for tap water that started at 10 degrees, and being a cloudy day as well. By the time we packed up, the temp of the water was at 72 degrees C. Certainly hot enough for a cup of hot tea.

Next to the tube is a Pyranometer which measures the amount of energy that the sun produces per square meter. It was hovering on about 600 watts for most of the day. To the left of the Pyranometer is a display to show kids about the heat absorption properties of different coloured metals, giving them an explanation of why most solar hot water collectors are black in colour.

On the other table, we had a few nifty gadgets.

There is a hand dynamo that produced 12 volts DC with a current strong enough to power a 12 v fan. The kids all had a go at that one. The faster you turned it, the more current they produced and therefore the faster the fan spun. Next to the fan to the right, is a great little toy the demonstrates two things. Firstly a solar cell generates power to split distilled water into its two component atoms of one oxygen and two hydrogen. The gas was stored in the two plastic tubes in the centre. The hydrogen and oxygen were then combined in a fuel cell and generated power to turn a small fan. This demonstration showed that solar energy can be stored in the form of a gas, that can be then utilised at a later time. It was a pretty cool display, and we received the most interest from it. Most people had heard of hydrogen powering prototype cars, but none had actually witnessed how it all worked. I was impressed with the simple technology, and wondered why this was not available in the mainstream right now. I suppose it is the oil companies who want us to keep using fossil fuels in our transport systems that keep this type of technology suppressed.

The last display was a Micro Hydro generator.

It was an older model, and in this instance it had a pump connected to it to demonstrate the amount of pressure that was required to generate electricity. It requires a 15 meter head (height of the water above the generator) to work at its rated output. We guessed that it was rated at about 400 watts, so if you have a stream on you property that you can divert a little of the water, then this is an ideal system for you.

That was about it for displays at the trailer. We had a lot of people enquire about PV systems, and how big did they need to be to power their house, how much did they cost, what were the available rebates, which type of solar hot water was the best, and so on. There was a fair bit of interest by a few keen visitors who were obviously doing their own research about purchasing Solar PV for their homes, and I think they just need some confirmation from someone who had done it before. I certainly had no hesitation sharing my experiences with Solar PV, and gave it a glowing big thumbs up for the area we live in.

There were a few other displays in the Environmental hub area where we were set up. Across from us was the compost and mulch tent.

They had examples of how a compost bin worked, and how to make good compost. There was a cut-away showing the insides of a plastic compost bin, and a worm farm.

Pretty cool I thought. It even had plastic worms working their way through the plastic food scraps.

We also had a visit from Vasli from the SBS TV show Vasili’s Garden. He was very entertaining, and played the piano accordion whilst getting everyone up to do the zorba dance.

There were a few other tents, one from the Melton Environment Group, showing native fauna from around our district, and of course the snake tent, which must have been the most popular display at the entire festival! The kids and teenagers flocked to it like bees to a honey pot. It is amazing what interests some people. I personally thought the solar power was far more exciting, because once you have seen and run away from as many snakes as I have as a kid, they really don’t hold that much interest any more.

All in all, a great way to spend a Saturday, promoting renewable energy. I hope the people of my town got something out of it, and I thank Bruce for bringing the solar trailer to our yearly festival.