Hydro Group Report

Summary

The hydro group, along with the help of many other students in the class, worked hard on two projects: Beginning the installation of a new hydro system at 3 Rivers EcoResort/Sustainable Living Initiative Center (SLIC) and attempting to fix one at the Springfield guest house.

Purpose of the project

3 Rivers EcoResort/Sustainable Living Initiative Center (SLIC) is expanding. A new building will house SLIC, and requires electricity for a computer, LCD projectors, and lights. Furthermore, the hydro sytem with greatly reduce the need to run the backup generator. Lastly, the hydro system will be an integral part of the Sustainable Living Initiative Center’s demonstration renewably energy systems.

3 Rivers is located on the crystal clear Rosalie River. The river has a very large flow, easily tens of thousands of gallons per minute. On the Three Rivers property, the river gently drops about eleven feet. Due to the mountainous terrain, the confluence of multiple river systems, hurricanes and impermeable rainforest soils, the river is prone to massive bank full events that move thousand pond rocks and send enormous trees downstream. Protecting the hydro system from damage is therefore a serious concern.

After weeks of calculations and discussions, we chose to install Energy System and Design’s LH-1000 generator. It is designed for high flow, low head situations. It’s design allows it to be installed above the flood level. It’s maximum output of 1000W, 24 hours a day is easily enough to meet all of 3 Rivers needs.

Becky training for her upcoming Ironman with the LH-1000, the microhydro generator being installed at 3 Rivers Sustainabile Living Initiative Center

Measurements, planning and installation for the LH 1000

Professor Gary Flomenoff demanded we go for maximum power. With our goal set; we needed to determine where the 10 feet of head location for our turbine would be. We already knew that our river provides 1000 gallons a minute, but we needed to find an appropriate place to capture the water and divert it away from the river. We found our turbine location all most 200 feet away. In that distance we needed a settling basin and a way to shut off the turbine, a way to divert the water from the turbine. We drew up our plans, as follows:

The first step was creating a water diversion so we could build the concrete and rock weir. We used leaves, gravel and rocks to divert the water away from the intake.

Below is the team building the form for the weir. The base consisted of river rocks that were then covered with crushed stone.

After the base was constructed a cement mixture with crushed stone was mixed with river rocks to complete the weir. With everyone’s help we were able to complete all this in just one day!

Unfortunately, last year’s work on the hydro system could not be used because the pipe size could not handle the volume of water for our new hydro unit. It was calculated that we needed a 12 inch pipe, but due to limited availability of supplies on the island we had to settle for an 8 inch and 6 inch PVC pipe. We ended up building on top of the pre-exsisting intake from last year.

Above is an image of the pipes and the newly constructed intake. As you can see, the form is higher than the pipes allowing debris to flow over the top. On the weir side there will be metal grating to avoid debris build up as well.

Here, Richard, a 3 Rivers employee, builds the support and protection wall for the PVC pipes. In storms the water and trees flows over the top of the wall shown above, so it was essential the pipes be protected.

One problem we ran into is that there were a few large rocks between our intake and our settling basin. We needed to keep our pipes running level from the intake to the basin, which was approximately 70 ft away. This was the quickest, easiest, and safest route away from the river.

The group of people in the background are standing at the location of our settling basin. Jared, seen in the foreground, is on the rocks that are too high for the PVC pipes to run level.

Big Lance is hammer drilling the rock. We needed to lower the rocks by 1 ft. and it needed to be 14 in. wide. However, after a morning of work, we barely lowered the rock by an inch. With the right tools unavailable, and a time crunch upon us, Jem decided to enlist a local Dynamite specialist.

Here he is seen drilling a hole in the rocks for the explosives.

The results!

G FLo working on Dominica time in the settling basin.

Here you can see the hole for the settling basin, which still needs to be finished with cement. Also, you can see the metal trough that we constructed to carry water to the turbine and back to the river. After weighing our options and considering our time constraints we opted for a metal trough over concrete. Posts, harvested from the 3Rivers propery, hold the metal trough in shape. The metal is only temporary and will be replaced with a concrete trough, because it will be flowing through the SLICK workshop soon to be built.

Marcia and Lincoln, a 3 River’s employee, are installing the supports around the trough. We had 80 ft of metal trough to set up from the settling basin to the wooden turbine trough. Guy is seen making the posts to support the trough.

Noah and Perry are seen building the wooden trough where the hole for the turbine is located. This 12 ft.trough connects to the end of the metal trough, juts out over the riverbank, and holds the turbine. It is still waiting for its sides but the “devil wood” got the best of our tools, breaking many a screw. Our biggest problem was not having the right tools available to us at the right time. Attached to the turbine will eventually be a ten foot draft tube that will suck the water through the turbine and into the river.

The river

The river after a rain.

As you can see the river rises a lot with only a little rain. It can be clear and nice at 3 Rivers, but up in the mountains it may be pouring and the rivers always reflect it. We were very concerned about protecting the system, because we were told the river easily flows over the bridge seen in the above picture.

At the end of the week the plans were finished and the project was well underway. We left with Jem’s crew working hard to finish.

Springfield Guest House Microhydro System

Over the past two years there has been a lot of work done to install this system. This project was based on 2001 “Sustainable Tourism in Small Islands of the Caribbean” workshop, which was held as Springfield Guest House. This workshop pointed out that there was a lot of potential for many renewable energy recourses on the island of Dominica including; solar, hydro, wind, bio-mass and maybe even geothermal. This left a lot of possibilities to be explored in how these renewable energy systems can be implemented in Dominica to help the Dominican people realize the great potential of these renewable energy systems. This was especially important because during the workshop it was learned that most of the electricity that powers Dominican home and businesses originate from diesel generators.

This paved the way for the students of a 2003 February work shop in which concern arose that there were no hydro systems installed in Dominica given that it is a land known for its 365 rivers and frequent rain fall.

Please check out this website for further background information

http://www.cem.uvm.edu/%7Emedialab/Spring05/ee195/MicroHydro/Background.htm

However, despite the efforts of previous students, the system was still not running up to par. It was barely producing 300 Watts, when it should be producing nearly 1000 Watts. Furthermore, the initial vale was exceedingly difficult to use. Our job was to diagnose and fix these problems.

Site location:

The little water fall across the road from Spring Field. This water flows into the intake tank on the other side of the road.

What we did

Installation of Gate Valve

The gate valve that was previously used was extremely difficult to open and close. To alleviate this problem it was decided that it was better to install a new gate valve. This new gate valve was installed in conjunction with the old valve, meaning that the old valve was not removed. The old valve will be the secondary valve, which will stay open. The new valve will now act as the primary valve.

Old Gate Valve

The cutting of the PVC to install the Gate Valve

The new Gate valve installed on the PVC

Installation of new screens

The screens originally installed to keep rocks and peddles out of the intake were in bad shape: One was completely missing, and the other was torn. We decided to install stronger, thicker screening in place, and more permanently attach it.

Installation of new screens to prevent debris from getting into the intake basin

New screens were also put onto the intake pipe

Purging of System of junk

There were lots of theories as to why the system was not working to its full potential, but none of them prepared us for how much build up of dirt and debris were clogging the system. While we were purging the system there was a big explosion of junk that came out, showing us that even with screens, that dirt can accumulate if the system is not running. For this reason new screens were put in place and there was talks of purging the system every once in a while.

Replacing broken PVC pipe with steel one

While trying to move the PVC pipe, a section of the pipe which was connected to the power house broke. It was thought that it would be better that since that part of the pipe that was broken is the weakest; it would be wiser to replace the PVC section of pipe with a steel section.

DIAGNOSTICS:

Powerhouse (The PVC pipe on the left hand side is what broke)

The hydro system

Finally, we managed to take measurements of flow, pressure, and power output Our measurements of head, using a altimeter, and flow, using a stopwatch and a bucket, confirmed our earlier estimates. The voltage was only 166 VAC, much lower than 220V.

The water pressure was also significantly below the level it should be. Unfortunately we were unable to measure RPMs, as our meter was broken.

Next steps

Springfield still needs more work! Our plan is to have the pressure gauge replaced, and to install a smaller nozzle. Our hope is a smaller nozzle will increase the water velocity, which should increase the pelton’s RPMs. If needed, we’ll change the pulley ratio to optimize the system.

Reflection

Fixing and diagnosing problems is a big issue since there is no specific point person to look to for the upkeep of the system. There are many points along the way where there could be problems the main two places being at the intake tank/settling basin and at the powerhouse, which houses the hydro system. Another problem arises when something breaks and you can not find that part in a timely manner or when that part does not exist in Dominica. Every possible instance of error has to be planned for which is not always possible.