Outdoor Services Crew

Tuesday, January 25, 2011

They said it couldn't be done

Recently we did a renovation/installation of a new landscape area at the corner of University and 17th. During this project we wanted to make sure to control the irrigation from the Network 8000 irrigation control system. We had a bit of a challenge in this area, the Network irrigation controllers use 120v power to operate and the nearest power was under a street and against Macky Auditorium. There are Xcel light poles in the area, but considering the small amperage of the controllers, it is not cost effective or time effiticient to tap power from these poles. I explored the possibility of a solar powered Network 8000 with a local vendor, but was informed that they had not attempted this and it wasn't feasible. After some discussion with our Facilities Electric shop we felt that we could do the work, and do it for far less than the cost of a bore shot under the road and all the associated electrical work to provide the power needed.

We spent some time to discover all the power sources in the controller and hooked up a power monitor for a 24hr period to determine total power usage during an irrigation cycle and associated communication with the central computer. Initially we thought we could bypass a couple of steps to create a solar system that did not need an invertor to convert the solar power from direct current (DC) to alternating current (AC). After a fair amount of discussion and data collection, we determined that it was not possible. We decided to put an invertor into the design-which added some power requirements considering you lose energy in the process-this addition increased the size of the battery and solar cells. Once we had all the power requirements figured out, I worked with our Planning, Design and Construction department, to determine the strength of pole and the size of caison we would need.

After all this work was finished, we were not only at a quarter of the cost of the bore shot option, we were also utilizing sustainable practices by irrigating with ditch water and using solar powered energy-instead of energy from the grid. It would be pretty challenging to use solar power for all of our controllers considering there is typically access to existing 120v power and the cost between a solar system and using traditional power make it fiscally challenging to use this method. However, in the future, if we run into a similar challenge we will have this option in our bag and we know it can be done.