Solar Site Evaluation and the New SunEye 210

Left: Solar Pathfinder; Right: Sunchart diagram

One of the leading manufacturers of solar site assessment technology announced therelease of a new version of its product today: the Solmetric SunEye 210is now available, ladies and gentleman of the solar industry. If you’renot thrilled to your fingertips, Gentle Reader, it’s probably becauseyou’re not a solar installer; but if you’re curious about why this issuch an important element of the install process (and to get moreproduct details), read on.

Perhaps the single most important piece of site assessment for asolar installer is shade evaluation. Will that big oak tree thirty feetaway from the house ever cast shade on the roof? During what hours ofthe day will shade from the chimney fall across the roof’s southernexposure? What kind of a shading issue will those pine trees present inwinter, when the sunlight will come in at a lower angle? There arenumerous tools on the market that solar installers can use to evaluatesun angle and shade factors.

The one essential tool is the Solar Pathfinder: cheap and utterlyreliable if used correctly, the Pathfinder uses a convex mirror toreflect a panoramic 360 degree view of its location onto alongitudinally-specific chart that plots the hours in the day againstthe months of the year. So if you set it on the part of a roof where asolar panel might go, you can see exactly what will be shading thatlocation, and when. The installer essentially traces the reflection tokeep an accurate record of when obstructions visible in the reflection(trees, buildings) will be shading the site in question. Here’s avisual for you, but check out Pathfinder’s “How it Works” page for more info.

You can scan the traced diagram into a computer with Pathfinder’ssoftware, but for some solar installers, having immediately accessibledata is worth a premium. So they use tools like the Solmetric SunEye, which essentially replicate the Solar Pathfinder’s technology but digitize it on site.

Infact, the SunEye digitizes the data in the palm of one’s hand usingessentially digital camera technology: the SunEye is a hand-held devicethat has a small fisheye lens that’s basically a mini-Pathfinder, plusa screen on which what the lens “sees” is projected as user-friendlycharts and data. It’s also got integrated GPS technology so you don’thave the manually adjust for true south as you do with the Pathfinder.Doing so is not difficult for the experienced solar installer, but it’sa step many are just as happy to skip if given the option.

The SunEye’s software options includes a PV design option tofacilitate module layout, and lets installers manipulate data intodifferent files formats. This “PV Designer” software also allows forbasic predictions of energy outputs.

So yeah, pretty fun stuff, and cuts out a bit of manual (er,intellectual?) labor for the solar installer. But here’s the catch: theSolar Pathfinder, which gives an installer all the data he or she needsin order to correctly design the most efficient solar panelinstallation for a given site, retails for about $300. The SolmetricSunEye, which adds some fun bells and whistles, offers an iPhone app (Solmetric IPV)for the relentlessly tech-enabled, and offers some variant outputs,retails for about $2,000–nearly 6.5 times more expensive than a toolthat also gets the job done. Small-shop operators are probably betteroff sticking with the tried, true, and affordable Pathfinder, but forthose who can budget around it, the SunEye is the best kind of toy: funand educational.

First Image: Left: Solar Pathfinder; Right: Sunchart diagram

Solar Site Evaluation and the New SunEye 210

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