“Arctic Ridge” Solar/Wind Hybrid Generator

Solar and wind power can be hybridized in a way that maximizes the combined power output using synergy.

Unfortunately, most renewable energy installers are not doing this, even though it is extremely simple.

By careful design choices, wind and solar PV arrays can be co-located, improving power production while reducing maintenance challenges for wind turbines that traditionally have to be placed on hills and mountains.

Design:

First, we refer to the following publicly available British study on wind flow around buildings:

Figure 8 from the study showing flow patterns around various roofs. Red areas are correlated with a substantially increased velocity.

This peer reviewed study indicates a 56% increase in power output from the Vaulted design (e) when the wind is perpendicular to the ridge.

For a wind turbine at 1.3 times the overall building height. This power increase is relative to a wind turbine mounted at the same height in a free stream of air.

Also, such a design eliminates the need for guy wires (by bracing the wind tower inside the structure), which many residents find unsightly and which is also implicated in bird deaths.

Solar panel glass is an ideal smooth surface to allow unrestricted air flow around the structure.

So PV arrays can be integrated on to this building or open air structure to produce synergistic wind and solar power.

Thin-film panels can form the rounded (“vaulted”) section of the roof, or standard PV modules can be arrayed in a linear segmented arc over the barrel roof.

The walls can be extended outwards at 45 degrees without compromising power boosting as long as the surface of the extended section is smooth.

45 degrees is usually a better elevation angle for optimizing solar panel performance.

Channeling the flow:

Standing seam metal roofing has ridges which should ideally run over the curved top surface. If possible, these seams should be enlarged. Also, the gaps between columns of solar panels can be fitted with a standing seam made of aluminum or any other material.

The standing seams act as a flow redirect, forcing more of the flow to happen perpendicularly to the structure and over the ridge where it will be accelerated by the shape of the structure.

Orientation and heading:

The selection of appropriate heading to place the axis of the barrel vault on will depend on your local Wind Rose:

Typical wind rose from Des Moines, Iowa (https://www.wcc.nrcs.usda.gov/climate/windrose.html)

If your wind is predominantly from the South or North, then it makes sense to arrange the ridge line of the structure east-west so that the wind blows directly over the ridge. Then, you can only feasibly put solar PV panels on the south face, since they would not be very effective on the north side (unless you are well above the Arctic Circle).

It is still important to ensure the North face of the structure has adequate smoothness to avoid disrupting the overall wind flow. Even downstream of the wind turbine, any impediments to smooth flow (like a rough surface) or sudden drop-offs (causing flow separation even at low wind speeds) will significantly decrease the energy output of the wind through the turbine.

If your wind is predominantly east or west, then arranging the ridge line north-south will be ideal. You can put solar PV modules on both sides of the structure; one will generate most of its power in the morning and the other in the afternoon and evening. Many modern PV arrays are designed this way, to reduce the need for batteries by providing steady power all day long.

Generally speaking, when you are installing a solar array at greater than 60 degrees latitude, or especially greater than 66 degrees (above the Arctic circle) it does not really matter which way you orient your solar panels, and it is better to optimize the design for wind power production using the local wind rose.

Installations further south may factor the solar PV orientation in more detail into their design choices.

If a smooth barrel vault is too difficult to design and manufacture, a 16% power increase can still be achieved with a simple triangular solar PV array while reducing wind tower bracing requirements.

For single-sloped and A-frame (or gable) PV arrays, the wind turbines should be placed immediately behind the 45 degree sloped PV array and at a height of about 1.6 times the peak height of the array.

If you are a remote community, research base or industrial site looking to develop solar and wind powered renewable energy solutions, contact us for a free consultation on how hybridizing your solar PV/wind system can work to improve your total power production (especially in low wind areas).