Concentration is basically the amount of substance present. A high concentration of something, like a hormone in the blood, means there is a lot of it. A low concentration of something means there is not a lot of it, but a little.
The important thing to know is that concentration in biology is almost always referring to the amount of something in a liquid solution — be it blood, water, an organic solvent in a test tube, etc.
If you want to get super technical, concentration usually refers to the molarity of a solution. That is, moles of a substance per liter of solution. You may have learned this in chemistry — if so that might help put it into perspective.
Low concentration PV (LCPV) systems have a concentration magnification ratio of less than 10X. Examples of these systems include compound parabolic concentrators, prism-based concentrators and V-troughs.
They typically use single junction silicon solar cells, have quite simple designs and often employ concentrating optics made of plastic. They are easier and cheaper to manufacture and maintain than high concentrating systems as they do not require tracking or cooling mechanisms. LCPV systems are suitable for stand-alone applications and building integration. They are capable of capturing a large part of the diffuse solar radiation, in addition to the direct component, making them particularly suitable for the climit of northern Europe.