The CLON concentrator follows, in principle, from the CPC concentrator. From the construction point-of-view (fig. 1) it has similarly placed parts like absorber, reflector and tansparent cover, but the reflector is intended to be from flat mirrors instead of parabolic curvatures. Like the CPC, CLON has two compund mirrors as well, when each of the mirror has its „focus" at the opposite corner, the intersection of the opposite mirror with absorber.

It is clear that system consist of flat-plate mirrors cannot have a focus. But assuming that the solar radiation should be reflected to area between points F1 and F2 (see fig. 2), functionality similar to CPC will be satisfied. Character of irradiation distribution on the plane of absorber (i. e. between Fi and F2) will not be interesting in that case because it will certainly differ from CPC. On the other hand we can expect that using flat mirrors, the distribution of irradiance will be more uniform than that formed by CPC and this may be useful for some applications (i. e. for use with solar cells where bad uniformity may lead to flow of compensation currents). For the CLON concentrator we will require:

1. concentration of all the radiation within angular range (-©A; ©A)

2. concentration with only one reflection on mirrors within the range (-©A; ©A).

In general, CPC concentrator redirects sun rays to absorber after one or more reflections. Especially rays comming under angles close to 0° are reflected to lower parts of concentrator where again a reflection acts. This way the optical efficiency is decreasing as it is, first of all, given by reflectivity of mirrors.

Properties of CLON can be compared to CPC type of concentrator. Similar properties are following:

• geometry: concentrator consist of a couple of compound mirrors, receiver is placed between lower rim of mirrors and upper transparent cover between top rim points.

• Solar radiation in the angular range (-©A; ©A) is concentrated

• Concentrator can be truncated

• The same construction of receiver can be used

• The same tracking requirements

Differences in comparison to CPC can be listed as follows:

• Concentrator’s forming curve is much simplier — linear, what leads to use of simple and inexpensive mirrors

• Irradiation of receiver is more uniform

• Lower optical losses due to single-reflection principle

• Lower concentration factor at the same acceptance angle (but for the same acceptance angle CPC has bigger size, therefore must be truncated and its concentration factor C decreases)

A — transparent cover, B — concentrator (reflector), C — receiver
1 — transparent cover, 2 — mirrors, 3 — receiver, 4 — selective layer, 5 — tubes with heat transfer media, 6 —

thermal insulation