solarkollector - SLFPC

solarkollector

Skylight Flat Plate Collector Technical Parameter

1. Sky/light Dimension (L*W*H) mm: 2000*1060*68/ 2000*1060*78/ 2000*1060*90

2. Skylight Core: all copper, ultrasonic welding

3. Skylight Coating: black chrome/ Blue titanium

4. Skylight Absorber material &thickness: copper, 0.15mm

5. Sky*light Header pipe material, dimension and quantity: copper T2; Φ25*0.6*1060mm; 2pcs

6. Skylight Riser pipe material, dimension and quantity: copper T2; Φ10*0.5/Φ12*0.6mm; 8pcs

7. Skylight Material & thickness of glass: tempered glass: 4mm /fabric tempered glass: 4mm/low iron fabric tempered glass: 3.2

8. Sky*light Material & thickness of frame: aluminum, 0.8mm

9. Skylight Insulation of material: high pressure high density polyurethane foam

10. Skylight Insulation thickness mm: 30

11. Sky+light Material & thickness of the back sheet: embossed aluminum, 0.3mm

12. Skylight Packing: carton

13. Sky-light Packing dimension (two pieces in one carton): 2020*1100*160/ 2020*1100*180/ 2020*1100*200

14. Sky-light Net weight: 32kg/33kg/35kg

15. Sky=light Qty of 20' container: 162/162/152pcs

16. Sky*light Qty of 40' container: 312/312/276pcs

17. Sky-light Qty of 40H' container: 332/332/312pcs

1. Glass gasket

2. Coating

3. Full copper absorber plate

4. Disposed special insulation

5. Gasket and sealant

6. Black sheet

7. Aluminum alloy batten

8. Aluminum frame

9. Tempered glass

Advantages

Flat-plate collectors will absorb energy coming from all directions above the absorber (both beam and diffuse solar irradiance). Because of this characteristic, flat-plate collectors do not need to track the sun. They receive more solar energy than a similarly oriented concentrating collector, but when not tracked, have greater cosine losses.

a. Non-tracking Option

Since tracking is not required, flat-plate collectors may be firmly fixed to a mounting structure, and rigid plumbing may be used to connect the collectors to the remainder of the system. Moving structure, motors, and tracking control systems are eliminated, thereby reducing the complexity of the system. As discussed in Chapter 5, however, because of the cosine effect, less total energy falls on a fixed surface over the period of a day than on a surface that tracks the sun about one or two axes.

In order to increase their output, flat-plate collectors may be repositioned at intervals or placed on a single- or two-axis tracking mechanism. Either of these options increases the output of the collector but eliminates the advantage of fixed piping and mounting structure.

b. Diffuse Solar Radiation Utilization

A flat-plate collector absorbs both the direct and the diffuse components of solar radiation. This partially compensates for the fact that fixed surfaces receive less energy because of the cosine effect. Although the diffuse solar irradiance is only about 10 percent of the direct normal solar irradiance on a clear day, on a cloudy day almost all of the available solar irradiance is diffuse.

A comparison between the energy falling on a fixed and a fully tracking flat-plate collector and on a fully tracking concentrating collector is shown in Table 6.1. The data are yearly average values taken from SERI (1981b). The comparison is location dependent because of the latitude effects on the incidence angle and the difference in cloud cover.

For both locations, the two-axis tracking flat-plate collector receives more energy. However, in the dry, high desert climate of Albuquerque, a fixed flat-plate collector loses more energy from the cosine effect than it gains by being able to collect diffuse energy. In the Midwestern climate of Madison, Wisconsin, the energy lost by fixing the flat-plate collector approximately equals that gained over a concentrator by its ability to collect the diffuse component of solar irradiance. It should be noted that Table 6.1 only indicates the relative amounts of energy available for collection. The choice of collector type or whether to track a flat-plate collector is generally based on system cost and energy output rather than energy input.

c. Cost

Currently, flat-plate collectors cost less than concentrating collectors. Part of reason is the lack of need for a complex tracking system. However, part of the reason is because many more flat-plate than concentrating collectors are being produced today. At large production rates, however, it is still not clear whether it is less expensive to cover an aperture area with an absorber plate or with reflective material.

Because of their potential to produce more low-temperature energy for a given cost, flat-plate collectors have been considered for use as pre-heaters for concentrating collectors in high-temperature industrial process heat systems. The major prototype of this system configuration is at Campbell Soup Company in Sacramento, California and is shown in Figure 6.2. The decision of whether to include flat -plate collectors as pre-heaters ultimately is based on the balance between performance and cost.