Calculations, tests and evaluations of the PV-window

Calculations have shown that the PV-window is thermally competitive to the nowadays low energy windows and equally fulfills the requirements within the Danish Building Regulation. Data for the developed PV-window is listed in table 1.

Table 1. Thermal data for the PV-windows illustrated in figure 1.

Dimensions (w*h)

U-value

[mm]

[W/m2K]

1230 x 1480

1.20

Furthermore the PV-window supply the building with electricity and reducers its need for primary energy. Electrical tests have shown that the PV-window is equally competitive to standard PV- panels. The only difference is the inclination of the profile and hence the electrical output.

Test at the Danish Building Research Institute has also shown, depending on the design and layout of the PV-pane, cf. figure 1, that the PV-window can supply daylight and electricity to buildings to fulfill different requirements in different areas in the building.

Students from Aarhus School of Architecture have in a workshop investigated how the developed PV-window can be used to create transparent building components which offer multiple functions apart from transparency and production of electricity. The architect found that the PV-window offers these multiple functions. Depending on the laying up, sizing and carving of the PV-cells the PV-window can offer a high production of electricity, income of daylight, solar shading and interesting reflections. The PV-pane also accentuates the changeability and dynamics within the many characters of daylight. The use of silicon wafers in building design has a cogent and technical expression and it communicate a global friendly/responsible production of electricity.

3. Conclusion

The project group is developing a low-cost PV-window with focus on optimizing the composition of the PV-pane and hence simplifying the production method. These factors can reduce the price of the PV-window with up till 20 % or more compared to similar products.

The PV-pane is built up as a 3-layer construction with gas filling and a TPS spacer profile. With a U-value of 1.2 W/m2K, the PV-window fulfills the Danish Building Regulation and is thermally competitive to the nowadays low energy windows.

As an additional choice the PV-window can be designed with screen printing, variations in the design of the PV-pane, e. g. the size of the silicon wafers and carving of patterns within the PV- cells. This will affect the price of the PV-window.

Summed up this makes the product very attractive for building owners and architects to use in building designs for both new and retrofit buildings in comparison to other renewable energy systems which often tend to deface the building from an architecturally point of view. The PV — window addresses the field of making energy right buildings, using the energy falling on the buildings to supply itself in a fully integrated an aesthetical way and not as an ad on to a building.

It helps reducing the need for primary energy, gives the building a clearly environmentally green profile and at the same time it fully fulfills the requirements within the Danish Building Regulation.

The development of this product has not been completed and will continue.

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Figure 5. Illustration of the developed PV-window