ZEMCH 2015 - International Conference Proceedings | Page 612

Cooling and heating load
Fig. 8 shows the annual indoor cooling and heating loads for the glass DSF and the PV DSF. In
winter, the heating load of the PV DSF was, on average 5.6%, higher than that of the glass DSF.
In summer, on the other hand, the cooling load of PV DSF was lower than that of glass DSF by
5.4% on average.
While the DSF transfers all of the solar radiation energy from the facade to the building, the PV
DSF generates electricity using solar power generation and only transfers the remainder to the
building. The temperature of the cavity, acting as a thermal buffer zone, is thus lower for the PV
DSF than the glass DSF. Therefore, the PV DSF is depended on the cavity temperature. That is disadvantageous in terms of heating load, but the reduced solar radiation in summer contributes to
a reduced cooling load.
The annual cooling/heating load of the PV DSF and the DSF was 8018.53kWh and 7801.42kWh,
respectively, which translates to the PV DSF model having a 217.12kWh higher load than the DSF.
However, the PV power generation in the PV DSF amounts annually to 1438.02kWh, corresponding to 18% of the cooling/heating load.
Finally, it was found that PV DSF can be saved building energy of 15% compared with existing DSF
through PV generation and reduced cooling load.

Figure 8: Monthly Load & PV Power

Conclusions
This study analysed the thermal characteristics and building energy performance of a PV DSF
through simulation modelling. It was found that the PV DSF model maintains lower cavity temperatures during both seasons compared to the DSF model due to solar-induced generation of
electricity. This model is thus more effective for the cooling load in summer, but not in terms of
the heating load in winter. The total annual energy was higher for the PV DSF model by a small
difference of 3%. It is considered that integration of PV into general DSF does not have a significant impact on building load.
The cooling load is greater than the heating load, in which building PV DSF is a better solution in
terms of preventing an increase of the cooling load by double skin, and may be more influential
when it comes to the cooling load. In particular, for PV power generation and prevention of PV

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ZEMCH 2015 | International Conference | Bari - Lecce, Italy