Visit to Plant

Rooftop Solar Plant Prevents Roof Damage From Typhoon (Part 1) (page 2)

No power generation for 3 weeks due to heavy snow

2019/05/21 10:17
Shinichi Kato, Nikkei BP Intelligence Group, CleanTech Labo
Print Page

Air conditioning cost reduced by heat insulating effect

Setting up solar panels on warehouse roofs brought about benefits other than power generation. For instance, solar panels boost the heat insulating effect of the roofs.

Solar panels keep the high temperature outside from transferring through the roof to inside the warehouse. This can reduce air conditioning costs in hot summers. On the other hand, solar panels block the sun's heat in winter, but they are more effective in keeping the temperature inside the warehouse from falling and help the heating system work better.

Such effects could even improve with a completely closed building. However, as warehouses are used with the shutters on the sidewalls kept open, it seems difficult to quantify the degree of these effects.

Even so, Saito Warehouse said it could realize the effects. For example, the room temperature used to rise above the set temperature when the air conditioner was set at 28° on a hot summer day, but it can be maintained at 28° since the solar panels were installed. Of the two buildings at the warehouse in Kofu, the power bills of the tenant companies in the old building have decreased noticeably, according to the company (Fig. 3).

Fig. 3: Tenant companies' power bills have noticeably declined (source: Saito Warehouse)

Unexpected benefit of rooftop solar plant highlighted by typhoon in fall 2018

When a typhoon passed through and caused serious damage around Kofu in the fall of 2018, Saito Warehouse realized that the rooftop solar panels seemed to have eased the damage from the strong winds on the roofs themselves.

This typhoon damaged building shutters and roof materials in the surrounding area and knocked over hundreds of trees at golf courses. The warehouse in Kofu is located near a river, where winds grow stronger, in particular, in a typhoon. As a result, part of the roof materials called "frieze boards," which protect the edge of the roof, came off after being bent up from below (Fig. 4).

Fig. 4: Frieze boards bent up from below. Already repaired in bottom photos (source: Saito Warehouse, bottom Nikkei BP)

The company believes that if it had not been for the solar panels on the roof, the damage would have extended to a wider range or to other roof materials. Saito Warehouse feels that the solar panels effectively worked like an anchor.