Footnotes
(Note) Metal roofs often used for large buildings such as factories, warehouses, and gymnasiums, and are usually made of steel plates that are 0.6 to 1.2 millimeters thick, and folded into trapezoids.
Roof Sprinkler System to Control Excessive Heat
ES-Waternet Co., Ltd.
Industry: Manufacturing
| Publication date | November 2, 2021(Posted on October 24, 2022) |
|---|---|
| Sector | Human Health |
Company Overview
Since its foundation, ES-Waternet Co., Ltd. has been working under the slogan, "contribute to agricultural water." As a specialized manufacturer of agricultural water, we have been incorporating the latest irrigation systems and accumulating extensive achievements in both public and private projects. Today, we are expanding the range of operations into environmental, industrial, and global fields, including snow removal systems for bullet trains, environmental/urban greening systems, water treatment systems, and ODA projects, using the know-how we cultivated in the agricultural field.
Climate Change Impacts
The environment is changing drastically on a global scale, including global warming, desertification, heat island phenomenon, and torrential rains. In response to these situations, since we have been contributing to the society through agriculture since our establishment, we are expanding our business into the fields of: global warming prevention/greenhouse gas control/creation of green dams (flooding prevention method that use trees and woods instead of concrete dams)/disaster prevention, utilizing our accumulated experience, knowledge, and developed products in the environmental field.
Adaptation Initiatives
We have developed a roof sprinkler system that prevents the temperature of the roof from rising by using heat loss (vaporization heat) from the roof surface that occurs when water from the sprinkler evaporates. This is the same idea as sprinkling water on gardens and streets to cool the air and prevent overheating. When the rise in the roof temperature is controlled, radiant heat transferred from the roof to the inside of the house is reduced, and as a result, the temperature rise inside the house can also be controlled.
We offer all the necessary equipment for roof sprinkling (sprinklers, controllers, ancillary equipment, etc.) and provide them as a system (Figure 1). In addition to the automatic sprinkler controller for general use, we also offer a controller specifically designed for roof sprinkling. The specialized controller can automatically control roof sprinkling by setting the sprinkling period, day of the week, starting/ending time, and sprinkling duration/interval time.
The roof sprinkler system can also be applied to cool solar panels (photovoltaic panels) on the roof. Solar panels are said to lose power generation efficiency when the temperature rises, so if power generation efficiency can be restored by cooling the panels with water, the effect of saving energy/power will be further enhanced.
Effects / Expected Benefits
In our verification of the cooling effect of sprinkling water on a trapezoidal roof (Note), the effect was most apparent around noon, when the solar radiation was stronger (Figure 2). The top part of the roof without water sprinkling rose to 51.5°C, while the part with water sprinkling only rose to 32°C. There was a difference of approximately 20°C depending on whether the sprinkler was used or not. We also compared the cooling performance of thermal barrier coating and shading sheets. The results showed that water sprinkling lowered the roof temperature by 5°C to 7°C more than thermal barrier coating and shading sheets, indicating the high cooling effect of sprinkling water on the roof (Figure 3).
The roof sprinkler system has been installed in factories, warehouses, large hardware stores, mega-solar panels, and school buildings. Users have commented that they felt cooler when they entered the room and that it made their work easier.
