Measuring more than 36 meters in height and 23 meters in diameter each, four white, giant inflatable silos stand at a grain reserve warehouse in Xinjin District, Chengdu City, southwest China's Sichuan Province.

A single silo is able to store 7,500 tonnes of grain, equivalent to the annual consumption of 70,000 people, according to its developer China Grain Reserves Group (Sinograin).

On Friday, the silos were officially put into service, with 30,000 tonnes of soybeans newly stationed.

When the temperature outside reaches about 30 degrees Celsius, the temperature inside would be about 22 degrees Celsius, showing good insulation performance, reported China Media Group (CMG).

Each grain silo is distributed with 25 blue multi-functional cables with 14 sensors on each cable, which enables a consistent optimal environment for the grain inside.

The inflatable grain silos out-perform the traditional ones in thermal insulation and airtight performance, which conserves the grain better, improving their final quality, Xue Fei, engineer at the Research and Design Center of Sinograin Chengdu Grain Storage Institute, told CMG.

Inspired by coal storage

As the first of its kind, the innovative grain silo is a result of four years' unremitting interdisciplinary collaboration.

It was first inspired by an inflatable membrane reinforced concrete spherical silo, developed by China National Coal Group (China Coal) to store coal, which was first displayed at an innovative achievements exhibition in Beijing in 2017.

However, the coal silo cannot be directly adjusted to store grain, as the storage requirements for the latter are far harsher.

Grain storage requires the temperature to consistently remain below 20 degrees Celsius with stable humidity conditions and smooth, flat silo walls, Yu Pengbiao, director of the Research and Design Center of Sinograin Chengdu Grain Storage Institute, told Science and Technology Daily.

Facing arduous technical transformation, Sinograin and China Coal set up a joint team to develop the air membrane silo.

After repeated discussions with experts in various fields from different scientific research institutes and universities, the team found that the coal silo should be completely transformed, and even the most basic part, the silo body configuration, must be redesigned.

Two-pronged research

To promote the research more efficiently, the team took a two-pronged approach – one was to build smaller prototype for testing and the other to simulate the theory calculations on software.

After four years of work, the team built three experimental silos to compare different design plans, by which they obtained many parameters required for the construction.

In March 2021, the pilot project of inflatable membrane reinforced concrete dome grain silos was officially launched.

Its first grain silo was constructed in June 2022, showing an air tightness of over nine times the national standard, said Yu.

The figures demonstrate the silo's excellent thermal insulation performance, Yu added.