No need for aircon, as Singaporean researchers invent gel that lowers humidity and produces electricity
Water-absorbing hydrogel absorbs moisture from surrounding air, block sunlight if applied to windows and generate a similar amount of electricity as a AA battery
By Justin Ong Guang-xi
Being in a tropical country means living with higher humidity levels, especially on warm days. Now, a group of researchers from the National University of Singapore (NUS) may have found a way to get around the physical discomfort without the use of air-conditioners.
They have invented a special hydrogel, a gel-like material that harnesses the moisture in the air to reduce ambient temperature, or the temperature of a person’s immediate surroundings. Upon absorbing the moisture, the hydrogel can be used for a wide range of practical applications as well — most interestingly, to generate electricity.
The water-absorbing hydrogel is eight times more efficient than previously known drying agents, and can quickly reduce the relative humidity of a small room from 80 to 60 per cent in a matter of minutes.
Unlike traditional cooling agents such as air-conditioners and fans, it does not depend on an external power source and can be simply coated onto walls and furniture, where it will perform its dehumidifying function.
The gel was invented by a four-member research team from the Department of Materials Science and Engineering at the Faculty of Engineering. The team had been working on this project for one-and-a-half years.
Assistant Professor Tan Swee Ching, who led the research, said: “Singapore, like many tropical countries, experience high levels of relative humidity between 70 and 80 per cent. In a humid environment, the air is saturated with water and as a result, perspiration on our body evaporates more slowly. This causes us to feel hotter than the real ambient temperature, leading to great discomfort. Our novel hydrogel aims to achieve a cooling effect by removing moisture from ambient air very efficiently.”
Hydrogels are not unheard of, such as its ability to hold large amounts of waters crucial for products including contact lenses and wound dressings. However, this is the first time hydrogels are being researched and engineered for its ability to absorb water from the surrounding air.
Besides just lowering ambient temperature, research has uncovered other practical applications.
After taking in water from the environment, the hydrogel becomes opaque and is able to block infrared light by 50 per cent. This means that if coated on windows, the hydrogel can reduce the relative humidity of a room while also blocking off the heat from natural sunlight.
The researchers also discovered that the hydrogel can generate small amounts of electricity of about 1.8 volts, similar to an AA battery. This means that it could power small electronic devices such as wall clocks and could be important in emergency situations where no power source or sunlight is available.
The development of the novel hydrogel is supported by NUS and the Ministry of Education. The research team has received substantial funding from Temasek Foundation Ecosperity (TFE) to test the application of the hydrogel to reduce relative humidity on a larger scale in both indoor and outdoor spaces.
Mr Lim Hock Chuan, chief executive of TFE, said that the organisation provides funding to projects and research that champion sustainability and liveability.
The NUS research team will conduct more studies to further advance the application of the different properties of the hydrogel and has since filed a patent for the invention.