(Yicai Global) July 17 -- Gree Electric Appliances, the world's biggest maker of home air-conditioners, is linking arms with Henan Wanjiang New Energy Development to enter the geothermal energy field.

The two companies signed a cooperation agreement in Zhuhai, Gree's hometown, the Securities Times reported today, citing an executive at Wanjiang New Energy. Details such as project costs have yet to be finalized.

Gree's new partner developed the first pilot for geothermal central heating in China's Henan province and has many projects in its cities, including the capital Zhengzhou. Wanjiang New Energy was set up in 2008 by Chen Zemin, founder of well-known Henan frozen-food brand Sanquan Food.

China has started to focus on geothermal energy, a clean source of power, in recent years. According to a national plan, geothermal projects will cover a total 1.6 billion square meters by 2020, equal to 70 million tons of coal use. They covered 150 million sqm at the end of 2017.

In 2017, Gree inked a CNY15 billion (USD2.2 billion) deal for a smart manufacturing industry base with the city government of Luoyang in Henan. The same year, Yinlong Energy, which counts Gree Chairwoman Dong Mingzhu as an investor, agreed a CNY15 billion deal on a new energy vehicle industrial park in the city.