What is the relationship between Tsinghua Tongfang and Tongfang Ruifeng?

Tsinghua Tongfang and Tongfang Ruifeng have a superior-subordinate relationship. According to official website and Guangzhou Tongfang Ruifeng Energy Saving Technology Co., Ltd., it can be known that this company was established in 2007, and it is a high-tech enterprise specialized in central air-conditioning business of green buildings under Tsinghua Tongfang. Tsinghua Tongfang Co., Ltd. is a high-tech company controlled by Tsinghua Holding Co., Ltd., which was established on June 1997 and listed on the Shanghai Stock Exchange.