Technology development, technology consulting, technology service, technology transfer, technology dissemination; Sales of compressors, mechanical equipment and accessories, solar equipment, instruments and meters, chemical products, computer hardware and software, lubricants; Equipment maintenance, installation, rental; Computer system integration; General construction contract; Investment management; Asset management; Contract energy management; Import and export of goods; Engineering design. (Market entities independently choose business projects and carry out business activities according to law; Engineering design and projects subject to approval according to law, and carry out business activities in accordance with the approved contents after approval by relevant departments; They shall not engage in business activities of items prohibited and restricted by the national and municipal industrial policies. Huahai (Beijing) Technology Co., Ltd. Has invested in 2 foreign companies.