Application Of Heat Recovery in Urban Area Heating
The application of heat recovery in regional heating is essentially to achieve the cascading utilization and circular regeneration of energy, and its core value lies in breaking the structural mismatch between "energy waste" and "heating demand". In the process of industrial production and urban operation, a large amount of medium and low temperature waste heat is directly discharged into the environment, which not only causes energy loss but also may lead to heat pollution. According to data from the Thermal Power Industry Committee of the China Energy Conservation Association, the annual recoverable residual heat in the national industrial sector is about 1.08 billion tons of standard coal equivalent, of which the economically feasible recovery potential is about 320 million tons of standard coal, equivalent to 47% of the total energy consumption of urban centralized heating in 2023. This provides sufficient potential heat sources for regional heating. Compared with traditional heating modes, heat recovery heating does not rely on the consumption of new fossil fuels. It can only capture, purify, and transport idle waste heat through technological means to meet the heating needs of residents, commercial and public buildings in the region, achieving the dual goals of "energy conservation and carbon reduction" and "livelihood security".
Currently, the application of heat recovery technology in regional heating has formed diversified scenarios, covering multiple fields such as industrial waste heat and urban waste heat, and adapting to the heating needs and resource endowments of different regions. Industrial waste heat recovery is the most mature and widely used scenario. The process waste gas, cooling water, flue gas and other waste heat generated by key high energy consuming industries such as steel, cement, chemical, and electricity can be directly connected to the regional heating network after targeted technical treatment. For example, the "Chatting Heat into Jinan" project in Shandong Province uses industrial waste heat from Liaocheng Xinfa Group's power plant as the heat source, and transmits heat energy to Jinan through a more than 100 kilometer long heating pipeline network. After reaching full capacity, it can meet the heating demand of about 100 million square meters in Jinan City. Each heating season can replace about 1.299 million tons of standard coal, reduce carbon dioxide emissions by about 3.56 million tons, equivalent to adding four new Saihanba forest farms for carbon sequestration in one year, becoming a benchmark project for cross regional industrial waste heat heating.
Urban waste heat recovery provides an innovative path for heating in densely populated urban areas, covering new heat sources such as waste incineration waste heat, data center waste heat, and wastewater treatment plant effluent waste heat. Tianjin Dongli District innovatively adopts the thermal energy cascade utilization technology to convert the medium and low temperature waste heat generated by garbage incineration into heating sources. Through a three-stage heat extraction process, the waste heat is converted into 80 ℃ heating hot water, which is transported to the Dabizhuang heating station through a 12 kilometer heating pipeline, covering a heating area of 3 million square meters. This not only fully utilizes the waste heat generated by the daily processing of 1900 tons of household garbage by the garbage incineration plant, but also directly cuts the heating cost in half. One heating season saves about 34 million yuan in subsidies for the government, achieving a win-win situation of ecological and economic benefits. In addition, a data center in Yizhuang, Beijing, uses a heat pump system to recover waste heat and provide winter heating for 120000 square meters of surrounding residential areas. The annual heat recovery reaches 150000 GJ, reducing carbon emissions by about 4200 tons, demonstrating the enormous potential of waste heat utilization in urban new infrastructure.
Technological innovation is the core support for empowering regional heating with heat recovery. After years of development, a mature technology system has been formed to adapt to different types of waste heat, mainly including heat pump technology, absorption heat exchange, organic Rankine cycle (ORC), and high-temperature water steam conversion system. Among them, heat pump technology is suitable for the recovery and utilization of low-temperature waste heat (below 100 ℃). By consuming a small amount of electricity, low-grade waste heat can be raised to a temperature that can meet heating needs, with an energy efficiency ratio of 3-4 or more. It is widely used in low-temperature waste heat scenarios such as data centers and sewage treatment plants; The absorption heat exchange and high-temperature water steam conversion system is suitable for medium to high temperature waste heat (above 100 ℃), which can directly convert high-temperature waste heat from industrial production into heating energy without additional heating treatment, reducing energy loss. At the same time, the integration of intelligent technology further enhances the stability and efficiency of heat recovery heating systems. Based on AI algorithms, the heat load prediction and dynamic control system can adjust the heating amount in real time according to outdoor temperature and user demand, avoiding energy waste. The application of new phase change thermal storage materials effectively solves the pain point of unstable waste heat supply and ensures heating continuity.
