“\"I’m saving energy; where are you?\" – 0604: Utilization of waste heat from heat pumps

Thread Content

This post was last edited by Qing_Xue on 2016-4-16 at 11:18. The utilization of waste heat from heat pumps is gaining momentum in the context of energy conservation and emission reduction; waste heat resources are considered to be the fifth major conventional energy source after coal, oil, natural gas, and hydropower. Our center focuses on comprehensive solutions for utilizing the waste heat from power plant circulating water (in wet-cooling units) and exhaust steam (in air-cooling units). By employing heat pump technology, we can recover and utilize this waste heat, and we have the capability to provide consulting, design, and renovation services for heat pump-based waste heat utilization projects in power plants of various capacities and specifications. This approach enables energy savings of around 40% (with a heat pump COP of generally 1.6–1.8), **improving the thermal efficiency of power plant units and bringing significant economic and environmental benefits. Comparison of the advantages and disadvantages of heat pump-based waste heat utilization for centralized heating versus conventional centralized heating: Advantages of heat pump-based waste heat utilization for centralized heating; Disadvantages of conventional centralized heating. Utilizing the waste heat from circulating water or exhaust steam reduces the cold-end losses of the system, thereby **improving the energy efficiency of the system.** In conventional systems, cold-end losses result in energy wastage. Heat pump systems reduce emissions, thereby minimizing thermal pollution in the atmosphere, offering significant environmental benefits. Conventional systems cause severe thermal pollution. They also reduce losses due to cooling tower evaporation, saving water or reducing electricity consumption in air-cooled systems; thus, electricity is saved. However, conventional systems have high losses due to cooling tower evaporation or high electricity demands from air-cooled systems. Heat pump systems reduce the coal consumption required for heating, thus conserving coal resources. The coal consumption in conventional systems is relatively high. Visual examples of heat pump-based waste heat utilization. Principles and technical characteristics of heat pumps: A heat pump is a device that transfers heat from a low-temperature source to a high-temperature source. It uses a small amount of heat from the high-temperature source to extract heat from the low-temperature source, generating a large amount of medium-temperature heat that can be utilized. In other words, it utilizes high-temperature thermal energy to raise the thermal energy of a low-temperature heat source to moderate temperatures, thereby improving the efficiency of thermal energy utilization. 1) Available waste heat: Generally, waste hot water with a temperature of 30°C to 70°C, as well as single-component or multi-component gases or liquids, can be used. 2) Heat medium available: A heat medium with a temperature about 40°C higher than that of the waste heat source, and not exceeding 100°C, is available. 3) Driving heat source: 0.1～0.8MPa steam, gas, or high-temperature flue gas. 4) The heating COP is around 1.6 to 1.8: This means that 1 MW of heat input can be used to generate approximately 1.8 MW of heat required for production and daily use. 5) The higher the inlet and outlet temperatures of the waste heat water, the higher the temperature of the heat medium obtained, and thus the higher the efficiency. System composition and scope: The equipment and piping systems within the range from the exhaust steam outlet of a certain stage of the steam turbine to the outlet of the heat network circulation water pump (with the boundary generally located 1 meter outside the plant’s perimeter wall). These mainly include: 1. Heat pumps; 2. Heat network circulation water pumps (steam-driven or electric); 3. Heat network heating steam system; 4. Heat network circulation water system; 5. Heat network drain system; 6. Waste heat utilization system; 7. Heat network pressure regulation and make-up water system; 8. Chemical water treatment system; 9. Electrical components; 10. Thermal control components. Services provided for the power plant’s heat pump heating system: Technical consultation on waste heat utilization by heat pumps. 1. Selecting the optimal heat pump heating solution based on the requirements of heat users; 2. Conducting economic and technical evaluations of the heat pump heating solutions; 3. Providing end-to-end design services for heating system projects. PS: The above content is reproduced from Huadian Zhengzhou Mechanical Design and Research Institute. Website: http://2014.hdmdi.com/sitefiles/services/cms/page.aspx?s=408&n=748&c=9496