Decarbonization of Industrial Process Heating using High-Temperature Heat Pumps
India’s heavy dependency on fossil fuels goes hand in hand with the nation’s substantial industrial demand for heating applications. As per the IEA 2021 report, India’s energy demand is set to rise by 35% between 2019 and 2030. Despite the increase in production and exploration of conventional and renewable fuel sources, we are import-dependent, which is not sustainable. Fossil fuel and electrical energy are used in Industries like manufacturing, automotive, pharmaceutical, textile, chemical, food, dairy, etc., to cater to the process heating demands. Stringent policies on CO2 emission norms and the requirement of sustainable energy systems have pushed the need for highly efficient low carbon technology. High-temperature heat pumps (HTHP) are one such emerging technology to address the heating demands in industries.
A heat pump is a system that moves heat from a cold zone to a hot zone. Heat pumps work on the inverse principle as that of a conventional air conditioner. It uses electricity to extract heat from the ambient to generate useful heat. The overall coefficient of performance (COP) of heat pumps is much higher than electric heaters. To put into perspective, heat pumps generate three units of heat and two units of cooling for every unit of electricity consumed. In contrast, an electric heater generates 0.95 units of heat for every unit of electricity consumed. Heat pumps with an output of 70°C hot water have applications in paint manufacturing, phosphating, de-greasing, oil separation, plating, cathode electrode deposition, component washing, feed water pre-heating, etc.
Energy and Emissions Research group (EnERG, IIT Madras), in collaboration with an IITM incubated startup, TrigenDC, has developed HTHP that can provide low pressure (1.5 bar) steam at a temperature and flow rate of 110 °C and 80 kg/hr, respectively. This was then installed at DCM Shriram sugar plant, Hariawan, in April 2022. This was a demonstration of HTHP technology for heating applications in industries. The heat pump consumed an average power of 26.8 kW with an average heating COP of 2.26. A similar steam-generating heat pump delivering steam at 110 °C and 80 kg/hr is being installed in WABCO India Ltd for cooking applications.
EnERG and AEPL are the winners of the Facility for Low Carbon Technology Deployment (FLCTD – 2019), which is financed by the Global Environment Facility (GEF) and implemented by the United Nations Industrial Development Organisation (UNIDO) in collaboration with the Bureau of Energy Efficiency (BEE) and Confederation of Indian Industry (CII). Through this, they have received a grant for the deployment of HTHP in industries for heating applications. Also, Mr. Sandeep Koundinya, under the guidance of Dr. Satyanarayanan Seshadri, Associate professor, in collaboration with the Norwegian University of Science and Technology (NTNU), Norway, is working on trans-critical CO2 Heat pumps that can deliver hot water at 95 °C in a single pass and simultaneously provide chilled water at 5 °C.
The research and development of heat pumps carried out in EnERG can provide an alternative heat source that is highly efficient and generates a low carbon footprint. With the use of heat pumps, it is estimated that 1.8 billion tonnes of CO2 per year could be saved.
Figure 1. Pilot demonstration of HTHP at an industry in DCM Sriram, Lucknow.
Figure 2. Steam Generating Heat Pump for rice cooking in WABCO India Ltd., Chennai.
Article on Heat pump: https://www.linkedin.com/pulse/heat-pumps-energy-efficiency-rent-satyanarayanan-seshadri/
Author: Gautam Subburaj, Research Scholar, @IIT Madras
