# Techno-Economic Analysis of Waste Heat Recovery in Automotive Manufacturing Plants
## 2 Literature Review  
Recent literature indicates a growing interest in research on waste heat recovery in automotive manufacturing plants, highlighting its potential to improve energy efficiency and reduce operational costs. Among these studies, the focus is specifically on the heat recovery potential within painting shops, where significant amounts of waste heat are generated during the drying and curing processes. These studies are summarised in Table 1 and examine various strategies and technologies for capturing and reusing this waste heat,contributing to overall energy savings and sustainability in automotive manufacturing plants, especially in painting shops. [PERSON] and [PERSON] [9] reported the development of an advanced solar combined heat and power system, Eco + Energy CPS Suntec, aimed at enhancing sustainability in the automotive manufacturing process. By combining a micro gas turbine with a Fresnel solar heat collector, the system effectively captures and reuses waste heat, achieving more than 90% efficiency. It also reduces reliance on fossil fuels by up to 35%, leading to significant cuts in both carbon and nitrogen oxide emissions. The system operates continuously, ensuring uninterrupted heat and power supply in industrial processes like curing automotive paint, which requires high temperatures. This case study demonstrated a 70% reduction in primary energy consumption alongside a decrease in carbon dioxide emission by 2800 tons per year. Furthermore, [PERSON] et al. [10] reported that the waste heat recovery from flue gas should be used directly in the pretreatment tanks, bypassing the steam boiler and reducing energy losses. The proposed system achieves a 69% improvement in energy efficiency over conventional designs, reducing flue gas temperatures from 160 \({}^{\circ}\)C to 110 \({}^{\circ}\)C. This case study demonstrated a payback period (PBP) of 2.8 years, significantly reducing energy consumption and carbon dioxide emissions. [PERSON] and [PERSON] [10] presented the modelling simulations that highlight the significant potential of low-temperature waste heat recovery, particularly from air compressors and dryers, which together emit a substantial amount of heat up to 93% of the power supplied to the compressor, which is released as waste heat. This study proposed using an air-source heat pump to recover and store this heat in a water tank for reuse in processes like air heating in the spray booth. The simulation results showed that recovering and repurposing this heat can significantly reduce energy consumption. Another study [11] highlighted waste heat recovery potential, particularly within paint shops where significant heat is lost during processes like paint curing and drying (from old baking ovens). The study proposed the use of an ORC combined with a TES system to recover and reuse this heat. By capturing the waste heat from these baking ovens, the proposed system can generate electricity, improve the thermal comfort of the workspace, and reduce overall energy consumption. [PERSON] et al. [13] reported waste heat recovery from regenerative thermal oxidisers (RTOs), compressed air systems, and chilled water systems to regenerate the liquid desiccant solution, which controls temperature and humidity within paint booths. This