Low-grade heat utilisation to obtain economically viable and environmentally sustainable automotive manufacturing

Lead Research Organisation: Newcastle University
Department Name: Mechanical and Systems Engineering


Technical background:
The PhD studentship will investigate possible utilisation of low-grade heat sources, for example surplus low grade heat from the new automotive paint shop of NISSAN UK being designed by GEICO TAIKISHA and which will be opened in March 2017. The objective of the research is to introduce a framework to ease the environmental characterization and improvement in end use energy demand. Energy efficiency has quickly become a top priority because of the high energy use in industrial operations, which are responsible for significant CO2 emissions and thus, climatic changes. An automotive manufacturing plant has very large energy use and the painting shop example is particularly major responsible for this. The application of the framework will identify opportunities for improving energy use in order to achieve a reduction in operating costs and greenhouse gas emissions. In industry, a significant amount of energy is commonly used by equipment such as pumps, compressors, boilers, prime movers, ovens, chillers, dryers, process heaters, process coolers, ventilation equipment, etc. Thermal energy loss in each operation cannot be avoided and therefore manufacturing industry, characterised by a large number of operation units, has an inevitable large source of thermal energy loss. Hence, with higher energy cost and the increased importance of rationalising energy use, thermal energy management is likely to become an increasingly fundamental issue in the future. Decreasing the amount of end-use energy demand would help NISSAN to achieve sustainable processes with subsequent important results in terms of cost competitiveness and making progress toward environmental goals. This can be achieved by recovering low-grade heat (T<260 C), which if not captured and used, is mostly released into the atmosphere, thus giving rise to energy and resource losses and missing an energy efficiency opportunity. Innovative technologies will be assessed for their ability to recovery this energy and the scope of their utilisation.

Project summary:
In order to identify and estimate all the possible low-grade heat sources and to utilise them, it is firstly required to evaluate how much heat can be theoretically recovered from the industrial processes. This evaluation will be done through a pinch and exergy analysis. Pinch analysis is a methodology for minimising the energy consumption of processes by calculating thermodynamically feasible energy targets and achieving them by optimising heat recovery systems, energy supply methods and process operating conditions. At the same time, exergy analysis results to aid in determining the potential usefulness of a given low-grade heat source and determine the maximum amount of mechanical work which can be obtained. After the characterisation of available low grade heat sources, the most appropriate innovative technical solution for recovery and utilisation will be evaluated in order to assess the potential end use energy reduction obtained. An economic analysis of the solutions will be conducted to explore the impact on capital and operational costs to determine payback periods and commercial viability.

Project outcomes:
Detail techno-economic reports analysing innovative solutions to utilise low grade heat sources to reduce manufacturing energy demand. It is expected that at least 4 high impact publications in leading journals such as Applied Energy and Applied Thermal Engineering. In addition, 3 presentations at world leading conferences such as Sustainable Energy Technology, and Heat Powered Cycles.

Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/N509528/1 30/09/2016 30/03/2022
1823413 Studentship EP/N509528/1 26/06/2016 25/06/2020 Alessandro Giampieri
Description Different strategies for waste heat recovery and use of liquid desiccant technology for automotive painting applications were evaluated by techno-economic analysis. The main objective of the study was the energy consumption reduction at the Nissan UK paint shop. The analysis was based on several steps: (i) different waste heat sources available in the paint shop, such as RTO, compressors, condenser of the chilled water system, wind farm and transformers, were identified and estimated; (ii) a strategy for the analysis of temperature and humidity control in the paint booth was described; (iii) a novel configuration for the use of liquid desiccant technology in automotive painting in cold climates was proposed; (iv) the annual performance of the system was evaluated and the potential economic benefits were estimated; (v) alternative potential uses, such as dehumidification of flash-off air, were analysed; (vi) alternative potential sites for the application of the technology were estimated; and (vii) a comparison with the techno-economic performance of the technology in hot and humid climates was conducted. The main conclusions drawn were:
1) the liquid desiccant technology is able to supply air within the temperature and humidity requirement all-year-round for ASU painting operation at the paint shop, varying its operating mode according to the temperature and humidity demand. The annual low temperature and moisture content of the outdoor air allows the use of cheap desiccant solutions, such as CaCl2, characterised by a lower dehumidification ability compared to LiCl but also by the ability to recover lower temperature heat sources, enabling the use of the heat available from the compressors in the paint shop. On the other hand, the use of liquid desiccant technology for ARU processes was discarded in cold climates. The cost of auxiliary components (solution pumping and air blowing) curtails the economic performance of the heat recovery technology;
2) the use of the RTO waste heat to drive the liquid desiccant technology for dehumidification of flash-off air exhibited a good performance from the technological and economic point of view at Nissan UK paint shop. The thermo-chemical energy storage ability of desiccant solutions enables them to bridge the intermittent operation of the RTO between the maximum and minimum operating conditions, regenerating more solution when more heat is available, storing it and ensuring continuous dehumidification of the air for the flash-off process. The recirculation of the air exhausted from the regenerator is required to limit seasonal variations of the waste heat requirement and the related cost for heat exchangers. A desiccant solution with a higher dehumidification ability is required by the process, such as LiCl, the high cost of which curtails the energy benefits; and
3) the novel technology showed promising application for different outdoor air conditions, such as in hot and humid climates. The ability of the desiccant solution to control the temperature and humidity of both the outdoor and recirculated air in climates such as Singapore enables significant economic savings in terms of electricity consumption for temperature and humidity control of both outdoor and recirculated air.
Exploitation Route A novel configuration of the liquid desiccant technology for automotive painting application was designed able to work in cold or hot/humid climates. The research was by investigating waste heat availability, thermodynamic feasibility and economic feasibility of different heat recovery processes at the considered paint shop with liquid desiccant technology. The research has shown positive results in all these three aspects. A new predictive model for the liquid desiccant system was created to evaluate the performance according to factors such as outdoor air conditions, operating conditions, desiccant solutions, packing material and dimension, etc. The predictive model was used for the analysis of the technology in different climatic conditions and with different desiccant solutions. The techno-economic analysis helped to identify what steps are required (solution pumping cost and pressure drop reduction) to further increase the cost-effectiveness of the technology towards the realisation of a small-scale pilot system for air-conditioning of paint shop using liquid desiccant technology.
Sectors Aerospace

Defence and Marine


Food and Drink


Communities and Social Services/Policy





Leisure Activities

including Sports

Recreation and Tourism


including Industrial Biotechology



Museums and Collections

Pharmaceuticals and Medical Biotechnology


URL https://www.h-disnet.eu/files/ci-attachment/H-DisNet_P4-Giampieri-Automotive-industry.pdf
Description The project was developed in a joint venture with Nissan UK. The study identified the feasibility and economic advantages resulting from the use of liquid desiccant technology for different processes, such as paint booth air-conditioning and flash-off air dehydration, in the paint shop. The technology would be able to recover different available waste heat sources, such as coolant of compressors, chilled water system, wind turbines, and transformer and exhaust air from the RTO. Energy savings were found in terms of natural gas and electricity. As requested by the manufacturer, an analysis of alternative sites of application of the technology, which performance is highly dependent on the outdoor air condition, was performed, identifying Singapore as an alternative and studying the ability of the liquid desiccant technology to control the temperature and humidity for painting operation in hot and humid climates. The techno-economic analysis helped to identify the energy consumption for solution pumping and air blowing as the main drawbacks of the technology, which limits its large use as a replacement of conventional technologies. As such, further research will investigate various combinations of desiccant solutions, packing materials and configurations to identify the design able to reduce as much as possible the energy consumption of auxiliary components and the overall costs of the technology, Further step of the research should include the preparation of a larger scale liquid desiccant test rig to reproduce the process performed in the paint shop.
First Year Of Impact 2017
Sector Energy,Manufacturing, including Industrial Biotechology
Impact Types Economic