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This paper presents pressure drops and heat transfer rates for compact heat exchangers, where the heat exchangers are angled 90°, 60°, 30° and 10° relative to the incoming airflow. The investigation is based on three heat exchangers with thicknesses of 19mm and 52mm. Each heat exchanger was mounted in a duct, where it was tested for thermal and isothermal conditions. The inlet temperature of the coolant was defined to two temperatures; ambient temperature and 90°C. For the ambient cases the coolant had the same temperature as the surrounding air, these tests were performed for five airflow rates. When the coolant had a temperature of 90°C a combination of five coolant flow rates and five airflow rates were tested. The test set-up was defined as having a constant cross-section area for 90°, 60° and 30° angles, resulting in a larger core area and a lower airspeed through the core, for a more inclined heat exchanger.

The automotive industry have become more and more interested in recovering waste heat from internal combustion engines, especially with future, tighter fuel and CO2 emission regulations in sight. In this study, we consider an automotive Rankine Waste Heat Recovery System on a long-haulage truck. This system transforms some of the combustion engine's waste heat into useful energy, but it still needs to return remaining heat to the surrounding, either through a direct condenser or from an indirect condenser via a Low Temperature Radiator, and this in the regular cooling module of the vehicle. We focus on the integration of WHR-dedicated LTR or condenser into a generic, conventional truck-cooling module with an AC condenser, a cross-flow Charge Air Cooler, a down-flow High Temperature Radiator, and a fan. WHR cooling concepts considered are an indirect system with LTR; either in front or back of CAC, a direct system with condenser either in front or back of CAC.

The European Union’s 2020 target aims to be producing 20 % of its energy from renewable sources by 2020, to achieve a 20 % reduction in greenhouse gas emissions and a 20 % improvement in energy efficiency compared to 1990 levels. To reach these goals, the energy consumption has to decrease which results in reduction of the emissions. The transport sector is the second largest energy consumer in the EU, responsible for 25 % of the emissions of greenhouse gases caused by the low efficiency (<40 %) of combustion engines. Much work has been done to improve that efficiency but there is still a large amount of fuel energy that converts to heat and escapes to the ambient atmosphere through the exhaust system. Taking advantage of thermoelectricity, the heat can be recovered, improving the fuel economy.