New system of heat recovery from parked vehicles: Experiments and analysis

The present study suggests a new concept of heat recovery applied to underhoods of vehicles parked in underground parkings. The advantages of this concept is twofold: (1) enabling cool the environment around the parked vehicle and under its hood (2) considering to use the excess of heat under the hood to heat/preheat water in use in public buildings. This system shows potential performance especially in car parking where a large number of vehicles is present such as supermarkets, universities, schools, etc. The feasibility of recovering energy from underhoods of parked vehicles is performed in the study. An experimental setup equipped with thermocouples, a heat exchanger and a fan is implemented. The engine is stopped after a certain period of operation then measurements are performed on two types of engines: V4 and V6. The temperature of the hot air aspirated by the V4 and V6 engine reached 40 °C and 54 °C respectively. The hot air is used for heating water using a finned-tube cross flow heat exchanger where the recovered heat rate reached around 500 W. In addition, a case study for the parking of the Lebanese International University along with an economic study are considered. From the study, 300 cars are assumed to be present daily in the parking, equipped by different engines (V4, V6 and V8). Consequently, the recovered energy obtained during the 80 min is estimated at 97 kWh, which permits to heat 4000 L of water from 20 °C to 40 °C.