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Power Transmission, Brakes and Cooling Systems
Published in Iqbal Husain, Electric and Hybrid Vehicles, 2021
Three heat exchangers are shown in Figure 14.26 stacked in series which would be located in the front of the vehicle. IC Engine has a separate heat exchanger (i.e., radiator), while two electrical component cooling loops use one heat exchanger. The third heat exchanger is for the air-conditioning system of the vehicle which is not shown in the figure. Series arrangement of the heat exchangers provides efficient packaging, but requires higher total fan power requirements due to increased airside pressure loss, and shared fan control. In the series stacking, the lowest temperature heat exchanger must be placed first in the direction of airflow. Parallel stacking of heat exchangers maximizes the frontal area. Airflow into each heat exchanger can be optimally controlled by individual fan control. Forward-facing heat exchangers can benefit greatly from dynamic air pressure created by vehicle motion, but adequate airflow is necessary at lower speeds. Lower vehicle speeds provide the more challenging cooling system design requirements due to higher loads for the devices and inadequate airflow.
Heating and Cooling
Published in Stan Harbuck, Donna Harbuck, Residential Energy Auditing and Improvement, 2021
The fan control prevents cold air from being circulated into the rooms without having first been warmed by the furnace. This prevents the blower from blowing cold air after the heat exchanger has cooled off (well after the thermostat has quit demanding heat). The fan control is a temperature-sensitive switch, completely independent of the thermostat, that turns the furnace blower on and off at preset temperatures. When the thermostat calls for heat, the furnace burner turns on. After the heat exchanger warms to a preset temperature (usually 110–120°F), the fan control activates the blower. The thermostat will shut off the burner when the building warms to the thermostat setting. After a while, when the heat exchanger cools to about 85°F, the fan control will switch off the blower. If, as you observe the above sequence, it is faulty, the fan control should be adjusted or replaced.
Electrical installations
Published in Duncan Marshall, Derek Worthing, Roger Heath, Nigel Dann, Understanding Housing Defects, 2013
Duncan Marshall, Derek Worthing, Roger Heath, Nigel Dann
Modern thermal storage heaters can be effective providing certain criteria are met: The system should not be installed in large, poorly insulated buildings as the low capital cost cannot justify the high energy costs.Ideally, the building should be of a low air volume and the construction should be with materials of high thermal insulation values.The heaters should be capable of dissipating the heat under fan control and some form of external optimising controls that are capable of regulating energy input relative to weather conditions should be incorporated.The capacity of each thermal heater needs to be carefully considered. If it is too large, its capital cost will be excessive and it will be under-utilised; if too small, the cost of supplemental (i.e. daytime on-peak) electrical heating in cold weather will be excessive.
Feasibility verification of reducing the total sound pressure level of multiple cooling fans for fuel cell vehicle
Published in International Journal of Green Energy, 2023
Weijie Dong, Donghai Hu, Yuran Shen, Jianwei Li, Qingqing Yang
In this study, a numerical calculation model of the vehicle’s exterior and interior sound field is established for multiple cooling fans. The model consistency is verified using experimental data. Then, a hybrid computational method of aeroacoustics is used to analyze the noise contribution of multiple cooling fans under the same duty cycle. Finally, a cooling fan control strategy is proposed, verifying the feasibility of noise reduction. The main conclusions are as follows: The numerical calculation model of multiple cooling fans is practical for estimating the sound pressure level. The maximum errors between the simulation and test results are 1.5, 2.5, 2.3, and 1.9% at the four monitoring points of FCV. These errors are ultimately caused by a combination of model simplification, model material parameters and grid division.Vehicle speed is an essential factor affecting the cooling fan noise. The noise of cooling fan is attenuated in the low-speed working condition of vehicle. With the increase in vehicle speed, pressure pulsation on the body wall is enhanced, and the wind noise gradually masks the noise of cooling fan.Considering the fan duty cycle staggered by 10%, 20%, and 30%, simulation results showed that noise is reduced compared with the same duty cycle. The total sound pressure level next to driver’s ear decreases by 0.6, 1.9, and 2.8 dBA in parking and charging working conditions; 0.4, 1.6, and 2.4 dBA in idling conditions; and 0.6, 2.2, and 3.1 dBA in constant speed working conditions.The cooling fan control strategy between the same duty cycle and stagger duty cycle is based on consistent heat dissipation. The simulation results showed that the total sound pressure level of multiple cooling fans can be reduced through the control strategy of stagger duty cycle.