Fundamental Study of Dehumidification and Heating by Pre-regenerated Silica gel Honeycomb Block for Electric Vehicles

Abstract

Electric vehicle doesn’t generate much amount of waste heat. Therefore, electric vehicles consume a relatively larger amount of electricity for heating. Normally, dry and low-temperature winter air is heated and supplied to the vehicle cabin to avoid water condensation on the windows. This results in further reduction of the vehicle cruising range. This paper discusses the applicability of a thermally regenerative desiccant block for dehumidification and heating of electric vehicles. Regenerated desiccant block adsorbs the water vapor generated by the passengers, therefore fogging of the windows can be avoided without air ventilation. Also, simultaneously generated heat due to heat of adsorption can support the heating. Experimental results employing a commercialized silica gel honeycomb block indicated that the regeneration time of the block was much shorter than dehumidification duration. This must be a suitable feature for the actual use. A field-test using a silica gel honeycomb block of four-liters set in a real vehicle cabin with two passengers showed anti-fogging effect during 30 min or more. This desiccant dehumidification and heating could reduce the heating load by 40 percent or more comparing to the conventional heating and ventilation.