Multipoint measurement method for air temperature in outdoor spaces and application to microclimate and passive cooling studies for a house

We propose a multipoint measurement method for air temperature in outdoor spaces using polyvinyl chloride pipes with fan-aspirated ventilation. The method is applied to microclimate measurement in the outdoor space of a residential house, and the cooling effects of plants and natural ventilation on the house were evaluated. The accuracy of the proposed method was verified in the outdoor space. Average systematic errors of the method were 0.43 °C during daytime on sunny days and 0.16 °C on cloudy days. Application of the method to microclimate measurement shows that air temperatures were reduced by evapotranspiration of plants and watering in the planted space during daytime. By placing the plants near a floor-level window, wind speed inside the window was reduced, although the cooled air flowed into the indoor space through the window. The cooling effects of the plants and watering in the outdoor space kept indoor air temperature cooler during daytime. The period in which the sensible heat flux from the outdoor to indoor space showed positive values, i.e., when there was a sensible heat load in the room, diminished from 9 to 4 h through the cooling effects. •A multipoint measurement method for air temperature is proposed.•The method is verified in terms of average systematic error and confidence interval by comparing with a standard instrument using aspirated ventilation and shield.•The method is applied to field measurements of microclimate and passive cooling of a house.•Air temperatures were reduced by evapotranspiration of plants in daytime.•The cooling effects reduced sensible heat flux into the indoor space and kept indoor air temperature cooler during daytime.