Availability of Heat Conduction for Environmental Control Method to Improving Thermal Environment and Preventing Oversensitivity to Cold and Air-Conditioning Disease on Female Office Workers

The purpose of this study is to demonstrate the effect localized heating of the feet has on physiological and psychological reactions of female in an air-conditioned environment in summer. In Japan, female office workers wear less clothing than their male counterparts. In an air-conditioned office space in summer, female conducts thermoregulation by putting on cardigans, etc. but this action does not greatly contribute to improving conditions for the legs and feet, the lower extremities of the body. The improvement of sensational and physiological temperature by localized warming of the body can contribute to a healthy working environment for female office workers, their safety, and a reduction in air conditioning’s energy expenditure. We used the indoor thermal environment evaluation index ETF to investigate the effect localized heating of the feet has on human physiological and psychological response in an air-conditioned environment in summer. The result of heating by means of heat conduction via the sole of the foot was expressed more strongly as a psychological effect than as a whole-body physiological effect. Heating by means of heat conduction via the sole of the foot was a thermal environment factor that compensates for a low temperature in whole-body thermal sensation and whole-body thermal comfort. The effect of heating due to heat conduction via the sole of the foot was expressed in the change in sole-of- the-foot skin temperature. Applying slight heat conduction by means of heating via the sole of the foot demonstrated the result of improved whole-body thermal sensation and whole-body thermal comfort.

The Influence of Foliage Plants on Psychological and Physiological Responses

This research aims to clarify the significance of incorporating visual stimulation, in the form of foliage plants, into office desktop spaces. The experiments were conducted in a thermal environment with a temperature range that was slightly uncomfortable. The indoor thermal environment evaluation index ETF was used to measure the effects that brain stimulation of foliage plants have on comprehensive thermal senses. We focus on visual stimulation with foliage plants, and quantitatively measure shifts in thermal senses that affect the body. Thermal environment conditions were established with air temperature in three stages (25℃, 28℃ and 31℃) and the atmosphere was kept homogeneous with wall surface temperature equal to air temperature. The visual stimulations consisted of seven types of office desk image: benjamin, pothos, oxycardium, baby tears, moss ball, cacti, and no plant. At around 27℃ to 29℃ ETF, improvements in thermal sensation, as measured by thermal sensation statements, were shown to have resulted from visual stimulation benefits. Also, at around 26℃ to 29℃ ETF, improvements in comfort were shown, due to visual stimulation benefits as well, in subjects’ comfortable-sensation statements. This benefit was significant when a foliage plant’s green coverage ratio came between 0.75% and 4.67%, the range which does not create an overwhelming feeling from the foliage plant.

Effects of Outdoor Thermal Environment upon the Human Responses

In a summer outdoor space, the influence of short-wave length solar radiation on the human body is strongly apparent, heat is retained in the body, and the risk of heat disorders such as heat stroke increases. To avoid this, it is essential to seek shade to avoid the influence of short-wave length solar radiation. In addition, natural ground surfaces such as green spaces and water surfaces are useful in reducing the air temperature. It is indispensable to consider climate mitigation effect of outdoor space. The purpose of this study is to clarify the influence of the thermal environment of an outdoor space on the human body in rural and suburban regions where paddy fields remain. Subject experiments were conducted to examine the relationship between the thermal environment evaluation index enhanced conduction-corrected modified effective temperature (ETFe) in an outdoor space and the physiological and psychological responses of the human body. Experiment sites were selected with consideration for the natural ground surface such as bare ground where the surface is gravel or soil;paved ground such as concrete, asphalt or blocks;green areas covered in plants;and water surfaces, as well as the sky factor due to buildings or trees etc. and the proportion of the solid angle of components of greenery and water etc. comprising the solid angle of the total celestial sphere. A ground surface feature with a high heat capacity may promote sensation of hot and deteriorate the thermal sensation. A landscape of thick vegetation with a high green factor may have a strong feeling of confinement, which can make it somewhat hot and somewhat uncomfortable thermal environment due to the sense of stagnation. Compared with the urban environment, it is conceivable that the difference in the perceptual environment, whereby it is subconsciously assumed to be a comfortable thermal environment, had an effect in the rural and suburban regional environment, resulting in an ETFe lower than the upper limit of comfort in a summer urban environment.

Effect of Visual Stimuli of Indoor Floor Plants upon the Human Responses

The biophilia hypothesis maintains that animals, which bring benefits for human survival, evolve adaptively to cause a positive emotional response or actions in the human evolution process. When connected in an advantageous environment for survival, effective relaxation and recovery from fatigue are brought about as further physiological functions, rather than a simple stress-free situation. The aim of this study is to clarify the significance of the visual stimulation of indoor floor plants placed in an office floor space. We examined how the green covering factor and gaze distance to indoor floor plants placed on the floor influenced thermal sensation. The thermal environment conditions were set at 3 levels, 25°C, 28°C, and 31°C and the floor and air temperature were homogenous. We set up 8 office floor plans that had no visual stimulation and used indoor floor plants including pachira, monstera, butterfly palm, yucca elephantipes, weeping fig, umbellate, and snake plant for a visual stimulation. The gaze distance, measured from the center of the subject presented with a visual stimulation and the center of the plant, was set at 3 distances: 2.0, 4.5 and 8.0 m. When the conduction-corrected modified effective temperature (ETF) was below 26°C, the visual stimulation of the indoor floor plants umbellata and monstera, which have a silhouette with low leaf density and rounded leaves, were shown to mitigate the sensation of being cool. The visual stimulation of indoor floor plants with rounded leaves, such as, pachira, monstera, weeping fig, and umbellata, were shown to decrease the feeling of discomfort. For a gaze distance below 4.5 m, a green covering accounting for less than 5% was shown to be necessary for mitigating the sensation of being cool and improving the feeling of discomfort.

Clothing Area Factor for Typical Seasonal Clothing of Infant

It is not ethical to conduct experiments on infants regarding the thermal environment. Therefore, to examine the thermal environment of infants, experiments and simulations using a human body thermal model may be feasible by clarifying the human body coefficient values of infants. When focusing on the heat transfer area of the infant’s body coefficient values, the body surface area and solar radiation area factor have only been clarified as the standard. The essential basic data for examining the thermal environment of infants have not been sufficiently obtained. Therefore, the purpose of this study was to determine the clothing area factor for infants’ clothing in a typical season. The clothing area factor of infants clothed in summer, mid-season, and winter clothing was measured using a photographic method. The clothing area factor was 1.22, 1.42, and 1.90 for summer, mid-season, and winter clothing, respectively, indicating a significant seasonal difference. It was also found that the clothing area factor was significantly greater for infants than for adults.

Thermal Manikin of Infant

Compared to an adult, an infant requires more consideration regarding the thermal environment so it is necessary to evaluate the thermal environment as it affects infants. However, experiments on infant subjects regarding their thermal environment based on the different heat balance of their body cannot ethically be conducted. We could instead consider using a thermal model for the human body, but thermal manikins based on heat transfer per unit area are rare. Therefore, this study aims to develop a thermal manikin to model the heat transfer per unit area and the body form of an infant in order to evaluate the infant’s thermal environment. When evaluating the thermal environment or heat balance of the body in the outside environment, it is essential to consider the asymmetry and unevenness of the temperature of the skin, as an element of the human body, and not just the unevenness and asymmetry of physical factors in the environment. Moreover, when receiving short wavelength direct solar radiation, light and shaded areas have significant differences in skin temperature. The following 20 body parts were investigated in the study: anterior head, posterior head, ventral trunk, dorsal trunk (including buttocks), right medial arm, right lateral arm, left medial arm, left lateral arm, right dorsal hand, right palmar hand, left dorsal hand, left palmar hand, right anterior leg, right posterior leg, left anterior leg, left posterior leg, right dorsal foot, right plantar foot, left dorsal foot, and left plantar foot. This paper measured the body surface area for each part of an infant’s body in order to establish the form of an infant model from the view of the heat transfer area, and verified the validity of the model.

Influence of Stroller upon Thermal Insulation of Infant

In outdoor spaces, infants in strollers are significantly affected by thermal radiation from the ground surface due to their proximity to it. Infants are at increased risk of heat stroke while riding in a stroller. Infants are less thermally adapted to their environment and can consequently be considered to need protective measures against thermal environments. In order to treat strollers as clothing, in the present study, experiments were conducted to clarify the thermal environment of an infant riding in a stroller. Using an infant thermal manikin, the clothing area factor fcl and the clothing thermal insulation Icl of the stroller were determined. The stroller clothing area factor fcl was 3.21 and the stroller clothing thermal insulation Icl was 0.47 clo. Therefore, it can be inferred that strollers have a pronounced effect on the body heat balance between an infant and their environment.

Clothing Thermal Insulation for Typical Seasonal Clothing of Infant with Infant Thermal Manikin

Infants are less thermally adapted to their environment and can be considered as needing protective measures against thermal environments. It is not ethical to conduct subject experiments on infants. Thermal insulation in clothing is an essential control coefficient for the evaluation of the thermal environment of an infant. A thermal manikin can be used as an alternative method for carrying out experiments and to control the thermal manikin based on heat balance. The purpose of this study was to clarify the thermal insulation of infants’ clothing. An infant thermal manikin was used to clarify the thermal insulation (Icl) of typical summer, mid-season, and winter clothing combinations for infants. The thermal insulation of typical seasonal clothing combinations was 0.30 clo for summer clothing, 0.57 clo for mid-season clothing and 1.02 clo for winter clothing. It was clarified that it is essential to consider clothing conditions by taking into account differences in posture and to define the clothing thermal insulation (Icl) when designing and evaluating thermal environments. When designing and evaluating an infant’s thermal environment, it is essential to investigate using data from infants.