New concepts for standards on the indoor thermal environment are being proposed on the international level, with ISO (International Standard Organisation) and CEN (European Standard Organisation), and on the national level with ASHRAE (American Society of Heating, Refrigerating and Air Conditioning Engineers). Among the new developments are recommendations for acceptable thermal environments to be speci ed as classes. This allows for differences in national requirements and for buildings designs to have different quality levels. This will require, and encourage better dialog between the client (builder, owner) and the designer. There is also an ongoing discussion within the standards review committees about how people can adapt to higher indoor temperatures during summer in naturally ventilated (free running) buildings. A method for a whole year evaluation of the indoor thermal environment is also proposed.The standards will be based on requirements for general thermal comfort (PMV, Operative temperature)and local thermal discomforts (radiant temperature asymmetry, draught, vertical air temperature differences, floor surface temperatures). One critical issue is the effect of air velocity. On one hand, increased air velocity has a bene cial effect at warm temperatures, but, on the other hand, increased air velocity may result in draught sensation in cooler temperatures. Another issue is the extent to which requirements of humidity need to be included in a standard for thermal comfort. Several recent research projects dealing with adaptation, in- uence of air velocity and the effect of humidity have been the basis for increasing the usefulness and accu-racy of the standards.
Floor heating systems have been recently become popular in Japanese houses. Many researchers have conducted their researches on floor heating from the viewpoint of creating a comfortable living environment in winter. They have gotten valuable information for architects, engineers and occupants. The objective of this paper is to review the previous studies on the effect of floor heating systems on human thermal comfort in Japan. Aims and findings of each research group are summarized based on research papers presented from 1975 to 1997 in Japan. Comfort zones, recommended conditions and limit conditions for humans using the floor heating system proposed by each researcher were illustrated in the charts consisting of air temperature and floor surface temperature. This review will contribute to the progress of future floor heating research.
Dry and evaporative heat resistances of 12 experimental garments were determined in a climatic chamber using a newly developed sweating thermal manikin of a two-year-old Japanese infant. The experimental garments were made of a polyethylene film that was i) un-perforated, and ii) perforated with two different hole diameters, i.e. 1.5 and 2.5 mm/cm2, in addition, four different garment designs were developed. Surface areas covered by the clothing ranged from approximately 10, 30, 65, and 83% of the manikin total body surface area. The dry heat resistance of the film clothing significantly increased as the surface area of the body covered by the clothing increased, but was affected by the hole diameters of the clothing. Linear regression equations were obtained between both the dry and wet heat resistance, and the area covered. The evaporative heat resistance also increased significantly with the area covered, while decreased significantly as the holes diameters of the clothing increased. Multiple regression equations were obtained between the evaporative heat resistance and the area covered by the clothing. The results showed that the dry and evaporative heat resistances of the clothing had a few characteristics differences, but the area covered by the clothing was the most dominant influence on both dry and wet insulation of the clothing. These results were similar to the results obtained using an adult manikin but the insulation value of the infant clothing were less than those of the adult clothing which is made of the same film and the same design.
This paper presents a numerical model of heat transfer and fluid flow in the air space formed between the human body (modeled as a horizontal cylinder) and clothing (modeled as porous media). Factors that affect heat transfer and fluid flow in the air space are the thickness of the space between the body and clothing, and properties of the clothing, such as porosity or air flow resistance. Several clothing parameters are used to approximate various types of fabric. A critical air-space thickness at which the clothing retains the most heat was identified and found to be a function of the environmental temperature. The simulation results showed that the porosity of the clothing had little effect on the heat transfer. As the air flow resistance of the clothing decreased, the heat flux from the body increased. An approximate formula for the mean Nusselt number of a clothed human body was determined. The results showed that a circulating flow was present in the air space.
Biliary atresia (BA) is one of most common of liver disease during childhood in Japan. BA is a cicatrical obstruction of extra-hapatic biliary system in the neonatal age. This disease requires corrective surgery on the porta hepatis, following reconstruction of bile draining intestinal tube, within 2 months of age ideally. BA children develop malnourish when their jaundice is not solved without proper drainage of bile juice and with progressive advancement of liver cirrhosis. However they have elevated energy expenditures and have kept normal appetites. We retrospectively studied the energy balance, body composition, and serum hormone concentrations in 18 BA children (age ranged between 1-13 years). The patients were divided into two groups: the jaundiced group (group J), in whom the serum bilirubin level was >=1.0 mg/dl; and the non-jaundiced group (group non-J), in whom the serum bilirubin level was <1.0 mg/dl. Anthropometric indices studied included height, weight, arm musclearea, and fat area as calculated by mid-upper arm circumference and triceps skin fold. An energy balance study was conducted, and serum interleukin (IL)-6 and serum leptin levels were measured. Lower adiposity, higher energy intake (overeating), higher energy expenditure, higher serum IL-6 levels, and lower serum leptin levels were found in group J compared with group non-J. To our knowledge, this is the first report correlating overeating with hypoleptinemia in pediatric BA patients with jaundice. Serum leptin levels may play a key role in eating abnormalities with persistent jaundice.
A movable sweating thermal manikin the size of a two-year-old infant was developed in this study. Heat was supplied through manganese wires of 0.3 mm diameter which were glued to the outside of the manikin. The manikin had 32 sweating pores drilled on its surface at the ratio of one per 110 cm2 of surface area. Water was supplied from a water bath through silicone tubes to each sweating pore with peristaltic pumps. The manikin was dressed in a tight-fitting cotton knit suit and a water-resistant/water vapor-permeable material to control body-surface wettedness. Joints such as shoulders, hips, and knees meant the manikin was able to be placed in a standing, sitting, or walking positions. The surface temperature of the sweating thermal manikin was maintained within 33±0.5°C for the duration of the experiment. Dry heat loss from the nude manikin was in good agreement with the value obtained by subtracting the evaporative heat loss from a 2-year-old Japanese infant’s metabolic rate at rest. The manikin’s sweat rate was able to be controlled at ten different sweating rates. The wettedness of the manikin changed from 0.49 when the water was supplied at 294 g/h•m2 to 0.83 when the water was supplied at 2184 g/h•m2. It was confirmed in the present study that the skin temperature and the wettedness of the newly developed manikin were controlled precisely and the heat exchange between the manikin and the environment simulated those of a two-year-old Japanese infant.