Thermal comfort studies in hungary

1. 1. Thermal comfort investigations have been carried out in Hungary from the second half of the 1970s, partly in laboratories and partly in the field, with humans and thermal manikins.

2. 2. The most important series of measurements have been made in the following fields: comparison of different heating systems from the point of view of thermal comfort, energy consumption and local discomfort; comparison of different heat and sunshine protection formulations; determination of acceptable temperature for different activities; checking different kinds of ventilation; examination of the thermal comfort conditions of disabled persons; determination of different clothing, e.g. the clo values of uniforms and polar suits, etc.

3. 3. This paper deals with the methods and results of laboratory and site examinations.

Thermal comfort conditions in the morning and in the evening

Eight females and eight males participated each in 4 comfort experiments on 4 different days. Two experiments took place in the morning and two in the evening. In each experiment (21/2 hours) the preferred ambient temperature was determined for each subject by adjusting the ambient temperature according to his wishes. The subjects were sedentary. Skin temperatures, rectal temperature and evaporative weight loss were measured. Although the rectal temperature and the mean skin temperature were slightly higher in the evening than in the morning the subjects did not prefer an ambient temperature which was different from that in the morning. This indicates that the same thermal comfort conditions can be used from morning to evening.     

Thermal comfort and thermoregulation in manned space flight

Exposure to thermal environment is one of the main concerns for manned space exploration. By focusing on the works performed on thermoregulation at microgravity or simulated microgravity, we endeavored to review the investigation on space thermal environmental physiology. First of all, the application of medical requirements for the crew module design from normal thermal comfort to accidental thermal emergencies in a space craft will be addressed. Then, alterations in the autonomic and behavioral temperature regulation caused by the effect of weightlessness both in space flight and its simulation on the ground are also discussed. Furthermore, countermeasures like exercise training, simulated natural ventilation, encouraged drink, etc., in the protection of thermoregulation during space flight is presented. Finally, the challenge of space thermal environment physiology faced in the future is figured out.     

Thermal comfort of sows in free-range system in Brazilian Savanna

The aim of this work was to evaluate the thermal comfort of sows in a free-range system in the Brazilian Savanna, based on behavior observation, availability of shading resources, meteorological and physiological variables. The sows were analyzed in the gestation sector at Água Limpa Farm from University of Brasília; the sows were housed in paddocks of 1000 m² each containing artificial and natural shading structures, where air temperature (T_air, °C), wind speed, relative humidity (R_H, %) and black globe temperatures (T_G, °C) were collected for the environment characterization in 20-min-intervals. From the black globe temperature, the Mean Radiant Temperature (T_MR, °C) and the Radiant Heat Load (R_HL, W m⁻²) were calculated in the sun and under the shade structures. The total short-wave irradiance was calculated through the sum of direct, diffuse and reflected radiations. For the behavioral evaluation, an ethogram was elaborated, taking in consideration where the animals were in the paddocks, body posture, and the activity performed. The physiological variables such as respiratory rate (breaths.min⁻¹), surface and rectal temperatures (°C) were measured during the experiment. The data was statistically analyzed through analysis of variance and frequency analysis. There was a difference at 11a.m., 2 and 3p.m., with values above 40 °C under the shade and above 70 °C in the sun for the T_MR. The preferential choice was for natural shading by the sows, due to the lower T_MR and R_HL throughout the day and resting activity had been predominated. The rectal temperature did not differ between the animals and the days evaluated, respiratory rate varied according to air temperature, and surface temperature only among the evaluated animals. It was concluded that even when there is a greater radiation incidence and meteorological variables above the condition of comfort for sows, they did not express any abnormal behavior that could indicate discomfort.     

Thermal comfort in naturally ventilated and air-conditioned buildings in humid subtropical climate zone in China

A thermal comfort field study has been carried out in five cities in the humid subtropical climate zone in China. The survey was performed in naturally ventilated and air-conditioned buildings during the summer season in 2006. There were 229 occupants from 111 buildings who participated in this study and 229 questionnaire responses were collected. Thermal acceptability assessment reveals that the indoor environment in naturally ventilated buildings could not meet the 80% acceptability criteria prescribed by ASHRAE Standard 55, and people tended to feel more comfortable in air-conditioned buildings with the air-conditioned occupants voting with higher acceptability (89%) than the naturally ventilated occupants (58%). The neutral temperatures in naturally ventilated and air-conditioned buildings were 28.3°C and 27.7°C, respectively. The range of accepted temperature in naturally ventilated buildings (25.0∼31.6°C) was wider than that in air-conditioned buildings (25.1∼30.3°C), which suggests that occupants in naturally ventilated buildings seemed to be more tolerant of higher temperatures. Preferred temperatures were 27.9°C and 27.3°C in naturally ventilated and air-conditioned buildings, respectively, both of which were 0.4°C cooler than neutral temperatures. This result suggests that people of hot climates may use words like “slightly cool” to describe their preferred thermal state. The relationship between draught sensation and indoor air velocity at different temperature ranges indicates that indoor air velocity had a significant influence over the occupants’ comfort sensation, and air velocities required by occupants increased with the increasing of operative temperatures. Thus, an effective way of natural ventilation which can create the preferred higher air movement is called for. Finally, the indoor set-point temperature of 26°C or even higher in air-conditioned buildings was confirmed as making people comfortable, which supports the regulation in China that in public and office buildings the set-point temperature of air-conditioning system should not be lower than 26°C.     

Thermal sensation and comfort during exposure to local airflow to face or legs

The present study examined the contribution of local airflow temperature to thermal sensation and comfort in humans. Eight healthy male students were exposed to local airflow to their faces (summer condition) or legs (winter condition) for 30 minutes. Local airflow temperature (Tf) was maintained at 18 degrees C to 36 degrees C, and ambient temperature (Ta) was maintained at 17.4 degrees C to 31.4 degrees C. Each subject was exposed to 16 conditions chosen from the combination of Tf and Ta. Based on the results of multiple regression analysis, the standardized partial regression coefficient of Tf and Ta were determined to be 0.93 and 0.13 in the summer condition, and 0.71 and 0.36 in the winter condition at the end of the exposure. Also, thermal comfort was observed to depend closely on the interrelation between Tf and Ta. The present data suggested that local airflow temperature is an important thermal factor regarding thermal sensation and comfort.     

Vietnamese culinary herbs in the United States

Identification, cultivation, chemistry, and uses of nine Vietnamese herbs, hitherto rare or unknown in the United States, are discussed:Giâp Cá (Houttuynia cordata),Lá Lôt (Piper lolot), Rau R?m (Polygonum odoratum),Rau Muông (Ipomoea aquatica),Ngò Gai (Eryngium foetidum),Rau Cân (Oenanthe javanica),Cân Dây Lá (Plectranthus amboinicus),Tía Tô (Perilla frutescens), andRau Ngo (Limnophila aromatica).     

Thermoregulation in the comfort temperature zone

Under constant adequate temperature conditions (comfortable for a man) the retention of temperature homeostasis was shown to require a continuous functioning of the physiological thermoregulation system to prevent short-term and whole day deviations of the temperature from the physiological level. Under adequate temperature conditions the thermoregulation system was shown to attain its highest sensitivity and accuracy. It is possible that this occurs owing to physiological control over the total body heat content being included into the process of thermoregulation. The data are given on the existence and "structure" of the physiological mechanisms of such a control.     

Thermal comfort modelling of body temperature and psychological variations of a human exercising in an outdoor environment

Human thermal comfort assessments pertaining to exercise while in outdoor environments can improve urban and recreational planning. The current study applied a simple four-segment skin temperature approach to the COMFA (COMfort FormulA) outdoor energy balance model. Comparative results of measured mean skin temperature ( [`(T)]\nolimits<sub>Msk</sub> \mathop{{\bar{T}}}\nolimits_{{Msk}} ) with predicted [`(T)]\nolimits_sk \mathop{{\bar{T}}}\nolimits_{{sk}} indicate that the model accurately predicted [`(T)]\nolimits<sub>sk</sub> \mathop{{\bar{T}}}\nolimits_{{sk}} , showing significantly strong agreement (r = 0.859, P < 0.01) during outdoor exercise (cycling and running). The combined 5-min mean variation of the [`(T)]\nolimits_sk \mathop{{\bar{T}}}\nolimits_{{sk}} RMSE was 1.5°C, with separate cycling and running giving RMSE of 1.4°C and 1.6°C, respectively, and no significant difference in residuals. Subjects’ actual thermal sensation (ATS) votes displayed significant strong rank correlation with budget scores calculated using both measured and predicted [`(T)]\nolimits<sub>sk</sub> \mathop{{\bar{T}}}\nolimits_{{sk}} (r <sub>s</sub>  = 0.507 and 0.517, respectively, P < 0.01). These results show improved predictive strength of ATS of subjects as compared to the original and updated COMFA models. This psychological improvement, plus [`(T)]\nolimits_sk \mathop{{\bar{T}}}\nolimits_{{sk}} and T _c validations, enables better application to a variety of outdoor spaces. This model can be used in future research studying linkages between thermal discomfort, subsequent decreases in physical activity, and negative health trends.     

Thermal regulation and comfort during a mild-cold exposure in young Japanese women complaining of unusual coldness.

We examined body core and skin temperatures and thermal comfort in young Japanese women suffering from unusual coldness (C, n = 6). They were selected by interview asking whether they often felt severe coldness even in an air-conditioned environment (20-26 degrees C) and compared with women not suffering from coldness (N, n = 6). Experiments were conducted twice for each subject: 120-min exposure at 23.5 degrees C or 29.5 degrees C after a 40-min baseline at 29.5 degrees C. Mean skin temperature decreased (P < 0.05) from 33.6 +/- 0.1 degrees C (mean +/- SE) to 31.1 +/- 0.1 degrees C and from 33.5 +/- 0.1 degrees C to 31.1 +/- 0.1 degrees C in C and N during the 23.5 degrees C exposure. Fingertip temperature in C decreased more than in N (P < 0.05; from 35.2 +/- 0.1 degrees C to 23.6 +/- 0.2 degrees C and from 35.5 +/- 0.1 degrees C to 25.6 +/- 0.6 degrees C). Those temperatures during the 29.5 degrees C exposure remained at the baseline levels. Rectal temperature during the 23.5 degrees C exposure was maintained at the baseline level in both groups (from 36.9 +/- 0.2 degrees C to 36.8 +/- 0.1 degrees C and 37.1 +/- 0.1 degrees C to 37.0 +/- 0.1 degrees C in C and N). The rating scores of cold discomfort for both the body and extremities were greater (P < 0.05) in C than in N. Thus the augmented thermal sensitivity of the body to cold and activated vasoconstriction of the extremities during cold exposure could be the mechanism for the severe coldness felt in C.     

Thermal comfort of various building layouts with a proposed discomfort index range for tropical climate

Recent years have seen issues related to thermal comfort gaining more momentum in tropical countries. The thermal adaptation and thermal comfort index play a significant role in evaluating the outdoor thermal comfort. In this study, the aim is to capture the thermal sensation of respondents at outdoor environment through questionnaire survey and to determine the discomfort index (DI) to measure the thermal discomfort level. The results indicated that most respondents had thermally accepted the existing environment conditions although they felt slightly warm and hot. A strong correlation between thermal sensation and measured DI was also identified. As a result, a new discomfort index range had been proposed in association with local climate and thermal sensation of occupants to evaluate thermal comfort. The results had proved that the respondents can adapt to a wider range of thermal conditions.Validation of the questionnaire data at Putrajaya was done to prove that the thermal sensation in both Putrajaya and UTM was almost similar since they are located in the same tropical climate region. Hence, a quantitative field study on building layouts was done to facilitate the outdoor human discomfort level based on newly proposed discomfort index range. The results showed that slightly shaded building layouts of type- A and B exhibited higher temperature and discomfort index. The resultant adaptive thermal comfort theory was incorporated into the field studies as well. Finally, the study also showed that the DI values were highly dependent on ambient temperature and relative humidity but had fewer effects for solar radiation intensity.