2 research outputs found
Thermal comfort prediction, conditions and air quality for younger and older children in Kuwait schools
The thesis presents the field and laboratory work conducted to investigate the applicability of different thermal comfort indices and equations to assess the thermal sensation of very young children (6-10 years) and older children (11-17 years) in Kuwait classrooms under different ventilation modes (hybrid, natural and air-conditioned), in addition to investigating the quality of the air inside the classrooms. Few thermal comfort and indoor air quality studies have been conducted to determine the thermal comfort and indoor air quality situation inside the classrooms (especially where the young children are presents) in comparison to that for adults in other building environments such as offices or vehicles. The aim of this thesis was to provide baseline data and expand the knowledge for young children s thermal comfort (as well as older children) and the effects of the indoor air quality inside classrooms on them throughout different ventilation modes (hybrid, natural and air-conditioned). The work was achieved by conducting both laboratory and field experiments, as follows:
Laboratory tests were conducted to measure the insulation value of the different schoolwear ensembles used in Kuwait classrooms. Three methods were used to indicate and compare the thermal insulation values of different schoolwear ensembles worn by girls and boys in Kuwait classrooms during summer and winter seasons. Results suggest that the clothing insulation values found from the measured and adapted data were similar to the adult s data in standards tables for the same summer and winter seasons ensembles. In addition, the temperature ratings of the clothing are close to, and in agreement with, the scholars comfort temperature.
A new thermal comfort questionnaire has been designed for gathering thermal sensation and reflected data from younger children. The questionnaire has been designed employing learning and educational techniques for very young people, and was statistically tested against the standard questionnaire and with old age groups to ensure no bias was introduced. The results show that the new designed thermal comfort questionnaire can help children to assess their sensation in a better manner than that of the standard questionnaire, and that it can be considered as a new subjective assessment tool that can support the thermal comfort standard by investigating the thermal comfort sensations of younger children age groups.
A large scale field study was then conducted to investigate the applicability of different thermal comfort indices for Kuwait classrooms along the academic year and under different ventilation modes to assess the thermal sensations for younger (6-10 years) and older (11-17 years) students age group during the school day. The newly designed thermal comfort questionnaire and the clothing insulation values mentioned previously were used to collect the subjects responses for comparison with a range of thermal comfort indices (PMV, ePMV, PMV10 and adaptive, and various comfort equations).
Results show that no difference in the neutral temperature between both age groups during the different ventilation modes and the PMV model is the most appropriate model to predict the thermal sensations of the younger subjects during the different ventilation modes, including the natural ventilation mode, since Kuwait classrooms largely considered as air-conditioned spaces. This work provides knowledge of thermal comfort and comfort conditions in Kuwait classrooms.
The final part of the field study was conducted to investigate the adequacy of the ventilation rates during naturally and air-conditioned ventilation modes inside 10 elementary classrooms in Kuwait occupied by 6-10 year old children by measuring the CO2 concentration levels inside these classrooms. The findings showed that naturally ventilated classrooms have lower average CO2 concentration levels (708 ppm) than air-conditioned classrooms (1596 ppm). The main reason for the high CO2 concentration in air-conditioned classrooms is attributed to the possibly inappropriate selection of ventilation system type (wall-mounted split units) inside the classrooms. This type of ventilation system cools recirculated room air provides no outside air (fresh air), which is may not be appreciated for high occupancy zones like classrooms. Suitable means for fresh air provision must be made for this mode of operation.
Some remedial solutions are theoretically suggested to reduce the high CO2 levels in air-conditioned classrooms which may enhance the students and staffs performance. The latter data on CO2 levels being above recommended values have been communicated to Kuwaiti government
A comparison of methods for assessing the thermal insulation value of children's schoolwear in Kuwait
In this study, three methods were used to determine the thermal insulation values of different school
clothing worn by 6 to 17 year old girls and boys in Kuwait classrooms for both summer and winter
seasons. The different clothing ensembles’ insulations were determined by 1: measurement using adultsized
versions of the clothing on thermal manikins, 2: estimations from adult clothing data obtained
from the standards tables in ISO 9920 and ASHRAE 55, and 3: calculations using a regression equation
from McCullough et al. (1985) that was adapted to accommodate children’s sizes for ages 6e17 years.
Values for the clothing area factor, fcl, were also determined by measurement and by using a prediction
equation from ISO 9920.
Results in this study suggested that the clothing insulation values found from the measured and
adapted data were similar to the adult’s data in standards tables for the same summer and winter
seasons. Further, the effect of the insulation values on the different scholars’ age groups were investigated
using the clothing temperature rating technique and compared to the scholars’ comfort temperature
found in recent field studies. Results showed that the temperature ratings of the clothing using the
three methods described above are close and in agreement with the scholars’ comfort temperature.
Though estimated and measured fcl data differed, the impact on the temperature ratings was limited.
An observed secular change in the children’s heights and weights in the last few decades implies that,
for adolescents, the children’s body surface areas are similar to those of adults, making the use of adult
clothing tables even more acceptable. In conclusion, this study gives some evidence to support the
applicability of using adults’ data in ASHRAE 55 and ISO 9920 standards to assess the thermal insulation
values of different children’s clothing ensembles, provided that careful selection of the garments,
ensembles material and design takes place