Evaluating the perception of thermal environment in naturally ventilated schools in a warm and humid climate in Nigeria

Field study was conducted in naturally ventilated primary school buildings in a warm and humid environment in Imo State, Nigeria to determine the thermal comfort perception of young children (aged 7–12 years) and to understand the thermal conditions in the classrooms. The comfort temperature was investigated in two types of classroom buildings during the rainy and dry seasons from October 2017 to May 2018. Approximately 7050 completed valid questionnaires were collected from 330 young children repeatedly surveyed twice a day. The children answered comfort questions at the same time the indoor and outdoor thermal variables were being measured. Results indicated that the combined ‘open-space’ classrooms produced a neutral temperature of 28.8°C with comfort range, 25.2–32.3°C. The neutral temperature of the combined ‘enclosed-plan’ classrooms is 28.1°C with 25.8–30.5°C as the comfort range. The differences in the comfort perceptions may be attributed to the differences in the architectural characteristics of both categories of classroom buildings. High temperature tolerance was shown by the participating children in the study area. This article, therefore, suggests that installing air conditioning in primary schools in the warm humid environment in Nigeria may not be necessary as it could lead to unnecessary energy consumption and carbon emission

Adaptive thermal comfort evaluation of typical public primary school classrooms in Imo state, Nigeria

Climate change is causing high-temperature increase, which is affecting people’s health especially the vulnerable group such as children. Literature reviews revealed various complaints about health issues caused by heat stress as they relate to this group exposed to poor indoor thermal conditions while they are engaged in class activities. This problem necessitated a need to evaluate the thermal conditions of occupants of some selected public primary schools, used as case studies, in which 134 pupils, aged 7-12 years, participated in the survey. The main objective was to determine the indoor thermal conditions of the classrooms and to compare the occupant’s thermal sensations, thermal preference and thermal acceptability in these selected spaces. This paper presents the results of this field survey conducted in the months of October and early November 2017 in two categories of naturally ventilated spaces; the ‘’open plan’’ and the ‘’enclosed space’’ classrooms located in Imo State, Nigeria. The indoor and outdoor thermal variables were recorded together with the simultaneous administration of the questionnaire to evaluate how the pupils feel about the indoor thermal conditions in the classrooms. Results revealed that the mean thermal sensation vote in the combined ‘’open plan classrooms’’ was -0.04, while that of the ‘’enclosed space classrooms’’ was +0.32, adopting the American Society of Heating, Refrigerating and Air-conditioning Engineers (ASHRAE) scale. Though the two classrooms reported different thermal sensations votes, the indoor thermal conditions were generally accepted by the occupants probably attributed to their adaptive abilities and the season the survey was conducted. The results may not be generalized to apply to all seasons since this very study was conducted during the late part of the rainy season. This, however, provides useful information to architects and engineers who are keen on designing and constructing sustainable indoor spaces

Rating the components of indoor environmental quality in students classrooms in warm humid climate of Uli, Nigeria

The indoor environment of classrooms needs to be comfortable for the occupants to perform their class work effectively. To achieve this objective, architects and engineers need to be proactive at the early design stage by considering the very component of Indoor Environmental Quality (IEQ) building occupants consider most as the hindrance to comfortable living. This paper presents the findings of a post-occupancy evaluation of students’ subjective responses to the various environmental qualities; lighting, odour, noise/acoustics and heat/thermal comfort in warm humid university classrooms. The aim was to rank the IEQ on the scale of students’ consideration for a comfortable indoor classroom work. This was done using questionnaire to get the subjective response from the respondents. The work was conducted in two university classrooms while the students were engaged in various class activities. Valid responses were gotten from sixty-five students. The result suggests that majority of occupants (62%) rated thermal comfort number one as the component of the IEQ that usually gives them the most concern, while 71% of the respondents rated ‘‘preference to sit beside windows’’. This result is consistent with earlier studies on IEQ attributes conducted in other climatic zones in Nigeria. The findings will be helpful to designers, engineers, facility maintenance managers when taking decisions in constructing sustainable classroom blocks

Thermal comfort assessment of primary school children in a warm and humid climate : a case study of Imo State, Nigeria

Thermal comfort study in buildings gained unprecedented momentum in recent times because of the concern over climate change. The increasing temperature caused by climate change is likely impacting the comfort and the health of building occupants, especially in a primary school setting where young children engage in-class lessons for an extended period. This thesis presents the results of the perception of the thermal environment by primary school children (aged 7-12 years), and that of their teachers and the thermal performance of the classrooms they use for class lessons. Fieldwork that involved the collection of objective and subjective data were carried out in six naturally ventilated classroom buildings that have two different architectural features. The studied subjects in the survey area (Imo State) represented a variety of users in a similar climatic context in Nigeria. The fieldwork covered two seasons associated with the study area; the rainy season and the dry season, during which the subjects were repeatedly surveyed twice a day. Structured comfort questionnaires were adopted to collect approximately 7050 valid copies of responses from 330 schoolchildren and 44 of their teachers at the same time data loggers were collecting indoor and outdoor environmental parameters. The data from the fieldwork were stored in a spreadsheet of Microsoft Excel and analyzed using both descriptive and inferential statistical techniques. Results found that at the prevailing indoor air velocity, not all the surveyed classroom spaces met the specifications of the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE) Standard 55-2017 comfort zone, adopting an 80% acceptability criterion as the primary consideration. Higher compliance was reported in the ‘open-space’ classrooms compared to the ‘enclosed-plan’ classrooms. The comfort temperature of the schoolchildren was found to be 28.8oC, at an observed mean indoor operative temperature of 29.1oC for the combined classrooms all season. Results also found that the schoolchildren were comfortable within the operative temperature range of 25.8oC-31.6oC for 80% ASHRAE acceptability limit with a greater majority of them voting comfortable at the temperature range between 26-28oC. The result of the comparison of the Predicted Mean Votes (PMV) and the Actual Mean Votes (AMV) found that the PMV overpredicted the students’ thermal sensation and underestimated the neutral temperature by 3.5K. The result further suggests that the schoolchildren in the warm and humid climate in Nigeria can tolerate high temperatures in naturally ventilated classrooms. Another important finding is that though the children generally preferred a cooler indoor environment, it was not all the time that they preferred a cooler environment. Furthermore, the comparison of the thermal perception of the schoolchildren with that of their teachers suggests that their teachers perceived the indoor classroom warmer than their students feel and are more sensitive to temperature changes than their students. The paper concludes that schoolchildren can accept high indoor temperatures and still become comfortable and may not need air-conditioning systems. This creates an opportunity for potential energy savings in primary schools in a warm and humid environment. The findings from this work are important information for researchers in the built environment, service engineers, and architects, and may help to discourage high energy use in Heating, Ventilation, and Air-conditioning (HVAC) systems in primary schools in the warm and humid climate in Nigeria. The study recommends extending future work to private schools and other schools in other climatic regions in Nigeria for comprehensive information about the comfort perception of primary schoolchildre

Determining the diurnal variation in comfort temperature in school buildings in the warm and humid climate

Purpose The paper aims to determine the thermal comfort perception of schoolchildren from a warm and humid environment. There is a concern about the effect of high temperature on the health and academic performance of schoolchildren. Design/methodology/approach Objective and subjective methodological approaches were adopted to collect data during the fieldwork in the selected primary schools. ASHRAE adaptive comfort model was adopted to analyze the data. Findings The paper provided empirical results about the comfort requirements of schoolchildren from the warm and humid environment. During the occupied school time, the studied schoolchildren were found to tolerate temperatures higher than the upper limit temperature recommended by ASHRAE Standard 55. The paper recommends that the studied children may not need any active ventilator to be thermally comfortable during the occupied school hours Originality/value The paper found the range of temperatures that schoolchildren from the warm and humid environment can adapt to. The information may be useful to architects, engineers and facility manager