120,869 research outputs found

    Thermal comfort in residential buildings with water based heating systems: a tool for selecting appropriate heat emitters when using 碌-cogeneration

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    As a consequence of people becoming more aware of their impact on the environment, there is an increasing demand for low energy buildings. Forced by regulation, building envelopes are improving and heating and cooling systems with higher efficiencies are being installed. The public are willing to embrace these new technologies, as long as they do not affect the quality of their indoor environment. In this paper, an introduction to research on the realisation of the indoor thermal comfort in residential buildings with water based, low-energy heating systems is given. The basis for this work is a more realistic definition of comfort temperatures for residential buildings. Subsequently, appropriate heat emitters to realise that thermal comfort in an efficient way are identified, taking into account the limitations of the production system under consideration. An example of a 碌-cogeneration system is presented as a case study

    Influence of Adaptive Comfort Models in Execution Cost Improvements for Housing Thermal Environment in Concepci贸n, Chile

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    Most of the operational energy needed by the housing sector is used to compensate energy losses or thermal gains through the building鈥檚 envelope. As a result, any improvement in the thermal behavior will provide important opportunities to reduce energy consumption. This research analyzes improvements in the thermal envelope in social housing in the Greater Concepci贸n area in Chile using adaptive thermal comfort models and thermal insulation investments. The objective set out is to evaluate the economic reduction of thermal envelope improvement costs for dwellings, which entails using the adaptive thermal comfort model obtained through monitoring and the surveys applied to the users of social housing in Concepci贸n (CAS), against the international adaptive thermal comfort models established by the EN 15251:2007 and ASHRAE 55-2017 standards. Finally, it is concluded that, on having applied the social housing adaptive thermal comfort model (CAS), execution costs are reduced by between 28.8% and 58.2%, reaching a time of comfort in free oscillation similar to that obtained from applying the models of the EN 15251:2007 (74.2%) and ASHRAE 55-2017 standards (59.9%)CONICYT FONDECYT 3160806VI PPIT-U

    The role of a building鈥檚 thermal properties on pupils鈥 thermal comfort in junior school classrooms as determined in field studies

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    Recent thermal comfort research in a light-weight junior school building showed that children were more sensitive to higher temperatures than adults and subsequently that current thermal comfort standards were not appropriate for the assessment of their thermal environment. This paper presents a comparison of these survey results to those from a survey conducted in a medium-weight school building, in order to evaluate the role of the construction type on the results. Both surveys followed the same methodology, including thermal comfort questionnaires and measurements of indoor environmental variables. A total of 2990 responses were gathered. The buildings had an average difference in air temperature of 2.7oC during occupied hours in the period of investigation (June and July 2012), with the medium-weight building being cooler than the light-weight building. However, the different construction type and the cooler overall thermal environment in the medium-weight school building had little impact on the pupils鈥 overall thermal sensitivity. The comparison showed a general agreement on the pupils鈥 warm thermal sensation trends, interpersonal variation and undeveloped adaptive behaviour. The results further support the finding that current thermal comfort criteria lead to an underestimation of pupils鈥 thermal sensation during summer

    Thermal Perception in Mild Climate: Adaptive Thermal Models for Schools

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    A comprehensive assessment of indoor environmental conditions is performed on a representative sample of classrooms in schools across southern Spain (Mediterranean climate) to evaluate the thermal comfort level, thermal perception and preference, and the relationship with HVAC systems, with a comparison of seasons and personal clothing. Almost fifty classrooms were studied and around one thousand pool-surveys distributed among their occupants, aged 12 to 17. These measurements were performed during spring, autumn, and winter, considered the most representative periods of use for schools. A new proposed protocol has been developed for the collection and subsequent analysis of data, applying thermal comfort indicators and using the most frequent predictive models, rational (RTC) and adaptive (ATC), for comparison. Cooling is not provided in any of the rooms and natural ventilation is found in most of the spaces during midseasons. Despite the existence of a general heating service in almost all classrooms in the cold period, the use of mechanical ventilation is limited. Heating did not usually provide standard set-point temperatures. However, this did not lead to widespread complaints, as occupants perceive the thermal environment as neutral鈥攙arying greatly between users鈥攁nd show a preference for slightly colder environments. Comparison of these thermal comfort votes and the thermal comfort indicators used showed a better fit of thermal preference over thermal sensation and more reliable results when using regional ATC indicators than the ASHRAE adaptive model. This highlights the significance of inhabitants鈥 actual thermal perception. These findings provide useful insight for a more accurate design of this type of building, as well as a suitable tool for the improvement of existing spaces, improving the conditions for both comfort and wellbeing in these spaces, as well as providing a better fit of energy use for actual comfort conditions

    Thermal comfort guidelines for production spaces within multi-storey garment factories located in Bangladesh

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    This research presents extensive field data on indoor thermal conditions along with workers' comfort votes taken at their workstations within three existing multi-storied garment factories during the three seasons (cool-dry, hot-dry and warm-humid) of Bangladesh. The main objective of the study was to observe the impact of thermal conditions on workers鈥 indoor thermal perception during each season of a year and from this identify thermal comfort guidelines (e.g. neutral temperatures, comfort ranges, preferred airspeeds and directions) to execute their production work comfortably. Subjective votes were collected from a total of 908 workers with the thermal data, physiological data and adaptive measures recorded simultaneously. Statistical analyses revealed that workers can accept a wider and relatively higher comfort range than the predicted band during cool-dry and hot-dry seasons, for instance, 22.7鈥29.1鈥癈 and 22.3鈥30.4鈥癈 respectively. A narrower comfort band (e.g. 28.7鈥30.9鈥癈), close to the predicted range, was found during the warm-humid season, which can be maintained by reducing radiant temperature and elevating airspeed. Further analyses indicated that workers prefer a mean airspeed of 0.3鈥痬/s and comfort range of 0鈥3.0鈥痬/s specific to their activities preferably from inlets located on south, north and east facades while upward and downward air movement, from for example ceiling fans, causes a rise of air temperature in the occupational zone and thermal discomfort. This research also suggested that the maximum distances of workstations from the ventilation inlets (windows) should be maintained at 12鈥18鈥痬 for sufficient cross ventilation, personal controls and adaptive opportunities to help maintain preferred thermal condition
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