Adaptive Comfort Equation Research Articles

Assessment of vulnerability to overheating at a regional scale through parametric simulation models and cooling degree-days analysis: The case of southern Spanish social housing stock

The urgent need to adapt urban environments to extreme weather conditions due to global warming has become a priority when allocating European funds. Current regional retrofitting plans focus on improving the well-being of the most vulnerable families by upgrading their homes. However, as there is no adequate characterization of the environmental behaviour of housing stock, local agents in charge of the management of social housing lack a procedure to identify the urban areas most urgently in need of retrofitting.This research aims to present a protocol for evaluating the vulnerability to overheating of social housing stock at a regional scale, as a prioritization decision support system. Parametric techniques for Building Stock Modelling were used in the development of 3000 models located in four climatic zones of southern Spain to assess their thermal behaviour considering adaptive comfort equations. Moreover, an index of vulnerability to overheating has been defined by normalizing comfort assessment through cooling degree-days. The comfort assessment outcome corresponds more closely with the analysis of cooling degree-days than with the Spanish regulations’ climatic zoning. According to the results, in the hottest climatic zone, occupants frequently endure discomfort up to 40% of the summertime, with hourly deviations of up to 7 °C above the indoor temperature comfort range.

Adaptive thermal comfort of residential buildings in the composite climatic region of India: a field study

ABSTRACT This paper presents the results of an adaptive thermal comfort field study conducted in the naturally ventilated residential buildings in the composite climate type of India over three main seasons i.e. monsoon, winter, and summer using ASHRAE’s class II field measurements protocols. 768 measurements were collated wherein subjective thermal comfort sensation, preference, and acceptance for indoor environment variables were thoroughly explored along with the adaptive actions of the users for four different times during a day. Correlation analysis helped decipher the relationship between subjective votes and thermal comfort evaluation parameters. Thermal environment acceptance during monsoon season and morning time was highest however the same was found lower during summers and afternoons. The middle age group had the lowest acceptance and well-acclimatized non-native participants had a good thermal acceptance. Education also affects thermal acceptance and it decreases with increasing education level. The comfort temperature and adaptive comfort equation were also studied and results were compared with national and international thermal comfort standards. This study predicted a wider thermal comfort range of 12.23–34.45°C and indicated revising TSI, the first thermal comfort index for Indian Subjects.

A Review on Adaptive Thermal Comfort of Office Building for Energy-Saving Building Design

The thermal environment quality of office buildings has an important role because thermal comfort is directly related to human productivity. Thermal comfort conditions are influenced by climate, location, and the built environment; hence, comfort standards are required to assist building designers in creating a comfortable indoor environment for building occupants. In this context, the present study analyzes the adaptive thermal comfort studies conducted in office buildings from various countries. A large number of research articles selected from the Scopus database were considered for this study. Based on the analysis, outdoor climatic conditions have a greater influence on indoor thermal conditions in naturally ventilated than in air-conditioned office buildings. The temperature required for comfort is as low as 17.6 °C and as high as 31.2 °C in naturally ventilated buildings. An adaptive comfort equation for naturally ventilated and air-conditioned office buildings has also been proposed to predict the indoor comfort temperature. Various studies show that a substantial amount of energy can be saved by changing the set point and natural ventilation. Furthermore, this study successfully provides hearty evidence that there is a need for climate-specific standards on thermal comfort for energy-efficient design development because existing comfort standards might not be applicable to all climates.

An adaptive thermal comfort model for naturally ventilated classrooms of technical institutions in Madurai

PurposeOccupants dwelling in hot climatic regions of India for a longer term are tolerable to high temperature levels than predicted by American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) standards. The purpose of this study is to evaluate the thermal sensations (TS) and neutral temperature of the occupants in naturally ventilated (NV) and air-conditioned (AC) classrooms of two technical institutions located in the same premises in the suburbs of Madurai. The main focus of this study is to understand the occupants’ behaviour in response to the thermal conditions of the educational buildings particularly in the warm and humid climatic zone of Madurai.Design/methodology/approachThis research collected data through field studies. The data included 383 survey questionnaires from NV classrooms and 285 from AC classrooms, as well as on-site measurements of interior and exterior weather conditions. The TS results show that the students preferred well-designed NV classrooms than AC classrooms. A new adaptive comfort equation derived from this study can be applied to NV classrooms in warm and humid climates where mean outdoor temperature exceeds 40°C.FindingsThe neutral temperature derived for NV classrooms in Madurai ranged from 29°C to 34°C. Thus, the occupants in the NV classrooms of the higher learning educational institutions in the warm and humid climatic region of Madurai can adapt well to higher indoor temperature levels than predicted by ASHRAE comfort levels with minimum adjustments.Research limitations/implicationsThe study was limited to only occupants in two premier higher learning technical educational institutions located in Madurai region within 5–10 km within the city limits to understand the implications of microclimate with respect to the urban context. Thus, further research is required to examine the tendency under local conditions in other regions beyond those applied to this study.Social implicationsThe findings of this study showed that occupants in higher learning educational intuitions in Madurai prefer NV classrooms than AC classrooms. Therefore, with rising demands of energy use for mechanical ventilation and the associated high cost for running AC buildings, architects should prioritize the design of energy efficient buildings through the optimal use of passive design strategies for ventilation and thermal comfort. This study gives a base data for architects to understand the adaptive limitations of occupants and design NV buildings that can promote natural ventilation and provide better thermal environments that can help increase the productivity of students.Originality/valueThis paper was an attempt to develop the adaptive comfort model for NV classrooms in Madurai regions. There has been no attempt to identify the adaptive comfort levels of occupants in higher learning technical educational institutions located in warm and humid climatic region of India.

The degree of adaptive thermal comfort in office workers in a hot-summer Mediterranean climate

This study aims to investigate occupants’ perception of feeling comfortable over different seasons in offices located in Amman, Jordan, to determine the comfort temperature zones, and to compare the results developed from this study with other adaptive models and standards. It is based on longitudinal field surveys, which were conducted in three office buildings, two mixed mode buildings and a free running building, during four seasons: April 2016 (spring), July/August 2016 (summer), October 2016 (autumn) and January/February 2017 (winter). A total of 119 occupants participated in the thermal comfort surveys and completed 659 questionnaires. The free running building experienced a variation in operative temperature during the four seasons, while median temperatures in the mixed-mode buildings stayed almost the same during all seasons. Occupants felt comfortable in a broad range of thermal sensations from ‘cool’ to ‘warm’. Thermal comfort was expressed by a high proportion of the occupants. Occupants changed their clothing insulation with season, whereby compared to winter some occupants showed a changed clothing insulation already in the spring survey and others only in the summer and autumn survey. A Loess analysis between the temperatures at which the occupants felt comfortable and the running mean outdoor temperature indicated independency between the two variables in case of the mixed-mode buildings at running mean outdoor temperatures below 22 °C, but a trend towards decreasing comfort temperature above 22 °C. The comfort temperature in both mixed mode buildings was around 23.5 °C. In the free running building, a monotonically increasing linear relation between the two variables was found at running mean outdoor temperatures below appr. 24 °C, but a constant comfort temperature of about 26 °C above this value. Compared to the adaptive comfort models in ASHRAE Standard 55 and EN 15251 the gradient in the adaptive comfort equation resulting from the free running building in Amman was higher. Although the occupants adjusted their clothing insulation level, the gradient in the comfort equation was close to zero in the mixed mode buildings.

Adaptive approach-based assessment of a heritage residential complex in southern Spain for improving comfort and energy efficiency through passive strategies: A study based on a monitored flat

The energy retrofitting of residential stock is not always straightforward where heritage protected housing is concerned. In southern Europe, many examples built under the Modern Movement codes are now obsolete in terms of energy efficiency. The aim of this paper is to assess the potential for improvement of comfort conditions and energy efficiency in Mediterranean heritage residential buildings, through the incorporation of passive strategies in keeping with preserving heritage values. Long-term monitoring and field tests in representative flats of the case-study building were carried out and, focusing on a single example, adaptive comfort equations were used to assess results. The passive strategies considered are the thermal isolation of the air cavities of walls, changing window frames, optimizing window glazing, and setting up regular mechanical ventilation rates for indoor air changes. Although simulation results generally predict a better energy performance after testing retrofit strategies, the potential decrease in energy demand is more noticeable than the potential improvement in comfort conditions.

First adaptive thermal comfort equation for naturally ventilated buildings in Bucharest, Romania

ABSTRACTNational and international adaptive thermal comfort (ATC) standards gain now wider acceptance. These standards propose adaptive comfort equations derived from specific databases. New ATC equations are developed worldwide, under different latitudes and climates. A field survey has been performed in 2013–2014 in six naturally ventilated buildings located in Bucharest (Romania, Köppen type D - temperate continental climate). Comfort parameters were measured and comfort questionnaires were distributed. Using the theory of ASHRAE 55 Standard an ATC equation specific to Romanian climate has been proposed for the first time. Also, the 80% and 90% acceptability bands were determined in this situation. The new ATC equation has been compared with other ATC equations found in literature for similar climates. New thermal comfort investigations have been performed one year later after the first survey, new comfort investigations were performed. The ATC equation has been checked and good agreement has been found.

Investigating the principal adaptive comfort relationships for young children

Thermal comfort surveys in school classrooms suggest that children have different thermal preferences to adults. This implies a need to revisit the current adult-based thermal comfort models. This paper investigates the principal adaptive comfort relationships that form the basis of adaptive comfort theory, using 2693 pupil thermal sensation responses and measured classroom temperatures from surveys in two naturally ventilated school buildings. The data were examined in two steps. Firstly, each survey set, obtained over one-day visits to the schools, was examined in order to derive the relationship between indoor temperature change and comfort vote with minimum impact of adaptation. Secondly, the data set was investigated over the entire survey period in relation to the weather experienced by the pupils in order to estimate their time for adaptation to outdoor temperature changes. The analysis shows that the basic adaptive comfort relationships are valid for children. However, a difference was found for the correlation coefficients of the comfort temperature to the outdoor running mean temperature between the schools, and a mismatch between their adaptive comfort equations. It is proposed that the difference in the consistency of the weather during the tests is the main reason for this discrepancy.

An adaptive thermal comfort model for the tropical climatic regions of India (Köppen climate type A)

Adaptive comfort standards have been gaining wider acceptance and are now considered an integral part of main stream comfort research. Several adaptive comfort equations have been developed, some as part of international comfort standards and some for specific climatic regions. In the current work, an attempt was made to find a best fit among available comfort equations for predicting occupant comfort in the tropical climatic regions of India. Comfort temperatures found in surveys done across tropical India were compared to comfort temperatures computed from five different adaptive comfort equations. Additionally, to estimate energy savings possible through implementation of adaptive comfort standards, adaptive comfort degree days (ACDD) were calculated across seven Indian cities using comfort temperature predictions from the five equations. Put together, results from these two analyses showed that the comfort equation from EN15251 may be used as a reasonable predictor of comfort in naturally ventilated buildings of hot–humid Indian regions and such use would also result in major energy savings. It is proposed that till further studies in India provide more detailed results, the EN15251's standard for naturally ventilated buildings may be used as a suitable option for Indian conditions. Formalisation of appropriate adaptive comfort standards for India would be a significant asset to the sustainable development of this country.

Thermal comfort in undergraduate laboratories — A field study in Kharagpur, India

A thermal comfort field survey is carried out inside a naturally ventilated laboratory in the tropical climatic region of India. The building chosen is used for courses in an undergraduate engineering curriculum. We aimed at assessing how the occupants perceive their thermal environment in a free running building while carrying out their normally scheduled tasks. A total of 121 acclimatized subjects were interviewed and 338 responses were collected during the months of spring semester. Survey results show a strong correlation between indoor comfort conditions and outdoor temperature. Occupants show adaptability across a comfort zone that is well beyond recommendations of rational models. Overall, 78% of the responses found their thermal environment to be acceptable. Based on indoor temperature observations, we calculate comfort temperatures for the subjects using Griffiths' method. The comfort temperature values are then related with prevailing mean outdoor air temperature to give an adaptive comfort equation. Predictions from our equation show satisfactory to good agreement with the predictions from similar equations in comfort standards.

An adaptive thermal comfort model for hot humid South-East Asia

The present paper presents a full procedure to develop an adaptive comfort model for South-East Asia. Meta-analysis on large number of observations from field surveys which were conducted in this region was employed. Standardization and bias control of the database were fully reported. Statistical tests of significance and weighted regression method applied in the analyses strengthened the reliability of the findings. This paper found a great influence of ‘Griffiths constant’ on the establishment of adaptive comfort equation and proposed an appropriate value. The adaptive comfort model generated is applicable to naturally ventilated building under hot and humid conditions of South-East Asia. The mean neutral comfort temperature (operative temperature, effective temperature, standard effective temperature) in naturally ventilated and air-conditioned building was compared and the differences have been discussed. The similar neutral standard effective temperature in both naturally ventilated and air-conditioned building proposes a new idea to implement SET* into building simulation tools to assess thermal comfort without the attention of building classification.Through the analysis, the effectiveness of behavioral adaptive actions on occupant's thermal perception has been argued. The extended PMV-PPD model for hot humid conditions was examined and its applicability was recommended. Other comfort-related issues, the differences and similarities between various adaptive comfort models were also addressed.