1,721,035 research outputs found
Overheating in vulnerable and non-vulnerable households
No full textTemperatures of living rooms, kitchens and bedrooms of 55 dwellings in Exeter (UK) were monitored during the summers of 2014 and 2015. Additionally, radiator temperatures and CO2 levels were also monitored. Occupant thermal comfort was investigated through a paper-based questionnaires at the end of summer 2014 and telephone interviews during summer 2015
The effects of thermal mass and air-conditioning on summer temperature thermal comfort and occupant behaviour in homes
Full text linkThe data collected during the longitudinal monitoring and survey campaign of the indoor environment, thermal comfort and occupant adaptive behavior during the summer season in Italian residential settings (Csa climate, Catania city). The campaign was completed in the period between 07/06/2019 and 19/09/2019, which includes the five heat health warnings and two heatwaves that occurred in the summer of 2019 in Catania, Italy.
The data collected and deposited here was used for the PhD thesis of Elisabetta Maria Patane': The effects of thermal mass and air-conditioning on summer temperature thermal comfort and occupant behaviour in homes.Longitudinal monitoring for air temperature, relative humidity, occupancy, and window and air-conditioning usage were employed. In addition, spot measurements were used to record air temperature, globe temperature, air velocity and relative humidity used for the thermal comfort analysis. All measurements were completed in the period between 07/06/2019 and 19/09/2019. The indoor dry bulb temperature (Ta, °C) and relative humidity (RH, %) were measured every 20 minutes with IButtons sensors. The sensors were placed in at least one living room and bedroom per flat and for households with high number of occupants, additional rooms were included such as a second or third bedrooms a dining, living and studio rooms. The air conditioning outlet temperature was recorded by IButton sensor, sampling every 20 minutes. Two units were targeted per home, one in the living-room or kitchen and the other one in the bedroom if available. It was placed on the horizontal louvre of the unit. The occupancy was recorded in 12 homes via HC-SR501 PIR infrared motion sensors, sampling each 5 seconds. The window opening state was recorded in 24 windows in 12 flats, for 6 days each, from the 25/08/2019 to the 19/09/2019. 8 state sensors of the HOBO UX90-001 type were employed. The state sensors were installed on openings that 62 inhabitants used most often when ventilating the dwelling. In order to monitor as many windows as possible, the 8 sensors were moved every 7 days from one flat to another one. The preferred windows were those in living or dining rooms and bedrooms.
The spot measurements were carried out with 8 heat stress meters; Extech HT30 and HT200 models; and the Testo 0560 4053 Stick Thermo-anemometer. The measurements were taken from 15 to 25 minutes while the occupants filled out the questionnaire in the room. The heat-stress meters were provided to eight families to undertake the measurements by themselves. The questionnaire included the protocol of measurements translated in Italian on the first page.
Thermal comfort and occupant behavior were monitored with a questionnaire administrated by the researcher. The procedure for this consisted of each occupant filling in the questions in a short time frame. All the questions were designed to be completed in 5 minutes in order to reduce the risk of participants leaving the study because of fatigue. The total number of questions is twenty-three, they are divided according to: contextual variables, thermal comfort votes, windows, shading and air-conditioning usage, spot measurements of indoor air temperature, relative humidity, mean radiant temperature and air velocity.
All instruments and measurements protocol were carried out in agreement with the following standards: UNI EN ISO 7726:2001, UNI EN ISO 7730:2005. The thermal comfort survey are based on the 7-point scale thermal sensation votes, 5-points of thermal preference, 2-points of thermal acceptability in ASHRAE 55-2020UNI and EN ISO 16798:2019.The first step was to create one file for each room; therefore, the different time-series files were concatenated according to the datetime index and the type of data. The second step was to find the outliers in the temperature datasets by checking the maximum and minimum values in each room.
Then, two datasets for indoor room environmental conditions were created, one with a sub-hourly time-step which is used to record the state of air-conditioning, and another one with an hourly time-step which was created by resampling the readings and taking the mean of the values.
The air-conditioning unit time-series were further manipulated in order to assign the “state” of the machine: switched on (1) or off (0). The difference between two consecutives sub-hourly outlet temperature readings was computed. It was assumed that if the difference was more than ± 5 °C, the air-conditioning was switched on or off. Whenever available, the self-reported data was also used to validate the air-conditioning status. The window state and the occupancy recordings were reported as collection of timestamps of the new position and occupant movement. The final data-set was generated for each variable by concatenating each room as a column and using the same time-series.
The answers to the thermal comfort section of the questionnaire were translated into categorical variables according to the ANSI/ASHRAE Standard 55-2020. The metabolic rate (MET) and clothing insulation values (Icl) were estimated using the “Table 5.2.1.2 Metabolic Rates for Typical Tasks” and “Table 5.2.2.2.A - Clothing Insulation Icl Values for Typical Ensembles” in the ASHRAE 55 standard. The position of the window and shadings is either open or closed, and the status of the air-conditioning unit is switched on or off. The open and on cases are recorded as 1 in the excel sheet and closed or off as 0. The duration is expressed as the number of hours and minutes since the last state or position change of the system. This information was recorded as it was in the excel sheet. It is important to stress that the questionnaires reported local time reference. The precision of the self-reported duration of the state was assumed to be higher whenever the reference was less than 24 hours; in other cases, it was created a single category for duration which specifies a minimum of a day of duration of the current state. The “trigger” or “driver” is the reason behind the occupant choice for the concurrent position or state of the window, blind and AC systems. This is an open ended question because the answer could involve any number of factors, or unforeseen events can occur
Derivation and validation of a whole-body dynamic mean thermal sensation model
Full text linkA new model predicting the whole-body Dynamic Mean thermal sensation Vote (DMV) is described. The model is useful for evaluating transient thermal conditions but is limited to uniform ones. It is based on physiological signals (mean skin temperature and its rate of change, mean skin wittedness, and core body temperature) simulated by using Gagge's two-node thermophysiological model. It is derived from empirical data obtained through experiments conducted under 160 steady-state thermal exposures at rest, 60 transient thermal conditions at rest, and 24 static thermal conditions during exercise. An independent validation is performed against 13 transient thermal conditions during exercise. The model shows good agreement (RMSE less than 0.5) with experimental observations within the range of air temperatures between 15 and 37 °C and when activity levels are below 3 met. It performs better than the widely used Fanger's PMV model, especially when far from thermal neutrality, for step-change thermal transients, and under exercise conditions. Furthermore, the model's simplicity and low computational cost are important advantages over more complex and computationally expensive thermal sensation models based on multi-segment and multi-node thermophysiological models
A review of factors affecting environmental and economic life-cycle performance for electrically-driven heat pumps
Full text linkSpace heating and cooling together with sanitary hot water supply have a significant share, approximately 50 %, of the global energy consumption of buildings. In order to fulfil energy and energy-efficiency building requirements, European and national legislations encourage the use of more sustainable heating and cooling options. A sustainable dimension implies that both environmental and economic aspects are taken into account; the life-cycle comparisons of different heating and cooling systems are therefore based on GHG emissions and costs. This work focuses only on the economic side of the life-cycle analyses (therefore excluding the environmental dimension) and presents a review of life-cycle cost (LCC) studies involving HP systems. The first objective is to present an overview of the most influential factors characterizing life-cycle cost methodologies for HP systems and to suggest methodological improvements which can make LCC analyses more robust. The second objective is to present an overview of factors influencing both the economic and the environmental success of HP systems. A greater awareness and understanding of these factors can, at a macro-level, increase confidence in HP systems so that governments can identify appropriate actions and develop legislation that provide support for HPs implementation.JRC.F.6 - Energy Technology Policy Outloo
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Ten questions concerning the usage of subjective assessment scales in research on indoor environmental quality
No full textThe usage of scales to assess subjective ratings related to indoor environmental quality (IEQ) is ubiquitous in
built-environmental research. Despite their importance, research and discussions on the scales themselves are
scarce and the number of variations in the field is huge, which is reducing the potential for cumulative research.
Motivated by the increasing interdisciplinary exposures of the authors, this 10 questions-paper addresses ten key
issues related to the current and potential future usage of subjective rating scales in built environment research.
These issues are particularly relevant in the context of multi-domain research, where an increasing number of
papers have revealed differences between IEQ-domains like thermal and visual aspects. The first question sets the
basis for the following discussion by giving a brief summary of the history of scales’ development. Questions 2 to
6 start with addressing specific challenges related to language and multi-domain applications and then broaden
the scope to more general issues like the type and variation of scales and potential biases through their application.
The third block of questions (Questions 7 and 8) discusses alternatives to scales like physiological signals
and observing behavioural reactions. With the last two questions we ask ourselves and the community to what
extend a fit-for-purpose approach to the use of scales would be beneficial, and what steps could lead to improving
the use of scales in the future. We conclude by acknowledging the central role of questionnaires in advancing
knowledge about IEQ and support their continued use with increased reliability and interpretability
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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