Subjective Evaluation of Thermal Comfort Using an Air Recirculation Device

1983 ◽  
Vol 27 (8) ◽  
pp. 751-756
Author(s):  
David A. VanDyke ◽  
Frederick H. Rohles ◽  
Michael P. Webster
Keyword(s):  
Thermal Comfort ◽  
Energy Demand ◽  
Energy Savings ◽  
Rating Scale ◽  
Thermal Sensation ◽  
Subjective Evaluation ◽  
Comfort Level ◽  
National Bureau ◽  
Environmental Laboratory ◽  
Fan Speed

To determine the effectiveness of a small fan in enhancing thermal comfort in an open office, eight subjects were studied at 24.4 C (76F), 26.1 C (79F), and 27.8 C (82F) (all at 50% RH), in an environmental laboratory where each workstation was equipped with a small variable speed fan. Control trials were run at all three temperatures without the use of the fan. Three subjective responses were measured: thermal sensation (a nine category rating scale), thermal comfort (a seven pair semantic differential scale), and temperature preference. During fan tests, subjects were allowed to adjust the fan speed to their preference at 15 minute intervals. Results showed that use of the fan could allow a 3°F temperature increase while maintaining the same comfort level, or increase comfort at temperatures of 79°F and up. The 3°F increase in temperature would result in a 9% energy savings, based on the National Bureau of Standards suggestion of a reduction in air conditioning energy demand of 6% per °C or 3% per °F. The study also shows that users prefer a fan that is adjustable in speed and placement.

Enhancing Thermal Comfort with Ceiling Fans

1982 ◽  
Vol 26 (2) ◽  
pp. 118-120 ◽  
Author(s):  
Frederick H. Rohles ◽  
Stephan A. Konz ◽  
Byron W. Jones
Keyword(s):  
Thermal Comfort ◽  
Energy Demand ◽  
Air Conditioning ◽  
Energy Savings ◽  
Rating Scale ◽  
Thermal Sensation ◽  
National Bureau ◽  
Category Rating ◽  
Temperature Preference ◽  
Subjective Responses

To determine the effectiveness of ceiling fans in enhancing comfort, 256 subjects were examined at 24.4 C (76 F), 26.1 C (79 F), 27.8 C (82 F), and 29.4 C (85 F) (all at 50% rh), in an environmental chamber that was equipped with a ceiling fan that produced four velocity conditions: 0.15 m/s (30 fpm), 0.25 m/s (50 fpm), 0.46 m/s (90 fpm), and 1.02 m/s (200 fpm). A fifth velocity, in which the fan was not employed, was 0.06 m/s (10 fpm); this served as the control velocity. Three subjective responses were measured: thermal sensation (a 9-category rating scale), thermal comfort (a 7-pair semantic differential scale), and a question on temperature preference. The results showed that an air plume from a ceiling fan whose velocity is between 0.5 and 1.0 m/s (90 and 200 fpm) compensates for a 2.8–3.3°C (5–6°F) temperature change; this represents an energy savings of 15–18% when based on the National Bureau of Standards' suggestion of a reduction in air conditioning energy demand of 6% per °C or 3% per °F. It also concluded that a ceiling fan may extend the upper limit of the summer comfort envelope from 26.1 to 29.4 C (79 to 85 F) and that the turbulent and variable characteristics of the air plume of the ceiling fan may be its major comfort-producing attribute.

scholarly journals Predicted Medium Vote Thermal Comfort Analysis Applying Energy Simulations with Phase Change Materials for Very Hot-Humid Climates in Social Housing in Ecuador

2021 ◽  
Vol 13 (3) ◽  
pp. 1257
Author(s):  
Luis Godoy-Vaca ◽  
E. Catalina Vallejo-Coral ◽  
Javier Martínez-Gómez ◽  
Marco Orozco ◽  
Geovanna Villacreses
Keyword(s):  
Thermal Comfort ◽  
Phase Change ◽  
Social Housing ◽  
Energy Demand ◽  
Phase Change Materials ◽  
Thermal Sensation ◽  
Electricity Consumption ◽  
Different Types ◽  
Climate Influences ◽  
Energy Simulations

This work aims to estimate the expected hours of Predicted Medium Vote (PMV) thermal comfort in Ecuadorian social housing houses applying energy simulations with Phase Change Materials (PCMs) for very hot-humid climates. First, a novel methodology for characterizing three different types of social housing is presented based on a space-time analysis of the electricity consumption in a residential complex. Next, the increase in energy demand under climate influences is analyzed. Moreover, with the goal of enlarging the time of thermal comfort inside the houses, the most suitable PCM for them is determined. This paper includes both simulations and comparisons of thermal behavior by means of the PMV methodology of four types of PCMs selected. From the performed energy simulations, the results show that changing the deck and using RT25-RT30 in walls, it is possible to increase the duration of thermal comfort in at least one of the three analyzed houses. The applied PCM showed 46% of comfortable hours and a reduction of 937 h in which the thermal sensation varies from “very hot” to “hot”. Additionally, the usage time of air conditioning decreases, assuring the thermal comfort for the inhabitants during a higher number of hours per day.

scholarly journals Determination of Optimum Envelope of Religious Buildings in Terms of Thermal Comfort and Energy Consumption: Mosque Cases

Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6597
Author(s):  
Ahmet Bircan Atmaca ◽  
Gülay Zorer Gedik ◽  
Andreas Wagner
Keyword(s):  
Thermal Properties ◽  
Energy Consumption ◽  
Thermal Comfort ◽  
Thermal Insulation ◽  
Energy Savings ◽  
Gain Factor ◽  
Building Envelope ◽  
Comfort Level ◽  
Humid Climate ◽  
Savings Rate

Mosques are quite different from other building types in terms of occupant type and usage schedule. For this reason, they should be evaluated differently from other building types in terms of thermal comfort and energy consumption. It is difficult and probably not even necessary to create homogeneous thermal comfort in mosques’ entire usage area, which has large volumes and various areas for different activities. Nevertheless, energy consumption should be at a minimum level. In order to ensure that mosques are minimally affected by outdoor climatic changes, the improvement of the properties of the building envelope should have the highest priority. These optimal properties of the building envelope have to be in line with thermal comfort in mosques. The proposed method will be a guide for designers and occupants in the design process of new mosques or the use of existing mosques. The effect of the thermal properties of the building envelope on energy consumption was investigated to ensure optimum energy consumption together with an acceptable thermal comfort level. For this purpose, a parametric simulation study of the mosques was conducted by varying optical and thermal properties of the building envelope for a temperature humid climate zone. The simulation results were analyzed and evaluated according to current standards, and an appropriate envelope was determined. The results show that thermal insulation improvements in the roof dome of buildings with a large volume contributed more to energy savings than in walls and foundations. The use of double or triple glazing in transparent areas is an issue that should be considered together with the solar energy gain factor. Additionally, an increasing thickness of thermal insulation in the building envelope contributed positively to energy savings. However, the energy savings rate decreased after a certain thickness. The proposed building envelope achieved a 33% energy savings compared to the base scenario.

scholarly journals Optimization of Design Parameters for Office Buildings with Climatic Adaptability Based on Energy Demand and Thermal Comfort

2020 ◽  
Vol 12 (9) ◽  
pp. 3540 ◽  
Author(s):  
Yuang Guo ◽  
Dewancker Bart
Keyword(s):  
Thermal Comfort ◽  
Energy Demand ◽  
Climate Adaptation ◽  
Building Energy ◽  
Comfort Level ◽  
Energy Utilization ◽  
Design Parameters ◽  
Building Energy Efficiency ◽  
Cold Zone ◽  
Climatic Adaptability

According to a Chinese building energy demand report of 2016, building consumption is accelerating at a spectacular rate, especially for urban public buildings. In this study, various design parameters that meet the principle of climate adaptation are proposed to achieve the unity of energy utilization and indoor thermal comfort level. According to the local energy conservation codes, five typical benchmark geometric models were established in Open Studio (Sketch-Up plug-in) for sites representative of various climates, meanwhile, adopting the engine of Energy Plus (EP-Launch) to calculate the instrument definition file (IDF), respectively, for assessing the coupling relationship between energy consumption as well as thermal comfort. Results implied that based on the time proportion (8760 h) that met the level 1 comfort range, total energy reductions of different Chinese climate regions were different. Among them, the severe cold zone (SCZ—Changchun) and hot summer and cold winter zone (HSCW—Shanghai) appeared to have the greatest energy saving potential with 18–24% and 16–19%, respectively, while the cold zone (CZ—Beijing) and mild zone (MZ—Kunming) approximately equaled 15% and 12–15%, and the saving space of the hot summer and warm winter zone (HSWW—Haikou) appeared relatively low, only around 5–7%. Although the simulation results may be limited by the number of parameter settings, the main ones are under consideration seriously, which is further indication that there is still much room for appropriate improvements in the local public building energy efficiency codes.

scholarly journals Evaluation of Thermal Comfort in the Traditional Bourgeoisie Houses in Beirut

2020 ◽  
Vol 3 (1) ◽  
pp. p1
Author(s):  
Jad Hammoud ◽  
Elise Abi Rached
Keyword(s):  
Thermal Comfort ◽  
Natural Ventilation ◽  
Heat Waves ◽  
Thermal Environment ◽  
Thermal Sensation ◽  
Residential Buildings ◽  
Ventilation System ◽  
Electricity Consumption ◽  
Comfort Level ◽  
Climate Zones

The increasing of energy demands has considerably increased the requirements for new and traditional buildings in different climate zones. Unprecedented heat waves have increased climate temperature, in particular, in moderate climate zones such as Lebanon. In Beirut, only the residential sector consumes 50% of total electricity consumption. HVAC (Heating, Ventilation and Air conditioning) systems are used to reach acceptable thermal comfort levels in the new residential buildings. In case of the traditional bourgeoisie houses in Beirut, there are no discussions about the use of HVAC systems to achieve the required thermal comfort level. Thus, to reach an acceptable thermal comfort level, these houses which already contain natural ventilation system shall adapt the modern thermal comfort requirements and thermal comfort strategies and technologies where their architectural features and existing materials condition the available solutions. In order to identify the best options within the possible intervention lines (envelopes, passive strategies, equipment, renewable energy systems), it is necessary to perceive the real performance of this type of houses. In this context, the article presents the results of the study of thermal performance and comfort in a three case studies located in Beirut. Detailed field data records collected are analyzed, with a view to identify the indoor thermal environment with respect to outdoor thermal environment in different seasons. Monitoring also included measurement of hygrothermal parameters and surveys of occupant thermal sensation.

scholarly journals Thermal comfort, thermal sensation and skin temperature measurements using demand-controlled ventilation for individual cooling

2020 ◽  
Vol 172 ◽  
pp. 06001
Author(s):  
Håkon Solberg ◽  
Kari Thunshelle ◽  
Peter Schild
Keyword(s):  
Thermal Comfort ◽  
Skin Temperature ◽  
Energy Demand ◽  
Thermal Sensation ◽  
Air Velocity ◽  
Climate Chamber ◽  
Biometric Data ◽  
Ongoing Research ◽  
Demand Controlled Ventilation ◽  
The Relationship

An increasing part of modern building's energy demand is due to cooling. An ongoing research project investigates the possibility to reduce the energy consumption from cooling by utilizing an individually controlled active ventilation diffuser mounted in the ceiling. This study looks at thermal sensation and thermal comfort for 21 test persons exposed to an innovative user controlled active ventilation valve, in a steady and thermally uniform climate chamber. Furthermore, the relationship between biometric data from the test persons skin temperature and sweat, and the test persons thermal sensation scores has been investigated. Each test person was exposed to three different room temperatures in the climate chamber, 24°C, 26°C and 28°C respectively, to simulate typical hot summer conditions in an office in Norway. At a room temperature of 26°C it was possible to achieve acceptable thermal comfort for most test persons with this solution, but higher air velocity than 0.75 m/s around the test persons bodies at room temperatures of 28°C is required to ensure satisfactory thermal comfort.

scholarly journals Indoor Thermal Comfort of Pregnant Women in Hospital: A Case Study Evidence

2019 ◽  
Vol 11 (23) ◽  
pp. 6664 ◽  
Author(s):  
Kristian Fabbri ◽  
Jacopo Gaspari ◽  
Laura Vandi
Keyword(s):  
Thermal Comfort ◽  
Pregnant Women ◽  
Thermal Sensation ◽  
Methodological Approach ◽  
Well Being ◽  
Comfort Level ◽  
Test Bed ◽  
Adaptive Thermal Comfort ◽  
Mixed Approach ◽  
Metabolic Unit

Despite studies on thermal comfort being consolidated in the scientific literature, people’s well-being in some specific conditions and places, such as hospitals, requires to be further explored. The paper describes the methodological approach adopted to evaluate thermal comfort level and perception of pregnant women hosted in the obstetric ward of a test-bed case (Sant’Orsola hospital in Bologna, Italy). The methodology adopts a mixed approach that compares the results of on-site monitoring by probe (as quantitative data) with the ones of a survey (questionnaire form) delivered to the involved subjects (as qualitative data) to understand if metabolic alteration may influence the pregnant women’s perception of comfort conditions. The first follows ISO 7730, the second, ISO 10551. The comparison between the instrumental collected data and the outcomes of the survey revealed a wide gap between TSV (Thermal Sensation Vote) and PMVm (Predicted Mean Vote, measured on-site). The reason can be identified in the use of a standardized metabolic unit from ISO that does not correctly reflect the physiologic condition of pregnant women. Following a trial and error methodology, a met value for pregnant women is accordingly proposed. Moreover, an adaptive thermal comfort approach is adopted. This research is a first step towards the definition of specific thermal comfort in a hospital ward hosting pregnant women and more generally offers a reflection about the need to define specific met in the standards for some particular categories (children, elderly, pregnant women, etc.) when investigating thermal comfort.

Reducing Energy Demand in Commercial Buildings: Balancing Convection and Radiant Cooling

2010 ◽  
Author(s):  
Lee Chusak ◽  
Andrew Harris ◽  
Ramesh Agarwal
Keyword(s):  
Thermal Comfort ◽  
Energy Demand ◽  
Energy Savings ◽  
Ventilation System ◽  
Computational Domain ◽  
Exterior Wall ◽  
Displacement Ventilation ◽  
Comfort Levels ◽  
Isothermal Wall ◽  
Chilled Ceiling

Using Computational Fluid Dynamics (CFD) software, three different cooling systems used in contemporary office environments are modeled to compare energy consumption and thermal comfort levels. Incorporating convection and radiation technologies, full-scale models of an office room compare arrangements for (a) an all-air overhead system (mixing ventilation), (b) an all-air raised floor system (displacement ventilation), and (c) a combined air and hydronic radiant system (displacement ventilation with a chilled ceiling). The computational domain for each model consists of one isothermal wall (simulating an exterior wall of the room) and adiabatic conditions for the remaining walls, floor, and ceiling (simulating interior walls of the room). Two sets of computations were conducted. The first set of computations utilized a constant temperature isothermal exterior wall, while the second set utilized an isothermal wall that changed temperatures as a function of time simulating the temperature changes on the exterior wall of a building throughout a 24 hour period. Results show superior thermal comfort levels as well as substantial energy savings can be accrued using the displacement ventilation, especially the displacement ventilation with a chilled ceiling over the conventional mixing ventilation system.

Assessment of energy and environmental performances of a bioclimatic dwelling in Algeria's North

2016 ◽  
Vol 38 (1) ◽  
pp. 64-88 ◽  
Author(s):  
N Belkacem ◽  
L Loukarfi ◽  
M Missoum ◽  
H Naji ◽  
A Khelil ◽  
...  
Keyword(s):  
Energy Balance ◽  
Thermal Comfort ◽  
Energy Demand ◽  
Energy Savings ◽  
Heating System ◽  
Building Energy ◽  
Energy Performance ◽  
Solar Heating ◽  
Environmental Study ◽  
Building Energy Efficiency

Bioclimatic architecture strategies and solar active systems contribute strongly to the reduction of building energy demand and achieving thermal comfort for its occupants over the whole year. This paper deals with the study of the energy performance improvement of a pilot bioclimatic house located in Algiers (Algeria). First, a series of experimental measures are conducted during cold period to show the effect of passive and active solar gains on the improvement of the indoor air temperature of the house. Then, a dynamic model of a solar heating system coupled with a bioclimatic house has been developed using TRNSYS software and validated with experimental data. The validated model has been used to establish the energy balance of the pilot bioclimatic house without solar heating system and to compare them to those of a conventional house. Finally, the improvement of the energy balance of the pilot bioclimatic house has been done by passive and active ways. The passive one includes the increase of south facing windows size and the use of night cooling with the use of shading device in summer. The active one consists of the integration of a solar heating system. Furthermore, an environmental study has been performed. The experimental results show that the energy requirements of a pilot bioclimatic house are very low which is suitable for the use of solar heating system in building. The simulation results show that the application of bioclimatic strategies is a better way to provide thermal comfort in summer and decrease the space heating energy demand of the house with 48.70%. The active solar system will cover 67.74% of the energy demand for heating of the house. These energy savings generate a significant reduction in CO2 emissions. Practical application: This work will enable engineers and designers of modern buildings of buildings in a Mediterranean climate to improve building energy efficiency and reduce CO2 emissions by a conjunction of different passive heating and cooling techniques such as insulation, thermal mass, window shades, night ventilation, and the solar heating system. The paper provides designers an effective strategy in terms of energy savings and indoor thermal comfort while reducing CO2 emissions.

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