Human Comfort Conditions Research Articles

Improving the building's thermal performance by using untraditional building blocks

AbstractIraqi buildings consume high-level electrical energy for air conditioning purposes to provide the standard human comfort condition. This paper adopted an experimental study by using Styrofoam adhesive or white cement as an alternative to ordinary Portland cement to manufacture building blocks with dimensions of 200 × 200 × 200 mm containing an internal core with dimensions of 90 × 130 × 130 mm, which were filled by using corrugated scratch-up or closed air gap. The samples were divided into two sets: the first had an aluminium foil layer applied to the external surface of the samples (reflective surface), while the second was without any layer (ordinary surface). The samples were tested under the climatic conditions of Baghdad city during the summer months (May to September) of 2021. These blocks were also evaluated by different structural tests. It can be seen from the test results that the use of Styrofoam adhesive with a reflective surface with panels of corrugated scratch-up increased the thermal insulation of the wall. It leads to reduce thermal leakage and the electrical energy consumed to provide comfortable thermal conditions by 52.7%, in addition to decreasing the mass density by 14.1% while compressive strength decreased by 21%.

Impact of indoor thermal environment on human thermal comfort, psychological response, and performance during winter in Jaipur, India

It is crucial to investigate the effects of indoor thermal environmental conditions on human performance, especially in India, during the winter when there is a significant need for space heating to maintain human comfort conditions. The present study was conducted in a controlled climate during winter, with 96 participants exposed to four air temperatures: 15 °C, 18 °C, 21 °C, and 24 °C. Participant's thermal comfort, emotion, and self-rated workload were assessed using a subjective questionnaire, while their performance was quantitatively evaluated using a neurobehavioral test. The data was analyzed to establish how the various thermal environmental factors influence performance, workload, emotion, and thermal sensations. The results show that the highest performance within the experimental thermal environmental conditions was observed when the thermal sensation ranges from neutral to slightly warm (+0.20) at the 23.5 °C mean standard effective temperature. At the same sensation, the occupant's mood disturbance and the mental workload for completing the task were minimal. These results would be helpful for facility managers of buildings by giving them insight into the impact of under or over-heating spaces on occupant performance during winter in the composite climate of India.

Optimization of design parameters and improvement of human comfort conditions in an upper-limb exosuit for assistance

Optimization of design parameters and improvement of human comfort conditions in an upper-limb exosuit for assistance

CFD Analysis on HVAC System Functionality in an Amphitheater

Heating, Ventilation and Air conditioning (HVAC) is an important part of residential structures such as single-family homes, apartment buildings, hotels and medium to large industrial and office buildings such as skyscrapers and hospitals, on ships, submarines and in marine environments.This paper investigates the characteristics of the performance HVAC system at “KUET auditorium” regarded as amphitheater for various internal and external conditions. A 2D model of the longitudinal section of the auditorium was drawn by using ANSYS-Fluent software in Design Modeler, for simulating the various functionality of the HVAC system for both summer & winter seasons. In this research, both the indoor & external conditions of KUET auditorium were considered, having the entire spectacle of hall is occupied by people. The main aim of this study was to observe the air temperature, air velocity and relative humidity for each case. The results are represented comparatively as graphs and spectra for various mass flow rates and indoor-outdoor temperatures. It was observed that the HVAC system provided sufficient human comfort conditions in terms of air flow and relative humidty recommended by (American Society of Heating, Refrigerating and Air Conditioing Engineers) AHRAE in the amphitheater for both the summer and winter season.
 Journal of Engineering Science 14(2), 2023, 01-14

Solar assisted CaCl2 desiccant wheel rotor system for simultaneous cooling and dehumidification operation: experimental and modelling approach

Abstract High temperature and humidity of many reason of India in the summer season is the major challenge for human comfort also in the drying. In the present work, experiments have been performed to examine the cooling and dehumidification process in the summer season for human comfort and industrial application with the help of calcium chloride (CaCl2) based desiccant material solid desiccant wheel integrated with solar heating arrangements. In this study experimental findings are also evaluated by the mathematical model. During the dehumidification of air in the process unit humidity changes from 17.75 to 29.03 g H2O/kg dry air to 2.8–3.9, 6.8–8.15, 8.92–10.9 & 9.79–11.87 g H2O/kg dry air for flow rate at 1, 2, 3 & 4 m/s, respectively. The process air outlet temperature is increased in the range of 2.58–3.53 K for all air flow rates. After humidification of process outlet air, human comfort condition (HCC) is produced with temperature and humidity in the range of 30–33 °C and 7.77–12.47 g H2O/kg dry air for different air flow rates. Overall airflow for velocity 2–4 m/s can be recommended for the HCC condition. The proposed modelled expression indicates less than 10 % error between the actual and modelled value for different sections.

Relevance of Urban Geometry and Outdoor Thermal Comfort in Urban Heat Island Mitigation – A Review

UHIs’ environmental and energy implications are well-known, but their significance in aggravating heat stress in populations is only recently being recognised. Planners, health managers, and public administrators now prioritise UHI prevention. Urban geometry, material finishes, and green and blue infrastructure are prominent UHI mitigation options. This paper examines urban geometry as a key parameter and reviews UHI research. This report also identifies information gaps and emphasizes the need for this type of research in key Indian metropolitan centers. The anticipated study will help public health planners and administrators. Methods: Authors compiled extensive literature on UHI and related concepts. The outcome intent was to understand the relevance of urban geometry parameters in UHI intensity and how it impacts outdoor thermal comfort. Various electronic databases were searched for publications meeting the criteria of outdoor thermal comfort and urban planning characters (urban geometry) as a mitigation strategy, ranging from 2000 to 2020. Summary: The impact of UHI on human comfort conditions cannot be ignored. Appropriate planning measures at the initial stages of city planning via urban geometry parameters can certainly yield encouraging results to reduce the intensity of UHI and improve outdoor thermal comfort conditions.

Performance assessment of novel solar still regenerated liquid desiccant-based evaporative air-conditioning system for an office in India

A liquid desiccant-based evaporative air-conditioning system (LDeACS) is one of the excellent alternatives to conventional vapour compression refrigeration system. The liquid desiccant (LD) requires less thermal energy at low temperatures for regeneration, therefore, the use of renewable (solar) energy is a promising source for the regeneration of LD. The prime motive of the research is to assess the applicability of novel solar still (SS) regenerated LDeACS for an office located at tropical savanna humid climate using numerical simulation. The novel solar still provides the combined function of a regenerator and LD heater. The simulation was carried out to evaluate the performance of sub-components of proposed LDeACS by varying the various input operating conditions (inlet mass flow rate of LD; inlet temperature of LD; temperature of absorber plate of SS) of SS. For the simulation, the mathematical model of sub-components of the proposed LDeACS is interlinked using commercial equation solver software. Simulated results indicated that the proposed LDeACS is capable to provide the required human comfort conditions. The parametric analysis of the system revealed that variations in performance parameters of sub-components of LDeACS are more sensitive to the inlet mass flow rate of LD at SS. An increment in the inlet temperature of LD at SS indicates an adverse effect on the performance indices of LDeACS. An increase in absorber plate temperature of SS enhances performance of SS, contrary to expectations, it degrades the performance of the dehumidifier.

Análise experimental de vibrações induzidas pelo caminhar em sistemas compostos de pisos e avaliação do desempenho considerando o conforto humano

Abstract NBR 8800 was updated in the year of 2008. Acceptance criteria of vibrations on floor performance considering human comfort were simplified and only minimum values of fundamental frequency are considered for performance evaluation. The objective of this article is to evaluate a methodology of experimental analysis of footfall-induced vibrations in steel and composite system floors and footbridges in order to check the human comfort conditions. The methodology was established according to international standard recommendations and international design guides. In order to present its applicability, it was applied to four case studies. The spectrum processing provided the values of natural frequency, damping ratio and peak acceleration. All the floors presented values of fundamental frequency greater than the minimum values recommended by NBR 8800. However, the obtained peak acceleration for some cases presented values greater than the maximum value recommended by international criteria. Therefore, the simplified acceptance criteria proposed by NBR 8800 were insufficient for performance assessment of some system floors and footbridges.

Building thermal comfort improving by using PCM and super insulators: Thermal and economic studies

The climate of the northern region of Morocco is Mediterranean, while the southern one is arid-type. They are both characterized by significant solar radiation during nearly eight months of the year, and as a result, direct and indirect solar energy contribute mainly to human discomfort in residential buildings. In this study, passive techniques such Phase Change Material (PCM) and super insulators (Aerogel and Vacuum Insulated Panels (VIP)) are used and analyzed to improve thermal comfort in the building. The resulting thermal behavior was studied using dynamic simulations and an experimental investigation of two test cavities located in the city of Casablanca. The potential energy savings to reach human comfort conditions were evaluated for a real scale cubicle. The comparison is performed with the active solution (air conditioning with classical local building wall composition), and the economic performances of these materials are evaluated by the Net Present Value (NPV) and Internal Rate Return (IRR). Special emphasis is given to the bulling roof. The optimum insulation thicknesses and payback periods were determined in the present study over 20 years. The results showed that PCM, VIP, and Aerogel could provide respectively as much as 94 %, 76.51%, and 73.61% economic benefit during the cooling period and 59.3 %, 46.56%, and 44 % during the heating period than the case of the roof without insulation.

Performance analysis of solar-powered integrated desalination and air conditioning system

ABSTRACT During the operation of the vapor compression refrigeration (VCR) cycle, heat is absorbed in the evaporator and rejected from the condenser to the environment. The heat rejected by the condenser is often wasted, and it raises the ambient air temperature, resulting in thermal pollution. Apart from that, freshwater scarcity is a severe concern in many areas. An integrated system of humidification-dehumidification (HDH) desalination and air conditioning using waste heat from the VCR system is proposed to address these difficulties. The system provides freshwater, cooled air, and hot water while preventing thermal pollution. Although the combination of desalination and cooling systems has piqued the attention of a few researchers, the duct architecture used in this work is a first. The study determines an appropriate humidifier spray water temperature based on human comfort conditions. It investigates the effects of ambient temperature and relative humidity, saline water temperature, and humidifier efficiency on output and performance metrics. The experimental studies are used to validate the thermodynamic model established in this paper. From one cubic meter of air, 31.50 kJ of heat and 40.53 mL of freshwater are extracted using 0.66 kW of power. The cooling performance (CP), gained output ratio (GOR), coefficient of energy performance (COEP), and exergy efficiency for the given operating parameters are 1.34, 4.29, 1.72, and 13.99%, respectively. The cost of freshwater production is $ 0.010076 per liter.

Experimental investigation of desiccant dehumidification based thermoelectric air-conditioning system

Vapor compression refrigeration system (VCRS) based conventional cooling systems run on the high amount of electricity and refrigerants responsible for greenhouse emissions. To save the environment and high-grade energy, traditional cooling systems should be replaced with some environment-friendly alternative. This paper proposed alternative eco-friendly air-conditioning systems based on an amalgam of two different technologies, i.e., desiccant dehumidification and thermoelectric (TE) cooling. The proposed air-conditioning system has the following subprocess: dehumidification of moist air by the solid desiccant wheel, cooling of processed air by TE modules, and regeneration of desiccant wheel by an electric heater and waste heat from TE modules. The air conditioning system has been experimentally studied for cooling performance, cooling effect, and energy input. The maximum coefficient of performance of 0.865 can be achieved with the proposed system, and it can be used for cooling effects up to 1442.24 W to maintain the human comfort condition in the chamber i.e. approximately 22 ℃ and RH 50% defined by ASHRAE.

Preparation of Industrial Noise Mapping and Improvement of Environmental Quality.

Environmental noise control is necessary for human health and auditory comfort conditions. In this respect, it is required that industrial noise should be kept under control and healthy living spaces should be obtained in residential areas. This paper aims to explain industrial noise control at urban and building scales. In this study, the strategic noise mapping process related to industrial activities in a line with the Environmental Noise Directive (END) was clarified. Besides this, what type of factors are effective in the industrial noise mapping process were defined, and important basic parameters, which are essential in the industrial noise mapping, were detailed. The preparation of the industrial noise mapping process was explained in detail. It was mentioned that the regions exposed to excessive noise should be defined according to the strategic noise map and improvement plans should be performed. Improvement methods that reduce excessive noise in living spaces are clarified and it was explained how the improvement of environmental quality can be acquired. In this regard, this paper gives information on industrial noise mapping and industrial noise control at the urban scale.

CULTURALLY RESPONSIVE TEACHING OF IMMIGRANTS IN ADULT EDUCATION: A CASE STUDY IN SWEDEN

Adult education has been criticized for its lack of focus on sociocultural aspects of individual learners, largely ignoring the importance of cultural identity to the learning process. The article’s aim is to investigate culturally responsive teaching of immigrants in adult education, theoretically and empirically underpinning the implementation of a case study for the elaboration of implications on culturally responsive teaching of immigrants in adult education. Research methods include theoretical and empirical methods. Theoretical methods imply analysis of theoretical sources and theoretical modelling. The empirical study was based on a case study. The sample was composed of 20 adult learners and three teachers of Swedish in May 2019 and February 2020. The case study was implemented at Folkuniversitetet, Kristianstad, Sweden. The theoretical findings allow defining religion and human comfort conditions such as thermal comfort as the dimensions of cultural norms and values to be addressed by culturally responsive teaching of immigrants. The findings of the empirical study allow drawing the conclusion on the necessity of a personalised approach to an adult learner in culturally responsive teaching of immigrants. The novelty of the present work is revealed in the implications on culturally responsive teaching of immigrants. Further research is proposed.

Effects of landscape composition and patterns on land surface temperature: Urban heat island case study for Nigde, Turkey

The urban climate has been disrupted with increasing urbanisation and consumption concepts, revealing climatic properties that affect human comfort conditions as a result of climate change. Decreasing vegetation and evaporative surfaces in cities, and increasing structural surfaces, such as concrete and asphalt, alter the topography, ecological structure, and atmospheric characteristics of nature, creating a different ecology and atmosphere. In this study, the relationship between the land surface temperatures (LSTs) of green and impervious surfaces was examined in Nigde, Turkey. Various satellite images were used, and statistical and geographical analyses were conducted. The results revealed that the LST values changed with the changing ratio of impervious and green surfaces, and have increased in Nigde over the past three decades even though the amount of green surfaces have increased. Furthermore, the LSTs of the impervious surfaces are 5–10 °C higher than that of the green surfaces. A correlation analysis showed that there was a significant difference in the LST values between green and impervious surfaces. Impervious surfaces contribute to the formation of the urban heat islands (UHIs), and green surfaces provide a cooling effect. Thus, increasing the amount of green surfaces in cities is crucial to improve urban life quality.

Acoustical retrofit of existing residential buildings: Requirements and recommendations for sound insulation between dwellings in Europe and other countries worldwide

Exposure to noise is proven to have important repercussions on human comfort and health conditions. In recent decades, efforts to increase awareness among users have focused on highlighting the benefits of an appropriate acoustic indoor environment. In addition, given the significant increase in complaints about noise, the control, reduction, and limitation of sound transmission have become important issues to be considered in acoustic retrofit work in buildings. Much of the housing stock was built in a period characterized by the limitation or absence of standards, and renovation interventions should be geared towards existing buildings. However, despite the major potential to improve quality of life, only a handful of countries consider old buildings in their national Building Codes and regulations. The main aim of this work is to develop a comparative study of the acoustic requirements for indoor sound insulation between dwellings of existing buildings established in current building regulations around the world. The analysis of the documents concludes that the usual difference between requirements for new and existing buildings is 5 dB, both for airborne sound insulation and impact sound insulation. To this end, this paper provides the basis for discussion regarding future cooperation for the optimization of acoustic regulations for old buildings.

Sustainable street architecture and its effects on human comfort conditions: Yazd, Iran

Sustainable street architecture and its effects on human comfort conditions: Yazd, Iran

Assessment on Human Comfort Criteria of Tall Building under Dynamic Wind Loading

The tall, light, flexible buildings may have large oscillating motions induced by wind or other causes that affect the comfort of the occupants. Wind induced motion in buildings may result in excessive vibrations such vibrations can cause discomfort conditions for occupants or damage to non structural elements. So it is essential to analysis the dynamic behavior of the tall building under the wind excitation which influences the human comfort. The purpose of present study is to anysied the range of human perception criteria associated with human comfort that is applied for serviceability limit state design. The design criteria were proposed based on the subjective perception test. The guideline for evaluating the acceptability of wind-induced tall buildings motions was defined by the expected value of motion perception acceleration. In this Project, human comfort condition of a tall building under wind excitation is assessed using estimation of peak acceleration by using Indian standard code IS 875(part3) :2015. Considering Four different Framed Tubes tall building circular structure having a G+20, G+30, G+40, and G+50 with different condition i.e. Normal Slab, Secondary Beam, Waffle Slab & Ribbed Slab are taken. Typical circular floor is 50 m in diameter and symmetrical in plan in both major directions. Then using ETABS-2013 software maximum displacement is evaluated using dynamic wind analysis of building by applying the gust factor method. With the help of maximum Displacement Peak acceleration will be calculated using is IS-875(part3); 2015 for different Framed Tubes structure conditions and modes of building. The peak acceleration obtained in the analysis is compared with the reference data given by Smith. S.B. and Coull book and human comfort perception level is calculating for Indian tertiary of the described location of India from which assessment of effective tall building under dynamic wind load is anysied.

Investigação experimental em escala reduzida sobre o uso de telhas cerâmicas como sistema de resfriamento evaporativo

<p>The present paper describes an experiment that clarifies the cooling effects of the constructed system. Tested in the Cuiabá, MT, environment, the system’s performance,, which works on the evaporative cooling principle made for this study using clay roof tiles was checked in terms of temperature drop and humidity rise air which passes through the system to the surroundings. The result showed that the cooling effect reached a maximum of 3.5 °C and increased the relative humidity of incoming air around 10%. The reduced-scale experiment has reached the appropriate temperature and humidity for air conditioning under human environmental comfort conditions in hot and dry climatic conditions, in 86.4% of the measurement periods. The use of porous ceramics as an evaporative cooling system offers the advantage of the integration into building elements.</p>

Thermal Energy Storage System using Bamboo in Combination with PCM

The design of a Thermal energy storage system indicates the progress being made in this field. It reflects the level of implementation of new ideas by local societies as well as the Energy policy at the National level. We are using heat storage capacity of bamboo in combination with phase changing material for space heating , bamboo has some beneficial properties like its heat storage capacity increases with increasing temperature and its conductivity too is quite slow which is why it can easily preserve heat for longer durations( nearly up to 7 to 8 hours.) We look forward to utilize phase changing material along with bamboo for further increasing the heat storage capacity (large quantity of heat can be easily stored) of system so that we can easily achieve the sufficient temperature in order to meet human comfort conditions in all seasons(especially winter). Space heating represents the largest end use in buildings, offices etc, and consumes more than 7 trillion Joules of site ener gy annually. With this project we intend to put the waste heat to better use by diverting it to a better heating system which includes the use of the heat storage capacity of bamboo amplified with the use of Phase Changing Material. In this project we intend to test various PCM with bamboo to get a better option to be paired with it. The iterations being carried out on our self designed test rig are expected to give us reliable and accountable results.

Experimental assessment of the impact of natural ventilation on indoor air quality and thermal comfort conditions of educational buildings in the Eastern Mediterranean region during the heating period

This paper aims to investigate the indoor comfort conditions in a typical classroom of a secondary school in Cyprus and explore the impact of natural ventilation on both thermal comfort and air quality. Natural ventilation is a significant parameter in the design of school premises as it affects human comfort conditions and thus students’ health, learning ability and performance. For the purposes of the study, indoor and outdoor environmental conditions were monitored. Various ventilation strategies and window opening patterns were examined, in order to identify the best option to exploit natural ventilation as a means to achieve optimum air quality, especially during wintertime. The in-situ measurements of temperature and relative humidity were analysed in correlation with CO2 levels. The measurements indicate values that often exceed the limits defined by standards. Moreover, the study shows that selected ventilation patterns, and window opening patterns, allow the improvement of air quality with minimum heat losses in wintertime. Conclusions present potential improvements in achieving better air quality and thermal comfort conditions. Educational buildings in Cyprus may utilize the proposed improvements, as well as other similar buildings in the Eastern Mediterranean region, with climatic conditions and building typologies as those described in the Cypriot setting.