Thermal Comfort Measurements Research Articles

Advances in Traffic Restraint Measures in Urban Areas

This paper first describes traffic restraint measures applied in urban and/or suburban areas and it assesses the role that these may play in easifying and calming traffic. The nature of these measures and some standard issues in their planning process are presented. The difficulties in the implementation of these measures are then discussed on the basis of a number of 17 traffic management studies carried out in the Athens’ northern suburban area of Maroussi.Following this, the paper proceeds to a further step in the design of such measures by introducing a set of environmental parameters in the whole planning process – the latter determine and affect the environmental quality of urban roads. These parameters are tested in practice for a representative network of roads in the urban complex of Maroussi forming an inner ring road, along which bicycle lanes are introduced and thermal comfort measures are taken. It is proposed these environmental parameters can be involved in the planning process and that can be used as potential tools of an advanced transport policy, which adds the environmental quality of roads to the targets of the whole traffic restraint process.

Experimental investigation of a mini-type solar absorption cooling system under different cooling modes

Solar absorption cooling systems are available from various reports, in large capacities up to several hundred kilowatts. However, in the range of small capacities (<50kW), only very few systems were reported. In this paper, a mini-type solar absorption cooling system was designed and installed at Shanghai Jiao Tong University. The system contains 96m2 solar collector arrays, one absorption chiller with a rated cooling capacity of 8kW, and a hot storage water storage tank of 3m3 in volume. The chilled water can be delivered either into fan coils or into radiant cooling panels, which are installed to satisfy the demands of the indoor thermal environment of the test room. As for the fan coil cooling mode, it was found that the average cooling output reached 4.27kW during 9h of operation under typical weather conditions for Shanghai. The PMV (predicted mean value, a measure of thermal comfort) inside the test room could be controlled between −0.29 and 0.32. With regard to the radiant cooling mode, an individual supply air unit was installed for the purpose of preventing condensation on the cooling panels. Comparing with the experimental results of the fan coil cooling mode, the average cooling output increased by 23.5%.

The Effects of Heat Exposure on Cognitive Performance

Abstract In addition to physical conditioning, successful sporting performance requires a level of perception coupled with efficiency and accuracy in movement. The FIFA World Cup is usually played during the summer months; therefore the aim of this study was to investigate the effects of heat exposure on cognitive performance. Three experiments were performed in an environmental chamber under hot (HOT: 50°C, 30% rH) and control (CON: 24°C, 30% rH) conditions. Exposure time ranged from 15 minutes to 4.5 hours. Subjects performed simple and complex cognitive tasks under different levels of thermal strain. Neuromuscular assessments were performed to assess neural drive and muscular force production. Central (Tcore) and skin (Tskin) temperatures were recorded along with subjective measures of thermal comfort (TC) and thermal sensation (TS). Hyperthermia had no impact upon attention tasks, however, impulsivity increased during sustained attention over prolonged periods. Significant increases in Tcore (>38.30°C) were associated with impaired complex cognitive task performance. The regular application of cold packs to the head limited the detrimental effects of hyperthermia upon short-term memory. However, rapid and substantial variations in Tskin of ∼3°C, independent of changes in Tcore, had similar detrimental effects upon cognitive task performance. Results suggest that reductions in complex cognitive performance with heat exposure occur via a decrement in motor cortical excitability when Tcore increases to ∼38.3°C, but they also originate from an additional cognitive load imposed by thermal strain and the resulting allesthesial Tskin variations; with both these factors acting as competing variables to the cognitive processes. The increase in Tcore with prolonged heat exposure impairs cognitive performance; however applying cold packs to the head can preserve these. Increases in Tskin during brief heat exposures appear to be a sufficient physiological response to alter the emotional state of individuals and impair effective decision-making. Hydration protocols and reducing exercise intensity and load can reduce the physiological strain. Strategies to minimise the ‘thermal shock’ of entering a warm environment should be developed to minimise the impact of subjective feelings of thermal discomfort upon cognitive performance.

Satisfaction Scale for Measuring Thermal Comfort and Illumination in Office

A suitable physical climate is needed if one wants to feel comfortable and ef ficient at work. The environment feels comfortable when you are barely aware of the climate conditions. It is only when temperature decreases and increases beyond ones' comfort limits that one becomes aware of discomfort. Artificial lighting is needed to provide task luminance and adequate visual environments to carry on the task when natural light is inadequate or not available. Good artificial illumination, prevent accidents, prospects health by minimizing eye strain and also contributes to the beauty in of fices. Hence, presence study was undertaken with an objective to develop scale for measuring thermal comfort and illumination in of fice. As the scale was found to be reliable and valid, the developed scale will serve as a scientific tool for the measurement of thermal comfort and illumination in offices.

Thermal comfort and IAQ characteristics of naturally/mechanically ventilated and air-conditioned bedrooms in a hot and humid climate

The characteristics of thermal comfort and indoor air quality (IAQ) in bedrooms, occupants’ perceptions and their impact on sleep quality are not often studied. It becomes even more interesting if climatic conditions allow Naturally/Mechanically Ventilated (NMV) concepts as opposed to Air-conditioning (AC) and this becomes very significant from an energy perspective. This paper reports our findings from such a study conducted in a hot and humid climate. Objective measurements of thermal comfort and IAQ were carried out during sleeping period in 12 NMV and 12 AC bedrooms over a period of 2 months. Questionnaire responses were sought from each subject at the end of the objective measurements to assess their perceptions on thermal comfort and indoor air quality of the bedrooms during sleep and their sleeping conditions. Although the “Historical” and “Immediate” responses for the NMV and AC bedrooms indicate that there was a good level of acceptability for both Thermal Comfort and Perceived Air Quality (PAQ), it was found that NMV bedroom was a better sleeping environment. The subjects’ immediate perception of PAQ and thermal comfort were reasonably correlated with their historical perceptions. The subjects’ perception of PAQ was fairly closely correlated to their perception of Thermal Comfort. There was a considerable increase in the carbon dioxide level in an AC bedroom relative to a NMV bedroom. However, there was no clear evidence to substantiate that sleeping duration decreased with increasing level of carbon dioxide, but the findings do suggest that high level of carbon dioxide may hinder the duration of sleep.

Thermal comfort of patients: Objective and subjective measurements in patient rooms of a Belgian healthcare facility

In healthcare facilities, the prediction of mean thermal comfort perception of patients and staff is necessary to formulate requirements for the architectural and building systems design and control, and for establishing guidelines for the use of clothing and bedding systems. In this study thermal comfort of patients is evaluated by comparing objective (environmental and personal) parameters and subjective measurements (questionnaires) of thermal comfort for different groups of patients, according to the ward they are occupied in. The study involved 99 patients of maternity, oncology, neurology, gastro-enterology, abdominal surgery and thoraco-vascular surgery wards. T tests reveal no significant difference between Predicted Mean Vote (PMV) obtained from objective measurements and Actual Mean Vote (AMV) for all the different wards except for neurology. Binomial tests show that the difference between the predicted percentage of dissatisfied (PPD) obtained by application of the PPD-formula in ISO 7730 as function of Actual Mean Vote and PPD obtained from personal acceptability votes is not significant on a 5% level for all wards. This means that PMV and PPD indices may be used to adequately predict mean thermal responses for these wards except for neurology.

A personalized measure of thermal comfort for building controls

A personalized measure for thermal comfort has been applied for use in combination with smart controls for building automation. Using data from a field study, we first show the superiority of personalized measures for thermal comfort compared to standard non-adaptive methods. Based on this knowledge we describe a methodology, using logistic regression techniques, to convert user votes to a probability of comfort. We also describe the interface used to collect the votes. We show that, for a given subject, our thermal profile converges against the probabilities found in the field study. As a case study we implemented the measure in a control algorithm to control the shading devices. The results clarify the mode of action and also show the effectiveness of the method.

A new dynamic sweating hotplate system for steady-state and dynamic thermal comfort measurements

This paper discusses design details and measurement principles of a dynamic sweating hotplate system used for both steady-state thermal and water vapor resistance and dynamic water vapor transmission rate measurements. Dynamic and steady-state transfer measurements were carried out by separate systems in preceding studies. Water vapor resistance and dynamic water vapor transmission rate values were determined according to the new principles put forward in this study. Relationships between properties obtained by the new system and standard permeability (water vapor and air) parameters were determined for different types of fabrics used for sports clothing. The materials and physical/constructional properties of the investigated fabrics varied in a wide range as the aim was to determine if the developed system could differentiate their comfort performances. According to the results, water vapor resistance is significantly correlated with fabric weight and water vapor resistance is the best in differentiating the water vapor permeability characteristics of the fabrics among other transfer properties.

Development of Light Powered Sensor Networks for Thermal Comfort Measurement.

Recent technological advances in wireless communications have enabled easy installation of sensor networks with air conditioning equipment control applications. However, the sensor node power supply, through either power lines or battery power, still presents obstacles to the distribution of the sensing systems. In this study, a novel sensor network, powered by the artificial light, was constructed to achieve wireless power transfer and wireless data communications for thermal comfort measurements. The sensing node integrates an IC-based temperature sensor, a radiation thermometer, a relative humidity sensor, a micro machined flow sensor and a microprocessor for predicting mean vote (PMV) calculation. The 935 MHz band RF module was employed for the wireless data communication with a specific protocol based on a special energy beacon enabled mode capable of achieving zero power consumption during the inactive periods of the nodes. A 5W spotlight, with a dual axis tilt platform, can power the distributed nodes over a distance of up to 5 meters. A special algorithm, the maximum entropy method, was developed to estimate the sensing quantity of climate parameters if the communication module did not receive any response from the distributed nodes within a certain time limit. The light-powered sensor networks were able to gather indoor comfort-sensing index levels in good agreement with the comfort-sensing vote (CSV) preferred by a human being and the experimental results within the environment suggested that the sensing system could be used in air conditioning systems to implement a comfort-optimal control strategy.

Effects of pre-cooling procedures on intermittent-sprint exercise performance in warm conditions

The aim of this study was to determine whether pre-cooling procedures improve both maximal sprint and sub-maximal work during intermittent-sprint exercise. Nine male rugby players performed a familiarisation session and three testing sessions of a 2 x 30-min intermittent sprint protocol, which consisted of a 15-m sprint every min separated by free-paced hard-running, jogging and walking in 32 degrees C and 30% humidity. The three sessions included a control condition, Ice-vest condition and Ice-bath/Ice-vest condition, with respective cooling interventions imposed for 15-min pre-exercise and 10-min at half-time. Performance measures of sprint time and % decline and distance covered during sub-maximal exercise were recorded, while physiological measures of core temperature (T (core)), mean skin temperature (T (skin)), heart rate, heat storage, nude mass, rate of perceived exertion, rate of thermal comfort and capillary blood measures of lactate [La(-)], pH, Sodium (Na(+)) and Potassium (K(+)) were recorded. Results for exercise performance indicated no significant differences between conditions for the time or % decline in 15-m sprint efforts or the distance covered during sub-maximal work bouts; however, large effect size data indicated a greater distance covered during hard running following Ice-bath cooling. Further, lowered T (core), T (skin), heart rate, sweat loss and thermal comfort following Ice-bath cooling than Ice-vest or Control conditions were present, with no differences present in capillary blood measures of [La(-)], pH, K(+) or Na(+). As such, the ergogenic benefits of effective pre-cooling procedures in warm conditions for team-sports may be predominantly evident during sub-maximal bouts of exercise.

A Preliminary Study of Thermal Comfort in Malaysia′s Single Storey Terraced Houses

In a tropical climate, passive cooling is difficult to achieve with respect to mass housing design. A good house design keeps the indoor environment favorable and comfortable during most of the year without the use of any mechanical devices. Terraced houses are typical examples with low comfort problem that need particular consideration. Low air velocity and high air temperature are experienced during the daytime and the wind effect is not well captured, especially in the single sided ventilation. Use of natural ventilation has been increasingly examined as an energy–efficient means to provide thermal comfort as well as a healthy indoor environment. This paper discusses the validation of Computational Fluid Dynamic (CFD) results and the measurement of thermal comfort in Malaysia′s single storey terraced houses. The thermal environment and comfort conditions were investigated using field measurement and CFD technique. Validation of CFD FloVent was carried out through the comparison of field measurements. Comparison of the results between simulations and measurements illustrated a good agreement. The simulations were performed on a selected day in a one–year climate condition. The results indicated that the design of single storey terraced houses is not effective in providing natural ventilation for achieving thermal comfort. The microclimate condition surrounding the terraced house indicated very low wind speed. Therefore, modification of the natural ventilation mechanism using a solar chimney as induced ventilation needs to be manifested and evaluated.

The effects of solar radiation on thermal comfort

The aim of this study was to investigate the relationship between simulated solar radiation and thermal comfort. Three studies investigated the effects of (1) the intensity of direct simulated solar radiation, (2) spectral content of simulated solar radiation and (3) glazing type on human thermal sensation responses. Eight male subjects were exposed in each of the three studies. In Study 1, subjects were exposed to four levels of simulated solar radiation: 0, 200, 400 and 600 Wm(-2). In Study 2, subjects were exposed to simulated solar radiation with four different spectral contents, each with a total intensity of 400 Wm(-2) on the subject. In Study 3, subjects were exposed through glass to radiation caused by 1,000 Wm(-2) of simulated solar radiation on the exterior surface of four different glazing types. The environment was otherwise thermally neutral where there was no direct radiation, predicted mean vote (PMV)=0+/-0.5, [International Standards Organisation (ISO) standard 7730]. Ratings of thermal sensation, comfort, stickiness and preference and measures of mean skin temperature (t(sk)) were taken. Increase in the total intensity of simulated solar radiation rather than the specific wavelength of the radiation is the critical factor affecting thermal comfort. Thermal sensation votes showed that there was a sensation scale increase of 1 scale unit for each increase of direct radiation of around 200 Wm(-2). The specific spectral content of the radiation has no direct effect on thermal sensation. The results contribute to models for determining the effects of solar radiation on thermal comfort in vehicles, buildings and outdoors.

Real-time measurement of thermal comfort by using an open networking technology

In this paper, a new measurement system was proposed to conduct real-time measurement of predicted mean vote (PMV). PMV is a well-recognized thermal comfort index for human beings but it is a complicated mathematical function. Thus, such measurement work has been regarded as difficult so far. By employing an open networking technology, the problems present in this work were solved. Inside the system, smart sensors were employed to handle individual own tasks including measurement and data manipulation. They transferred data over a network in which open communication protocols were adopted. The data transfer greatly facilitated one of the sensors to derive the PMV values. Six smart sensors were developed with open networking capabilities. They were employed to demonstrate that an open networking technology enabled the system to successfully handle real-time PMV measurement. Also, six favorite attributes were obtained for the system, namely low cost, small dimension, ease of installation, easy and low-cost operation, ease of retrofit in existing spaces and independence of particular manufacturers. Therefore, it was found that such technology was an essential element inside the system to handle a complicated measurement work.

Integrated modeling of pedestrian energy exchange and thermal comfort in urban street canyons

An open-air scale model is used to quantify pedestrian radiative and convective energy exchanges in street canyons of varying geometry, as well as surface-atmosphere energy exchanges above the urban canopy. A semi-empirical model based on measured data in summer is developed to link between the two levels, for the prediction of pedestrian energy exchange within a given street canyon based on climatic conditions above the street array. The relationships identified in the semi-empirical model are then tested with an independent data set from the winter season, demonstrating that the semi-empirical model may be used to predict the effect of street geometry on pedestrian comfort under varying seasonal conditions. Finally, the estimation of pedestrian energy exchange by street geometry is refined to include the effects of humidity and evaporative heat loss along with radiation and convection, and results are used to correlate between physiological energy exchange and thermal sensation, which is a more direct measure of human thermal comfort. The results reinforce previous findings, which indicate that in a hot-arid climate, compact street canyons can substantially reduce overall pedestrian thermal discomfort if their axis orientation is approximately north–south, while in east–west oriented canyons the effect of street proportions is much less pronounced.

DRESSMAN a thermal comfort measurement device for drivers and pilots

DRESSMAN (Dummy REpresenting Suit for Simulation of huMAN heatloss) designates a novel measurement device for climate measurements that allows the prediction of human thermal comfort experienced normally inside rooms (vehicles, aircraft, railway compartments, buildings, etc.), on the basis of climate measurements. It is specially designed for use by an operating driver or pilot. Measurement results can be listed in tabular form and can also be represented by way of colour gradations in a virtual 3D human model. Optionally, visualisation may be either online or by post processing. Due to its very quick response, DRESSMAN is particularly suited to nonstationary processes, to get information about fast physical thermal variations. DRESSMAN was specially developed to measure the expected local thermal sensations at different body parts, which are influenced by air temperature, air velocity and thermal radiation.

Energy-cost allocation based on the theory of frequency response

Energy-cost allocation systems apportion heating and/or cooling costs among the individual apartments in centrally-metered buildings based on various measures of relative energy use or thermal comfort. The most commonly used systems measure one or more parameters related to the thermal output of the terminal elements. In this paper, a new method for energy-cost allocation purposes was developed and studied. Taking advantage of the theory of frequency response, the individual apartments' energy consumption for cooling in summer may be calculated using several parameters that include indoor and outdoor temperatures and the values of solar radiant-intensity. Experiments were done in this study, which indicates that the method of frequency response is fairly good in calculating the energy use of cooling.

Computational fluid dynamics

The improvement in the quality of life together with thermal comfort, air quality, health, workplace security and energy conservation measures justify the integral education of environmental (outdoor and/or indoor) phenomena. Environmental education, through the appropriate tool, can play an important and vital role in this domain. Computational fluid dynamics (CFD) is the analysis of systems involving fluid flow, heat transfer and associated phenomena such as distribution of pollutants by means of computer‐based simulation. This technique, allowing the simulation and the visualization of environmental problems, represents a powerful tool to motivate, guide and educate on the environment. The main objective of this paper is to introduce this new advanced active tool in environmental education, directed to indoor‐environment quality, that permits the prediction and visualization of air movement, air temperature and air contaminant (such as tobacco smoke) distribution in rooms. With suitable mathematical models and boundary conditions, a computational code has been developed to predict and visualize these phenomena. In order to demonstrate its applicability, the simulation of air contamination distribution in an office room with a smoker was performed.

A COMPARISON BETWEEN A PHYSIOLOGICAL AND PERCEPTUAL STRAIN INDEX FOR INDICATING HEAT STRESS OF FIREFIGHTERS

Recent findings have shown that a perceptual strain index (PeSI) using measures of thermal comfort (TC) and ratings of perceived exertion (RPE) was similar to the physiological strain index (PhSI) calculated from measures of rectal temperature (Tre) and heart rate (HR) during exercise in the heat (Tikuisis et al. MSSE 34: 1454–1461, 2002). PURPOSE It was the purpose of this study to examine whether PeSI was similar to PhSI for firefighters wearing protective clothing in warm environments. METHODS Thirty-seven Toronto Firefighters were allocated to one of four groups that performed heavy (H, 4.8 km/h, 5% grade), moderate (M, 4.5 km/h, 2.5% grade), light (L, 4.5 km/h) or very light (VL, 2.5 km/h) exercise while wearing their full protective ensemble and self-contained breathing apparatus. Subjects performed a familiarization trial followed by experimental trials at 25°C, 30°C and 35°C with 50% relative humidity. Measures of TC, RPE, Tre and HR were recorded after 20 min of exercise and every 30 min thereafter until exhaustion. RESULTS After 20 min of exercise PeSI (2.15 ± 0.81) was significantly lower than PhSI (3.05 ± 0.60) regardless of the environmental conditions or metabolic rate. As the duration of exercise increased to 50 min with light exercise the underestimation of PhSI with PeSI was maintained. At exhaustion, PeSI (6.18 ± 1.32) was significantly lower than PhSI (6.89 ± 0.60) but this difference was evident only at 25°C (5.78 ± 1.62 and 6.80 ± 0.77 for PeSI and PhSI, respectively) and 30°C (5.94 ± 1.59 and 6.96 ± 0.72 for PeSI and PhSI, respectively). At 35°C there was no difference between PeSI (6.80 ± 1.52) and PhSI (6.91 ± 0.67). CONCLUSIONS It was concluded that PeSI underestimates PhSI for these firefighters working at various intensities and environmental conditions but the underestimation was less prevalent in the warmest climate. Supported by the Province of Ontario Workplace Safety Insurance Board.

Fuel poverty, thermal comfort and occupancy: results of a national household-survey in Ireland

Fuel poverty is perhaps the strongest adverse social impact resulting from the inefficient consumption of energy in the domestic sector. Despite considerable research examining the plight of those affected, there has been very little empirical work examining the relationship between fuel poverty and thermal comfort and the extent of indoor cold strain resulting from inadequately heated housing. Furthermore, the effects of fuel poverty on household occupancy have not been addressed formerly. This paper employs a new national household survey of Ireland—a country with a level of fuel poverty similar to Britain—to examine these key issues. Both self-reported and objective measures of thermal comfort are utilised, and the study pays particular attention to the age profile of those affected by thermal discomfort. The results show, inter alia, that two-thirds of fuel-poor householders demonstrate cold strain, and over half of elderly households endure inadequate ambient household temperatures during winter.

Indoor air quality comparison of two air-conditioned zones served by the same air-handling unit

Most indoor air quality (IAQ) investigations take an air handling unit (AHU) - based zone as the basic unit for investigation from the logical viewpoint that the AHU constitutes the mechanism for mixing and (cross-) transportation of pollutants within the zone. If there is very good air-mixing, as indicated by a high air exchange effectiveness, the single zone approach may be sufficient. However, when there is large discrepancy in pollutant generation between spaces within the spaces served by the AHU, or when the ventilation is impeded due to inappropriate partitioning, the zonal characteristics are likely to differ from space to space. This paper reports a comparison of the zonal characterisation of an office space whose ventilation and thermal comfort parameters are different. In this study an integrated approach to IAQ auditing which includes measurements of chemical, biological, particulate, thermal comfort and ventilation parameters was adopted. Significant differences in the values and time profiles of the various pollutant dimensions have been observed between the two zones. These differences are attributable to the dominant influences of interior layout and partitioning, degree of exposure to the exterior, occupant activities, occupant intervention of the ventilation system by operating the operable windows, and the materials deployed for interior partitions.