Thermal comfort is the condition of mind that expresses satisfaction with the thermal environment. The temperature is an indication of the physical environment.

Thermal comfort describes ones satisfaction based not only on the ambient temperature but also on the overall quality of the air and depends on the metabolism parameters, clothing etc. Nowadays there are some norms (e.g. ANSI/ASHRAE Standard 55) that quantifies thermal comfort index. While measuring some metabolism parameters is difficult methods based on statistics (e.g. PMV) are applied. To study the metter further I propose to look at Fanger's works (to get the idea behind it) and also the norm I've mentioned.

Thermal comfort  depends upon the transmission properties of fabric i.e. air-permeability, moisture vapour transmission and thermal insulation of the fabric. The satisfaction can be achieved as per optimizing these three transmission properties according to temperature and humidity of the environmental conditions.

According to ASHRAE Standard 55 (2013), Thermal comfort is the condition of mind that expresses satisfaction with the thermal environment and is assessed by subjective evaluation. The main factors that influence thermal comfort are those that determine heat gain and loss, namely metabolic rate, clothing insulation, air temperature, mean radiant temperature, air speed and relative humidity (de Dear and Brager, 1998).

de Dear and Brager some article related to indoor thermal comfort. and see the ASHRAE Standard 62.

Regard

I prefer the definition from ASHRAE (already quoted by Amar Bennadji). It suggests two dimensions of thermal comfort. One, the objectively assessable thermal environment (temperature, humidity, air velocity etc.). Second, the human dimension of the occupant, his/her psychological state or state of mind. While the first is necessary from point of view of design, the second is equally important from point of view of the building’s actual performance.

Thermal comfort has two school of thoughts now. One follows heat balance approach ( Fangers PMV-PPD method) and other is Adaptive thermal comfort. Both has different definitions as PMV-PPD method assumes that subject is passive to environment but adaptive comfort assumes that subject is active in environment and takes steps to restore comfort either by personal adaptation or by actions that lead to modification of indoor environment itself ( Behaviour). So mean thermal comfort is a sensation corresponding to thermal environment expressed by group of subjects. I will suggest you to read Prof Fanger research papers for PMV-PPD approach and For adaptive read Prof. Humphreys, Prof Nicol, Prof. Barger and Prof de Dear papers.

My research interest is adaptive thermal comfort and Inclusion of Occuapnts behavior in Building Energy Simulation. You can also read my papers if you are interested.

Regards,     

A state of mind where a person feels thermally comfortable. Factors affect this state of mind are two types 1/ climatic: namely internal air temperature, air movement, mean radiant temperature, and relative humidity.

2/ personal: such as metabolic rate, clothing, body build, and sex.

I would recommend reading the following paper as a good literature review in the field:

"From thermal boredom to thermal pleasure"

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1678-86212012000100006

@Harimi Djamila I'll write you back...And thank you very much for the message.

@Aryan Shahabian, @Manoj Kumar Singh, @Omer Abuelzein, @Asit Mishra, @Nisha Verma, @Abdollah Baghaei Daemei , @Amar Bennadji , @Szymon Ogonowski

Thank you very much for all your answers, they help me to achieve my work.

Thank you again

Thermal comfort is the sensation of human of the surrounding conditions which includes temperature, relative humidity, air speed, and irradiation of enclosure.

I think the above answers define it clearly. But comfort is a neutral quality and we should be aiming for much more. See the work on Flourish in Healthy and Wellbeing in Homes Report 2016 by UKGBC page 14 also Creating the Productive Workplace book September 2017 Taylor and Francis.

Apart from the technical definitions, thermal comfort is a state of mind of feeling neither hot nor cold. It IS not a temperature setpoint. 

Best!

To complete the valuable opinions offered, we can define the thermal comfort according to adaptive thermal comfort aproach as a conditions that depends on the difference between perceived comfort and desired comfort, and on the part that cannot be compensated with clothing, activities or psychology; vs a neutrality condition, which expresses PMV index.

Alipour

Article Thermal comfort evaluation in kindergarten: PMV and PPD meas...

I think you have to read this thesis (author: Chris Mackey). In particular, in chapter 2, you can read: "most thermal comfort research can be classified into two broad camps of methodology.

The first takes as its starting point the notion that thermal comfort is fundamentally tied to the physical laws that govern a human’s energy balance. This energy balance equation is broken down into a number of terms and is validated against the responses of subjects in conditioned climate chambers” (Fanger's research and PMV/PPD indexes of EN ISO 7730). "The second camp takes as its starting point the notion that comfort is a complex state of mind with a multitude of factors - both physical and social, which make it impossible to predict with only a physics-based model. Instead of testing subjects in tightly-monitored climate chambers, this research seeks out building occupants within their daily routine" (adaptive models as defined by de Dear and Brager researchers activities and ASHRAE 55 or EN 15251). To study the comfort in real life at ITC-CNR we have developped the nEMoS device with low-cost sensors and a 3D printer. It's useful to monitoring some aspects of the Indoor Environmental Quality (the IEQ also includes the Indoor Climate Quality, ICQ) for example in offices, at home and schools: you can read more details here and here or directly from my researchgate page.

Regards,

Francesco

https://dspace.mit.edu/bitstream/handle/1721.1/99261/922640711-MIT.pdf?sequence=1

http://www.mdpi.com/1424-8220/15/6/13012

http://www.mdpi.com/1424-8220/17/4/828

https://www.researchgate.net/profile/Francesco_Salamone

 @ Francesco Salamone

Thank you very much Francesco for this ansewer which is very helpful to me.

Regards, 

Ahmed Lotfi

The next stage is to link Francesco's system to a wearables sensor system to assess the physiological and mood changes of the occupant. 

Dear D. J. Clements-Croome, we are carrying out an experimental monitoring campaign that incorporates nearable, wearable solutions and user feedback. More to come. Stay tuned

Hi,

if I were in you I would look to Fanger and his experiments. He is the father of thermal comfort and the first one (I guess) that have introduced such concept. His theory has been analyzed and developped in detailed through the decades, but the basic principles come from him. Regards,

Christian

Just as an addition to the useful answers above, thermal comfort is perceptual and maybe different from one person to another. So it cannot be solely be defined based on temperature set-points, RH setponits, etc. It should be calculated based on conditions that at least 75% of people feel thermally comfortable. It can be determined based on several environmental conditions.

Thermal comfort is the condition of mind that expresses satisfaction with the thermal environment and is assessed by subjective evaluation (ANSI/ASHRAE Standard 55). The six factors affecting thermal comfort are both environmental and personal. These factors may be independent of each other, but together contribute to an employee’s thermal comfort.

Environmental factors:

• Air temperature
• Radiant temperature
• Air velocity
• Humidity

Personal factors:

• Clothing Insulation
• Metabolic heat

Thank you Sarfaraz

Thanks for good your ans

Here below, as promised 10 months ago, a new paper that reports the results of an experimental monitoring campaign that incorporates IoT system (nearable and wearable solutions), user feedback and machine learning:

Article Integrated Method for Personal Thermal Comfort Assessment an...

@Md. Sarfaraz Alam and @Francesco Salamone

thank you very much.

You can find a good technical answer in UNI EN ISO 7730:06, alternatively ASHRAE 55:04 or subsequent updates.

If you want, read the article linked below

https://www.scopus.com/record/display.uri?src=s&origin=cto&ctoId=CTODS_974229247&stateKey=CTOF_974227315&eid=2-s2.0-84939421580

Thank you so much Roberto for your answer.

I think PMV algorithm could be useful:

PMV=(0,303e-2,1M)·((M-W)-H-R-Ec-Cres-Eres)

Where:

M: metabolic rate.

W: mechanical power.

H: heat exchange by convection. H=f(fcl, hc, Tcl, Ta)

R: heat exchange by radiation. R=f(fcl, Tcl, Tr)

Ec: heat exchange by sweating of the skin. Ec=f(M, W, HR)

Cres: dry respiration heat loss. Cres=f(M, Ta)

Eres: latent respiration heat loss. Eres=f(M, HR)

@Golsa Eghbali I really appreciate your reply. Thank you so much

Best regards

Thermal comfort of a human being is defined as that state of mind that expresses satisfaction with the thermal environment

It also expresses a person’s sense of the surrounding conditions, which include temperature, relative humidity, air velocity, and the radiation of the can.

Thermal comfort is the sensation that expresses the satisfaction of building users with the thermal environment. Therefore it is subjective and depends on various factors. The human body consumes food and generates waste heat, similar to any thermal machine. To keep its interior at a temperature of 37 ° C, it has to dissipate heat and it does this through conduction, convection, radiation and evaporation. As the ambient temperature approaches body temperature, the body can no longer transmit heat for lack of a thermal gradient, and evaporation remains the only form of cooling. One of the main functions of buildings is to provide interior environments that are thermally comfortable. Understanding the needs of the human being and the basic conditions that define comfort is essential for the design of buildings that satisfy users with a minimum of mechanical equipment.