Thermal comfort of organism

Thermal comfort of an Organism:   

The thermal comfort of an organism is defined as “the condition of mind which expresses satisfaction with the thermal environment.” Psychologically it is a state of mind that describes how hot or cold a person is feeling. Thermal comfort is different for all people, and numerous environmental as well as personal factors that affect it. Most sources say that thermal comfort is attained as long as 80% or more people feel comfortable in that climate. Thermal comfort is comparable to the new nature of proteins. The same way that proteins are denatured and unable to sanction when they are not at optimum temperature, neither can humans when they are not at optimum temperature. If it is slightly cold the person may start to shiver, or their body may start to produce more thermal energy unconsciously. Although if the thermal comfort is too distant from equilibrium, the person will consciously assess the situation and proceed to put on a jacket of turn the heat up.

There is much more than just room temperature that leads to thermal comfort or discomfort. There are 6 major aspects that it can be broken down to. (UZAMA add stuff)

To create thermal comfort for an organism, we must consider the factors that contribute to thermal comfort. temperature is arguably the most commonly used indicator of thermal comfort. as it is commonly used and most people can use interchangeably in their daily lives. At first glance temperature appears to be an accurate indicator of thermal comfort, however alone, its is both a not valid nor accurate indicator of thermal comfort. Thus temperature should always be considered in relation to other environmental and personal factors when trying to create a comfortable thermal environment for an organism.

the six factors that can be used as indicators(ie contribute) to thermal comfort are both environmental and personal, and act in together in unity or independently  of each other

personal factors:are factors pertain to the organisms in a particular environment. environmental factors:are conditions in a specific thermal enivronments

Environmental factors:

mean radiant temperature:

Thermal Radiation is heat that radiates from a hot object, this is by infrared radiation. If there  is a hot object in the room there will be radiant heat, thus  radiant temperature can be defined as the temperature that pertains to the individual object. and this certain temperature radiates heat or absorbs heat via radiation .A hot object will have a high radiant temperature and a cold object will have a low one. Mean radiant radiant temperature is a measure of how much warming (or cooling) you get from the exchange of radiant heat, tkaing into account to ALL the objects in the room. so a oil heater, will raise the mean radiant temperature significantly, while a cold floor or window will lower the mean radiant temperature.

Radiant temperature has a greater effect on how we lose or gain heat from the environment our skin absorbs almost as much heat as a black matte object, although this can be reduced by wearing reflective clothing. air velocity: this is how fast air is moving thru the room.

humidity:

humidity increases the thermal the amount of heat condution to a certain body per certian temperature. so at the same temperature, cold air will seem colder and hot air will seem hotter. wet air has a greater heat capacity than dry air so it can remove more heat from you faster than dry air. moist hot air will heat you up by a higher degree, as per m square of air surface, the more air droplet in the air the more water they will be hitting your body per m2 and if the water dropplets are hot, they more water youll have transferring that huge specifc heat capcity of theirs on to your skin.

personal factors: Activity Rate: describes what you are doing ...afternoon nap, or playing tennis perhaps? (Learn More) activity rate/metabolic rate: describes the heat that we produce in our bodies when carrying out physical activity. the more physical/active of a activiy you take part in the more heat we reproduce,. The more heat we produce, the more heat needs to be lost so we don’t overheat. Thus the impact on metabloic heat Clothing Level: describes what you might be wearing while doing an activity. a thick garnament willl insulate your body more

Maintaining a thermal environment is important in everyday life wherever we go. Whether it is at home, at work or when you are simply outside. Let’s take work as an example. If people aren’t in an environment that suits them well, they might take shortcuts, be unable to focus, and behave unsafe. Along with this, the risk of errors occurring increases, and the unit decreases in their efficiency. On the other hand a good thermal comfort increases the performance, sadness and health of the workers. If workplaces have a good thermal environment, the people will be able to focus well and not have to devote their attention to staying in homeostasis.

Once thing that is constant everywhere is that everyone has a thermo neutral zone, which describes a range of temperatures where a person feels normal without needing to use energy that exceeds the normal metabolic rate. For a naked man in still air this value would be about 27 degrees Celsius. Note this is for a resting human and does not allow for shivering, sweating or exercising. With clothing, radiation and convection losses are reduced, and TNZ is changed. Humans produce a standard 100 watts of heat energy as a normally from metabolic processes like pumping blood, digesting, breathing, biochemical synthesis and more. So if the body would not give off any energy, the core temperature would continue to increase until the body is extremely overheated. But this in not common because we are usually surrounded by colder air and much of our thermal energy flows from the core to the surroundings. Therefore, it is important for the body must find a effective way to lose 100 watts through the skin in order to maintain core temperature The 100 watts of heat must be lost in relatively warm environments, but in cold ones the body must make sure it does not lose too much over 100 watts.

There are several way that people adapt to an environment. When it is hot, it is not uncommon to see people, for example students at lecture, slouching. Although, in colder environments there are more likely to it up and listen more intently. This is an example of postural changes that go along with thermal comfort. Some other adaptions that people can do include removing clothing, changing the heating, moving away from hot or cold sources such an air conditioner. But adaptation can only be done to a certain extent. For example it a person removes their jacket and it is still hot, they may no longer be able to adjust. Thermal comfort can be influenced by the processes that people do in a job, which can sometimes not be adapted to. This is an example of thermal stress. People’s subcutaneous fat and skin acts as an adjustable insulator that adjusts blood flow to the periphery. Or their veins can vasoconstrict/ dilate depending on the conditions. For example if it is cold, blood flow is reduced to the skin, so that heat loss is reduced. These direct connections between artery and vein which bypass nourishing capillaries, are controlled by the sympathetic nervous system.

Perhaps the most important is controlling and producing a thermal comfort. Thermal comfort is one of the important factors that comes into play when constructing housing or workplaces. Engineers strive make the place is ecofriendly, while making sure that the people there will have thermal comfort. Measuring whether someone is in thermal comfort is determined by asking their opinions on the 6 factors that compose it. If they are content with it, then it has been achieved.

Overall, being satisfied with a thermal environment is important for productivity and health.

FINISH:

Controlling thermal comfort

Risk assessment

What can arise: Cold stress/heat stress