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NP14 Heat diagram (comfort zone)

Q: What is A, B and C on the heat diagram/heat balance at temp< body T? and A-B and A-C

A = LCT B = UCT A-B = thermoneutra zone A-C = comfort zone Red line = passive heat loss (Hp) Hp -> = constante x (s/i) x delta (Ts-Ta) s= surface i = insulation Ts = skin temp

14 important questions on NP14 Heat diagram (comfort zone)

What are (the) temperature zone"s

Specific windows of environmental temp.

homeothermic zone ± physiological
thermoneutra zone (TNZ) ± metabolic
comfort zone ± instinctive, behaviour

Thermoneutrality
where in a graph do you find the thermoneutral zone (TNZ)

In the middle, next to the basal metabolic rate

Where is the lower critical temperature (LCT) located? And where the upper critical temperature (UCT)?

LCT left side of the thermal neutral zone. UCT right side of the thermal neutral zone.

Where is the thermal comfort zone located compared to the TNZ

It is wider compared to the TNZ and it goes lower than the LCT

Thermoneutral zone (TNZ, metabolic) =

Window of environmental temperatures that allows maintaining the body temp

The heat production vs environmental temp. is constant.

No consequences for energy requirements

Comfort zone (instinctive - behaviour)

Window of environmental temperatures that allows maintaining the body temp.

The heat production vs environmental temp. is constant.

Temp-regulation is not unpleasant. Preferred temp-range. Motivation!

Personal comfort zone?

What is for yourself the window of environmental temperatures that give you a feeling of thermal comfort, without prior acclimatisation?

You will get an impression when you discuss what will happen upon an increase/decrease of environmental temperature.

comfort zone is about 5 degrees window, from 18 - 23 *C

What is on the x and y asses of the heat diagram / heat balance at different temperatures?

X = ambient temperature (celcius)
Y = heat load / heat loss (maintenance)

you can not get lower than 1 on the Y as , then you are dead

What is A, B and C on the heat diagram/heat balance at temp< body T?
and A-B and A-C

A = LCT
B = UCT
A-B = thermoneutra zone
A-C = comfort zone

Red line = passive heat loss (Hp)

Hp -> = constante x (s/i) x delta (Ts-Ta)

s= surface
i = insulation
Ts = skin temp

How can you get the skin temperature in a heat diagram?

Connect all the A's and see what the temperature on the X-as is.

In the image the skin temperature is 30*C

How can you determine the lower critical temperature (Tc)

Where the line from Ts is crossing the line at 1 of the y-as.

How can you achieve a heat load = heat loss. Looking at the picture?
A:
B:
C:
D:
E:

A: more insulation, put on a cap [increase insulation]
B: You increase your environmental temperature [increase Ta]
C: it is not possible, because it is lower than 1 [start sweating]
D: increasing metabolic rate from 1 to 2 --> becoming more active [increase heat load]
E: [start sweating]

Increasing external heat load

When Ta is increased, you have to consider two different phases, which ones

Ta <= Tb
Ta >= Tb

Increasing external heat load; Ta >= Tb

External heat gain is the driehoek rechts onder. --> sweating

Bx -> B0 = making use of maximal evaporation -> the line lowers because the rest will go the external heat gain (environment)

VI total heat load
VII is your UCT

II maintenance heat production
IV Ta > Tb; heat loss only by evaporation and external heat load from environment
V Max. Evaporation = evaporation capacity
VI external heat load (He) vs. Ta
VII UCT for maintenance heat production (B0)
VIII Evaporation space = Me - He
IX heat load = heat loss = max. Evaporation

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Nutritional Physiology

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NP14 Heat diagram (comfort zone)

14 important questions on NP14 Heat diagram (comfort zone)

What are (the) temperature zone"s

Thermoneutrality where in a graph do you find the thermoneutral zone (TNZ)

Where is the lower critical temperature (LCT) located? And where the upper critical temperature (UCT)?

Where is the thermal comfort zone located compared to the TNZ

Thermoneutral zone (TNZ, metabolic) =

Comfort zone (instinctive - behaviour)

Personal comfort zone?

What is on the x and y asses of the heat diagram / heat balance at different temperatures?

What is A, B and C on the heat diagram/heat balance at temp< body T?and A-B and A-C

How can you get the skin temperature in a heat diagram?

How can you determine the lower critical temperature (Tc)

How can you achieve a heat load = heat loss. Looking at the picture?A:B:C:D:E:

Increasing external heat loadWhen Ta is increased, you have to consider two different phases, which ones

Increasing external heat load; Ta >= Tb

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Thermoneutrality
where in a graph do you find the thermoneutral zone (TNZ)

What is A, B and C on the heat diagram/heat balance at temp< body T?
and A-B and A-C

How can you achieve a heat load = heat loss. Looking at the picture?
A:
B:
C:
D:
E:

Increasing external heat load

When Ta is increased, you have to consider two different phases, which ones