Terminology BEC
CHAPTER 1:
Enthalpy: total energy/heat content of a system
Wet/dry bulb T: dia 55
+ alle concepten van condensation/evaporation en refrigorator!!!
CHAPTER 2:
Basal metabolism: metabolism of an inactive, wake organism with an empty
stomach in a thermoneutral state and in a neutral mental state = energy
consumption at rest
Direct calorimeter: used to measure the amount of heat produced by a system.
It measures the heat exchange DIRECTLY by observing change of T
Person is in a room with oxygen supply (for heat production) and in the
walls flows cold water in. The person generates heat and gives this off
to his environment. Heat is taken up by the water in the walls so the
water is heated up. Heated water goes out of the system. Temperature
difference between the incoming and outgoing water lets us know how
much heat is taken up by the water and thus how much heat is given
off by the person. (wordt nog weinig gebruikt)
Air flow calorimeter: measures SENSIBLE AND LATENT heat exchange (ook
directe calorimeter)
Sensible: by change of temperature of an air flow passing through the
system. Q = deltaT*m*c of the air = non-evaporative heat exchange
Latent: by change in water vapor content of the air flow = evaporative
heat exchange
Indirect calorimeter: measures heat production by measuring respiratory gas
exchange (O2 consumed and CO2 produced) during physical activity of the person
measures REE
Resting energy expenditure (REE): the energy consumption while a person is
at rest and awake. An indirect calorimeter measures VO 2 and VCO2 and REE =
[(VO2 * 3,941) + (VCO2 * 1,11)] * 1,440
Metabolic rate: rate at which the body uses food energy to sustain life and to
do different activities [W or W/m² or met]
Met = metabolic equivalent: amount of oxygen consumed (while sitting at
rest) is equal to 3,5 ml O2 per kg body weight per minute 1 met = 58 W/m² (m²
is body surface of a person = 1,8 m²)
Energy storage: when an organism absorbs more energy (from food) than it
uses
, Feed conversion rator: kg of feed needed for the animal to produce 1 kg of
body mass (higher = less efficient)
Thermoregulation: animals try to maintain a constant body temperature by
regulating heat loss/gain (this is what warm blooded animals do) different
mechanisms: conduction, convection, radiation, latent heat loss (= evaporative
bv sweating/respiration)
Heat production:
o More heat produced when: environmental T is very low or very
high
o Cte heat production in themoneutral zone
Sensible heat loss:
o Convection, conduction, radiation when T increases, this
decreases
Latent heat loss:
o Sweating/respiration happens when T is relatively high
Production and loss IN BALANCE
Thermoneutral zone (TNZ): range of ambient temperatures where body can
maintain a constant body temperature without needing extra heat production
from metabolic processes. (it only regulates the circulatory system which is heat
transport via blood (vasoconstriction, …))
Upper/lower critical temperature (UCT/LCT): highest/lowest temperature at
which the body can maintain a constant body temperature without extra heat
loss/production
Under LCT: body begins to shiver and increase metabolic heat
production to prevent undercooling
Above UCT: body begins to sweat/pant/… (thermoregulatory
mechanisms) to prevent overheating
Thermal comfort zone (TCZ): range of ambient temperatures where a person
feels optimally comfortable. Out of this zone a person will shiver/start sweating
which is more uncomfortable. In this zone the heat production and both heat
losses are at a constant rate. minimal energy needed for the body to keep a
constant temperature
Before TCZ: regulation by heat production
After TCZ: regulation by latent heat loss (ECT)
Evaporative critical temperature (ECT): temperature at which latent heat
loss starts
Total energy balance: Etot = EBM + Eact + Etherm + Emental + Estorage
Activity will influence energy consumed by thermoregulation processes
(sweating)
CHAPTER 1:
Enthalpy: total energy/heat content of a system
Wet/dry bulb T: dia 55
+ alle concepten van condensation/evaporation en refrigorator!!!
CHAPTER 2:
Basal metabolism: metabolism of an inactive, wake organism with an empty
stomach in a thermoneutral state and in a neutral mental state = energy
consumption at rest
Direct calorimeter: used to measure the amount of heat produced by a system.
It measures the heat exchange DIRECTLY by observing change of T
Person is in a room with oxygen supply (for heat production) and in the
walls flows cold water in. The person generates heat and gives this off
to his environment. Heat is taken up by the water in the walls so the
water is heated up. Heated water goes out of the system. Temperature
difference between the incoming and outgoing water lets us know how
much heat is taken up by the water and thus how much heat is given
off by the person. (wordt nog weinig gebruikt)
Air flow calorimeter: measures SENSIBLE AND LATENT heat exchange (ook
directe calorimeter)
Sensible: by change of temperature of an air flow passing through the
system. Q = deltaT*m*c of the air = non-evaporative heat exchange
Latent: by change in water vapor content of the air flow = evaporative
heat exchange
Indirect calorimeter: measures heat production by measuring respiratory gas
exchange (O2 consumed and CO2 produced) during physical activity of the person
measures REE
Resting energy expenditure (REE): the energy consumption while a person is
at rest and awake. An indirect calorimeter measures VO 2 and VCO2 and REE =
[(VO2 * 3,941) + (VCO2 * 1,11)] * 1,440
Metabolic rate: rate at which the body uses food energy to sustain life and to
do different activities [W or W/m² or met]
Met = metabolic equivalent: amount of oxygen consumed (while sitting at
rest) is equal to 3,5 ml O2 per kg body weight per minute 1 met = 58 W/m² (m²
is body surface of a person = 1,8 m²)
Energy storage: when an organism absorbs more energy (from food) than it
uses
, Feed conversion rator: kg of feed needed for the animal to produce 1 kg of
body mass (higher = less efficient)
Thermoregulation: animals try to maintain a constant body temperature by
regulating heat loss/gain (this is what warm blooded animals do) different
mechanisms: conduction, convection, radiation, latent heat loss (= evaporative
bv sweating/respiration)
Heat production:
o More heat produced when: environmental T is very low or very
high
o Cte heat production in themoneutral zone
Sensible heat loss:
o Convection, conduction, radiation when T increases, this
decreases
Latent heat loss:
o Sweating/respiration happens when T is relatively high
Production and loss IN BALANCE
Thermoneutral zone (TNZ): range of ambient temperatures where body can
maintain a constant body temperature without needing extra heat production
from metabolic processes. (it only regulates the circulatory system which is heat
transport via blood (vasoconstriction, …))
Upper/lower critical temperature (UCT/LCT): highest/lowest temperature at
which the body can maintain a constant body temperature without extra heat
loss/production
Under LCT: body begins to shiver and increase metabolic heat
production to prevent undercooling
Above UCT: body begins to sweat/pant/… (thermoregulatory
mechanisms) to prevent overheating
Thermal comfort zone (TCZ): range of ambient temperatures where a person
feels optimally comfortable. Out of this zone a person will shiver/start sweating
which is more uncomfortable. In this zone the heat production and both heat
losses are at a constant rate. minimal energy needed for the body to keep a
constant temperature
Before TCZ: regulation by heat production
After TCZ: regulation by latent heat loss (ECT)
Evaporative critical temperature (ECT): temperature at which latent heat
loss starts
Total energy balance: Etot = EBM + Eact + Etherm + Emental + Estorage
Activity will influence energy consumed by thermoregulation processes
(sweating)
