Meaning

c 
    
 

 
      



 



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 m    September 1, 2010

 

c "#$%#&' Ê i
rease i the amou t of heat
o tai ed i a spa
e, resulti  from dire
t solar radiatio , heat flow throuh walls, wi dows, a d other buildi  surfa
es a d the heat ive off by people, lihts, equipme t a d other sour
es.

c "#$()** Ê de
rease i the amou t of heat
o tai ed i a spa
e, resulti  from heat flow throuh walls, wi dows, roof a d other buildi  surfa
es a d from exfiltratio of warm air.

c ))(&'%()#+ d xpressed i Btu/h): The maximum amou t of heat, u der desi
o ditio s, that builds up i a spa
e without a
ooli  system operati . It is
al
ulated to determi e the
apa
ity of air
o ditio er required.

·c "#$&'%()#+ The rate of heat ai required to mai tai i door
omfort; measured i BTU's per hour.

c "#$",$-#.$&)'-#$" The rate at whi
h heat is removed from the
o ditio ed spa
e a d is equal to the spa
e
ooli  load if the room temperature remai s
o sta t.

c "#$#++&$&)'-#$" The rate at whi
h heat is added from the
o ditio ed spa
e a d is equal to the spa
e
ooli  load if the room temperature remai s
o sta t.

!c "#/()#+ The ele
tri
load that
orrespo ds to a maximum level of ele
tri
dema d i a spe
ified time period. Peak periods duri  the day usually o

ur i the mor i  hours from 6 to 9 a.m. a d duri  the after oo s from 4 to about 8 or 9 p.m. The after oo peak dema d periods are usually hiher, a d they are hihest duri  summer mo ths whe airʹ
o ditio i  use is the hihest. Ê

ual peaks e erally o

ur o hot summer days.

*c "'*&0("1"#$ Se sible heat is defi ed as the heat e ery that
auses a
ha e i temperature of a substa
e but does ot
o tribute to a
ha e i state dfor example, steam to liquid water) for the substa
e.

c #$"'$1"#$ |eat e ery that must be tra sferred to or removed from a substa
e to
ha e its state. For example, e ery used to boil water dlate t heat e ery)
a

ot raise the

temperature of the water beyo d 212°F / 100°C. Êddi  more heat will a

elerate the boili  dphase
ha e) but will ot raise the temperature of the water.

c )'+2.$&)' Ê mode of heat tra sfer i whi
h heat e ery is tra sferred withi a obje
t itself or betwee obje
ts i
o ta
t. Whe a
old spoo is left i a pot of boili  water, the spoo eve tually be
omes hot. This is a example of
o du
tio . Co du
tio is o e of the three forms of heat tra sfer, whi
h also i
lude Co ve
tio a d Radiatio .

c )'3".$&)' Ê mode of heat tra sfer i whi
h heat e ery is tra sferred from a obje
t to movi  fluid su
h as air, water, or refriera t. The heat si k of a
omputer pro
essor is a example of heat tra sfer by
o ve
tio . Co ve
tio is o e of the three forms of heat tra sfer, whi
h also i
lude Co du
tio a d Radiatio .

c#+&#$&)' Ê mode of heat tra sfer i whi
h heat e ery is tra sferred via ele
troma eti
waves. Ê item warmed by su liht is a example of radia t heati . Radiatio is o e of the three forms of heat tra sfer, whi
h also i
lude Co ve
tio a d Co du
tio .

c 3#4)-#$&)' The pro
ess of a liquid be
omi  a vapor. If a
up of water were boiled for lo  e ouh, all the water would be o e. By addi  heat, all the water be
omes a vapor a d mixes with the air.

·c"54"-#$2-" The measureme t of heat e ery withi a body or substa
e. There are two
ommo s
ales used to measure temperature, Ce tirade a d Fahre heit. The Ce tirade s
ale dalso
ommo ly referred to as Celsius) is widely used i ter atio ally while the Fahre heit s
ale is
ommo ly used i the U ited States.

 c"(#$&3"125&+&$6 The amou t of water vapor
o tai ed i air relative to the maximum amou t the air is
apable of holdi . xpressed i per
e tae d
).

c )57)-$8)'" The ra e of temperatures, humidity a d air velo
ities at whi
h the reatest per
e tae of people feel
omfortable.

!c)(#&-$"54"-#$2-" d÷sol-air) is a variable used to
al
ulate
ooli  load of a buildi  a d determi e the total heat ai throuh exterior surfa
es.

*c9"'$&(#$&)' The i te tio al moveme t of air from outside a buildi  to the i side. It is the Ë i | ÊC. With
lothes dryers, a d
ombustio

equipme t su
h as water heaters, boilers,

firepla
es, a d wood stoves, their exhausts are ofte
alled
 or 
 Ͷ this should ot be
o fused with
  . The ve ts or flues
arry the produ
ts of
ombustio whi
h have to be expelled from the buildi  i a way whi
h does ot
ause harm to the o

upa ts of the buildi .

c '7&($-#$&)' The u i te tio al or a

ide tal i trodu
tio of outside air i to a buildi , typi
ally throuh
ra
ks i

the buildi  e velope a d throuh use of doors for passae

I filtratio is sometimes
alled air leakae.

cm"'"*$-#$&)' The pla
eme t of wi dow ope i s i a buildi  wall, o e of the importa t eleme ts i
o trolli  the exterior appeara
e of a buildi . Êlso, a wi dow, door or skyliht a d its asso
iated i terior or exterior eleme ts, su
h as shades or bli ds.

c )'+&$&)'"+*4#." The part of the buildi  that is desi ed to be thermally
o ditio ed for the
omfort of o

upa ts or for other o

upa
ies or for other reaso s.  c '+))-#&-:2#(&$6 Term referri  to the air quality withi a d arou d buildi s a d stru
tures, espe
ially as it relates to the health a d
omfort of buildi  o

upa ts.

c1"-5)*$#$ Ê devi
e for reulati  the temperature of a system so that the system's temperature is mai tai ed ear a desired 
  temperature. The ame is derived from the Greek words thermos "hot" a d statos "a sta di ". The thermostat does this by swit
hi  heati  or
ooli  devi
es o or off, or reulati  the flow of a heat tra sfer fluid as eeded, to mai tai the
orre
t temperature.

·c..24#'$ Ê perso who o

upies a pla
e or a positio ; Ê ow er or te a t of a property; Ê perso sitti  i a
ar or other vehi
le.

 c"$#0)(&.1"#$ |eat ai from o

upa ts i air
o ditio ed spa
es at differe t derees of a
tivities - i Watts.

c*6.1-)5"$-&. 1#-$ Graph of the thermody ami
properties of moist air at a
o sta t pressure dofte equated to a elevatio relative to sea level).

!c"#$$-#'*7"- The tra sitio of thermal e ery from a hotter mass to a
ooler mass. Whe a obje
t is at a differe t temperature tha its surrou di s or a other obje
t,  
 
 

, also k ow as 
  
, or 

 
, o

urs i su
h a way that the body a d the surrou di s rea
h thermal equilibrium; this mea s that they are at the same temperature. |eat tra sfer always o

urs from a hiher-temperature obje
t to a
ooler-temperature o e as des
ribed by the se
o d law of thermody ami
s or the Clausius stateme t. Where there is a temperature differe
e betwee proximity, heat tra sfer betwee them
a

obje
ts i

ever be stopped; it
a o ly be slowed.

*cm&-*$(#;)7$1"-5)+6'#5&.* Ê expressio of the pri
iple of
o servatio of e ery, states that e ery
a be tra sformed d
ha ed from o e form to a other), but
a

ot be
reated or destroyed.

͞The i
rease i the i ter al e ery of a system is equal to the amou t of e ery added by heati  the system mi us the amou t lost as a result of the work do e by the system o its surrou di s.͟  c1"-5)+6'#5&.4-)4"-$&"* |ere is a partial (&*$)7$1"-5)+6'#5&.4-)4"-$&"* of fluids: temperature [K]

[c

÷

[c

š de sity [k/m3]

[c

 spe
ifi
heat at
o sta t pressure [J/dkK)]

[c



[c

ß dy ami
vis
osity [N/dm²s)]

[c

ki emati
vis
osity [m²/s]

[c

ü

thermal
o du
tivity [W/dmK)]

[c

 thermal diffusivity [m²/s]

[c

] volumetri
thermal expa sio
oeffi
ie t [Kо1]

[c

| e thalpy [J/k]

[c

2

[c

› ibbs free e ery [J/k]

[c

Ê |elmholtz free e ery

[c

 pressure [N/m²]

[c

Ë volume

[c



[c

a
tivity

[c

ß
hemi
al pote tial

spe
ifi
heat at
o sta t volume [J/dkK)]

e tropy [J/dkK)]

fua
ity