0 - Hanford Site

•
s
29.18
RPP-24544 REV Id
• HEAT GAIN THROUGIIrf UORSURFACES
•
I a space with a din.
Attachment: 6 separa ti ngphysical
Cale. No.: 145579-V-CA-004 ue It given by
+ Rev. No: 1 (20)
Sheet 1 of 2
Originals:
Date: lti
Checked by -
adjacent and
. t Date: O`Ttf&R_6S -u, Tempera turerb
a Idtrhes or boiler
above the outdoor
g spaces should be
wn except that the
• I contains no beat
rat Baia rb-4 may
rdoor air and con-
• _,__ ^^ ^e•—.-_^ -.anus 3 l(. In some
t^ the air temperature In the adjacent apace wi ll eovespood to
• the outdoor air tmperahe or higher.
Floors
For floors directly In contact with the g round or over an undaground
baseme nt that is add= ven tilated nor conditioned, beat
ttansfet may be neglected for cooling lad estimates.
INFILTRATION AND VENTILATION 11EAT GA IN
Vent il
ation
Outdoor air must be int roduced to ventilate conditioned spaces.
Chapter 26 suggests minimum outdoor air requdnmeius for reprotenta
tive applications• but the minimum levels am not necessarily
adequate for all psychological attitudes and physiologi cal respouses.
When maximum economy in space and load Is essen tial,
as in subma ri ne& oromer re stricted spsoes, as little is OS Us of outdoor
air per person an be suBlelect, p rovided that recirculated air
Is adequately decontaminated (Consoluio and Pe cora 1944
Local codes and ordinances frequeady spe ci fy ven tilation
requirements
for pub lic places and for Industrial Insta llations. For
exa mple. minimuum requirements for Ufa practice in besot&' open-
• Ming rooms arc given in NFPA $Wndard 99. Although 100% out-
. door air is sometimes used In operating rooms, this s tandard does
not *ulm I% and limiting the Outdoor air to 6 to 8 changes per how
. is finding Increasing aoaptence.
ASIMAE Srmrdord 62 moommeods m(Olo am v entilation ra tes
for most common applications. For bed applica ti ons. ncb ss
office, 101.1s per peasou B suggested.
. Vent ilation air is annua lly introduced at the air-conditioning
apparatus rather man direc tl
y into the conditioned Rum and thus
becomes a cooling Coll load componeraimtead of & spaceload compomrnt•
Calculationsfaestimating this *again am discussed W ct
inthe section on Beat Gain Calculations; Using Standard Air Values.
Reducing her gain from Outdoor star by using filmed reciteu-
^c
2001 ASHRAE Fundamentals Handbook (SI)
the Cooling &coo n. infiltration CsJcub ms ate usually limited b
doors and windows. Air leakage through doors an be estimated
using the informa ti on in Chapter 26. Tab le 3 in Chapter 26,
adju sted for the average wind velocity in the loca lity, may be used
to compute in filtra tion for window s. In calculating window lac.
tra tion for an entire suucutm, the tuW window area on a ll side$ of
the bu il
ding B not Involved since wind does not act on a ll
tides
simttha0eously. In any ease. infiltration from all windows in any
two adjacent wa ll
exposures should be included. A 1mowtedge of
the preva iling wind d irection and velocity is betpfid to selecting
expOsuses.
When ecoaonica lly feasibl e, sufficient outdo or air should be
int ro duced as ven tilation air through the air-condidaaing equipment
to maintain a constant outward escape of air and thus elimina te the
infiltratrom por ti on of the gain. The press ure maintained must bvm
come wind pressure th rough cracks and door ope0lags• When the
quantity of outside air introduced through the cooling equipm en t is
00 suffidMt to n the required press= to el imina te infdha•
lion, the entire infiltra tion load should be included in the space beat
gain calculations.
Standard Ali Volumes
Because the apeeifie volume of air v ades appreciably, alcula•
lions are more accurate when made on the basis of air mass inst ead
of volume. However, volume valu es am often requ ired for seloction
of coils, fans, ducts, etc., in which cases volume valu es based on
meacumeot at standard condi tions may be used for rxvnte
results. One standard value Is 12 kg (dry airyms (0.833 nalk4l.
This deadly co rr esponds to about 16°C at sa turati on and 21 0C dri
air (at 101325 kPa)_ Beca use air usua ll
y panes through the coils,
fans, ducts, em, at a density dose to s ta ndard, the accuracy dcsbW
norma lly requires no correc ti on. When sirflow is to be me as u re d at
a particular condi tion orpoio% such as at a coil entrance orcxlG Ibe
corresponding specific volume can be read from she psychromeaic
chart.
Fsample•3. Stand ar d air calculation. Assume outdoor air at suodaa
condi tions Is Bowleg at 10 mrla. Wbat Is the 1 1 us we when the Wdoor
sir in at 35'Cdry-butt and 24'C wet-bulb (0.193 msAg)7
Solution: The measured rate at that cond i tion sbould be 10
(0.8919.133) -10.7 m31s.
Heat Gain Calculations Using Standard Air Valu es
Alt conditioning design often requires calcula tion of the
fo ll
owing.
1. TOW beat
Total heat Baia 4r eonespoading to the change pf a given saadatd
flow rate 0, through an enthalpy, d$'ereaadh is
where air density. 12 kgW.
2. Sensible beat
4r.12Q^h
Sendbb beat gain ga earapoodmg to the change of dry -b%*
umpctatme ,U for given aullow (shdad coo&bons) Q is : a
4.=12(1.006+1.84W)Z&
d Iced air In combiorion with outdo or air'shoAd be consid ered.
where
L006 . spod& bus 0(&y akIsl/(kg•&)
W. bomkity redo, it Redmoiated air can also be hated to costnal odor (see
lnflltrat(on
$(waeryag(*)-'
1.84. specific beat of watifvVoc kIA4-lii) :eta
The specific heats wefor& range front about 73 so90°Cp
The p rinciples of estimating In filtra tion in buildiogs, with
emphasis on the bating season, am discussed in Chapter 26. For
W- 0,tbevalueofl20(IA06+1.84W)=1 21;whcnW-M0l
value is 123; wh en 8'. 0.02, the value Is I25; ad wben W,i
Chapter ^.
'
13
of th4 volume and Cbapta 44 of the 1999 ASHRAE lfmdbook-
Apparadoet).
A5-656
I