425 1 design temps lecture and hw

8/6/2019 425 1 Design Temps Lecture and HW

1/17

ME 425 Overview & Design Conditions

ME 425

Air Conditioning System Design

Keith E. Elder, P.E.

ME 425

In enclosed spaces, the combinedtreatment of the air to control, as

specified, temperature, relative humidity,velocity of motion, and radiant heatenergy level, with consideration of theneed for removal of air-borne particlesand contaminant gases.


2/17


ME 425

Chilled Water Pump

Heat

Exchanger

Heat

Exchanger

Compressor Expansion

Valve

Cooling

Coil

Fan

ColdAir

WarmAir

Warm

Water

Chilled

Water

Hot

Gas

GasCondensed

Liquid

CoolingTower Condenser

Pump

Hot

Water

WarmMoist Air

Cooler

DryerAir

Warm

Water

Emphasis ofME 425

ME 425

Formal Version

)/Btuin(5.4

)/in(4840

min)/in&Btu/hrin(1.1 3

airtotal

airwaterlatent

sensible

lbmhhQq

lbmlbmWWQq

ftQqtQq

Designers Version (based on air volume)

hmq

Wmq

tcmq

total

latent

psensible


3/17


ME 425

Calculate Sensible & Latent loads

Determine space air quantities

Select & layout diffusers

Layout & size ductwork

Select Air Handler(s)

Calculate Coil Loads & Select Coil(s)

Pipe coils & select pumps

Select primary systems (chillers, boilers)

Write specifications (including controls)

ME 425

Major Steps in Load Calculations

Determine indoor/outdoor design conditions

Research & Calculate thermal properties ofenvelope components

Determine zoning

Perform Area Takeoffs

Calculate Space Sensible & Latent Loads

Determine Ventilation & Other SystemEffects

Calculate Coil Loads


4/17


ME 425

Indoor Conditions (Comfort-based) Indoor Dry Bulb Temperature

Indoor Relative Humidity

Outdoor Conditions (Statistical-based) Dry Bulb Temperature

Mean Coincident Wet Bulb Temperature

Daily Range

Degree Days

Ground Temperatures

ME 425

Dry Bulb Temperature


5/17


ME 425

ME 425

Indoor Dry Bulb Temperature

Indoor Relative Humidity

Temperature Stratification

Temperature Symmetry Draft

Carbon Dioxide Concentration


6/17


7/17


ME 425

Age

Activity Level

Gender (see page 8.16 under Sex)

Temperature

Relative Humidity

Dress & Activity Level

Adaptation Resignation is not adaptation

Seasonal & Circadian Rhythms

ME 425

The Comfort Chart

Comfort Based On Operative Temperature Room Humidity Heating/Cooling Mode

Op. Temp. Based On Room DB Temp. Mean Radiant Temp. Local Air Velocity


8/17


ME 425

o

The uniform temperature of a

radiantly black enclosure in

which an occupant would

exchange the same amount of

heat by radiation plus

convection as in the actual non-

uniform environment

to = Ata + (1-A)tr

ta = Local Air Temp.

A = f(air motion)

tr = Mean Radiant Temp.

Velocity(fpm) A

10 0.42

30 0.42

40 0.46

60 0.52

80 0.55

100 0.58

120 0.61140 0.63

160 0.65

ME 425

r

The uniform surface temperature of a

radiantly black enclosure in which an

occupant would exchange the same amount of

radiant heat as in the actual non-uniformenvironment.

tr = F1t1 + F2t2 + ... Fntn

Fn = Angle Factor


9/17


ME 425

n

ME 425

Determination of Outdoor Design Conditions

0

50

100

150

200

250

300

350

400

450

14 17 20 23 26 29 32 35 38 41 44 47 50 53 56 59 62 65 68 71 74 77 80 83 86 90 93

AnnualTe mperature Occurence s (F)

HoursperYear


10/17


ME 425

0

50

100

150

200

250

300

350

400

450

14 17 20 23 26 29 32 35 38 41 44 47 50 53 56 59 62 65 68 71 74 77 80 83 86 90 93

AnnualTemperature Occurences (F)

HoursperYear

99.6%

99.0% 1.0%

0.4%

ME 425


11/17


ME 425

ME 425

Heating Load

Design Conditions

Cooling Load

Design Conditions


12/17


ME 425

Seasonal Hours

Criteria Exceeded Representative Application

Summer

0.4% 35 Hospital, Data Center

1.0% 88 Average Project

2.0% 175 Promotional (Cut Corners)

Winter99.6 % 35 Medium Construction, 24 Occupancy

99.0% 88 Heavy Construction

ME 425

Homework for Friday Name______________________

1. A room is maintained at an air temperature of 70F.The occupant sits near a large window, which has aninside surface temperature of 50F and accounts for30% of her thermal view. The occupant hascomplained that the space feels cold. Assuming the

local air temperature to be equal to the room airtemperature:

a. What operative temperature does the occupantexperience?

b. How would you advise the HVAC technician whois trying to troubleshoot the complaint?

Reference: Chap 8 - ASHRAE Fundamentals


13/17


ME 425

Homework - Continued

2. Specify a suitable set of indoor and outdoor designconditions for each of the following

Outdoor

DB/WB

Indoor

DB/RH

Outdoor

DB

Indoor

DB

Steel & Glass Office Building

Seattle, Washington

Computer Data Center

Quantico, Virginia

Nursing HomeLong Beach, CA

Heavy Masonry Office Building

Fargo, North Dakota

SummerWinter

Reference: Chap 28 - ASHRAE Fundamentals (CD)


14/17

2005 ASHRAE Handbook - Fundamentals (IP) 2005 ASHRAE, Inc.

Station Information

1b 1c 1d 1e 1f 1g 1h 1i

FARGO 727530 46.90N 96.80W 899 14.225 -6.00 NAC 7201

Annual Heating and Humidification Design Conditions

99.6% 99% DP HR MCDB DP HR MCDB WS MCDB WS MCDB MCWS PCWD

2 3a 3b 4a 4b 4c 4d 4e 4f 5a 5b 5c 5d 6a 6b

1 -21.1 -16.5 -29.8 1.1 -20.4 -25.0 1.4 -16.0 36.5 5.0 32.8 6.4 7.9 180

Annual Cooling, Dehumidification, and Enthalpy Design Conditions

DB MCWB DB MCWB DB MCWB WB MCDB WB MCDB WB MCDB MCWS PCWD

7 8 9a 9b 9c 9d 9e 9f 10a 10b 10c 10d 10e 10f 11a 11b

7 21.6 91.1 71.6 87.8 69.9 84.8 68.5 75.3 85.6 73.2 83.6 71.1 81.3 14.8 170

DP HR MCDB DP HR MCDB DP HR MCDB Enth MCDB Enth MCDB Enth MCDB

12a 12b 12c 12d 12e 12f 12g 12h 12i 13a 13b 13c 13d 13e 13f

72.2 123.4 81.5 69.6 112.4 79.9 67.5 104.4 77.1 31.8 86.0 29.7 83.8 27.8 81.3

Extreme Annual Design Conditions

1% 2.5% 5% Max Min Max Min Max Min Max Min Max Min Max Min

14a 14b 14c 15 16a 16b 16c 16d 17a 17b 17c 17d 17e 17f 17g 17h

28.5 25.7 23.4 82.4 97.3 -25.7 3.9 5.1 100.1 -29.4 102.4 -32.4 104.6 -35.2 107.4 -38.9

Monthly Design Dry Bulb and Mean Coincident Wet Bulb Temperatures

DB MCWB DB MCWB DB MCWB DB MCWB DB MCWB DB MCWB

18a 18b 18c 18d 18e 18f 18g 18h 18i 18j 18k 18l

0.4% 39.0 35.0 46.5 40.8 58.8 49.3 82.5 60.1 88.7 66.4 92.8 71.6

1% 36.7 33.6 43.6 39.1 55.0 46.6 78.1 57.3 86.4 65.5 90.9 71.5

2% 34.8 32.3 40.8 37.2 51.5 45.2 73.8 55.2 83.7 63.8 88.3 70.0


18m 18n 18o 18p 18q 18r 18s 18t 18u 18v 18w 18x

0.4% 95.7 73.0 95.3 72.8 91.3 70.0 78.4 60.0 61.9 50.7 43.9 38.3

1% 92.8 73.3 92.7 72.6 87.3 67.9 74.3 58.1 57.8 48.7 40.1 35.6

2% 90.4 72.1 90.3 71.5 84.2 66.0 70.8 56.7 54.1 46.8 37.2 33.8

Monthly Design Wet Bulb and Mean Coincident Dry Bulb Temperatures

WB MCDB WB MCDB WB MCDB WB MCDB WB MCDB WB MCDB

19a 19b 19c 19d 19e 19f 19g 19h 19i 19j 19k 19l

0.4% 35.3 38.4 41.6 45.7 50.6 55.7 62.5 78.5 70.2 83.7 76.5 86.3

1% 33.9 36.2 39.3 43.0 48.0 53.9 60.0 73.7 68.5 81.2 74.6 85.3

2% 32.6 34.6 37.2 40.6 45.4 50.6 57.2 69.8 67.0 79.0 72.9 84.2


19m 19n 19o 19p 19q 19r 19s 19t 19u 19v 19w 19x

0.4% 78.8 88.0 77.9 89.4 72.8 85.7 63.6 72.0 53.1 58.6 38.9 43.9

1% 77.4 87.2 76.1 87.2 71.0 82.0 61.2 70.1 50.2 56.1 36.0 39.5

2% 75.9 85.8 74.7 85.2 69.2 78.5 59.2 67.8 47.6 53.3 34.1 36.5

Monthly Mean Daily Temperature Range

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

20a 20b 20c 20d 20e 20f 20g 20h 20i 20j 20k 20l

17.0 16.3 15.4 20.9 22.9 21.6 21.6 22.3 22.2 20.3 15.3 15.1

WMO# World Meteorological Organization number Lat Latitude, Long Longitude,

Elev Elevation, ft StdP Standard pressure at station elevation, psi

DB Dry bulb temperature, F DP Dew point temperature, F WB Wet bulb temperature, F

WS Wind speed, mph Enth Enthalpy, Btu/lb HR Humidity ratio, grains of moisture per lb of dry air

MCDB Mean coincident dry bulb temperature, F MCDP Mean coincident dew point temperature, F MCWB Mean coincident wet bulb temperature, F

MCWS Mean coinc ident w ind speed , mph PCWD Preva il ing coinc ident wind di rect ion, , 0 = Nor th, 90 = East

Time zone

code

Coldest month WS/MCDB

0.4% 1%

Period

1a

Hours +/-

UTCElevLong

n-Year Return Period Values of Extreme DB

2%

MCWS/PCWD

to 0.4% DB

Standard deviation n=50 years

0.4% 1% 2%

Enthalpy/MCDB

Cooling DB/MCWB

MCWS/PCWD

to 99.6% DB

StdP

Humidification DP/MCDB and HR

Station name WMO#

Coldest

month

Heating DB99.6%

Lat

99%

2% 0.4%

Evaporation WB/MCDB

0.4% 2%1%

Dec

%

Jan

Feb Mar

Feb Mar

% Aug

Jun

Extreme

Max

WB

Hottest

month1%

Extreme Annual DB

Mean

Dehumidification DP/MCDB and HR

0.4% 1%

Extreme Annual WS

Hottest

month

DB range

n=5 years

JunMay

n=20 yearsn=10 years

Apr May

%

Jan

NovJul

Apr

Design conditions for FARGO, ND, USA

Aug Sep Oct Nov

Dec

%

Jul

Sep Oct


15/17


Station Information

1b 1c 1d 1e 1f 1g 1h 1i

LONG BEACH 722970 33.82N 118.15W 56 14.666 -8.00 NAP 7201



2 3a 3b 4a 4b 4c 4d 4e 4f 5a 5b 5c 5d 6a 6b

12 40.8 43.1 12.7 10.5 60.7 19.6 14.8 62.1 21.6 57.0 18.7 58.2 3.0 300



7 8 9a 9b 9c 9d 9e 9f 10a 10b 10c 10d 10e 10f 11a 11b

8 16.7 91.5 68.0 87.7 67.3 84.5 66.6 72.2 84.1 70.8 82.0 69.5 79.8 9.5 280



68.7 105.7 76.3 67.1 100.0 75.5 65.8 95.4 74.6 28.2 83.9 27.0 82.0 26.0 80.2




17.9 15.5 12.9 79.5 101.8 35.8 4.2 2.9 104.8 33.7 107.3 32.0 109.6 30.4 112.7 28.3



18a 18b 18c 18d 18e 18f 18g 18h 18i 18j 18k 18l

0.4% 82.1 56.2 82.4 58.0 84.3 60.0 88.0 61.0 88.1 65.0 94.3 66.7

1% 79.2 55.6 79.3 57.4 80.1 58.9 84.3 60.5 83.8 64.6 88.9 67.1

2% 75.8 54.8 76.2 56.0 76.6 58.1 81.1 60.1 80.3 63.8 85.1 66.5


18m 18n 18o 18p 18q 18r 18s 18t 18u 18v 18w 18x

0.4% 92.2 69.1 95.2 70.9 96.9 69.8 94.4 64.2 87.7 59.5 81.0 55.0

1% 89.1 69.4 91.4 71.1 92.9 69.3 89.9 62.8 84.1 58.7 78.2 54.7

2% 86.9 68.9 88.8 70.2 90.2 69.5 86.3 62.5 80.6 57.2 75.6 54.5



19a 19b 19c 19d 19e 19f 19g 19h 19i 19j 19k 19l

0.4% 61.4 67.7 62.0 72.7 64.1 75.3 65.8 79.9 68.7 80.1 70.2 84.4

1% 60.4 66.4 61.0 69.4 62.4 72.4 64.4 77.4 67.5 78.9 69.2 82.1

2% 59.6 65.3 60.2 67.6 61.5 70.6 63.2 75.1 66.2 76.2 68.3 80.4


19m 19n 19o 19p 19q 19r 19s 19t 19u 19v 19w 19x

0.4% 72.2 85.7 74.3 88.0 74.8 86.5 70.0 80.3 65.6 74.5 61.5 66.9

1% 71.3 84.1 73.3 86.4 73.4 83.8 69.0 78.7 64.3 72.5 60.4 66.3

2% 70.6 82.6 72.3 84.4 72.4 83.1 68.0 77.6 63.3 71.1 59.5 65.9



20a 20b 20c 20d 20e 20f 20g 20h 20i 20j 20k 20l

18.9 17.4 15.7 16.9 14.2 15.1 16.2 16.7 16.8 17.3 19.9 20.4







Time zone

code


0.4% 1%

Period

1a

Hours +/-

UTCElevLong


2%

MCWS/PCWD

to 0.4% DB


0.4% 1% 2%

Enthalpy/MCDB

Cooling DB/MCWB

MCWS/PCWD

to 99.6% DB

StdP


Station name WMO#

Coldest

month

Heating DB99.6%

Lat

99%

2% 0.4%

Evaporation WB/MCDB

0.4% 2%1%

Dec

%

Jan

Feb Mar

Feb Mar

% Aug

Jun

Extreme

Max

WB

Hottest

month1%

Extreme Annual DB

Mean


0.4% 1%

Extreme Annual WS

Hottest

month

DB range

n=5 years

JunMay


Apr May

%

Jan

NovJul

Apr

Design conditions for LONG BEACH, CA, USA

Aug Sep Oct Nov

Dec

%

Jul

Sep Oct


16/17


Station Information

1b 1c 1d 1e 1f 1g 1h 1i

QUANTICO MCAS 724035 38.50N 77.30W 13 14.689 -5.00 NAE 8401



2 3a 3b 4a 4b 4c 4d 4e 4f 5a 5b 5c 5d 6a 6b

1 15.8 19.8 -2.0 4.9 19.2 2.8 6.4 24.9 23.4 39.4 19.9 36.5 5.9 320



7 8 9a 9b 9c 9d 9e 9f 10a 10b 10c 10d 10e 10f 11a 11b

7 17.5 93.0 76.5 90.6 75.8 88.3 74.5 79.4 89.5 77.9 87.8 76.6 85.6 5.6 170



76.6 138.8 85.3 75.0 131.2 83.6 73.5 124.7 81.8 35.1 89.9 33.6 88.0 32.2 85.5




18.5 16.2 13.6 90.0 97.6 7.6 3.0 7.5 99.8 2.2 101.5 -2.2 103.2 -6.4 105.4 -11.8



18a 18b 18c 18d 18e 18f 18g 18h 18i 18j 18k 18l

0.4% 63.4 54.5 71.7 57.7 81.5 62.3 87.3 65.6 90.9 72.9 94.3 75.7

1% 60.8 52.3 67.4 57.0 77.0 59.6 83.1 63.9 88.5 72.0 92.3 75.1

2% 57.4 50.2 63.6 55.0 72.9 58.8 80.0 62.5 86.2 70.7 90.5 75.1


18m 18n 18o 18p 18q 18r 18s 18t 18u 18v 18w 18x

0.4% 97.5 78.2 95.1 76.9 92.0 76.4 83.2 70.1 74.8 62.3 70.3 60.4

1% 95.7 77.5 93.0 77.3 89.0 74.6 81.0 69.4 72.3 60.9 67.0 57.1

2% 93.6 77.2 91.3 76.8 86.7 73.4 78.6 67.9 69.1 58.4 63.6 55.6



19a 19b 19c 19d 19e 19f 19g 19h 19i 19j 19k 19l

0.4% 57.6 61.2 61.5 69.7 63.8 78.0 69.7 79.7 77.5 88.2 79.4 88.7

1% 55.1 58.3 58.8 65.3 62.1 75.0 67.7 78.1 75.7 84.8 78.3 87.6

2% 53.0 56.0 55.9 63.0 60.2 70.9 65.7 75.3 73.8 81.8 77.6 86.9


19m 19n 19o 19p 19q 19r 19s 19t 19u 19v 19w 19x

0.4% 82.0 90.0 81.5 88.8 78.3 87.1 72.9 79.3 64.7 72.2 61.7 67.3

1% 80.8 90.2 80.0 89.0 77.1 85.2 71.2 77.3 63.3 68.6 59.3 66.2

2% 79.9 90.1 78.8 88.3 76.0 83.8 70.0 76.4 61.6 66.0 57.0 61.9



20a 20b 20c 20d 20e 20f 20g 20h 20i 20j 20k 20l

15.9 16.8 18.6 20.2 19.2 18.2 17.5 16.8 17.5 19.7 18.2 16.1







Time zone

code


0.4% 1%

Period

1a

Hours +/-

UTCElevLong


2%

MCWS/PCWD

to 0.4% DB


0.4% 1% 2%

Enthalpy/MCDB

Cooling DB/MCWB

MCWS/PCWD

to 99.6% DB

StdP


Station name WMO#

Coldest

month

Heating DB99.6%

Lat

99%

2% 0.4%

Evaporation WB/MCDB

0.4% 2%1%

Dec

%

Jan

Feb Mar

Feb Mar

% Aug

Jun

Extreme

Max

WB

Hottest

month1%

Extreme Annual DB

Mean


0.4% 1%

Extreme Annual WS

Hottest

month

DB range

n=5 years

JunMay


Apr May

%

Jan

NovJul

Apr

Design conditions for QUANTICO MCAS, VA, USA

Aug Sep Oct Nov

Dec

%

Jul

Sep Oct


17/17

425 1 design temps lecture and hw

Documents