ME 425 – Overview & Design Conditions
ME 425 Air Conditioning System Design Keith E. Elder, P.E.
In enclosed spaces, the combined treatment of the air to control, as specified, temperature, relative humidity, velocity of motion, and radiant heat energy level, with consideration of the need for removal of air-borne particles and contaminant gases.
ME 425
ME 425 – Overview & Design Conditions
Chilled Water Pump Cold Air
Cooling Coil Fan
Chilled Water
Warm Air
Emphasis of ME 425 Warm Moist Air Cooling Tower
Warm Water
Heat Exchanger
Gas Condenser Pump
Compressor
Hot Gas Cooler Dryer Air
Expansion Valve
Heat Exchanger
Condensed Liquid
Hot Water Warm Water
ME 425
Formal Version
q sensible
c p t m
W qlatent m qtotal
h m
Designer’s Version (based on air volume)
q sensible
t 1.1Q
qlatent
4840Q W (W in lbmwater / lbmair )
qtotal
4.5Q h
ME 425
(q in Btu/hr & Q in ft 3 / min)
( h in Btu / lbmair )
ME 425 – Overview & Design Conditions
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 of envelope components Determine zoning Perform Area Takeoffs Calculate Space Sensible & Latent Loads Determine Ventilation & Other System Effects Calculate Coil Loads ME 425
ME 425 – Overview & Design Conditions
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
ME 425
ME 425 – Overview & Design Conditions
ME 425
Indoor Dry Bulb Temperature Indoor Relative Humidity Temperature Stratification Temperature Symmetry Draft Carbon Dioxide Concentration
ME 425
ME 425 – Overview & Design Conditions
Draft is an undesired local cooling of the human body caused by the coincident effects of temperature & air velocity. Draft has been identified as one of the most annoying factors in offices.
ME 425
2
ME 425
ME 425 – Overview & Design Conditions
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
ME 425
ME 425 – Overview & Design Conditions
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 nonuniform environment to = Ata + (1-A)tr ta = Local Air Temp. A = f (air motion)
Velocity(fpm) 10 30 40 60 80 100 120 140 160
A 0.42 0.42 0.46 0.52 0.55 0.58 0.61 0.63 0.65
tr = Mean Radiant Temp. 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-uniform environment. tr = F1t1 + F2t2 + ... Fntn Fn = Angle Factor ME 425
ME 425 – Overview & Design Conditions
n
ME 425
Determination of Outdoor Design Conditions 450
400
350
300 r a e 250 Y r e p s r u 200 o H
150
100
50
0 1 4
7 1
0 2
2 3
6 2
9 2
2 3
5 3
8 3
4 1
4 4
7 4
0 5
5 3
6 5
9 5
2 6
5 6
AnnualTe mperature Occurence s (°F)
ME 425
8 6
7 1
7 4
7 7
0 8
8 3
6 8
0 9
9 3
ME 425 – Overview & Design Conditions
450 99.0%
1.0%
400
350 99.6%
0.4%
300 r a e 250 Y r e p s r u 200 o H
150
100
50
0 1 4
7 1
0 2
2 3
6 2
9 2
2 3
5 3
8 3
4 1
4 4
7 4
0 5
5 3
6 5
9 5
2 6
5 6
AnnualTemperature Occurences (°F)
ME 425
ME 425
8 6
7 1
7 4
7 7
0 8
8 3
6 8
0 9
9 3
ME 425 – Overview & Design Conditions
ME 425
Heating Load Design Conditions
Cooling Load Design Conditions
ME 425
ME 425 – Overview & Design Conditions
Seasonal Hours Criteria Exceeded
Representative Application
Summer
0.4% 1.0% 2.0%
35 88 175
Hospital, Data Center Average Project Promotional (Cut Corners)
35 88
Medium Construction, 24 Occupancy Heavy Construction
Winter
99.6 % 99.0%
ME 425
Homework for Friday
Name______________________
Reference: Chap 8 - ASHRAE Fundamentals 1. A room is maintained at an air temperature of 70°F. The occupant sits near a large window, which has an inside surface temperature of 50°F and accounts for 30% of her “thermal view.” The occupant has complained that the space feels cold. Assuming the “local” air temperature to be equal to the room air temperature: a. What operative temperature does the occupant experience? b. How would you advise the HVAC technician who is trying to troubleshoot the complaint? ME 425
ME 425 – Overview & Design Conditions
Homework - Continued Reference: Chap 28 - ASHRAE Fundamentals (CD) 2. Specify a suitable set of indoor and outdoor design conditions for each of the following Winter Indoor DB Heavy Masonry Office Building Fargo, North Dakota Nursing Home Long Beach, CA Computer Data Center Quantico, Virginia Steel & Glass Office Building Seattle, Washington
ME 425
Outdoor DB
Summer Indoor DB/RH
Outdoor DB/WB
2005 ASHRAE Handbook - Fundamentals (IP)
© 2005 ASHRAE, Inc.
Design conditions for FARGO, ND, USA Station Information
WMO#
Lat
Long
Elev
StdP
Hours +/UTC
Time zone code
1b
1c
1d
1e
1f
1g
1h
727530
46.90N
96.80W
899
14.225
-6.00
NAC
Station name 1a
FARGO
Period 1i
7201
Annual Heating and Humidification Design Conditions Coldest month
Humidification DP/MCDB and HR 99.6% 99% HR MCDB DP HR 4b 4c 4d 4e
Heating DB
2
99.6% 3a
99% 3b
DP 4a
1
-21.1
-16.5
-29.8
1.1
-20.4
-25.0
1.4
MCDB 4f
Coldest month WS/MCDB 0.4% 1% WS MCDB WS MCDB 5a 5b 5c 5d
-16.0
36.5
5.0
32.8
MCWS/PCWD to 99.6% DB MCWS PCWD 6a 6b
6.4
7.9
180
Annual Cooling, Dehumidification, and Enthalpy Design Conditions
7
Hottest month DB range 8
DB 9a
MCWB 9b
7
21.6
91.1
71.6
DP 12a
0.4% HR 12b
MCDB 12c
72.2
123.4
81.5
Hottest month
Cooling DB/MCWB 1% DB MCWB 9c 9d
0.4%
87.8
2%
69.9
Dehumidification DP/MCDB and HR 1% DP HR MCDB 12d 12e 12f
69.6
112.4
79.9
0.4%
Evaporation WB/MCDB 1% WB MCDB 10c 10d
DB 9e
MCWB 9f
WB 10a
MCDB 10b
84.8
68.5
75.3
85.6
DP 12g
2% HR 12h
MCDB 12i
Enth 13a
MCDB 13b
67.5
104.4
77.1
31.8
86.0
73.2 0.4%
83.6
MCWS/PCWD to 0.4% DB MCWS PCWD 11a 11b
2% WB 10e
MCDB 10f
71.1
81.3
14.8
Enthalpy/MCDB 1% Enth MCDB 13c 13d
Enth 13e
MCDB 13f
29.7
27.8
81.3
83.8
170
2%
Extreme Annual Design Conditions
1% 14a
2.5% 14b
5% 14c
Extreme Max WB 15
28.5
25.7
23.4
82.4
Extreme Annual WS
Extreme Annual DB Mean Standard deviation Max Min Max Min 16a 16b 16c 16d
97.3
-25.7
3.9
5.1
n-Year Return Period Values of Extreme DB n=10 years n=20 years Max Min Max Min 17c 17d 17e 17f
n=5 years Max Min 17a 17b
100.1
-29.4
102.4
-32.4
104.6
-35.2
n=50 years Max Min 17g 17h
107.4
Monthly Design Dry Bulb and Mean Coincident Wet Bulb Temperatures Jan
Feb
Mar
Apr
May
Jun
%
DB 18a
MCWB 18b
DB 18c
MCWB 18d
DB 18e
MCWB 18f
DB 18g
MCWB 18h
DB 18i
MCWB 18j
DB 18k
MCWB 18l
0.4% 1% 2%
39.0 36.7 34.8
35.0 33.6 32.3
46.5 43.6 40.8
40.8 39.1 37.2
58.8 55.0 51.5
49.3 46.6 45.2
82.5 78.1 73.8
60.1 57.3 55.2
88.7 86.4 83.7
66.4 65.5 63.8
92.8 90.9 88.3
71.6 71.5 70.0
%
DB 18m
MCWB 18n
DB 18o
MCWB 18p
DB 18q
MCWB 18r
DB 18s
MCWB 18t
DB 18u
MCWB 18v
DB 18w
MCWB 18x
0.4% 1% 2%
95.7 92.8 90.4
73.0 73.3 72.1
95.3 92.7 90.3
72.8 72.6 71.5
91.3 87.3 84.2
70.0 67.9 66.0
78.4 74.3 70.8
60.0 58.1 56.7
61.9 57.8 54.1
50.7 48.7 46.8
43.9 40.1 37.2
38.3 35.6 33.8
Jul
Aug
Sep
Oct
Nov
Dec
Monthly Design Wet Bulb and Mean Coincident Dry Bulb Temperatures Jan
Feb
Mar
Apr
May
Jun
%
WB 19a
MCDB 19b
WB 19c
MCDB 19d
WB 19e
MCDB 19f
WB 19g
MCDB 19h
WB 19i
MCDB 19j
WB 19k
MCDB 19l
0.4% 1% 2%
35.3 33.9 32.6
38.4 36.2 34.6
41.6 39.3 37.2
45.7 43.0 40.6
50.6 48.0 45.4
55.7 53.9 50.6
62.5 60.0 57.2
78.5 73.7 69.8
70.2 68.5 67.0
83.7 81.2 79.0
76.5 74.6 72.9
86.3 85.3 84.2
%
WB 19m
MCDB 19n
WB 19o
MCDB 19p
WB 19q
MCDB 19r
WB 19s
MCDB 19t
WB 19u
MCDB 19v
WB 19w
MCDB 19x
0.4% 1% 2%
78.8 77.4 75.9
88.0 87.2 85.8
77.9 76.1 74.7
89.4 87.2 85.2
72.8 71.0 69.2
85.7 82.0 78.5
63.6 61.2 59.2
72.0 70.1 67.8
53.1 50.2 47.6
58.6 56.1 53.3
38.9 36.0 34.1
43.9 39.5 36.5
Jul
Aug
Sep
Oct
Nov
Dec
Monthly Mean Daily Temperature Range Jan 20a
Feb 20b
Mar 20c
Apr 20d
May 20e
Jun 20f
Jul 20g
Aug 20h
Sep 20i
Oct 20j
Nov 20k
Dec 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# Elev DB WS MCDB MC WS
World Meteorological Organization number Elevation, ft Dry bulb temperature, °F Wind speed, mph Mean coincident dry bulb temperature, °F M ea n c oi nc ide nt w in d s pe ed , mp h
Lat StdP DP Enth MCDP P CW D
Latitude, ° Long Standard pressure at station elevation, psi Dew point temperature, °F WB Enthalpy, Btu/lb HR Mean coincident dew point temperature, °F MCWB P re va il ing c oi nc id ent wi nd di re ct io n, °, 0 = N or th, 90 = E as t
Longitude, ° Wet bulb temperature, °F Humidity ratio, grains of moisture per lb of dry air Mean coincident wet bulb temperature, °F
-38.9
2005 ASHRAE Handbook - Fundamentals (IP)
© 2005 ASHRAE, Inc.
Design conditions for LONG BEACH, CA, USA Station Information
Station name 1a
LONG BEACH
WMO#
Lat
Long
Elev
StdP
Hours +/UTC
Time zone code
1b
1c
1d
1e
1f
1g
1h
56
14.666
-8.00
NAP
722970
33.82N 118.15W
Period 1i
7201
Annual Heating and Humidification Design Conditions Coldest month
Humidification DP/MCDB and HR 99.6% 99% HR MCDB DP HR 4b 4c 4d 4e
Heating DB
2
99.6% 3a
99% 3b
DP 4a
12
40.8
43.1
12.7
10.5
60.7
19.6
Coldest month WS/MCDB 0.4% 1% WS MCDB WS MCDB 5a 5b 5c 5d
MCDB 4f
14.8
62.1
21.6
57.0
18.7
MCWS/PCWD to 99.6% DB MCWS PCWD 6a 6b
58.2
3.0
300
Annual Cooling, Dehumidification, and Enthalpy Design Conditions
7
Hottest month DB range 8
DB 9a
MCWB 9b
8
16.7
91.5
68.0
DP 12a
0.4% HR 12b
MCDB 12c
68.7
105.7
76.3
Hottest month
Cooling DB/MCWB 1% DB MCWB 9c 9d
0.4%
87.7
2%
67.3
Dehumidification DP/MCDB and HR 1% DP HR MCDB 12d 12e 12f
67.1
100.0
75.5
0.4%
Evaporation WB/MCDB 1% WB MCDB 10c 10d
DB 9e
MCWB 9f
WB 10a
MCDB 10b
84.5
66.6
72.2
84.1
DP 12g
2% HR 12h
MCDB 12i
Enth 13a
MCDB 13b
65.8
95.4
74.6
28.2
83.9
70.8 0.4%
82.0
MCWS/PCWD to 0.4% DB MCWS PCWD 11a 11b
2% WB 10e
MCDB 10f
69.5
79.8
9.5
Enthalpy/MCDB 1% Enth MCDB 13c 13d
Enth 13e
MCDB 13f
27.0
26.0
80.2
82.0
280
2%
Extreme Annual Design Conditions
1% 14a
2.5% 14b
5% 14c
Extreme Max WB 15
17.9
15.5
12.9
79.5
Extreme Annual WS
Extreme Annual DB Mean Standard deviation Max Min Max Min 16a 16b 16c 16d
101.8
35.8
4.2
2.9
n-Year Return Period Values of Extreme DB n=10 years n=20 years Max Min Max Min 17c 17d 17e 17f
n=5 years Max Min 17a 17b
104.8
33.7
107.3
32.0
109.6
30.4
n=50 years Max Min 17g 17h
112.7
Monthly Design Dry Bulb and Mean Coincident Wet Bulb Temperatures Jan
Feb
Mar
Apr
May
Jun
%
DB 18a
MCWB 18b
DB 18c
MCWB 18d
DB 18e
MCWB 18f
DB 18g
MCWB 18h
DB 18i
MCWB 18j
DB 18k
MCWB 18l
0.4% 1% 2%
82.1 79.2 75.8
56.2 55.6 54.8
82.4 79.3 76.2
58.0 57.4 56.0
84.3 80.1 76.6
60.0 58.9 58.1
88.0 84.3 81.1
61.0 60.5 60.1
88.1 83.8 80.3
65.0 64.6 63.8
94.3 88.9 85.1
66.7 67.1 66.5
%
DB 18m
MCWB 18n
DB 18o
MCWB 18p
DB 18q
MCWB 18r
DB 18s
MCWB 18t
DB 18u
MCWB 18v
DB 18w
MCWB 18x
0.4% 1% 2%
92.2 89.1 86.9
69.1 69.4 68.9
95.2 91.4 88.8
70.9 71.1 70.2
96.9 92.9 90.2
69.8 69.3 69.5
94.4 89.9 86.3
64.2 62.8 62.5
87.7 84.1 80.6
59.5 58.7 57.2
81.0 78.2 75.6
55.0 54.7 54.5
Jul
Aug
Sep
Oct
Nov
Dec
Monthly Design Wet Bulb and Mean Coincident Dry Bulb Temperatures Jan
Feb
Mar
Apr
May
Jun
%
WB 19a
MCDB 19b
WB 19c
MCDB 19d
WB 19e
MCDB 19f
WB 19g
MCDB 19h
WB 19i
MCDB 19j
WB 19k
MCDB 19l
0.4% 1% 2%
61.4 60.4 59.6
67.7 66.4 65.3
62.0 61.0 60.2
72.7 69.4 67.6
64.1 62.4 61.5
75.3 72.4 70.6
65.8 64.4 63.2
79.9 77.4 75.1
68.7 67.5 66.2
80.1 78.9 76.2
70.2 69.2 68.3
84.4 82.1 80.4
%
WB 19m
MCDB 19n
WB 19o
MCDB 19p
WB 19q
MCDB 19r
WB 19s
MCDB 19t
WB 19u
MCDB 19v
WB 19w
MCDB 19x
0.4% 1% 2%
72.2 71.3 70.6
85.7 84.1 82.6
74.3 73.3 72.3
88.0 86.4 84.4
74.8 73.4 72.4
86.5 83.8 83.1
70.0 69.0 68.0
80.3 78.7 77.6
65.6 64.3 63.3
74.5 72.5 71.1
61.5 60.4 59.5
66.9 66.3 65.9
Jul
Aug
Sep
Oct
Nov
Dec
Monthly Mean Daily Temperature Range Jan 20a
Feb 20b
Mar 20c
Apr 20d
May 20e
Jun 20f
Jul 20g
Aug 20h
Sep 20i
Oct 20j
Nov 20k
Dec 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
WMO# Elev DB WS MCDB MC WS
World Meteorological Organization number Elevation, ft Dry bulb temperature, °F Wind speed, mph Mean coincident dry bulb temperature, °F M ea n c oi nc ide nt w in d s pe ed , mp h
Lat StdP DP Enth MCDP P CW D
Latitude, ° Long Standard pressure at station elevation, psi Dew point temperature, °F WB Enthalpy, Btu/lb HR Mean coincident dew point temperature, °F MCWB P re va il ing c oi nc id ent wi nd di re ct io n, °, 0 = N or th, 90 = E as t
Longitude, ° Wet bulb temperature, °F Humidity ratio, grains of moisture per lb of dry air Mean coincident wet bulb temperature, °F
28.3
2005 ASHRAE Handbook - Fundamentals (IP)
© 2005 ASHRAE, Inc.
Design conditions for QUANTICO MCAS, VA, USA Station Information
WMO#
Lat
Long
Elev
StdP
Hours +/UTC
Time zone code
1b
1c
1d
1e
1f
1g
1h
724035
38.50N
77.30W
13
14.689
-5.00
NAE
Station name 1a
QUANTICO MCAS
Period 1i
8401
Annual Heating and Humidification Design Conditions Coldest month
Humidification DP/MCDB and HR 99.6% 99% HR MCDB DP HR 4b 4c 4d 4e
Heating DB
2
99.6% 3a
99% 3b
DP 4a
1
15.8
19.8
-2.0
4.9
19.2
2.8
Coldest month WS/MCDB 0.4% 1% WS MCDB WS MCDB 5a 5b 5c 5d
MCDB 4f
6.4
24.9
23.4
39.4
19.9
MCWS/PCWD to 99.6% DB MCWS PCWD 6a 6b
36.5
5.9
320
Annual Cooling, Dehumidification, and Enthalpy Design Conditions
7
Hottest month DB range 8
DB 9a
MCWB 9b
7
17.5
93.0
76.5
DP 12a
0.4% HR 12b
MCDB 12c
76.6
138.8
85.3
Hottest month
Cooling DB/MCWB 1% DB MCWB 9c 9d
0.4%
90.6
2%
75.8
Dehumidification DP/MCDB and HR 1% DP HR MCDB 12d 12e 12f
75.0
131.2
83.6
0.4%
Evaporation WB/MCDB 1% WB MCDB 10c 10d
DB 9e
MCWB 9f
WB 10a
MCDB 10b
88.3
74.5
79.4
89.5
DP 12g
2% HR 12h
MCDB 12i
Enth 13a
MCDB 13b
73.5
124.7
81.8
35.1
89.9
77.9 0.4%
87.8
MCWS/PCWD to 0.4% DB MCWS PCWD 11a 11b
2% WB 10e
MCDB 10f
76.6
85.6
5.6
Enthalpy/MCDB 1% Enth MCDB 13c 13d
Enth 13e
MCDB 13f
33.6
32.2
85.5
88.0
170
2%
Extreme Annual Design Conditions
1% 14a
2.5% 14b
5% 14c
Extreme Max WB 15
18.5
16.2
13.6
90.0
Extreme Annual WS
Extreme Annual DB Mean Standard deviation Max Min Max Min 16a 16b 16c 16d
n=5 years Max Min 17a 17b
n-Year Return Period Values of Extreme DB n=10 years n=20 years Max Min Max Min 17c 17d 17e 17f
97.6
99.8
2.2
101.5
-2.2
7.6
3.0
7.5
103.2
-6.4
n=50 years Max Min 17g 17h
105.4
Monthly Design Dry Bulb and Mean Coincident Wet Bulb Temperatures Jan
Feb
Mar
Apr
May
Jun
%
DB 18a
MCWB 18b
DB 18c
MCWB 18d
DB 18e
MCWB 18f
DB 18g
MCWB 18h
DB 18i
MCWB 18j
DB 18k
MCWB 18l
0.4% 1% 2%
63.4 60.8 57.4
54.5 52.3 50.2
71.7 67.4 63.6
57.7 57.0 55.0
81.5 77.0 72.9
62.3 59.6 58.8
87.3 83.1 80.0
65.6 63.9 62.5
90.9 88.5 86.2
72.9 72.0 70.7
94.3 92.3 90.5
75.7 75.1 75.1
%
DB 18m
MCWB 18n
DB 18o
MCWB 18p
DB 18q
MCWB 18r
DB 18s
MCWB 18t
DB 18u
MCWB 18v
DB 18w
MCWB 18x
0.4% 1% 2%
97.5 95.7 93.6
78.2 77.5 77.2
95.1 93.0 91.3
76.9 77.3 76.8
92.0 89.0 86.7
76.4 74.6 73.4
83.2 81.0 78.6
70.1 69.4 67.9
74.8 72.3 69.1
62.3 60.9 58.4
70.3 67.0 63.6
60.4 57.1 55.6
Jul
Aug
Sep
Oct
Nov
Dec
Monthly Design Wet Bulb and Mean Coincident Dry Bulb Temperatures Jan
Feb
Mar
Apr
May
Jun
%
WB 19a
MCDB 19b
WB 19c
MCDB 19d
WB 19e
MCDB 19f
WB 19g
MCDB 19h
WB 19i
MCDB 19j
WB 19k
MCDB 19l
0.4% 1% 2%
57.6 55.1 53.0
61.2 58.3 56.0
61.5 58.8 55.9
69.7 65.3 63.0
63.8 62.1 60.2
78.0 75.0 70.9
69.7 67.7 65.7
79.7 78.1 75.3
77.5 75.7 73.8
88.2 84.8 81.8
79.4 78.3 77.6
88.7 87.6 86.9
%
WB 19m
MCDB 19n
WB 19o
MCDB 19p
WB 19q
MCDB 19r
WB 19s
MCDB 19t
WB 19u
MCDB 19v
WB 19w
MCDB 19x
0.4% 1% 2%
82.0 80.8 79.9
90.0 90.2 90.1
81.5 80.0 78.8
88.8 89.0 88.3
78.3 77.1 76.0
87.1 85.2 83.8
72.9 71.2 70.0
79.3 77.3 76.4
64.7 63.3 61.6
72.2 68.6 66.0
61.7 59.3 57.0
67.3 66.2 61.9
Jul
Aug
Sep
Oct
Nov
Dec
Monthly Mean Daily Temperature Range Jan 20a
Feb 20b
Mar 20c
Apr 20d
May 20e
Jun 20f
Jul 20g
Aug 20h
Sep 20i
Oct 20j
Nov 20k
Dec 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
WMO# Elev DB WS MCDB MC WS
World Meteorological Organization number Elevation, ft Dry bulb temperature, °F Wind speed, mph Mean coincident dry bulb temperature, °F M ea n c oi nc ide nt w in d s pe ed , mp h
Lat StdP DP Enth MCDP P CW D
Latitude, ° Long Standard pressure at station elevation, psi Dew point temperature, °F WB Enthalpy, Btu/lb HR Mean coincident dew point temperature, °F MCWB P re va il ing c oi nc id ent wi nd di re ct io n, °, 0 = N or th, 90 = E as t
Longitude, ° Wet bulb temperature, °F Humidity ratio, grains of moisture per lb of dry air Mean coincident wet bulb temperature, °F
-11.8
2005 ASHRAE Handbook - Fundamentals (IP)
© 2005 ASHRAE, Inc.
Design conditions for SEATTLE/TACOMA, WA, USA Station Information
Station name 1a
SEATTLE/TACOMA
WMO#
Lat
Long
Elev
StdP
Hours +/UTC
Time zone code
1b
1c
1d
1e
1f
1g
1h
400
14.485
-8.00
NAP
727930
47.45N 122.30W
Period 1i
7201
Annual Heating and Humidification Design Conditions Coldest month
Humidification DP/MCDB and HR 99.6% 99% HR MCDB DP HR 4b 4c 4d 4e
Heating DB
2
99.6% 3a
99% 3b
DP 4a
12
23.8
28.4
5.8
7.5
28.5
13.0
Coldest month WS/MCDB 0.4% 1% WS MCDB WS MCDB 5a 5b 5c 5d
MCDB 4f
10.8
32.6
26.2
44.4
23.9
MCWS/PCWD to 99.6% DB MCWS PCWD 6a 6b
45.8
9.3
20
Annual Cooling, Dehumidification, and Enthalpy Design Conditions
7
Hottest month DB range 8
DB 9a
MCWB 9b
8
18.2
84.9
65.2
DP 12a
0.4% HR 12b
MCDB 12c
60.2
79.1
70.1
Hottest month
Cooling DB/MCWB 1% DB MCWB 9c 9d
0.4%
81.2
2%
63.7
Dehumidification DP/MCDB and HR 1% DP HR MCDB 12d 12e 12f
58.9
75.5
68.5
0.4%
Evaporation WB/MCDB 1% WB MCDB 10c 10d
DB 9e
MCWB 9f
WB 10a
MCDB 10b
77.6
62.3
66.5
82.5
DP 12g
2% HR 12h
MCDB 12i
Enth 13a
MCDB 13b
57.7
72.2
67.3
23.6
83.1
64.7 0.4%
78.9
MCWS/PCWD to 0.4% DB MCWS PCWD 11a 11b
2% WB 10e
MCDB 10f
63.1
75.8
9.7
Enthalpy/MCDB 1% Enth MCDB 13c 13d
Enth 13e
MCDB 13f
22.2
21.0
75.7
78.9
0
2%
Extreme Annual Design Conditions
1% 14a
2.5% 14b
5% 14c
Extreme Max WB 15
20.4
18.3
16.5
83.1
Extreme Annual WS
Extreme Annual DB Mean Standard deviation Max Min Max Min 16a 16b 16c 16d
n=5 years Max Min 17a 17b
92.1
95.0
15.7
20.0
4.1
6.0
n-Year Return Period Values of Extreme DB n=10 years n=20 years Max Min Max Min 17c 17d 17e 17f
97.4
12.2
99.7
8.8
n=50 years Max Min 17g 17h
102.7
Monthly Design Dry Bulb and Mean Coincident Wet Bulb Temperatures Jan
Feb
Mar
Apr
May
Jun
%
DB 18a
MCWB 18b
DB 18c
MCWB 18d
DB 18e
MCWB 18f
DB 18g
MCWB 18h
DB 18i
MCWB 18j
DB 18k
MCWB 18l
0.4% 1% 2%
56.7 54.9 53.2
49.0 48.4 48.2
61.6 58.5 56.5
50.6 49.7 48.8
65.2 62.4 60.2
50.9 50.6 49.5
74.8 71.2 68.2
56.0 55.8 54.6
81.5 78.4 75.6
62.9 61.4 60.2
87.0 83.3 80.4
64.5 63.7 62.6
%
DB 18m
MCWB 18n
DB 18o
MCWB 18p
DB 18q
MCWB 18r
DB 18s
MCWB 18t
DB 18u
MCWB 18v
DB 18w
MCWB 18x
0.4% 1% 2%
90.5 87.4 84.6
67.3 66.2 65.5
90.0 86.9 84.2
68.1 66.6 65.5
84.7 81.7 79.4
63.4 63.0 62.3
73.7 70.0 67.0
58.2 57.2 56.4
60.9 58.6 57.1
54.2 53.2 52.4
56.1 54.2 52.9
52.5 50.7 49.5
Jul
Aug
Sep
Oct
Nov
Dec
Monthly Design Wet Bulb and Mean Coincident Dry Bulb Temperatures Jan
Feb
Mar
Apr
May
Jun
%
WB 19a
MCDB 19b
WB 19c
MCDB 19d
WB 19e
MCDB 19f
WB 19g
MCDB 19h
WB 19i
MCDB 19j
WB 19k
MCDB 19l
0.4% 1% 2%
52.1 50.9 50.1
53.9 52.8 52.1
53.9 52.7 51.3
57.2 55.5 54.2
54.0 52.9 51.8
59.2 57.8 56.9
59.5 57.5 55.9
69.5 68.0 65.1
64.1 62.6 61.3
78.1 75.4 73.3
66.2 64.9 63.5
83.4 81.1 78.2
%
WB 19m
MCDB 19n
WB 19o
MCDB 19p
WB 19q
MCDB 19r
WB 19s
MCDB 19t
WB 19u
MCDB 19v
WB 19w
MCDB 19x
0.4% 1% 2%
68.6 67.6 66.5
86.0 85.2 83.0
69.2 68.0 66.7
87.4 84.9 82.1
66.0 64.5 63.6
81.3 78.3 76.7
60.5 59.3 58.2
68.5 66.1 64.1
56.4 55.1 53.9
58.7 57.2 56.0
53.2 51.5 50.4
55.2 53.4 52.3
Jul
Aug
Sep
Oct
Nov
Dec
Monthly Mean Daily Temperature Range Jan 20a
Feb 20b
Mar 20c
Apr 20d
May 20e
Jun 20f
Jul 20g
Aug 20h
Sep 20i
Oct 20j
Nov 20k
Dec 20l
8.8
11.1
12.8
14.6
15.8
16.5
18.5
18.2
16.7
12.6
9.5
8.5
WMO# Elev DB WS MCDB MC WS
World Meteorological Organization number Elevation, ft Dry bulb temperature, °F Wind speed, mph Mean coincident dry bulb temperature, °F M ea n c oi nc ide nt w in d s pe ed , mp h
Lat StdP DP Enth MCDP P CW D
Latitude, ° Long Standard pressure at station elevation, psi Dew point temperature, °F WB Enthalpy, Btu/lb HR Mean coincident dew point temperature, °F MCWB P re va il ing c oi nc id ent wi nd di re ct io n, °, 0 = N or th, 90 = E as t
Longitude, ° Wet bulb temperature, °F Humidity ratio, grains of moisture per lb of dry air Mean coincident wet bulb temperature, °F
4.4