Admittance Method

Question 1

What are the steps of the admittance method calculation i.e what do you calculate at each step?

Answer 1

1. Mean Solar Gain
2. Mean Casual Gain
3. Total Mean Gain
4. Mean Environmental Temperature (Need to calculate Cv term)
5. Swing Solar Gain
6. Structural Gain
7. Swing Casual Gain
8. Swing Air-to-air Gain
9. Total Swing
10. Swing Internal Environmental Temperature
11. Resultant Internal Temperature

Question 2

What is the equation for mean solar gain and the terms?

Answer 2

Q’s = S’It’Ag

S'= Mean solar gain factor (table)
It'= Mean total solar irradiance (table)
Ag= Sunlit area

Question 3

Mean casual gain eqn and terms?

Answer 3

Q’c= (gc1t1 + gc2t2…)/24

gc1, gc2= Instantaneous casual gains
t1,t2= Gain duration

Question 4

Total mean gain?

Answer 4

Q’t= Q’c + Q’s

Question 5

Mean environmental temp and cv value equation?

Answer 5

Q’env = [((sumAgUg) +Cv)(O’ei-O’ao) + (sumAfUf)(O’ei-O’eo)

1/Cv = 1/0.33NV + 1/4.8A

A= exposed areas
U= U value
Cv= Ventilation loss
O'ei= Mean internal environmental temp
O'eo= Mean sol-air temp (table)
O'ao= Mean outdoor air temp (table)
g,f= refer to glazed or opaque(non transparent)

N= rate of air interchange
V= Volume of room
A= total surface area of enclosure

Question 6

Swing in solar gain and units?

Answer 6

Q’’s= SaAg(Ip-I’)

Sa- Alternating solar gain(table)
Ip- peak solar radiation intensity(table)

Question 7

Structural gain?

Answer 7

Q’‘f= fAU(Oeo-O’eo)

f- decrement factor
Oeo- Sol-air temp at peak time (lag given)

Question 8

Swing casual gain?

Answer 8

Q’‘c= Qc-Q’c

Q’c- casual gain factor at peak hour

Question 9

Air-to-air gain swing?

Answer 9

Q’‘as=(AgUg+Cv)O’‘ao

Where O’‘ao= Oao-O’ao

O’‘ao- swing in outdoor air temp

Question 10

Total swing?

Answer 10

Q’‘t= Q’’s+Q’‘f+Q’‘c+Q’‘as

Question 11

Swing internal environmental temp?

Answer 11

O’‘ei= Q’‘t/((sumAY)+Cv)

Question 12

Internal temp

Answer 12

Oei= O’ei + O’‘ei