
530 Principles of Sustainable Energy Systems
© 2008 Taylor & Francis Group, LLC
TABLE 9.2 (continued)
Designations and Characteristics for 94 Reference Systems
(b) Direct-gain (DG) system types
Designation
Thermal Storage
Capacity
a
(Btu/
ft
2
/°F)
Mass
Thickness
a
(in.)
Mass
Area-to-
Glazing
Area Ratio
No. of
Glazings
Nighttime
Insulation
A1 30 2 6 2 No
A2 30 2 6 3 No
A3 30 2 6 2 Yes
B1 45 6 3 2 No
B2 45 6 3 3 No
B3 45 6 3 2 Yes
C1 60 4 6 2 No
C2 60 4 6 3 No
C3 60 4 6 2 Yes
(c) Vented trombe-wall (TW) system types
Designation
Thermal Storage
Capacity
a
(Btu/
ft
2
/°F)
Wall
Thickness
a
(in.)
ρck
(Btu
2
/h/
ft
4
/°F
2
)
No. of
Glazings
Wall
Surface
Nighttime
Insulation
A1 15 6 30 2 Normal ...