MIL-HDBK-1003/13A
Table 2-4.
Guide to Selection of Number of Transparent Cover Plates.
Optimum Number of
Cover Plates
Collection
  Typical Applications 
Temperature Above
 Black-Painted   Selective 
Ambient Temperature
Absorber
  Absorber 
(tc - ta)
[epsilon] =  [epsilon] =
  0.9 or 0.95
0.2 or less
 -5 deg. C to +5 deg. C
Heat source for heat
(-10 deg. F to +10 deg. F)pump
Heating of swimming
none
none
pools in summer
Air heating for drying 
 5 deg. C to 35 deg. C
Domestic water heating 
(10 deg. F to 60 deg. F)  
Heating of swimming
pools in winter
1
1
Air heating for drying 
Solar distillation
freezing climates
 35 deg. C to 55 deg. C
Winter water heating
(60 deg. F to 100 deg. F) 
2
1
(100 deg. F to 150 deg. F)
Steam production in
summer
3
2
Refrigeration
Cooking by boiling
23