DESIGN
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A completely site-built solar-heated home design which can supply up to 75% of its own heat
almost anywhere in the United States has been
designed, built, tested and released by USDA'S
Rural Housing Research Unit. The house design
incorporates a built-in solar collector system in
the attic, thus eliminating the need for expensive
and complicated factory-built solar collector units.
The attic solar collector system can be readily
adapted to nearly any house size or floor plan.
The prototype home, for which detalled construction plans are available at a cost of seven
dollars ($7.00), is a 1,100-square foot, three-bedroom, one-bath ranch-style wood frame structure
It is conventional in all respects except for the.
heat-collecting attic, a crushed rock heat sink in
the crawl space and use of 2 x 6 stud wall construction. The solar heat collector can be built on
front or back roof of house but must face south for
maximum sun exposure
Solar heat is transferred through two layers
of reinforced (greenhouse quality) fiberglass plastic panelling into the specially designed and
shaped attic, which Is painted black on the interior
for maximum heat absorption. A system of air
ducts and blOwers transfers the trapped solarheated air frOm the attic to the living area for heat-
ing, or to the crushed rock heat sink for storage
and later use at night or on cloudy days. The 600
to 800 cubic feet f heated railroad ballast rock
can. store a three-day supply of reserve hoat.
Auxift-
ary or back-up heatis supplied by a çon#entlonal
electric resistance hot au furnace or heat pump
unit in the air distribution system. The back-up'
unit, which is sized to satisfy local conditions,
operates only when no heat is available from the
solar-heated attic or rock bed heat sink.
Solar energy c-an also be utilized for summer
ng
attic ventilation and water heating. By
the ridge and eave vents, air clrculatseithrough
the attic. As it exhausts through the rtdQo vent,
cooler outside air is drawn Into the lowàr plenum
through the open eave vents. -This co*r air will
keep attic tempj!atues 20 to 400 .eler than
conventional affies. The rock bed bei*ath the
house is also used to cool the housi during
hot
summer daysrocks are cooled at night id air
is circulated through the cooled rock bed during
re.
the heat of day to lower living area tefl
Performance data indicate the system is eco'nomica1Iy feasible In areas having heating energy
costs of about 3-4/2 cnts per KWH for electric
resistance heattfl (6 to 6 Cents per KWH for heat
pump), 50 to 70 nts per. therm for gas, 70 to
90 cents per gallon for fuel oil, or 45 to 80 cents
per gallon (or 10 to 15-cents per pound) for LP gas.
With present-day interist in solar energy for space
heating and domestic water heating, many families
will want tO explore th. possible applications of
this oncept 10 .thelr
resent. r planned home.
WRAES7I
NOvEMBER 1977
Western Regional AgriculturaL Enqine.$ag Service is an othcia4 oo peratsvEzena4n activity ol western bnd grant universities and USDA Extensien progearnVe avaabe to alt persons regartless t* cir. treefl nstional ongin. race
are the-Unversvties ol Attelia,
Universities.. Headquart5rs
are
w sex Cooperating
Cifernie. Idaho. Neveda a dWmn, 8do. Oegon Utah and Washsnqzoo State
located at Oregon State Uflivetsity. Corva, OrØaI -9731.
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End view oi house showing coNsoler slope and
solar zone 1 Most øfflcient colI.cter slope
1. epproxlmetes latitude plus 1$, l.S.a 40° latItude UseS
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DEC21
SOLAR LINE
sun mets
SOLAR ANGLE
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sf1 height (hches)
I1100r bee
Length of eave overhang (dimension "'1") for best
solar control depends on roof pitch and roof posi-
lion relative to ceiling tine. To determine proper
overhang for southern exposure windows, sketch
to scale as follows:
1. Floor line, wall with window and ceiling line
2. Measure and mark sill height from Iloor
3. Pick latitude and sill height columns on chart for Specific
situation
4.
Select measurement "x" from chart (use boldface when
designing primarily for 8olar heat gain during cold months;
use lightface when designing primarily for solar shade to
reduce air conditioning Load)
6. Draw line "x" from outside wail/ceiling Intersection
6. Drew solar line from outer end of "x" to sill (as a check,
uie solar angle from chartit should Intersect sIIl)
1. Sketch eave (rafter or upper truss chord extension) posilion and slope to intersect solar line
6. Meesure eave overhang "V."
Noon Solar Angle
Apr 11 & Aug 31
42°
38°
530
540
590
Mar 21 &, Sept 21
400
440
48°
LatItude
4inches
36 inches
32 inches
30 inches
.
24lnohes
18 Inches
12 Inches
Note:
Above chart applicable to
540
Distance
SRI Height
48lnches
finished
34
39
44
47
49
54
59
64
4829
54
34
81
38
66
87
41
43
7447
80
87
52
56
40
46
82
56
58
64
70
76
24
28
32
35
36
40
44
49
34
39
44
47
49
54
59
64
ceiling heights ranging from 7'-9" to 8'-l"
TO ORDER PLANS: Make check or money order
Payab!e to "WRAES." Mail to: WRAESI Gitmote 116,
Oregon State University, Corvallis, OR 97331.
sets #7220 at $7. Enclosed find $...
Name..... .........................................................
Address ............................................................
City
State............................................ .Zip
540
O
50°
46°
20
23
26
29
30
33
36
39
2*°
32
750
62°
56°
"f (Inches)
24
28
32
35
36
12
14
16
29
34
38
15
18
41
23
43
47
52
56
24
26
40
19
21
32
44
48
23
26
21
29
17
29
26
29
39
*
29
26