UFC 3-440-01
14 June 2002
,100. The second option investigated was the use of a 12 to 24 inch (305 to 610
mm) pipe coated and capped for use as a domestic water storage tank. The price for
this storage system was estimated to be ,900 for 705 gals (2669 L) of storage. The
primary problem with both of these options was the delivery time of the equipment. The
fastest shipment available was approximately six weeks. The storage option used in
this project was nine 80 gal (303 L) storage tanks priced at ,279.90. The tanks are
electric water heater tanks with the heating elements removed. The advantage to this
type of storage is that the tanks are available immediately. Disadvantages to the use of
a large number of smaller tanks include maintenance, system balancing, and increased
heat loss due to increased surface area. The use of a large number of small tanks is
also less cost effective with the price per gallon of storage being .94 versus .55 per
gallon for the single tank and .53 per gallon for the 24-inch (610 mm) pipe system.
Piping is also more extensive and therefore more costly for multiple tanks.
G-4.
SYSTEM DESCRIPTION
a. Overall Design. After many design iterations, a system was configured with
the assistance of Sandia National Laboratories for installation in the rock area next to
Building 80306. The system consists of twelve 4 by 8 ft (1219 by 2438 mm) collector
panels arranged in two rows of four and eight panels. An overall view of the system
can be seen in Figure G-1.
Figure G-1. Photo of Collector Arrays
b. Array Design. The system is divided into three arrays: east, west, and
south. Each array contains four collector panels, one "quad rod" double-walled heat
exchanger, two circulation pumps, and three 80 gal (303 L) storage tanks. A detailed
piping diagram of the entire solar hot water system can be seen in Figure G-2. A
schematic for the west zone, which is typical for the three, can be seen in Figure G-3. A
detailed schematic of the "quad rod" double-walled heat exchanger can be seen in
Figure G-4. As previously stated, each zone contains two circulation pumps that are
G-2
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