Page 320 - Handbook of Energy Engineering Calculations

For this industrial building solar-energy system, a lithium-bromide
absorption air-conditioning unit (a frequent choice for solar-heated systems)
develops 100 tons (351.7 kW) of refrigeration for cooling with a coefficient
of performance of 0.71 by using heated water from the solar collectors.
Maximum heat input required by this absorption unit is 1.7 million Btu/h

(491.8 kW) with a hot-water flow of 240 gal/min (909.6 L/min). Variable-
speed pumps and servo-actuated valves control the water flow rates and route
the hot-water flow from the solar collectors along several paths—to the best

exchanger for heating or cooling of the building, to the absorption unit for
cooling of the building, to the storage tanks for use as domestic hot water, or
to short-term storage before other usage. The storage tanks hold enough hot
water to power the absorption unit for several hours or to provide heating for
up to 2 days.

TABLE 1 Spacing to Avoid Shadowing, ft (m) *

Another—and more usual—type of solar-energy system is shown in Fig. 7.
In it a flat-plate collector absorbs heat in a water/antifreeze solution that is
pumped to a pair of heat exchangers.