Innovations for reducing conduction heat losses from salt-gradient solar ponds

Thesis/Dissertation · Tue Jan 01 04:00:00 EST 1985

OSTI ID:5904549

Lowrey, III, D P

A recent publication suggested using a storage zone (SZ) full of opaque water instead of a conventional lower convecting zone. This opaque SZ would be warmer on its top than bottom, and therefore thermally stratified and nonconvecting. Since the conductivity of water is less than that of many types of ground, this opaque zone would act like an added layer of insulation and reduce heat losses to the ground. This strategy can be improved by inducing a slow, upward flow through the opaque SZ. This flow can be produced by decanting warmed water near the top of this opaque SZ, and returning the same water to the bottom of the SZ after extracting heat. The flow will convect heat upward, and therefore reduce downward heat losses. A numerical analysis of this system under typical circumstances predicts 20-60% higher heat extraction rates for a given extraction temperature. Downward heat losses could be virtually eliminated in some cases. Similarly, heat losses up through the pond's surface could be reduced by inducing downward convection through the nonconvecting (NCZ) zone. However, the downward velocities needed to reduce these heat losses would soon sweep the essential salinity gradient to the pond's floor. Fortunately, the desired convection can be produced indirectly. This involves moving the NCZ horizontally across a heat exchanger in which a second fluid absorbs heat and then convects downward.

• Research Organization: North Carolina State Univ., Raleigh (USA)
• OSTI ID: 5904549
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
142000* -- Solar Energy-- Heat Storage-- (1980-)
CONVECTION
ENERGY LOSSES
ENERGY STORAGE
ENERGY TRANSFER
EQUIPMENT
HEAT EXTRACTION
HEAT LOSSES
HEAT STORAGE
HEAT TRANSFER
LOSSES
MASS TRANSFER
PONDS
SALINITY GRADIENTS
SOLAR COLLECTORS
SOLAR EQUIPMENT
SOLAR PONDS
STORAGE
SURFACE WATERS