Fish and algae growing together in a solar pond create an aquatic ecosystem that does not exist in nature. A solar algae pond ecosystem has high light levels, rapid cycling of nutrients, and a unique biochemistry driven by daily sunlight pulses.

The ponds act as giant test tubes for research as well as tanks for practical fish production. A major research effort of New Alchemy has been to scientifically develop methods to optimize fish production at home and on a community scale.

For more information, please read A Summary of Fish Culture Techniques in Solar Algae Ponds. This highly condensed summary explains how to optimize aquaculture in a solar pond, based on years of careful research, experimentation and monitoring: a priceless collection of practical aquaculture knowledge.

Heat storage in solar ponds

image - heat storage, day-night - drawing

The water in solar ponds warms up when the sun hits them or when the air around them is warmer than they are. In a greenhouse they collect and store solar heat during the day and release it later at night into the greenhouse air.

A pond will release heat whenever the water is hotter than the air around it, often for several days during sunless cold conditions. It’s passive and automatic – no fossil fuel, no machinery, no sound of fans. For more information, read Solar Ponds for Heat Storage by Earle Barnhart.

Passive Solar Heat Storage in Water Tubes

These Greenway Passive Solar Heat Storage Tubes absorb and store excess heat from greenhouse air during the day and release the stored heat into the greenhouse at night. Water is the best material for heat storage, storing the most heat for its volume. Each tube, made from Teflon, is 100% transparent, letting sunlight pass on through to growing plants in the greenhouse. Heat is absorbed automatically from warm air, and is released automatically back into colder air. Water tubes are most efficient if hung high in a greenhouse where the air is warmest and above the soil and crops. Water tubes are 1) automatic (the air and heat move naturally); 2) silent; no fans, no power, no fuel, no burners; 3) simple, no mechanical or digital controls — you can see them working; water condenses on the outside when it is actively storing heat; and 4) more attractive than ducts.