Some technology just doesn't change. Around for decades, water storage tubes provide thermal mass to moderate indoor air temperatures. Use to store heat during the day and keep warm at night, you can accomplish passive solar heating these solar storage tubes...
Water storage tubes prevent wide temperature swings by absorbing and diffusing solar energy, making it a very low tech form of radiant heating and cooling, which is most comfortable for people. The radiant energy of tubes will naturally temper your house, but shouldn't be specifically used as a substitute for heating/cooling needs. Dyes can also be used to provide not only added color but also increased solar gain.
When installed adjacent to a south facing window, the tubes function as a Direct Gain Water Wall. The tubes absorb and store solar energy, while transmitting natural daylight. The tubes temper both the heat and light from the sun by removing the wide temperature fluctuations and also help reduce glare from the south facing windows.
The tubes can also be installed in a separate cavity for Controllable Passive heat gain. When opaque or translucent panels are used, the built up heat is transmitted naturally or via a fan.
We've used these in a project or two, and they provide not only a cool, passive form of controlling indoor air temperature but also a sculptural centerpiece for the home.
Made by Solar Components Corporation, the tubes are 12 or 18-inches in diameter and are available in heights from 4 to 10-feet high. Prices start at $103 for a 12" x 4' tube and goes up to $229 for a 18" x 10' tube.