Water Energy Nexus: New Tanks Save Water and Energy

New tank technologies will contribute to the water-energy sustainability


Doug Pushard | April 6, 2014

When designing a rainwater harvesting system or a solar thermal system, it is the tank that drives the costs. Designs take into consideration how much water is needed and, in the case of rainwater systems, how much water can be harvested. These factors ultimately determine how much storage, and the tank size, that is required.

Improvements in tank design can enhance system design and lower costs. For a solar thermal system, the base configuration is one storage tank; plus additional tanks in larger or more demanding situations. Extra tanks can keep water hot for three to four cloudy days, providing additional hot water and heat to the household. They tend to be big — 36 to 100 inches in diameter and six to seven feet tall — each storing hundreds of gallons. They can also connect to each other so that multiple units can be used in a system.

In the 1970s and 1980s, solar hot-water systems typically used standard tanks that offered little in the way of insulation. Blankets are recommended for tanks even today. These days most solar hot-water tanks have at least two inches of insulation bundling the tank for an R value of 2 to 10.

New tanks boast eight to 10 inches of insulation and an R value of 40 or more. They are larger and lose almost no heat. This added storage lowers the dependency on a backup heating system, thereby reducing the complexity and costs of most solar hot-water systems. This leads to lower utility bills and, in southern latitudes like New Mexico, may eliminate the need for a backup heating system entirely. One example is the new Cocoon Tank (www.cocoontanks.com), which has an R value of 32.

Rod Hyatt, Solar Skies national sales manager and HTP National Solar Products manager, has been involved in the design of several of these new tanks. “These new, super-insulated tanks will save space, reduce complexity and the installation effort required, and ultimately save customers money,” Hyatt said.

New technologies such as these new super-insulated tanks will enable us to seamlessly reduce our current water and energy footprint and become more sustainable in an environment of diminishing resources. The quicker we adopt these new technologies, the better it will be for the current generation, future generations, and our long-term quality of life. But will we take advantage of these new innovations fast enough?


This blog was originally posted on Santafenewmexican.com.