Solar Thermal & Solar Thermal Storage Tanks

Heat storage can be an ongoing issue for commercial and residential installations. While many don’t consider solar thermal water storage to generate heat, these non-pressurized tank systems offer the dependable heat delivery you want, along with cost savings and increased efficiency.

At Hydroflex Systems, Inc., we can help bring your home or business into the 21st century through expert installation of a new solar thermal compatible water storage system.


Advantages of Hydroflex Systems Solar Water Storage Tanks

Due to their light weight and flexibility, larger Hydroflex tanks can accommodate more solar collectors and store more heat over longer periods of time than smaller pressurized tanks. Hydroflex tanks are durable and do not rust. All 42 sizes of tanks, from 100 gallons to 5000 gallons, are flexible so that they are able to fit through small openings such as a standard doorway. They arrive to a job site completely manufactured, insulated, and ready for a simple installation process. They require minimal maintenance. Hydroflex offers more than 11 different sizes of heat exchangers for a completely customized system.


What Is Solar Thermal Water Storage to Generate Heat?

Solar thermal is using sunlight to generate heat. This is different from photovoltaic systems, which use sunlight to generate electricity. The benefits are similar in that you are taking advantage of an inexhaustible natural resource to generate heat more efficiently and inexpensively.

People often equate the generic word "solar" with photovoltaic because it is discussed in the media on a daily basis. Solar Thermal is not as well publicized, yet. For now, many do not understand the fundamental differences that make solar thermal a much more cost-effective option for commercial and residential applications. But solar thermal is catching on fast...

Solar thermal is the more cost-effective way to generate heat. Hydroflex makes it fast and easy to store and re-use solar thermal energy.


Solar Thermal: Twice the power, half the cost.

Without question, solar thermal costs less per unit of power than photovoltaic. Solar thermal collectors combined with our hot water storage tank maximize the sun's energy with efficiency up to 70 to 90%. Photovoltaic systems only generate 12 to 15% maximum efficiency after inverter losses and de-rating. A typical solar thermal system can offset more than twice the power of a photovoltaic system at less than half the cost.


System Maintenance

Solar thermal is a simple system with basic components. Initial costs are low. Equipment lasts long with minimal maintenance. Some of the tanks we manufactured have been in service for 30 years! Replacement parts are available, if ever needed, and easy to install. Photovoltaic is complex, high-tech, and very pricey. It is expensive and complicated to repair or replace, especially the inverter, and does not have the same longevity. Batteries must be replaced and recycled regularly.



Solar thermal systems most effectively store heat, in an insulated tank, for use at any time of the day or night. Hydroflex Systems, Inc. offers several levels of insulation for every size solar water storage tank based on necessity. In contrast, photovoltaic stores electricity in batteries OR puts it back into the electrical grid. Solar thermal offers true, off-the-grid existence and independence from the power companies.


Compatibility of Hydroflex

Solar thermal energy is most efficiently utilized at "low temperatures" (95°F to 170°F). These temperatures allow collectors to transfer more heat. Standard Hydroflex tanks and those equipped with double-insulation kits can be used with any solar collector commercially available, in either a closed or open loop systems. Our EPDM liners are perfect for low temperature applications remaining cost-effective and durable.


Uses for Solar Thermal

Homes and businesses everywhere are discovering the many uses for solar thermal for hot water systems, space heating, forced air heating, baseboard heat, radiant floor systems and more. Here’s a look at how you can leverage the power of solar thermal energy:


1. Domestic Hot Water

Solar Thermal for commercial drying

Solar thermal systems for domestic hot water and commercial hot water are designed to provide consistent access to water at the temperature you need it, no matter the time of day. This is true regardless of your location and climate, including areas that offer little in the way of solar radiation. Many home and business owners choose solar systems for domestic hot water because city or well water typically arrives at between 50 and 55 degrees Fahrenheit. Solar systems for domestic hot water heat this incoming water while creating as much as an 80 percent reduction in related costs. You’ll find solar systems for domestic hot water in each state in the U.S. and every province in Canada.


2. Space Heating utilizing Radiant Floor Systems

Solar Thermal for radiant heating

Solar thermal systems for radiant floor systems provide the uniform distribution of heat that is so often lacking in alternatives. When you choose solar thermal systems for domestic space heating and radiant floor systems, you get extremely efficient space heating that allows you to set a thermostat 5 to 10 degrees cooler while enjoying the same level of comfort as with other space-heating options. Solar thermal systems for radiant floor systems also feature tank temperatures as low as 95 degrees, which means tanks can store all needed heat for an appropriately sized system.


3. Space Heating utilizing Forced Air Systems

Solar Thermal for forced air systems

Solar thermal systems for forced air heating feature water-to-air heat exchangers that are used in ducted systems. To fully access the benefit of solar thermal systems for forced air heating, a system redesign may be required. With tank temperatures as low as 120 degrees, solar thermal systems for forced air heating can store all the heat needed for a right-sized system.


4. Space Heating utilizing Hydronic Baseboard

Solar Thermal for space heating

When you have a new construction or retrofit project, consider solar thermal systems for baseboard heat. These systems generate about 225 Btu per foot with water at 120 degrees, 275 Btu per foot at 130 degrees and 335 Btu per foot at 140 degrees.


Contact technical support for assistance in sizing.


Stratification and Heat Exchangers

Stratification occurs in the tank when hotter water rises to the top. Heat is delivered to AND removed from the tank through heat exchangers. Vertical, spiral, heat exchangers sit inside the tank. They are designed specifically to eliminate laminar flow.

The solar "loop" uses its own set of heat exchangers to input hot water at the top of the tank. In a closed loop system, the water inside the tank remains undisturbed and serves as the heat storage medium. Water cools on its way to the bottom, exits the tank, and then is reheated by the collectors. The load "loops" which are separate and have different sets of heat exchangers remove hot water from the top of the tank and return cooler water at the bottom.


Check out our selection of heat storage tanks for solar thermal systems.

Did you Know?

Solar thermal and wood burning sources can be used to heat the same tank.