With so many homeowners recognising the benefits and switching to solar, more options are coming to market. Solar water heating systems are expanding with innovative options tailored to specific needs and climates, making the switch to solar a smarter move than ever.
One option worth exploring is the open circuit system, also known as an open-loop solar water heater. These systems are popular for their simplicity and efficiency, especially in warmer climates, and could be the right solution for your home.
The basic idea of open circuit solar water heating systems is quite simple: they use your household (potable) water, circulating it directly through solar collectors (like panels), where it’s heated by the sun and then stored for later use.
Let’s delve a little deeper into how the solar hot water system works. There are two main ways this water moves through the system:
The basic flow goes like this:
Unlike closed-loop systems that use a separate heat-transfer fluid, open-circuit systems heat the actual water you’ll use. This makes the design straightforward and efficient (in suitable climates) while also reducing costs.
Each component in the system plays a key role in keeping the water moving and the temperatures rising. Let’s take a closer look at these components.
Here is a list of the components and the role they play in making an open circuit system operate efficiently.
These are the main heat collection panels that absorb solar energy and transfer it directly to the water flowing through them. They’re the equivalent of the solar panels you see on roofs, but designed to heat water.
This well-insulated tank stores the heated water until it’s needed. It maintains warmth even when the sun isn’t shining.
The circulation system can be passive (thermosiphone, where hot water rises naturally) which is great for energy efficiency, or active (pump-driven), which provides more control over water flow but consumes more energy.
In active systems, this device monitors temperatures and activates the pump when heating conditions are ideal.
For safety and efficiency, they include pressure relief valves, check valves to prevent backflow, and tempering valves to avoid scalding.
Connects the collectors, tank, and home plumbing system.
Essential for keeping the heat in by insulating both the pipes and tank, while reducing energy loss and improving efficiency.
Used to position and angle solar collectors for maximum sun exposure.
So why should you choose an open circuit system over other types of solar hot water systems?
Let’s take a look at some of the other types of hot water systems available to better understand how they compare to the open circuit system.
These use a separate heat transfer fluid to warm the water via a heat exchanger. They are better suited for cold climates and have freeze protection built in. This means that they’re more complex and often costlier to install and maintain. For cold regions, they can be a better choice.
These rely on the grid and gas systems. While they have lower upfront costs, there are significantly higher long-term operating expenses, especially as energy prices climb.
These are also energy efficient but still require electricity to operate. They use different technology that may not suit every home layout or hot water demand.
Other considerations you need to keep in mind include maintenance, lifespan, and installation complexity. Open circuit systems generally require less upkeep than closed-loop systems but more than a basic electric tank. With proper maintenance, solar systems can last 15–20 years or more, longer than traditional water heaters.
While open systems are simpler to install than closed systems, they still require plumbing knowledge, which is something to consider if you’re thinking about a DIY installation.
Finally, climate suitability is another important factor. Open systems perform best in warmer regions as freezing conditions could lead to pipe damage.
If you’re planning a solar hot water setup, it’s important to get the design and installation correct from the start. We always advise finding a professional hot water system installer to ensure maximum efficiency and adherence to safety standards.
Choose a system size based on how much hot water your household uses. A small family might only need a compact system, while larger ones may need something more substantial.
Identify the best location for the solar collectors. Consider the amount of sun and orientation (facing north in the Southern Hemisphere), and angle. You will also need to determine the best location for your hot water system.
Decide how to integrate the solar system with your current water heating infrastructure. If replacing an old system, consider the necessary plumbing modifications for a retrofit. This is where a professional can offer expert advice.
For retrofit installations, plan and make any required plumbing adjustments to connect the solar hot water system to your home’s water supply. Again, a professional plumber is advised here.
Always check with your local council to ensure compliance with building codes before installation commences. In Australia, certain projects require permits, and certain standards need to be met.
If you’re considering DIY installation, ensure you have the necessary skills for a successful installation. While installing a solar hot water system yourself is possible, it’s certainly not easy, and professional installation ensures optimal performance and compliance with local regulations.
The whole installation should typically take a few days, depending on factors such as the complexity of the system, roof space and plumbing configurations.
Additionally, be prepared for potential challenges like roof space limitations, shading, or complex plumbing connections. Hiring an experienced installer not only smooths out the process but also provides priceless peace of mind that everything is set up correctly.
Solar collector efficiency is influenced by design, materials, and environmental factors such as climate and location. What’s in your control is the ideal orientation and tilt for maximum output. Don’t worry if performance drops over time due to wear and environmental conditions; this is normal. However, regular maintenance helps the system’s longevity and maintains efficiency.
If you’re interested in solar, then you might also be keen on exploring alternative energy sources. Future trends point to more integrated renewable energy solutions, with funding and incentives available for multi-technology installations.
For example, integration with photovoltaic systems, hybrid setups, and heat pumps can ensure year-round reliability. Furthermore, biomass serves as a backup during cloudy periods. Smart tech is also increasingly playing a role, with smart control systems optimising multi-source configurations.
If you’re interested in learning more about open circuit systems, speak to a member of the Same Day Hot Water team today to get the best solution for your home.
Solar hot water heating systems use solar collectors to absorb sunlight and heat water, which is then stored in an insulated tank for household use.
Open systems heat potable water directly, while closed systems use a separate fluid and heat exchanger to transfer heat to the water supply.
Active systems use electric pumps and controllers to circulate water or heat transfer fluid through the solar collectors.
Solar water heating can be less effective in cold or cloudy weather and may have higher upfront installation costs compared to traditional systems.
Yes, many Australian systems support integration with solar PV panels or solar thermal collectors for water heating.