Going off-grid is a terrific opportunity to reassess life decisions. It gives time to reflect on what is essential. It also involves making some cold and hard decisions. What degree do we want to go off-grid, how much can we afford to invest, and what technologies do we want to support, e.g., solar tubes or solar panels.
Solar Tubes are superior in almost every metric when compared to Solar Panels. Solar Tubes are more efficient. They retain heat better; generate more heat over a given area, and are more durable than Solar Panels. Solar Tubes are more expensive than Solar Panels.
Both Solar Tubes and Solar Panels are viable water heating solutions. Choosing the most appropriate technology for you will depend on several factors.
A Quick Guide Comparing Solar Tubes Vs. Solar Panels
| Solar Tubes | Solar Panels |
| Over 160% more efficient than Solar Panels | Less Effective than Solar tubes |
| Works in Freezing Conditions | It only works If Temperatures are above freezing |
| Very Durable | Not as Durable |
| Resists Rust | Rusting is an issue |
| Use less roof space than solar panels | Use more roof space |
| Most expensive | Least expensive |
When Do You Decide To Convert To Solar Water Heating?
Moving to solar power systems is a significant and expensive decision.
Factors to consider are
- Is the house a new build or a conversion of an existing building?
- What budget is available
- How stable does the utility supplier provide the energy?
Existing Build Vs. New Build
Retro-fitting a solar power system into an existing building is more complex. Do you re-plumb the whole house, or can you incorporate the new system into the current infrastructure?
With a new build, you only need to decide on what system to install and whether you should consider Solar Tubes vs. Solar Panels.
Some countries and states have promulgated legislation requiring new builds to incorporate solar systems. In these cases, the decision is automatic. Although the bill may require a renewable energy installation, there is often a financial benefit offered to do so.
If your utility supply is stable, it may be harder to find the motivation to convert to solar. Let’s face it. Solar water heating comes at a particular cost of convenience.
Suppose you decide to install a solar water heating system. Do you choose Solar Tubes or Solar Panels?
How Do You Choose Between Solar Tubes And Solar Panels?
The two main types of solar water heating systems are Solar Tubes and Solar Panels. Both systems harness the sun’s energy to create heat. The collected energy heats the water.
Central to both Solar Tube and Solar Panel technology is a Collector. The differences between the function and efficacy of the collectors determine the effectiveness of each design.
1. What Are The Features Of Evacuated Solar Tube Collectors?
This Solar Tube system consists of smaller glass tubes suspended within a larger primary tube. The space between the smaller tubes and the larger tubes has the air removed, which creates a vacuum. This vacuum creates a natural thermal insulation barrier.
This design component is the most critical factor in the panel’s efficacy.
The inside of the primary glass tube is coated with a light absorber composed of titanium nitride oxide or aluminum nitrate. The genius of these coatings is that they screen out unwanted light frequencies and only collect those which the tube needs.
The filtering action maximizes the efficiency of the tube over a select band of light wavelengths.
This design makes evacuated solar tubes the most efficient and expensive. As the water moves around the tubes, it is heated up by transferring energy from the system.
2. What Are The Features Of A Flat Plate Solar Panel System?
The technology behind Flat-plate Solar Panel Water Heating systems is straightforward.
There are various iterations of designs, but they all follow the same basic process to convert the sun’s energy into water heat. The process is listed below.
- The system uses a heat transfer fluid contained in tubes within the panel. This fluid is usually comprised of antifreeze and water.
- Coldwater is collected into a tank.
- When the sun’s energy reaches the panel, it activates the heat transfer fluid within the collector.
- As the fluid heats up, the heat transfer fluid transfers energy to the water, which heats up.
- As the water heats up, using the principles of convection, the hot water rises and starts moving around the tank.
- The hot water reaches the top of the system and is available.
- If not used, it begins to cool as it moves away from the heat source. As it cools, the water sinks to the bottom of the tank and repeats the whole process for as long as the sun’s energy is present.
Are Solar Tubes Or Solar Panels The Better Option?
Solar Tubes and Solar Panels use very similar technology. The different technologies have very different outcomes. The following examines the strengths and weaknesses of both Solar Tubes and Solar Panels.
Evacuated Solar Tube Collectors have eight advantages over Solar Panels.
- Evacuate Solar Tube Collectors are the most effective system
- Evacuated Solar Tubes expose a greater surface area to the sun, which results in more energy being available for the heat transfer to the water.
- Australian researchers have compared the two technologies and concluded that Evacuated Tubes are 163% more efficient in transferring heat than the equivalent Flat Plate Systems.
- Evacuated tubes continue to transfer energy, even if the ambient air is freezing.
- Evacuated tubes are very durable. As each tube is separate, only the broken tube needs to be replaced.
- A benefit of the tubes being more efficient is that Evacuated Tubes take up a smaller area to generate the same heat than a flat plate solar panel system.
- Evacuate Tube Systems are constructed mainly from glass and, therefore, are less prone to corrosion.
- Evacuated tubes still operate in overcast conditions.
Flat Plate System (or Solar Panels)
There are three main benefits to using flat plate solar water heaters.
- The main advantages of a flat plate solar system relate to the cost. Flat plate systems are cheaper to produce, which means that the retail price is less than Evacuated Tube Systems.
- They require minimal maintenance.
- Within the limitations of the technology, Flat Plate Solar Panel Systems capture energy efficiently and can access both beam energy (energy directly from the sun) and diffuse energy (indirect suns energy which has been scattered by the atmosphere).
Conclusion
If a sufficient budget is available, we recommend choosing Solar Tubes that are Superior to Solar Panels.
Solar Panel technology is lower cost but is less efficient than the equivalent Solar Tube devices.
Solar Tubes cost more but are certainly a worthwhile investment in a long time in the longer term.