Solar PV & Thermal
Panels
How Do They Work?
- Solar PV Panels: Use silicon cells to capture sunlight and convert it into electricity
via an inverter, powering household appliances. - Solar Thermal Panels: Absorb solar radiation to heat a liquid (a mix of water and glycol), which then transfers the heat to a water cylinder for use in showers and taps.
To determine which system suits your needs, it’s essential to compare their differences,
benefits, and limitations.
How Do Solar Thermal Panels Work?
Solar thermal panels collect energy from the sun and convert it into heat. For optimal performance, they should be installed on south-facing roofs. However, they still work efficiently on any roof facing between southeast and southwest. They are commonly mounted on pitched roofs but can also be installed on flat roofs or ground-mounted structures. In most cases, installation falls under permitted development, meaning no planning permission is required.
Closed-Loop System
Most solar thermal systems operate in a closed-loop circuit using a glycol-based heat transfer fluid with antifreeze. The system works as follows:
- The panels capture solar energy and heat the transfer fluid.
- This heated fluid flows through a twin-coil hot water cylinder inside the home.
- Heat is transferred to the water in the cylinder, which is then used for showers, taps, and other hot water needs.
Since the system is closed-loop, the heated liquid in the collector never directly mixes with the household water supply.
Twin-Coil Hot Water Cylinder
A twin-coil cylinder has two heat sources:
- Solar Coil (Bottom Coil): Positioned at the base of the cylinder, where the water is cooler, to maximize heat transfer from solar energy.
- Boiler/Auxiliary Coil (Top Coil): Used when solar energy isn’t sufficient, often powered by a boiler, air-source heat pump, or ground-source heat pump.
- Immersion Heater (Optional Backup): An electric backup that can be used if necessary, though it should be rarely needed with effective system controls.
Types of Solar Thermal Collectors
- Flat Plate Collectors:
- Feature an absorptive panel covered with a transparent layer (usually Perspex) and insulated to retain heat.
- Better suited for snowy conditions as snow melts and slides off.
- Evacuated Tube Collectors:
- Consist of double-layered tubes with a vacuum in between to minimize heat loss.
- More efficient in heat retention but can struggle with snow accumulation.
Since solar thermal panels use antifreeze in the collector fluid, they are unlikely to freeze in winter.
Advantages of Solar Thermal
More Space-Efficient
Requires less roof space than solar PV.
Higher Energy Conversion Efficiency
Converts up to 70% of solar energy into heat, whereas solar PV typically converts around 25% into electricity.
Simpler Technology
Easier to install and operate compared to solar PV.
Environmentally Friendly
A sustainable solution for hot water heating.
Cost Savings
Reduces reliance on traditional heating systems, lowering energy bills.
Disadvantages of Solar Thermal
Less Effective in Winter
Requires direct sunlight, meaning reduced efficiency on cloudy or short winter days, whereas solar PV can still generate power in low-light conditions.
Occupies Indoor Space
Needs a dedicated hot water cylinder inside the home, whereas solar PV systems take up minimal indoor space unless paired with battery storage.
Limited Versatility
Primarily used for hot water, whereas solar PV provides electricity for multiple uses.
Shorter Lifespan & Higher Maintenance
Involves moving parts (pumps, heat exchangers) and liquid systems that require maintenance, whereas solar PV has a longer lifespan with minimal upkeep.
Why switch to Solar Photovoltaic or Solar Thermal?
Choosing between solar PV and solar thermal depends on your priorities. If your main goal is electricity generation, solar PV is the better option. However, if you want a dedicated hot water heating solution that maximizes efficiency, solar thermal could be the right choice. Some homeowners even combine both systems to achieve greater energy independence and sustainability.
Reduce your heating bills
Save as much as 60% on your heating bill.
A comfortable home
Enjoy the benefits of a warmer home.
Grants available
www.seai.ie
Viessmann
- Up to A+++ Rating
- Heat from outdoor air even
- at -25 celsiuis
- Can bring refreshing cool air into your home during the summer.
- Sleek design
Hitachi
- Highest COP on the market at 5.25
- Up to A+++ Rating
- Heat from outdoor air even at -25 celsiuis
- Can bring refreshing cool air into your home during the summer.
- Sleek design
Alfea Excellia
- Compatible with all kinds of low temperature transmitters (underfloor heating/cooling, fan coil)
- NAVISTEM 200S regulator
- Perfect solution for high heating demand
- 16L buffer tank integrated
- Patented coaxial heat exchanger
- Inverter regulation
- Class A low energy consumption circulation pump
Daikin
- First R32 air to water heat pump
- Up to A+++ rating
- Up to 65°C
- Inclusion of all hydraulic components
- Heat from the outdoor air, even at -25°C
- Combine with a stainless steel tank or ECH2O thermal store.
What our clients are saying
Great Service
I am very happy to whole-heartedly recommend their services and I plan to continue to engage Total Heating for all of our plumbing requirements in the future.
