Hot Water With Solar

Solar Panels and Solar Tubes can be a very cost effective way to generate hot water for your home. They can be used in any climate, and the fuel they use, “The sun” is free.

How They Work

Solar water heating systems include storage tanks and solar collectors. The two most popular types of solar water heating systems on the Irish market are Solar panels (Flat Plate) and Evacuated Tubes.
Most solar water systems require a well-insulated storage tank. “Solar ready” cylinders have an additional coil for connection to and from the Solar collector.
Using buffer (or Thermal stores) the solar water heater preheats water before it enters the conventional water heater. In one cylinder systems, the immersion heater or boiler is combined with the solar collector in one cylinder.
The two most popular types of solar collectors used for in Ireland are:

• Flat-plate collector

Glazed flat-plate collectors are essentially insulated, weatherproofed boxes that contain a dark absorber plate under one or more glass or plastic (polymer) covers. The heat gathered is transferred using copper loops which usually contain Glycol as the transfer fluid to the hot water cylinder.

• Evacuated-tube solar collectors

They feature parallel rows of transparent glass tubes. Each tube contains a glass outer tube and metal absorber tube attached to a manifold which transfers the heat collected to the cylinder usually by means of Glycol which is circulated through the hot water cylinder.
There are two types of active solar water heating systems:

• Direct circulation systems

Pumps circulate household water through the collectors and into the home. They work well in climates where it rarely freezes or a drain back system is used.

• Indirect circulation systems (Most popular in Ireland)

Pumps circulate a non-freezing, heat-transfer fluid (Glycol) through the collectors and a heat exchanger / coil in the cylinder. This heats the water that then flows into the home.

Passive solar water heating systems are typically less expensive than active systems, but they're usually not as efficient in the Irish climate, they tend to be used more where a person wishes to experiment with the potential power of the sun.

Thermosyphon systems.

Water flows through the system when warm water rises as cooler water sinks. The collector must be installed below the storage tank so that warm water will rise into the tank. These systems are reliable, however they are not popular in Ireland due to the physical size. Most Irish consumers may have seen these systems when on holiday in countries like Spain and Turkey.

Solar water heating systems almost always require a backup system for cloudy days and times of increased demand. Conventional storage water heaters usually provide backup and may already be part of the solar system package.
A backup system is usually part of the solar cylinder, such as immersion heaters or a second loop direct from the central heating boiler.

Selecting a Solar System.

Before you purchase and install a solar water heating system, you want to do the following:

• Determine the correct system size for you and your family.
• Determine the system's energy efficiency.
• Ensure your roof is facing in the right direction to get the most from your solar system. South, South West, South East are optimal. Systems can also be installed using an East / West configuration however they tend to cost more and may not be as efficient.

 
For information about a specific solar system to suit you, contact us.

Installing and Maintaining the System.

The proper installation of a solar system depends on many factors. These factors include availability of solar power, studies show that Solar can provide up to 70% of hot water needs in Ireland. The direction your roof / wall is facing, the number of people residing in your home and of course safety issues. Therefore, it's best to have a qualified / approved solar systems contractor install your system.
After installation, properly maintaining your system will keep it running smoothly. Solar systems do not require much maintenance. We recommend that you discuss the maintenance requirements with your supplier / contractor.
Plumbing and other conventional water heating components require the same maintenance as most conventional systems such as the pump and pressure levels.
Regular maintenance on simple systems can be as infrequent as every 3–5 years, preferably by a solar contractor. Systems with electrical components can require a replacement part and the Glycol should be tested to ensure it can not freeze. For more information about system maintenance, see the following:

• Solar Water Heating System Maintenance and Repair 

When screening potential contractors for installation and/or maintenance, ask the following questions:

• Does your company have experience installing and maintaining solar water heating systems?
  Choose a company that has experience installing the type of system you want and servicing the applications you select.
• Have you or your company carried out training with the system manufacturer and / or completed training with a recognised training centre?
  
• Is your company on the SEI / Greener Homes installer list?
  Grants will not be paid on systems installed by persons or companies who are not registered with SEI / Greener Homes Scheme.

Improving Energy Efficiency.

Before or after your Solar System is installed, try some additional energy-saving strategies to help lower your water heating bills, especially if you require a back-up system. Some energy-saving devices and systems are more cost-effective to install with your Solar System.

• Reduce your hot water use
• Lower your water heating temperature
• Insulate your water heater Cylinder
• Insulate hot water pipes
• Install a timer and use off-peak power for an electric water heater