FAQs

HOW DOES A SOLAR THERMAL SYSTEM WORK?

A solar thermal system consists of a number of components; a solar collector, a pump station, a solar controller and an indirect hot water storage tank.

The solar collector, located on the roof, collects the solar energy and transfers the heat to the storage tank via the tanks internal heat exchanger. The storage tank allows the hot water to be stored until it is used at night or in the morning.

The storage tank acts as a pre-heat tank for the existing hot water tank. As hot water is being drawn from the existing tank, hot water from the pre-heat tank replaces it.

WHAT IS THE LIFE EXPECTANCY OF A SOLAR THERMAL SYSTEM?

The life expectancy of a solar thermal system is between 20 and 30 years. If a solar thermal system receives regular annual maintenance checks, they can last over 30 years. It is recommended that a service contract be made with your qualified solar installer.

WHAT IS THE AVERAGE PAYBACK FOR A SOLAR THERMAL SYSTEM?

Solar hot water systems can save the home owner or business a substantial amount of money and reduce GHG emissions. At current energy prices, these systems can pay for themselves in 5-10 years, depending on the application. If fuel prices continue to rise, the payback time reduces.

HOW LONG WILL IT TAKE TO INSTALL A SOLAR THERMAL SYSTEM?

On average, 1-3 days are required to install a solar thermal system.

HOW MUCH MAINTENANCE AND SERVICE IS REQUIRED?

Solar thermal systems should receive an annual service check so that they can function at their optimum level. Check with your service contractor. Evacuated tube technology requires virtually no regular maintenance of the system. If a tube is broken, the system can remain operational, only the efficiency of the system will be reduced slightly.

WILL A SOLAR HOT WATER HEATING SYSTEM WORK ON A CLOUDY DAY?

Yes. Although the heat output of the solar collector is reduced on overcast days it will still be able to provide heating. Approximately 25-30% of the solar energy actually gets through the clouds.

CAN I USE A SOLAR HOT WATER HEATING SYSTEM WITH MY EXISTING HOT WATER SYSTEM?

Yes, under normal circumstances. An additional storage tank will be required to be installed to pre-heat the cold water prior to entering the existing tank.

WHAT ARE THE ADVANTAGES OF EVACUATED TUBE SOLAR COLLECTORS VERSUS FLAT PLATE COLLECTORS?

Easier Installation
One person can quickly and easily install a GreenLand Systems collector without a hoist or special tools because the vacuum tubes, manifold, and frame are installed separately. This unique feature results in substantial savings in installation time and expense. This is not possible with most flat plate products because of their one-piece construction.

Superior Insulation
As any good thermos bottle proves, there is no better insulator to heat transfer than a vacuum. GreenLand Systems glass tubes are evacuated to 10-5 mbar, which provides excellent resistance to heat losses via conduction and convection, even under extreme environmental conditions like cold winter temperatures and wind. Flat plate collectors lose a considerable part of the heat energy collected back to the environment.

Easier Servicing
Since the evacuated tubes are installed in the manifold via dry connections, any tube can be replaced without shutting the system down. Flat plate systems must be shut down and drained.

Longer Life
High vacuum tubes protect the absorber surface from moisture, condensation, corrosion, and degradation of the selective coating over the entire life of the collector, which easily exceeds 15 years. Flat plate collectors are not immune to these effects since air contacts the absorber and all interior surfaces.

Better Efficiency
Vacuum technology insures a high year round efficiency. Flat plate collectors are less efficient during cold seasons.

Dual Use Potential
Domestic water and space heating are possible.

Better Conversion Threshold
More energy is collected earlier in the day and during partly cloudy days because of the special absorber coating and superior insulation.

WHAT IS THE TYPICAL POWER USAGE OF THE WATER CIRCULATING PUMP IN A SPLIT-TYPE SOLAR HEATING SYSTEM?

Typically the ratio between the pump power consumption and the solar energy that you collect free is about 1:200 in domestic solar water heating systems. This means that the circulating pump uses about 0.5% as much energy as provided free by the solar collector.

In large commercial / industrial solar heating systems this fraction is even smaller. It can be as low as 0.1% or less.

SOMEBODY TOLD ME THAT THE FLAT PANEL COLLECTOR ABSORPTION IS 88%, WHICH IS ONLY ABOUT 5% LOWER THAN YOUR COLLECTORS. HOW CAN GREENLAND SYSTEMS CLAIM THEIR COLLECTOR EFFICIENCY TO BE OVER TWICE AS HIGH AS THAT OF MANY FLAT PANEL COLLECTORS?

When we talk about efficiency, we must also mention the ambient and other factors. Salesmen normally tell you only the good news about efficiency, but can forget to tell you that the peak efficiency of their collector only happens on hot summer days, but not during the rest of the year. GreenLand Systems solar collectors can perform very efficiently the whole year round. Even in winter or on a cloudy day when most other collectors can not collect any heat at all. Please refer to the graphs below for year-round performance comparison.

HOW HEAVY IS A GREENLAND SYSTEMS SOLAR COLLECTOR? DO WE NEED ANY ROOF STRENGTHENING BEFORE INSTALLING A GREENLAND SYSTEMS SOLAR COLLECTOR?

Usually you do not need any roof strengthening, because GreenLand Systems solar collectors are very light. Each GreenLand Systems solar collector weighs less than 100kg.