Energy Saving Technologies

Solar energy and heat collectors

Solar collectors absorb solar radiation (sunlight) and convert its energy to heat. Usually the solar collector has channels where water (or another heat carrier) circulates, warms up and is transported to the place where the heat is needed or accumulated. Most common use is for heating of domestic hot water, space heating, heating of swimming pools.

A solar collector collects solar energy more effectively or less effectively, depending on construction and the choice of materials. An effective collector with low losses can deliver heat with a high temperature and work all seasons, but it is relatively expensive. If high temperatures are not required, unglazed panels of lower cost could be adequate for applications.

It is important to know that solar collector surface (absorber) – should absorb as much radiation as possible and reflect as little as possible and heat in absorber must be transmitted effectively to the heat carrier (usually water or antifreeze). The collector must be well insulated and some types are vacuumed (evacuated) to minimise heat losses. Water is the most common inexpensive heat carrier in solar collectors but has the disadvantage to freeze. Adding antifreeze avoids the freezing problem but adds cost and increases the risk for environmental impact and even poisoning.

There are several types of solar collectors on the market with different efficiency characteristics. The flat plate solar collector is the most common where water runs through channels or pipes. Other type is collector made of vacuumed pipes for high collector efficiency. Systems are generally roof-mounted, south facing and inclined. Solar heating is most common in single-family houses but can also be used in larger systems in apartment blocks. Other important parts of the solar systems which will influence the price and efficiency are pumps, valves, controls and automation, expansion tanks, heat accumulators, insulation, additional heaters etc.

In Ukraine’s climate zone 1 (Vinnytsia, Cherkassy, Poltava, Kharkiv, Sumy oblasts) a solar collector accumulates 1150 kWatt/hour per 1 m2 of the collector’s surface. In climate zone 2 (Zakarpattya, Kirovograd, Dnipropetrovsk, Lugansk oblasts, except of Crimea) accumulated energy is 1250 kWatt/hour per 1 m2 of the collector’s surface. In Crimea, it is 1350 kWatt/hour per 1 m2 of the collector’s surface. In Lviv, Ternopil, and Ivano-Frankivsk Oblasts it is only 1000 kWatt/hour per 1 m2 of the collector’s surface.
For Ukraine climate the annual delivered heat from solar energy depends on the region, efficiency, pattern of use, type of solar energy system, level of automation etc.

The prices can vary from 300 to 800 EUR per m2 for “turn key” solar energy system and are dependent on efficiency, type, complexity, quality, size etc.

The most important disadvantage about solar energy is that on a short-term basis the availability can be uncertain. The total incoming radiation normally doesn’t vary much from year to year, but it is not easy to predict on a weekly, daily or hourly basis. Usually solar energy systems are combined with other energy sources or backup systems.

See also:

• Installation of a solar battery (video)

Useful links

• ATMOSFERA (solar heaters, heat pumps) (in Ukrainian)
• ENERGY SAVING SYSTEMS (in Ukrainian)
• ECOTEPLO (solar heaters, heat pumps, photoelectric equipment) (in Ukrainian)
• HEAT GROUP (solar heaters, solar water heaters, heat pumps) (in Ukrainian)
• KORDI, solar water heaters (in Ukrainian)
• ROGRESS XXI (solar collectors)
• SintSolar (solar equipment) (in Ukrainian)
• TermoSol (solar heaters, heat pumps, warm floor, heating systems) (in Ukrainian)
• VIESSMANN
• ZELENAYA ENERGIA (Green Energy, Solar Collectors) (in Ukrainian)