Solar Thermal: advantages and disadvantages

 

Heating and showering with solar power. It is undoubtedly green, sustainable and good for the climate. But the investment is considerable - and it is not worthwhile for everyone.

[Solar Panel in Pakistan]The prognosis is not daring: energy will become even more expensive in the future. So, it is wise to tap into the richest and cheapest source of energy available to us: the sun. Solar thermal converts the rays into heat and helps to reduce the costs for heating and hot water. [ SunLife] From May to September, an average solar thermal system can cover the heating requirements of a single-family home. Then it may even be possible to use the sun's heat for cooling with the help of an absorption cooling system. In winter, on the other hand, the output of the solar heating is not enough to even come close to covering the heat demand. As a rule of thumb, around 20 percent apply here - the majority of the rest has to be bought in other ways, such as district heating or oil heating.

The prognosis is not daring: energy will become even more expensive in the future. So, it is wise to tap into the richest and cheapest source of energy available to us: the sun. Solar thermal converts the rays into heat and helps to reduce the costs for heating and hot water. [ SunLife] From May to September, an average solar thermal system can cover the heating requirements of a single-family home. Then it may even be possible to use the sun's heat for cooling with the help of an absorption cooling system. In winter, on the other hand, the output of the solar heating is not enough to even come close to covering the heat demand. As a rule of thumb, around 20 percent apply here - the majority of the rest has to be bought in other ways, such as district heating or oil heating.

More than two million systems have already been installed on roofs. In existing single-family houses, systems with a collector area of ​​20 square meters could already save up to a quarter of the consumption of heating oil or natural gas. [Solar Panel in Pakistan] That corresponds to 430 to 620 liters of heating oil or the same number of cubic meters of natural gas annually. The more the prices for heating oil or natural gas rise, the sooner a solar thermal system pays for itself.

In order to accelerate the envisaged energy transition, the federal government is subsidizing the retrofitting of solar thermal systems in existing buildings. Most of the investment of up to 10,000 euros, however, has to be raised by yourself.

 A system for a four-person household requires around four to six square meters of collector area and a solar thermal storage system in the basement or in the attic with a capacity of 300 to 400 liters.

Benefits of solar thermal

Long-lasting, uncomplicated technology

 Solar thermal is technically mature. The installed systems are low-maintenance and durable; service life of at least 25 years is assumed. Compared to photovoltaics, they are also more efficient - that is, they use the sun's rays more efficiently. A particularly high level of efficiency can be achieved if solar thermal energy is intelligently combined with condensing boilers or heat pumps.

No other heat source required in summer

 From around May to September, even in our latitudes, the solar collectors can harvest so much heat that the conventional heating can often remain switched off.The transformation of the sun's heat into cold is then also possible. [Solar Panel in Lahore]

Savings even in winter

In the cold season, the solar system does not standstill. With much less radiation, however, it ensures that you can save up to 20 percent of the costs for heating and hot water.

Public funding

The state supports buyers of a solar thermal system. In existing buildings, there are 50 euros per square meter of collector surface and at least 500 euros. For systems that also support heating, on the other hand, there is at least 2,000 euros or 140 euros per square meter for a renovation.

Disadvantages of solar thermal

·         Lots of heat in summer, little in winter
A disadvantage of solar thermal energy is its dependence on solar radiation. When it is needed most - in the dark season - it provides the least warmth. So you can't do without another source of energy at least from October to April.[SunLife Pakistan]

·         The "dark sides"

Some roofs or residential areas are not suitable for solar thermal energy. The causes can be the unfavorable “non-southern” orientation of the roof surfaces - or also tall trees or tall buildings very close by, which impair the yield of the system through their shadow effect.

·         High initial investment

A system pays for itself over time, but it takes patience. Despite public funding programs, the purchase remains an investment in the high four-digit range.