帮助人类可持续发展和对环境友好的科学技术，一直是我们孜孜不倦追求知识领域。传统的燃料能源正在一天天减少，对环境造成的危害日益突出，同时全球还有20亿人得不到正常的能源供应。这个时候，全世界都把目光投向了可再生能源，希望可再生能源能够改变人类的能源结构，维持长远的可持续发展。近几年来，科学家也在这方面做出了不少努力，并取得了显著成就。可再生能源技术已不再是限于书本上的概念或想法，而是变得越来越切实可行，例如潮汐能、风能、水能、太阳能等等的开发技术已经到了比较纯熟的阶段。这之中太阳能以其独有的优势而成为人们重视的焦点。丰富的太阳辐射能是重要的能源，是取之不尽、用之不竭的、无污染、廉价、人类能够自由利用的能源。

      在公民住宅生活用水用电的解决方案上，我们也多了一个新选择，那就是太阳能。太阳能的可持续利用主要分为光热技术和光伏发电技术。光热利用是将太阳辐射能收集起来，通过与物质的相互作用转换成热能加以利用。目前使用较为普遍的太阳热能转化装置有太阳能热水器、开水器、干燥器、太阳灶、太阳能温室、太阳房、太阳能海水淡化装置以及太阳能采暖和制冷器等。在光热转换中，当前应用范围最广、技术最成熟、经济性最好的是太阳能热水器的应用。另一方面，通常民间所说的太阳能发电往往指的就是太阳能光伏发电，简称光电。光伏发电是根据光生伏特效应原理,利用太阳能电池将太阳光能直接转化为电能。不论是独立使用还是并网发电,光伏发电系统主要由太阳能电池板（组件）、控制器和逆变器三大部分组成，它们主要由电子元器件构成，不涉及机械部件。所以，光伏发电设备极为精炼，可靠稳定寿命长、安装维护简便。

      太阳能可以有效帮助屋主节省生活能源开支，并且有助降低污染和垃圾产生。很多家庭已经开始用太阳能热水器为家中供应热水，大大节省了天然气和煤炭的燃烧成本，同时也减少了了对环境尤其是空气的污染。目前这一技术正在朝着兼具实用和美观的方向发展——美国特斯拉汽车公司已经推出了太阳能屋顶。该产品类似正常屋顶，但瓦片内含太阳能电池板。它可以同特斯拉电力墙相连接，后者为整栋房屋供电。首批推出的太阳能屋顶有黑色纹理和灰色光滑款，材质为钢化玻璃，硬度是一般屋顶的三倍，可以抵御极端天气。可以想象，未来的太阳能利用不仅将成为大趋势，而且有望融入我们的生活，成为日常居家离不开的必备能源来源。
In recent times, sustainable energy sources have become increasingly important and feasible, because of the risks involved with non-regenerative energy methods and also because of the advancement in technology and efficiency of the former. Among sources such as flowing water courses, wind and ocean, solar energy shines out as probably the most accessible renewable source of energy available to individual homeowners or small collectives.
 

A lot of energy has been put into developing cost-efficient solutions for homeowners and a recent drop in prices and increase in efficiency has finally come to a point where a usual person can actually think about implementing this solution in his own house. Given that in some countries, the municipality will support this endeavor financially or by reducing taxes, this option has indeed become cost effective. The investment usually takes a couple of decades to return its value, depending on the surface area of the solar system, location and climate, consumption of energy and the chosen technological method. Topping this, in some countries it is possible to even sell the surplus of electrical energy produced, further reducing the return period. All in all, from an economical aspect, investing in such a system is already worthy of consideration.
 

From the technical point of view, there are two main categories which a usual homeowner can apply to his house: solar panels and/or photovoltaic panels. Solar panel system works by way of heating water which runs through pipes, thus generating a source of hot water which can be used in the household for applications such as generally heating the house or even creating a provision for running hot water. Thus, it reduces the energy costs of the home.

On the other hand, a photovoltaic system uses solar light to produce electric energy directly, which can be used for any purpose afterwards, for example fueling the heating system (especially if this is also electrical), lighting and ventilation, appliances and even for being stored in special home-use batteries designed specifically to work with the photovoltaic panels system. Thus, the batteries keep solar generated electricity flowing during the night or on cloudy days. Of course, the surplus can usually be sold to the local electricity provider, which supplies you when your solar energy is missing due to particularly cloudy spells. In the end, a very efficient system and a collaborating provider can bring your electricity bill ideally down to 0.

As stated above, solar energy is one of the most worked on technologies in the energy sector, providing affordable solutions with long term gains even for the average homeowner. First, depending on the needs, consumption, budget and long term plans of the client, a strategy is devised – talk to a certified specialist to find the optimal solution for your specific needs – and the best system is chosen: a solar panel system, or a photovoltaic version. Next, and depending on the chosen strategy, and on layout, orientation and possible surfaces, the perfect technical solution is chosen. As general remarks, we can state that the orientation of solar panels should be south-facing and at an optimal angle of 45 degrees.

The main positioning spot of the panels is usually the roof (be it sloped or terraced), in case of applying the system to a house or block where the desired inclination and orientation may already be good, lessening the operations needed for the montage of the system. Of course, not all houses have a sloping roof facing directly south and with an inclination of 45 degrees. Also, depending on geographical position and implicitly on the sun’s path, a different inclination angle may be more efficient. So, in real life, the strategy takes into account the optimal layout of the panels, efficiently using the roof conformation as it is in each specific case.

Tesla's Solar Roof

Further going into details, we want to specify more possible solutions regarding the use of these solar roofs. Firstly, these panels can be mounted on the existing shingles of the roof, either directly or through a light substructure. In some cases, this substructure can even adjust the angle of the panels to more efficiently take in solar energy, though this system, including motors, structure and sensors, needs more of an initial investment.
 

Another possibility, developed recently by large companies such as Tesla for example, is solar or photovoltaic panels which are constructed directly into the shape of shingles, mimicking the appearance of different shingle materials and which can be used instead of regular shingles on the south facing part of the roof. Tesla states in some studies that arguably the cost of these solar shingles, including all the necessary complementary system parts and after subtracting the energy cost saved on a timespan of 30 years will be more or less the same as the cost of a regular shingle solution for the roof. Sensors and monitor systems allow you to see afterwards the efficiency of your implemented system and the percentage of energy that you are using each moment from your solar roof source.
 

In the end, whichever solutions you would find more appropriate to your needs and budget, the use of solar and photovoltaic roof systems will prove to be a beneficial investment, economical in the long term and ecological and environmentally healthy from the moment of installation. Take part in this “greener” and energy aware future scenario for contributing to the environmental health of our planet, both on global and on local scale.
 

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