The current boom of photovoltaic energy installation is such that even the laboratories of the Science Academy of the Czech Republic have been asked which is the best photovoltaic panel. There is no easy answer for such question. The ideal panel should have the highest efficiency, which should be independent of either temperature or intensity of illumination. In addition, the panel should not degrade, nor should need maintenance and should be the lightest, yet strong and durable. Thus far, nobody has built such panel (and price is not even being considered). Will we see in the future more efficient panels? Not easy with the conventional silicon technology. One thing is to build complex technology by way of a record cell of 1cm2, and another, to mass produce square kilometres of low-cost photovoltaic cells. However, the advent of nanotechnology is bringing new ideas that will lead to increased efficiency of photovoltaic cells. Further research and development, together with mass production, are bound to progressively make photovoltaic panels less expensive. In 10-15 years photovoltaics will be able to directly compete with other forms of electricity production, and the installed capacity will be in the hundreds of gigawatts worldwide.
Archiv článků od 12.10.2009 do 22.3.2010
The gross production of electricity from renewable sources in 2008 was 5.2% of the national gross electricity consumption. The share of renewable energy in primary sources reached 5%. The share of renewable energy sources in the production of thermal energy is around 7%. According to the Ministry of Industry and Commerce, in 2009 the share of electricity coming from renewable sources was 6.8% of the final electricity consumption in the Czech Republic.
The calculate the balance of annual fuel requirement it is important to correctly determine the specific calorific value of the fuel and to asses the real efficiency of the boiler itself. Not always this data is consistent with what is reported by manufacturers or retailers of pellets and pellet boilers. Just to get an idea, for a 1kW heat loss the consumption would be 520kg of high quality pellets. This is of course an estimate, because it depends on the concrete weather conditions in a given year (length of the heating season, etc.), but it also depends on the chosen temperature for the heated area (for some people 22ºC is too much, others feel cold even at 26ºC. It is normally calculated that to heat water for a family of four the annual consumption is 25GJ. That, calculated for a boiler and pellets gives as an approximate of 1.7 tonnes of pellets a year.
As of the 1st Octo 2009 is in force in the Slovak Republic the decree 311/2009 Z.z., which lays down the details for he calculation of the energy performance of buildings and the contents of the energy certificate. It is a binding document resulting from the law 555/2005Z.z., in which the Directive 2002/91/EC on the energy performance of buildings is implemented.
Originally the text was a review of previous article "Životný štýl udržateľnosti, udržateľnosť životného štýlu". On one hand the reviewer made a number of commetns, on other hand he decided the article as very stimulative. That is why his review is extensive. Editors then decided to publish the review as separate article.
It is explained that main outlines are known for about 40 years and some of theoretical concepts are more than 60 years old. Despite of that they are poorly spread recently.
In the last few years, the concept of sustainability has become a universal trend in the Western countries. All political programs include sustainable housing, economy or management. Although the expression “sustainable development” is in itself a fundamental paradox, it (and everything related to it) has become a victim of the market, or more specifically, of consumerism.
The paper presents the possibility of heating regulation by using of zoning regulation systems. The paper describes the main functionality of zoning wired a wireless regulating systems. Detail description of wired and wireless zone systém differences is mentioned. By using of zone regulating systems it is possible to reduce heating costs and improve comfort in our homes.
The costs for the support of energy from renewable sources is one of the regulated items in the prices of electricity. The costs for the distribution of electricity are also among the regulated items. The price of the electricity itself is not regulated and is determined by the trade at the power exchange market based on supply and demand.
From the phase of architectural studies, the building process goes through steady changes. The expert "forecast" of the thermal behaviour of these buildings will almost always be hampered by the lack of input data. However, even in such cases there are ways to provide valuable information about future features of the project. The information doesn't need to be always accurate. For example, if we asked if the building will be low-energy, it would be enough to know, among other things, if the resulting heat needed for heating will not exceed a certain threshold. We are able to identify this already at the stage where we have a clear idea about, for example, the properties of windows or the exact shape of the building. In this case, it is appropriate to extend the standard calculation procedures to be able to describe not only one chosen object, but a number of variations that may occur depending on what the we know about the building at a given moment. This presents a method for design and estimation of thermal-technical properties of family houses with very low energy requirements. The method uses the creating of variants with the Monte Carlo simulation applied to the parametric model house (monthly calculation according to EN ISO 13790 and 730329 DESERT). The results show the influence of individual characteristics of the building on the heat balance and makes it possible to optimise the overall building.
We can observe in the Czech press a significantly higher frequency of expressions suchs as passive house or energy-efficient construction, specially in connection with the subsidy program “Zelená Úsporám”. However, the reality is that the number of passive houses built is very low, moreover, in some of the so called passive houses there can certainly be doubts about their actual properties.
The concentration of greenhouse gases in the atmosphere has been dramatically rising for the past 150 years. This fact and the possible link between GHG concentration and rising temperature of the Earth caused that the reduction of greenhouse gases has recently emerged as widely discussed issue.
First step to cut CO2 emissions is to identify countries with the highest contribution to the worldwide emissions. From this point of view the emissions of China and USA are very similar.
However the information about absolute CO2 emissions per country is not fully correct for most of comparisons. Much better is to compare CO2 emissions per capita. From this point of view, which comes from idea that every people have the same right to consume the natural resources and produce waste, the emissions of China are much lower than that of the USA.
Information about CO2 emissions is relatively simple indicator. There are more complex indicators that should be used in case of sustainable development assessment.
Alternative energy sources are gradually taking a growing share in the worldwide production of electricity. Solar power is perhaps the easiest to implement and least expensive, its use is not too complicated and can you can easily experiment with it even in a small scale. It is easily accessible to anyone interested in environmentally friendly production of energy. To get started with it, it is just enough to buy one solar panel with a few additional components, and place it on a sufficiently sun-lit place and the production of energy can begin. Certainly, an interesting idea for users is that after the initial investment the system for several years basically doesn't have any requirements, and that it will produce energy for free.
A solar panel (photovoltaic panel or module) is a part of several interconnected solar units with a usual output of around 300W, which generated an voltage corresponding to the multiple voltages of the interconnected individual units. The source of higher outputs consisting of several interconnected solar panels is usually referred to as a solar power plant.
In the 1970's the interest in renewable energy sources increased considerably due to the energy crisis. At that time, the fist extensive and reputable studies were published, which talked seriously about the fact that conventional energy sources are exhaustible. The Czech republic adopted its first energy policy in 1992 in agreement with the regional environmental limits of coal.
The article deals with real experiences of growing of an energetic crop - the sorrel. There are described four selected locations concerning the crop production and applied treatment, including future outlook. The article also includes the price estimation of energy of 1 GJ from the sorrel, based on available data.
The interpretation of the concept of sustainability in the construction industry has developed these twenty years. In the first phase the problem of limited resources, especially energy had to be addressed as well as minimising the environmental impact of buildings and constructions processes. The next phase focused on the technical design of structures, particularly the choice of materials, building components, construction technologies and building design in order to increase their energy efficiency. Currently, the "soft" aspects of sustainability are gaining importance. They are generally regarded as crucial for a sustainable development in construction. The study results show that the traditional evaluation of projects can not dequately and comprehensively reflect effects of the environment and therefore, does not meet the principles of sustainable development. The work was created as part of the research project "Management of sustainable development, life cycle of buildings, construction firms and territories" (MSM 6840770006) funded by the Ministry of Education, Youth and Sports at the Czech Technical University in Prague, Faculty of Civil Engineering, and offers not only evaluation but also new options and Trends.
Air conditioning and ventilation systems show big energy consumption in buildings. Measure of the consumption of electrical energy for the conveyance of air is SFP. SFP is defined as the total consumption of electrical energy by the all of fans in the air-distribution systems, defined by the total volumetric air flow through the operated space under nominal loads. The article presents influence of design equipment on energy consumption.
Energy Regulatory Office (ERÚ) announced „adequate“ feed-in-tarif (FiT) for photovoltaic electricity. Based on actual situation on Czech PV market it is recommended to reduce FiT for systems below 30 kWp to 11 200 CZK/Wp and for systems above 30 kWp to 9 000 CZK/Wp (actual exchange rate is 25,785 CZK/EUR, see this site).
The recommended values of FiT correspond with actual situation on Czech PV market. Unfortunately exchange rate of Czech koruna (CZK) to Euro is instable. Exchange rate of Czech koruna to Euro oscillate in wide range from about 28 in beginning of 2008 to about 23 in August 2008 and back to about 29 in February 2009. In case the exchange rate will be on upper level the growth of photovoltaic installations will cease. On lower level FiT will be very profitable again.
On other hand future prices of PV modules are unpredictable. Actual rapid fall of prices is mostly based on decrease of price of Silicon as raw material. If the price of Silicon will rise after financial crisis will end, the prices of PV modules will rise too. The prices of modules will probably never exceed last year level, however prices high above 2 €/Wp are possible. According to those uncertainties the FiT could become either excessively profitable or purely restrictive.
The application potential for solar energy use in buildings lies in supply of thermal and electric energy and natural daylighting. To use incident solar energy from building envelope effectively, multi-functional construction elements combining several purposes should be introduced as a standard part of building construction. Examples of such concepts are presented: hybrid air/liquid collectors for heating and ventilation purposes, hybrid photovoltaic-thermal (PV/T) collectors for combined thermal and electric energy supply (glazed, unglazed, air/water cooled), linear Fresnell lenses collectors for removal of heat load from direct component of solar irradiation to thermal storage and allowing the natural diffuse daylighting.
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