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.

The paper presents the possibility of heating regulation by using of room thermostats. The paper describes the main functionality of room thermostats and differences between non-programable and programable room thermostats.

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.

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.

Solar collector is designed to obtain part of heating requirements of the buildings from the sun. Air-type collector that use air as the heat transfer medium is one of the simplest methods of solar heating. This solar heating technique can be made part of house design and construction.

From point of view of energy balance every biomass is accumulated solar radiation. It is estimated that about 30 % of biomass is used as food and feed and 20 % is production of forest. Despite fossil fuels the biomass is the most significant energy source in the world. Recently it is not issue however in case of large expansion the energy use of biomass can compete with use as food and feed.
In the Czech Republic it is assumed that the biomass will remain the most significant renewable energy source (RES) at least until the end of the next decade. Energy potential of biomass is limited by production ability of landscape on one hand and by other opportunities of use of biomass on other hand. Expansion of the other opportunities is usually not taken into account in energy predictions.
Energy balance (EROEI) of biomass plantation strongly depends on proportion of use of heavy machinery and transportation distance. EROEI of spatial energy crops is better than that of food production. Although energy yield is highest when the biomass is harvested in summer the biomass harvested next year in spring contains much less moisture and thus is suitable for direct combustion.
Compared to other RES the advantage of the biomass is easy accumulation or (if you like) possibility to harvest in desirable time, easy control of energy supply in accordance with actual demand. In most cases exploitation of equipment designed for fossil fuels is applicable. In renewable energy mix responsible position of biomass is (despite other potential) in balancing of production of sources that are fully dependent on weather - photovoltaic and wind.

From point of view of energy balance every biomass is accumulated solar radiation. It is estimated that about 30 % of biomass is used as food and feed and 20 % is production of forest. Despite fossil fuels the biomass is the most significant energy source in the world. Recently it is not issue however in case of large expansion the energy use of biomass can compete with use as food and feed.
In the Czech Republic it is assumed that the biomass will remain the most significant renewable energy source (RES) at least until the end of the next decade. Energy potential of biomass is limited by production ability of landscape on one hand and by other opportunities of use of biomass on other hand. Expansion of the other opportunities is usually not taken into account in energy predictions.
Energy balance (EROEI) of biomass plantation strongly depends on proportion of use of heavy machinery and transportation distance. EROEI of spatial energy crops is better than that of food production. Although energy yield is highest when the biomass is harvested in summer the biomass harvested next year in spring contains much less moisture and thus is suitable for direct combustion.
Compared to other RES the advantage of the biomass is easy accumulation or (if you like) possibility to harvest in desirable time, easy control of energy supply in accordance with actual demand. In most cases exploitation of equipment designed for fossil fuels is applicable. In renewable energy mix responsible position of biomass is (despite other potential) in balancing of production of sources that are fully dependent on weather – photovoltaic and wind.