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 second article on heat saving when adjusting heating systems is focused on the importance of good transfer of heat between external and internal networks. including the effect on the activation of temperature sensors and economical operation of dynamic heating systems, including the effect on the activation of temperature sensors and high-economy operation of the dynamic heating systems (thermostatic valve reverse curve, the dependence of operating parameters on the system differential pressure and problem solving of the central heating supply thermal hydraulics)

The article contains supporting evidence for the treatment of heating systems, describes the effect of adjustments to the internal wiring and piping on the outside heat supply network of central heating (CPP), analyzes the causes of low heat savings and provides information on the best solution practices for actual adjustments.

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.

The paper presents the usage of programmable thermostatic heads. By using of electronic thermostatic heads the possibility of heating regulation is really extended. The overview of all implemented functions in electronic thermmostatic valves is described in detail.

Products resulting from the combustion of gas that contain harmful substances (carbon monoxide CO, carbon dioxide, CO₂, water vapor, H₂O) can penetrate into a room during the activity of Type A gas appliances. The concentration of oxygen, O₂, also decreases during the combustion of gas. Water steam should also be considered harmful. The results of calculations show that the rate of humidity is most important for determining the minimum volume of the room or the minimum volumetric flow rate of ventilation air.

The article reacts on changes that were made in program "Zelená úsporám" in recent days. Previous article described how to reach required standards for successful subsidy application in two ways. Following text focuses on changes in this approach both from subsidy amount and possibility of subsidy itself viewpoints. In general, portfolio of potential subsidy applicants has been extended, but necessary quality of subsidized measures has been kept.

The author deals with a numerical analysis of temperatures and flow fields in heated rooms in relation to the location of the radiator. Two designs for radiators are discussed in the form of four possible solutions. A radiator with a classical design was placed under a window on the wall cladding, on an inner wall and on an inner wall opposite. A radiator designed with a balance method was placed only under a window.

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.

The paper presents the possibility of heating regulation by using of thermostatic valves in combination with thermostatic heads. Basic principles of functionality of thermostatic valves and heads are briefly explained.

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.

The article includes the epitome of project documentation that is not available in the technical practice or that is newly elaborated but that is necessary for the reconstructions, replacements of obsolete radiators and for adaptations of heating units performance connected with the heat cladding of the construction objects.

Separation of yellow waste water and rainwater, and their subsequent use in agriculture (yellow water) and residential (rainwater) is real. When using tank rainwater, tanks to stabilize urine and domestic wastewater treatment plant we will have 85% savings in potable water.

The article deals with the influence of the floor area of house energy supplied to the hot water. Mutually compare three methods of calculation and one of them use in the calculation of delivered energy for hot water system, through which energy class is designed for local consumption - the warm water.