In Amendment Z1 of ČSN 75 5455, annexes B, C and G, respectively, a new method of computational flow in the internal water supply piping, calculation of longitudinal heat loss and an example of calculation of the internal water supply are important.

An important task of the present is the preparedness of the Czech Republic for more frequent and intense drought episodes. One of the partial issues is also the evaluation of the importance of water resources protection zones in order to fulfill their function not only in the normal situation, but also in dry seasons. The paper contains the following parts: experience from the analysis of pilot areas, protection zones as an operative or preventive tool in drought, protection of yield, protection of groundwater infiltration areas, protection zones as a reflection of time of its creation, national database of protection zones, professional level of protection zone proposals, structure of risk assessment in proposals of protection zones.

Measuring and control devices as well as other HVAC systems, run through their lifecycle, at the end of which the system needs to be reconstructed. A key condition for a successful retrofit is to determine the required life of the refurbished equipment.

Water and sewerage systems are known from ancient Greece and Rome. The aqueducts were made of burnt clay or lead. Besides archaeological finds, there are also aqueducts and written testimonies. Sewerage was mainly made of bricks, the most famous of which is the Roman sewer Cloaca maxima from the 6^th century BC.

The paper deals with the analysis of thermal losses of pipe distributions in the small solar system model created in the TRNSYS energy simulation tool. Attention is paid to the impact of heat loss through pipelines on the overall energy balance. Several variants of pipe lengths for one type of system have been selected. The results presented in the articles illustrate the influence of different pipe lengths on heat losses and the consequent impact on the energy balance of the monitored system.

By applying preventive measures and using risk management, we can achieve a secure system and eliminate costly solutions. The order of danger of infection sources is very difficult to determine unambiguously.

The article describes basic principles of the SBToolCZ green building assessment methodology stressing its up-to-date methods for school buildings. An example of a certified school is given. Renovation of this school was assessed and optimised by the SBToolCZ system which lead to the conversion into intelligent, zero energy building.

In July 2018, a two-year monitoring of the FENIX Group a.s. in Jeseník. During this time, different battery operating modes were applied to test their capabilities to ensure the power operation of the object. This article describes the entire period in terms of energy flows in the building. The key parameters are energy consumption, supply to the grid, self-sufficiency of the building from the photovoltaic source and its local use. A number of articles have been written about the building, detailing the building and energy aspects [1, 2]. Therefore, the description of the energy economy in the building will be given only to the extent necessary for a general view of the building's energy.

The methodology for determining energy-neutral or energy-zero houses is different at national levels. The interest in the realization of such houses is not only influenced by the methodology but also by the market conditions in the area of moving surplus energy production from one object to another. This is an economically disadvantageous purchase price when delivering to the network. If the existing conditions in the Czech Republic are not changed, the implementation of energy-zero houses for investors will not be interesting and the potential for reduction of CO₂ production will not be utilized.

Where is the biggest obstacle to implementing rainwater management? What is the right motivation? What is the effect of the exemption from the drainage water drainage payment? What are the experiences with plants on building façades? And what are the investment and operating costs of a green roof?

The methodology for determining energy-neutral or energy-zero houses is different at national levels. The interest in the realization of such houses is not only influenced by the methodology but also by the market conditions in the area of moving surplus energy production from one object to another. This is an economically disadvantageous purchase price when delivering to the network. If the existing conditions in the Czech Republic are not changed, the implementation of energy-zero houses for investors will not be interesting and the potential for reduction of CO₂ production will not be utilized.

The notion of a nearly zero building, usually NZEB or nZEB, is no longer a novelty. This energy standard was introduced in 2016 and is gradually expanding into family houses. There are legislation, standards, but little has been gained. That's why the authors analyzed 130 already existing family houses with different heat sources. The result is an assessment of the influence of different heat sources on the energy intensity of homes and therefore an orientation aid for decision-makers of future builders.

The article focuses in detail on the effect of the storage tank size on the yearly balance of the photovoltaic power plant using a 10-minute calculation step that will allow us to take a closer look at the processes associated with the production of electricity, the hot water consumption and its accumulation. The results are assessed not only from the point of view of the energy balance, but also from the point of view of economic advantage.

By replacing the non-condensing gas boiler with condensing is connected with the necessity to solve the condensate drain from the boiler into the sewer. For boilers, especially in households, it may be as simple as introducing condensate into the flushing cistern of the WC. The article discusses operational and hygienic contexts. The conclusion is that without the additional installation of a special fitting – the pipe separator into the drinking water supply to the cistern, it is a solution that is inconsistent with current regulations and cannot be recommended.

The aim of the paper is to highlight the most common mistakes in sizing of domestic hot water (hereinafter only DHW) storage tanks and heat sources for DHW preparation. The article describes two basic ways of designing: Method using heat supply and demand curves of the DHW preparation system and Method of priority DHW preparation. Sizing of the DHW storage tank should primarily correspond to the used heat source and expected hot water consumption profile. When using the heat supply and demand curve method, the designer places the greatest importance on the minimum size of the DHW storage tank (i.e. the shape of the supply curve), regardless of the potential changes in the DHW consumption profile (i.e. the demand curve). When using the so-called priority DHW preparation, the basic precondition is often neglected that the required heat output of a common heat source must comply not only with the DHW preparation system but also with other connected heat consumption points.

This design and technical solutions for sewage effluent are recommended based on the requirements of EN 12056-2 and experimental hydraulic pipeline measurements. Individual adjustments for pipe breakage are contained in national standards, e.g. STN 73 6760, ČSN 75 6760 and DIN 1986-100, which must comply with EN 12056-2.

The principles are set out in CSN 75 6760. Priority is given to sufficient drainage of waste water from equipment without extraction of odor closures and backflow.

The security elements and their connection vary depending on the type of heater and the amount of heated water. The connection of the safety valve pipe to the drainage system must be ensured by a so-called free spout in accordance with ČSN EN 1717.

For instantaneous heating, heated water is immediately consumed. Accumulating water heating is obtained especially when there is insufficient heat source available. For district heating, the water is heated outside the object in the heat exchanger station. For multi-stage heating, the water is heated by several heat sources.

On average, every citizen of the Czech Republic consumes about 40 liters of hot water per day. Approximately 2.2 kWh of thermal energy is consumed to heat this water.