Sulfate attack is one of the major threats for durability of concrete in sewage collection systems where concrete sewer pipes are exposed to sulfates from waste water as well as from biogenic activity of bacteria. Damage due to sulfate interaction can result in the cracking and softening with loss of strength of concrete and it may lead to the concrete desintegration. Gypsum is the primary product of sulfate attack on concrete, after which ettringite is subsequently formed. Ettringite and gypsum are considerably larger in volume than the initial compounds, which leads to increased pressure within the concrete structure. This paper is focused on the sulfate attack on fine-grained concrete where the effect of 12 months contact of 0.5% sulfuric acid, simulating biogenic sulfuric acid corrosion, 5% sodium sulfate solution and solution simulating sewage water on various types of concrete has been investigated. The concrete specimens were characterized after exposition to the corroding media by their mechanical parameters, changes in pH and content of sulfates. It was found that after one-year exposure to sulfuric acid solution, the compressive strengths of all types of concrete significantly decreased. Sodium sulfate solution and the artificial waste water did not represent the significant corrosion environments for the concretes in terms of their strength reduction, increasing of sulfate ions content and the reduction in the pH of their aqueous leaches. The fine-grained concretes containing metakaolin and ground limestone showed the highest coefficient of corrosion resistance for the applied corrosive solutions.

The article deals in detail with the solar water heater from the EU Commission Regulation 812/2013. It describes what information provides the label and how it originated classification in the relevant energy efficiency class water heating.

The paper gives a simple method for calculating the annual production of condensate in the condensing boiler.

This article summarizes the basic concepts of Commission Regulation EU 811/2013 and 812/2013, focusing on solar equipment, solar water heaters and solar packages. Describes the responsibilities of suppliers who place such products on the market.

Rainwater is largely perceived as a waste water in Slovakia and in the Czech Republic, which should be divert as soon as possible to the sewage system. For many years it was mostly only one way of drainage of buildings and paved surfaces generally called “conventional way” of drainage. This paper describes the possibility of using rainwater in the school building, on the basis of the measured volume of rainwater runoff draining from the roof construction. The data were compared with the theoretical values of the water needs for the building.

This paper describes measured data and evaluation of water consumption in a family house, where secondary source of water was introduced - water from a well. Potable water was fully replaced by well water for the purpose of flushing toilets and laundry . This paper also describes the measurement data of stormwater runoff from the roof of the school building as a potential alternative water source for this building. Next step was the comparison of the current potable water consumption in the building with inflowed rainwater and evaluation of its potential for supplying the object in case of accumulation of this water.

Paper shows the results of laboratory testing of heat exchanger and its application in real operation in household. Although the efficiency of shower heat exchanger reaches even above 40 %, achieved energy savings for hot water preparation range between 10 and 15 %.

The introduction of stricter Ecodesign requirements for products associated with the consumption and production of energy is related to a smooth transition to the use of gas condensing boilers. In practice, exchanges of old boilers meet incorrect interpretation and perceptions about the benefits of condensing boilers. The article therefore assesses the impact of condensation theory and measurement and answers some practical issues.

There are a number of hydrogeological sites unsuitable for construction - there is nowhere to drain and building in the inappropriate area creates barriers to drain rainwater from the site. Then, the only solution is to minimize runoff.

The introduction of stricter Ecodesign requirements for products associated with the consumption and production of energy is related to a smooth transition to the use of gas condensing boilers. In practice, exchanges of old boilers meet incorrect interpretation and perceptions about the benefits of condensing boilers. The article therefore assesses the impact of condensation theory and measurement and answers some practical issues.

The article deals with possibilities of using heat from waste water discharged by outlet pipes of house appliances. The first section describes the basic possibilities of the local heat recovery (recuperation), used mainly in showers and shower baths. Theoretical analysis of the efficiency and related achievable savings is supported by an experimental measurement of a selected type of recuperative heat exchanger. The results of the measurement are compared with the classification according to the Passive House Institute. In addition to the efficiency and energy savings achieved by deploying the recuperative heat exchanger, the economic return of the specific heat exchanger is also determined for different boundary conditions.

In practise we meet more and more places that are not connected to the utility network and must be dealt individually. At the same time number of technical solutions which can tackle this task as effectively as possible and take individual requirements into account is increasing. Solutions range reaches from small savings in water consumption to total replacement of drinking water, from the use of gray water for flushing to its full recyclation.

The article describes the requirements for domestic hot water in residential houses. It deals with determining the need for hot water depending on the type of house, hot water consumption profile in residential buildings and with three basic methods for designing storage hot water tank and heat output of hot water heaters.

The article compares legislative regulations in hot water preparing and their impact on the determination of hot water requirements. It is based on analysis of hot water consumption in hotels compared with hot and cold water requirements. The influence and aplication of the legislative regulation are described in relation to reducing warm water energy consumption.

The question is: is gas condensing boiler with a hot water flow requiring power of 24 kW suitable for the apartment with little heat loss? Because under these conditions for the entire heating time, or a large part, boiler will cycle. Will this cycling be negatively reflected on the natural gas bill?

The question is: is gas condensing boiler with a hot water flow requiring power of 24 kW suitable for the apartment with little heat loss? Because under these conditions for the entire heating time, or a large part, boiler will cycle. Will this cycling be negatively reflected on the natural gas bill?

Water prices drop in most of the Pilsen region. Minister of environment Richard Brabec asks: Where goes the rest of the water charges if the state has 2 CZK/m³ of water. Who earns on the water? Minister calls for a national debate about water prices.

2000 respondents were asked about their water usage for personal hygiene and other common purposes. Respondets were also asked about their water-saving knowledge, using that knowledge and about reasons why to save water.