Issue 3/2019

The article deals with various possibilities how to connect the boiler circuit with consumer circuits. It analyses the advantages and disadvantages of different distributors. It is considered in relation to the circulating pump control possibilities. Finally, it presents a trouble-free possibility of using a pressure distributor together with circulating pumps provided with ada ptive control.

A design of a solar system for domestic hot water preparation in an apartment building is analysed by computer simulation in order to verify certain design recommendations. The analysis shows the influence of solar collector design area, the influence of climatic conditions, the influence of the circulation circuit configuration and the influence of the design volume of the solar storage tank on the solar fraction and specific heat gains of the solar system.

Energy consumption for cooling buildings is currently a significant factor, accounting for almost 40 % of energy consumption worldwide [1]. The paper points out the importance of monitoring of the cooling energy consumption as a means of potential energy savings. It presents real consumption for cooling of 15 selected buildings measured for a period of mostly five years. Subsequently, the results of analysis of the measured data are presented.

The quality of the indoor environment is often deteriorated with the gradually increasing requirements on the energy performance of buildings leading to the goal that by 2020 all new buildings will be in nearly zero-energy standard. The attention to this issue was already drawn on 29th July 2016 in Commission Recommendation (EU) 2016/1318 on guidelines for the support of nearly zero-energy buildings (nZEB). The paper focuses on one of the parameters of the indoor environment, which is the indoor air quality. It shows the example of a newly built nZEB residential building with controlled ventilation and outlines the possible causes of perceived deterioration of air quality but also the possible implica tions of building in the nearly zero-energ y standard on this issue.

This study was focused on quantification of the effect of TiO2 – WO3 – V2O5 active monolithic catalyst on real flue gas. The catalyst was placed directly into a small combustion appliance, or immediately behind it. Combustion tests were carried out with variant positioning of the catalyst. The conversion rates of carbon monoxide and total organic carbon for steady state operation of the appliance were compared, while the conversion values were related to the measured mass concentrations of pollutants in the flue gas of the combustion appliance without the catalyst. The dependence of the conversion rate of pollutants on the increase in the active area of the catalyst was outlined as well. The impact of the monitored catalyst was compared with the previous research of the platinum and palladium-based catalysts. The last part describes a long-term combustion test in which sooting of the catalyst by solid pollutants resulting from combustion process and the effect of this sooting on the function of the ca talyst was observed.

The paper deals with the design of HVAC systems for acoustically demanding spaces. It identifies the individual causes of problems in design of a system and presents specific design examples. The design emphasises the acoustic arrangement rather than the requirement for air exchange.

The article summarizes the experimental development of a prototype shower plate heat exchanger for recovery of heat from wastewater. New prototype is designed in order to respect the requirements arising from the arrangement of the heat exchanger case and to allow suitable wastewater flow on both sides of the heat-transfer surface. At the same time, emphasis was placed on the minimum height of the heat exchanger with regard to the expected wastewater flow rates during the shower cycle and also to the requirements for the smallest possible built-up space.

The article discusses the possibilities of elimination of odor problems due to the formation of hydrogen sulfide in warm water after its heating in the boiler. At the same time, the article clarifies the conditions under which the sulfide is formed in hot water from the boiler especially when the water source is a well. Interesting case study from one bigger premise with several heaters is presented. The most suitable and sustainable solution is to replace the magnesium anode in a boiler with zinc or aluminum ones. Our work at the same time has documented on the anode currents, why the use of aluminum or zinc anodes is more suitable than magnesium anodes: lower electron formation, low activity of sulfur bacteria and subsequently fewer odor problems with sulfide in hot water.

Cooling of building structures to increase their fire resistance is conventionally done by direct wetting of the structure’s surface with a spray (drencher) or sprinkler device. However, a considerable part of the applied water volume remains completely unused. Cooling of the building structures by low-pressure water mist combines the direct wetting of the surface of the structure with the cooling of hot gases in its surroundings, thereby reducing the emissivity of the environment. The paper presents partial results of research on the effect of low-pressure water mist on reduction of the temperature of gases around the protected steel structure (ceiling beam).