Issue 2/2017

Reducing the consumption of energy resources in sports facilities is the goal of all operators. Among the main energy consumers in a winter stadium belong ice-rink cooling, heating of water for the ice resurfacer, hot water preparation, heating, HVAC systems and ice-rink illumination. The most demanding on the power consumption is the ice rink cooling. The heat generated as a byproduct of cooling can be subsequently used and thus the operation costs can be reduced. Integration of a heat exchanger to utilize the superheated refrigerant vapors of the cooling cycle is already an extended application, whereas heat recovery is not. Consumption of natural gas in the boiler room, water consumption for ice resurfacer and hot water consumption in the locker room are analyzed for a case study of one hockey season at the winter stadium in the Czech Republic. The heat of superheated refrigerant vapors is utilized in the facility. Potential benefit of low-potential condensation heat recovery in combination with a heat pump is assessed computationally. Utilization of condensa tion heat is evalua ted in terms of the prospective sa vings and investment costs.

With increasing demands for energy savings and better efficiency of appliances, the “brushless directcurrent motors” get to the forefront in some application areas. The aim of this article is to briefly show how they work, how they are constructed, what are their parameters and characteristics, typical applications and methods of their control.

This article aims to broaden knowledge about behaviour of different types of local wood-burning heaters in term of time course of heat delivery into the room. The article presents a comparison of performance of the selected heater – fireplace insert, which was gradually rebuilt and tested as stove with/without accumulation heat exchanger and closed fireplace with accumulation in different stoking regimes. In the end of the article, the measured results are compared with previously obtained hea t output course of individually built stoves.

The article discusses measurement of air flow rate and air pressure in the track cross-passage no. 2 of the metro line A Dejvická - Bořislavka. It defines problems and pitfalls of this measurement and provides concrete results and conc lusions of the measurement.

Smoke mass flow rate is one of the most important input variables used for design of buildings’ fire safety and fire safety equipment. Considerable number of methods is currently available to determine the smoke mass flow rate. They have been created by different authors often under very different conditions. The article describes some of the currently used methods and compares their results using selected statistical methods, which assess their mutual deviations. The comparison was performed separately for the flame zone and smoke zone of the vertical smoke column formed above centre of the fire.

The paper summarizes findings regarding indoor environmental quality and energy performance of heating and ventilation in building after renovation of the facade. Some of the drawbacks of the commonly used techniques are highlighted on a case study of a representative office building. Results of the indoor environmental quality monitoring in the building after renova tion are presented.

The paper deals with a question of possible ways to influence the measuring accuracy of a velocity water meter. It describes the need to pay attention not only to the selection of a water meter, but also to its installation position. The first part shows the way to obtain values of individual flow rates, which form intervals to define errors. The second part provides examples of how the nominal flow rate and its range affect the measurement accuracy. The last part deals with an example of how the installation position influences the range and accurac y of measurement.

The article deals with uncertainties of temperature measurement using contactless devices. The theoretical part analyses calculation of measurement uncertainty, including example of uncertainty calculation for measurement of radiator surface temperature by contactless thermometer and thermal imaging camera. The experimental part describes the impact of the angle between normal of the measured surface and measuring device.

-

-