Issue 3/2016

The authors deal with the issue of the low flow rate separative sampling of pollutants – fraction PM10. They describe the development of a ?73 mm cyclone with diameter of the inlet pipe 17.8 mm and results of measurements to validate it as a separator of the PM10. Two corrected dependencies of the fractional separability on the aerodynamic particle size Of´(a1) have been experimentally determined on the test track, for the different extrusion of the cyclone outlet tube, in the range of 8-50 mm. The separability threshold value a1,m was in the ranged from 8.1 to 10.8 mm. Based on the dependence of the separability limit on the ejection of the outlet pipe a1,m(v), it has been determined the ejection of the outlet tube 45 mm, for which the cyclone at a volume flow rate 2.3 m3/h separates according to the requirements of the PM10 fraction. In conclusion, it is highlighted the benefits of the cyclone separators for use in the long-term air pollution monitoring of the fraction PM10 in comparison with the conventional impact separators, namely their operation reliability and high operation capacity.

The article deals with thermal balance of the administrative building during winter operation. It refers to the fact that for the existing administrative buildings the internal heat gains are often higher than the overall losses by heat transfer. The balance includes the influence of ventilation and heat recovery. The study is supplemented with detailed hourly analysis. The article discusses the conceptual solution for heating, ventilation and cooling of such buildings in winter. The article is also accompanied by actual experience with winter operation of selected buildings.

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.

The paper compares four computational models for determination of the thermal performance of a flat-plate solar collector. Individual models were compared by calculating the annual heat output of the flat-plate solar collector in the simulation environment TRNSYS, at the chosen operating temperatures and climatic conditions in Wuerzburg locality. Simulations showed that neglecting the optical characteristics of the collector can significantly overestimate the heat gains of the collector by approximately 25 %. The difference between the dynamic model and the stationary model is very small due to the small time constant of the flat-plate collectors. The difference between the heat output model expressed by the coefficients of the efficiency curve and the detailed model with simulation of the temperature distribution in the collector is within the range of a few percent.

The article deals with the mean thermal transmittance of building envelope. It is a characteristic that determines the heat loss by heat transfer through the building envelope. Thus the mean thermal transmittance substantially determines the overall thermal characteristics of the building H/V. The mean thermal transmittance of building envelope belongs to the characteristics covered by the current normative requirements. The parametric expression of the mean thermal transmittance of building envelope is derived in the paper. Based on the analysis of the parametric relations it is found dependence of the mean thermal transmittance of building envelope on two parameters describing the geometrical arrangement of the building - the ratio of the built-up area to the total heat transfer surface of the building envelope and the ratio of the window surface to the surface of the facade. The paper presents an example of calculation of the mean thermal transmittance of building envelope for different categories of buildings, discussing the relations and the current normative requirements.

The article deals with radiators with serial flow-through the individual panels and radiators with non-parallel flow-through. The results are based on laboratory measurements of two radiators, one with serial flow-through and one with controlled flow into the panels. The mathematical simulation in the software Fluent has been used for evaluating the behaviour of the radiators in the heated space. The possible energy savings and their effect on the mean radiant temperature, affecting also the resulting temperature in the heated space, were assessed on the basis of the obtained results.

The author briefly and competently provides, from the perspective of the measurement and control, an overview of requirements of the related professions, such as air conditioning, heating, electrical installations and construction. The reader finds in the article also a comprehensive insight into the issue on hand and into the requirements on the other than the mentioned professions.

The article discusses the current state of the art in the information transfer between design and operational phases of a project. It is remaining a constant concern to approach and fulfil the vision of building management with use of design documentation and other documents for facility management, without loss of data. The problems of transferring information to an operational phase is pointed out, and the solution is suggested based on implementation of BIM into CAFM using tools COBie (Construction-Operation Building Information Exchange). It is a data format for transferring information about the building, focusing on the operational phase, which is identified as the most appropriate method for information transfer into the operational phase of a building.