Issue 4/2014

Energetic efficiency of the building operation is its important qualitative characteristics. It can be acquired also by optimal heat and domestic hot water preparation from renewable sources, with important role of heat pumps. When using heat pumps it is necessary to consider not only their primary importance from energy point of view, but also their secondary effects on the environment. The paper deals with the necessity to cope with the noise and vibration generated by heat pumps during their whole operating life cycle. An important role has already the design stage (the noise study and simulation of noise levels spreading), which is usually absent. Consequently, the sources of the additional noise are reason of complaints from the occupants of houses. In the paper are stated the optimal management practices for placing the heat pumps and possible technical adjustments in order to achieve allowed noise and vibration levels in the living environment.

The paper points out possible difficulties in stability of hydraulic networks where are installed pumps with controlled rotational speed of impeller. It suggests recommended and proved functional installations of these pumps.

In the third part of the paper series is described the formulation of analytical model for pressure loss calculation of capillary mats, based on iterative and approximate solution. The variance between different ways of solution is demonstrated on an example. The results obtained from the presented model are compared with experimental data. In the paper is presented the ratio of the individual components on the total pressure loss of capillary mats.

The aim of the paper is to introduce specific requirements for building installation products within the scope of EP directive about Ecodesign, for which the concrete regulation measures has already been issued by the European Commission. It concerns following appliances: electric motors (regulation (EC ) no. 640/2009), pumps (regulation (EC ) no. 641/2009), fans (regulation (EC ) no. 327/2011) and air-conditioning devices (approved by the European Council on 31. 5. 2011, regulation (EU ) no. 626/2011 about energy labelling). This well-arranged information should help to get oriented in the outgoing process of increasing energy efficiency of the appliances consuming energy or influencing energy consumption. The paper is targeted primarily at HVAC designers, HVAC supplier companies and also investors in the related fields.

The paper deals with a model of swirl diffuser for CFD, which was developed in order to speed up the calculation and simplify the setting of the boundary conditions for numerical simulations of the air flow in ventilated and air-conditioned rooms.The model of swirl diffuser was experimetally validated by comparison with measurement and with data provided by the manufacturer of the diffuser.

The published paper summarizes the crucial information about the actual topic – garage ventilation in the Czech Republic. The contribution is divided into three parts, due to the broad scope of the matters. The first part [14]discussed regulations and methodology of service ventilation design. This second part concerns emergency ventilation. All the three papers are based on the legal and normative enactments related to the issue. They deal among the others with the new situation of parking possibilities of natural gas powered vehicles. The design principles of every ventilation system to be found in garage are discussed, including regulation, operating regimes, detection and monitoring of pollutants. The contribution also mentions explosive atmosphere risk assessment in the case of parking of natural gas powered vehicles and protocol determining external influences. The contribution is aimed not only to HVAC designers, but also to architects and designers of all related construction fields. Valuable information can be found also by the other interested groups such as investors, developers, suppliers, operators, building authorities, involved state administration bodies, etc.

The paper presents indoor air quality measurement in the classroom of elementary school by analysis of carbon dioxide CO2 concentration during the class time. The measurement was realized first in the classroom with natural ventilation and after that with forced, neutral-pressure, ventilation system. Due to the installation of the air-handling unit inside the classroom, it was proceeded to measurement of acoustic pressure level in three control points, for all the power levels of the air-handling unit.

The paper deals with revision of technical normalization directive TNI 73 0302 for simplified assessment of solar thermal systems for hot water preparation. The aim of the revision was to approximate the results of the simplified calculation procedure to the results of advanced computational simulation in TRNSYS, and introduce climate data presented in TNI 73 0331 for assessment of buildings. The results of calculations according to the original and revised TNI are compared with the results of computational simulations and also with results of calculation according to ČSN EN 15316-4-3, when considering identical input conditions. The revised method TNI 73 0302 shows a deviation in the range of ±8 %, which is considerably lower deviation that in the case of the original TNI and ČS N EN 15316-4-3.