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Archiv článků od 2.1.2012 do 30.4.2012

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30.4.2012
Ing. Martin Lopušniak, PhD., Ing. Anna Vašková

Concept of energy efficiency buildings provides provable reduction in consumption of energy in compliance with the required user’s comfort. Taking into the account the trend to minimize heat escape and heat loss and increase of the airtight buildings, the installation of controlled ventilation is one of the steps leading to the optimal sanitary requirements and the overall energy efficiency of buildings. Quality indoor environment of energy efficient buildings, as well as the maximum level of comfort in this case is a controlled ventilation system with heat recovery and hot air heating. This article presents partial monitoring in situ measurements of selected parameters of the indoor environment during the operation of the upper and lower distribution system of hot air heating and ventilation in the selected experimental building.

vzduchotechnické klapky
16.4.2012
Ing. Miroslav Kučera, Ph.D., doc. Ing. Richard Nový, CSc.

The topic area of this article continues in focusing to noise and control properties of round dampers in HVAC systems. The acoustic and hydraulic properties of the round damper and systems of two dampers lined in series with a differently designed control flap under the pre-defined conditions are presented herein in mutual relationships. Authors submit recommendation as to the selection of a suitable damper type with respect to the noise lowering and good control abilities.

PCM
2.4.2012
Ing. Milan Ostrý, Ph.D., Ing. Roman Brzoň, Ing. Tomáš Klubal

Thermal stability of rooms without air-conditioning depends mainly on the thermal energy storage capacity of envelope and possible heat gains. Sensible heat storage structures, e.g. brickwork, concrete walls and slabs, usually do not have sufficient thermal storage capacity and some additional thermal storage mass is needed for cold storage. Passive cooling with thermal storage in phase change materials (PCMs) is a very effective way to improve thermal stability of the rooms with light-weight envelope. The main advantage of the phase change materials storage in buildings is the possibility to store a huge amount of heat in a rather narrow temperature interval. Passive cooling based on the latent heat storage technology can contribute to the energy and operative cost savings during summer season. The efficiency of this kind of passive cooling significantly depends on the heat transfer rates between the ambient environment and the thermal storage material. Modern administrative buildings or wooden buildings are often made of light-weight materials with rather small thermal mass. The latent heat cold storage in the phase change materials seems to be quite promising in this respect since it offers high thermal storage capacity.

požární větrání
2.4.2012
Ing. Stanislav Toman, Projektová kancelář ÚT+VZT

The author brings the fundamental view concerning the problem of ventilation in residential buildings with respect to the building fire protection, in his contribution. No each designer or supplier of air conditioning systems designed for use in multiple dwelling or family houses is aware of this aspect importance and adheres it in the required level. He introduces interested parties with the substantial requirements that must be solved and taken into consideration, in the article.

výměník tepla
26.3.2012
Ing. Jaroslav Pavlů

Wide range of air cooled Compact Heat Exchangers is used in Heating, Ventilating, Air-Conditioning and Refrigeration industry (HVAC-R). Compact heat exchangers large air side area is characteristic for air cooled condensing units. Comparison includes 3 types of cross flow heat exchangers. These are expanded copper round tube on aluminium fin, expanded aluminium round tube on aluminium fin and extruded aluminium multiport flat tube heat exchanger with corrugated aluminium fin. Compactness of heat exchanger, pressure losses or its performance is in many cases the decisive parameter for customer choice. An article compares these parameters on various cross flow heat exchanger types in performance ranges 5kW and 60kW. Performance is measured in ambient temperature conditions of 25°C, due to the 40°C of condensing temperature and azeotropic refrigerant R404A, which is common medium for Air Conditioning systems. Selected performances are chosen to compare results on real applications, which is house air-conditioning unit at first case and bigger one for residence air-conditioning system or small industrial cooling.

19.3.2012
Ing. Milan Bechyně, redakce TZB-info

The amount of volume coefficient depends on elevation of location of gas consumption and the temperature of gas flowing through the gasometer. In this paper we describe the procedure by which you can check that the coefficient of volume on the invoice is correct. The coefficient is one of the factors that affect your cost of gas.

zemní výměník tepla, předchlazení a předehřev vzduchu
12.3.2012
doc. Ing. Karel Papež, CSc., Ing. Kristýna Smutná

The article deals with the introduction of underground heat exchanger for preheating and precooling air for buildings. The introduction is devoted to the description of the system and its individual components and parameters that influence the behavior and performance of the system most. The second part presents a simple model, where you can see how each change affects the actual parameters of heat and cold, which can be gotten from the system.

chlazení mořskou vodou, moře, Neils Henrik Harbo a Claus Larsen Skyth, cooling with seawater
5.3.2012

Benefits of cooling with seawater from cooling with the air is lower temperature of seawater and better properties of water for heat transfer. In most cases, this means lower costs. If the building is located near the sea, lakes or rivers, then this water can be used as a cooling medium.

27.2.2012
Oliver Kah, Překlad: Ing. Petra Šrubařová

This is a highly relevant article dealing with the comparison of two types ventilation - Natural ventilation through windows and controlled mechanical ventilation. The issue of ventilation in renovated homes in our country is still relevant. This paper describes a broad-based experiment measuring the intensity and quality of ventilation in two almost identical apartment houses. The conclusion confirms the well-known experience that controlled ventilation provides both - improved indoor air quality and the energy savings.

27.2.2012
MUDr. Ivana Holcátová, CSc.

Inadequate ventilation is risky in connection with the pollutants indoors as there is no other way to dilute them. Indoors sources can produce allergens ( pets, house dust mites), toxic compounds like toluene or carbon monoxide, carcinogenic substances (e.g. benzene, formaldehyde etc.) and also such environment is ideal for spreading of infectious agents from the human sources (e.g. pandemic flu) or from the ventilation system (e.g. Legionella). Adequate ventilation is mostly the only way to improve the indoor environment and decrease health risks.

20.2.2012
Ing. Stanislav Števo, PhD., Ing. Jozef Dorner

Micro-level is optimization of the individual segments of the heating system, for example, greater operating efficiency of heat recovery units. Followed by middle-level, such as designing of heating circuits, and the macro-level - management optimalisation due to energy consumption.

13.2.2012
doc. Ing. Aleš Rubina, Ph.D., Ing. Zdeněk Tesař

The article deals with the description of possible solutions to the specific problem of air with respect to existing installed equipment and climatic conditions that were in August this year. The article shows the importance to outdoor weather conditions on the operation of HVAC equipment and its design. Real running back shows problems in equipment design.

6.2.2012
Ing. Milan Bechyně, redakce TZB-info

Supply of gas or electricity is so important that many customers do not want to risk a possible interruption when changing suppliers. New legislative rules defined in an amendment to the Energy Act No. 458/2000 Coll. (as amended by Act No. 211/2011 Coll.) but fill existing gaps in legislation and establish a procedure for changing supplier.

6.2.2012
Ing. Petr Polák

The paper describes basic principles, advantages and limitations of the air conditioning of buildings by adiabatic cooling. The principle of adiabatic (evaporative) cooling is the conversion of sensible heat to heat coupled with evaporation. Water sprayed into the air evaporates and the air temperature decreases and humidity increases.

30.1.2012
Ing. Vladimír Zmrhal, Ph.D., ČVUT v Praze, Fakulta strojní, Ústav techniky prostředí

The ventilation rate in residential buildings is very discussed in present. The situation was complicated by missing or inaccurate requirements in legal regulations and technical standards. In February 2011 came into force on the national annex Z1 of European standard EN 15 665, which defines requirements for ventilation of residential buildings and also recommend suitable ventilation systems. Article briefly informs about the contents of the National Annex.

30.1.2012
Ing. Renata Straková, Ing. Josef Knob

Regular inspection is focused to the boiler, smoke flue and accessories condition, its security and regulation. In addition to the technical condition and maintenance, the documentation, operating instructions, manuals and other documents are under inspection. It quantifies the overall boiler efficiency of measurement results, sets reference respectively minimum boiler efficiency and suggests possible actions.

16.1.2012
doc. Ing. Václav Kupilík, CSc.

In industrial plants, in case of fire there is accumulation of smoke that endangers the user object. Under these conditions the building must be opened to the smoke can ventilate out into the atmosphere, and that firefighters could enter the building. However, this opening causes the new oxygen support combustion. It is also one of the reasons why firefighters recommend the use fire damper with automatic controls and other devices (eg, smoke curtains, screens, blinds, etc.) as soon as possible after the beginning of fire, so as to prevent any accumulation, and that remove heat and smoke. This paper deals with the equipment for smoke and heat outlet.

9.1.2012
doc. Ing. Tomáš Matuška, Ph.D., Ing. Martin Zajíc

Passive houses reduce the need for heating to compensate the heat loss through the building facade and ventilation. But at the same time it increases consumption of the auxiliary energy for circulation pumps and fans. The analytical result can be for many readers quite surprising.

2.1.2012
Vladimíra Henelová, Michael Ten Donkelaar

IPMVP is a framework of definitions and methods established for the proper assessment of energy consumption or consumption or water. IPMVP provides guidance for users in developing plans for M & V (measurement and verification) for specific projects.


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