Issue 5/2007

The author compares the possibilities of cold deck (ventilated) roofs design according to ČSN 73 0540-4 standard and using CFD simulation. The calculations and simulation solutions of the water vapour condensation risk indicate that the procedure according to ČSN standard provides results with security margin for simpler roof designs. However the standard methodology does not include effects of all factors influencing the air flow in the ventilated air layer – in such case, an evaluation the CFD simulation is of use.

The author deals with reflections on longitudinal ventilation management at road tunnels construction fires. A brief division of tunnels with regard to problems being solved, description of ventilation modes and design philosophy represent the introduction for the part focused on tunnel tubes longitudinal ventilation and its management on fire situation. With regard to the existing design standard and procedures applied in practice a system of logical dependences was set up for management system decision-making process at the anticipated kind of extraordinary event.

This contribution summarizes recent multinational information and experience regarding smoke control in road tunnels in the case of fire and compares it with recommendations in Czech Republic.

The paper is based on literal citations from the three fundamental technical standards for buildings fire safety, i.e. CSN 76 0802, CSN 73 0804 and CSN 73 0810. It gives basic information about the smoke and heat removal system requirements according to the Czech standards. The first part is focused on parking garages, the middle deals with general principles and the last one informs about the fire resistance rating of individual components of smoke and heat removal systems.

At present time politicians as well as scientists endeavour for improvements of environment and decreasing of energy consumption. The improved environment includes also clean air in a working place. Generally the larger part of the return air is recirculated. The recirculation of air is not economical and it contributes to increase of pollutants in the air supplied into the building. The pollutants can be also bacteria. These insufficiencies can be removed if the building is ventilated solely by outdoor air in short intervals which can also save energy.

The second part of the paper deals with air conditioning of multi-cinemas. Developers’ requirements and spatial arrangements in multi-cinemas are discussed in details. The paper gives a close description of the design and dimensioning of systems for auditoria, projection booths, entrance halls, food preparation rooms and sanitary facilities for visitors.

High attention is currently paid to the environmental impact of refrigeration units in air conditioning caused both directly by refrigerant leaked by leakages, defects, servicing and disposal at life-end and indirectly by energy consumption for life-time operation.

The aim of observations was evaluation of microbial contamination (specially – caused by moulds) of HVAC filters in personal railways carriages, in indoor air of these carriages and comparison with findings in the outdoor air. Comparison of all results should had led to scale the possible influence of HVAC filters on indoor air quality from point of view of microbial contamination.

The paper deals with hydraulic connection of radiators in respect of their pressure loss. A survey of the desk radiators pressure loss with and without installed valve is presented in a graphic form. A comparison of other radiator types with regard to their pressure loss expressed by local resistance coefficient is also included.

The paper describes the accomplishment of a phytomass central heat source for the town Kašperské Hory, including its parameters and the knowledge gained from one-year operation of the boiler house.

The paper describes author’s experience with seasonal storage of solar energy by so-called chemical heat pump. The solar and geothermal energy is transferred by hydration reaction from an underground horizontal heat exchanger with surface area of about 450 m2 into an accumulator with sorbent (Na2S . 5 H2O). The system is designed for the heating of a house with floor area of 80 m2. The sorption accumulator has 8 times smaller volume than an equivalent standard hot-water accumulator, in adition there is not heat loss.

The paper describes an entirely new terminal element – a roof rain defence louvre, which can be installed horizontally or aslant according to the roof slope. The louvre prevents water from penetrating into air ducts even when air is blown out or taken in vertically.

The author describes in detail the whole process of biogas production and exploitation. He specifies the individual process stages, their technological requirements and the possibilities of biogas utilization. The assessment of the investment and operation costs of biogas stations is not of minor importance.