Issue 1/2007

The article informs about the course and character of the heating season 2005/06 in Prague. From the climatic elements measured at Praha-Karlov observatory the quantity values have been determined that are necessary for the calculation of heat demand for heating by degree-day method for the indicated season and its demand factor has been evaluated in comparison with the previous period and with the fifty years normals. Further selected data finish drawing the climatic conditions in Prague and sum up the weather character in the course of this period in the whole Czech Republic.

In the article, the author revisits the original approach to design of the air conditioning system used to control the air quality at the St. Cross Chapel of the State Castle Karlstejn and points to the six years of successful operation of the system. The microclimatic protection of 129 medieval wood–panel paintings in the Chapel is based on maintaining a thermodynamic equilibrium between the panels and conditioned air. The equilibrium is denoted by an index u whose histogram is presented graphically. In the Summary, acknowledgement and appreciation for the work of cooperating partners on the project are expressed.

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In the contribution, the fire test in the automobile tunnel Mrazovka, carried out in August 2004 as part of completing the COST Project is described. In addition to test results, their impacts on the tunnel ventilation system are outlined. A part of this contribution is also a set of information on the design of ventilation systems for complicated tunnel structures, such as those of the Prague City beltway system. Analyzed are also the directives, requirements, and the methodology of a conceptual design of ventilation systems, in view of their impact on safety in tunnels.

The article deals with noise problems of thermostatic valves in a relation to hydraulic conditions in a heating system. Presented facts represent the results of experiments with thermostatic valves. The A – level sound pressure, ascertained at control points are reviewed in accordance with the Governmental Decree No. 148/2006 Coll.

Currently, the demand for providing comfort conditions in rail vehicles is growing. This trend is felt to exist not only for express and commuter trains, but also for trams and underground cars. Passenger compartments and driver‘s cabin air conditioning has been used as standard equipment of cars in warm climate countries for some time. In the mild climate countries, e. g. in Central Europe, a combination of a driver‘s cab air conditioning unit with a heating and ventilation unit for passenger compartments has often been used, namely to reduce the acquisition and operating costs.

In the article of Prof. Petrák and the subsequent “Explanation and text annotations” of associate Professor Brož two views of environmental evaluation of electric energy consumption are described. It is up to the reader to form a proper judgement about these views. The clearing up of the standpoints and views on the data for evaluation of electric energy savings ecologic assets represent an advantage of both parts of the contribution.

In the article the author analyzes the experimental results of measuring the thermal environmental conditions of large-area heating and high-temperature cooling systems. Presented are assessments of the potential of using systems with capillary mats, however, it deals neither with an economic evaluation of such a system, nor with a return on investment.

The author deals with problems of bio mass combustion and subsequent removal of solid particles. He presents an example of a wood chip boiler installation with an output of 1. 1MW where the Czech Environmental Inspection Authority imposed stricter limits on polluting solid particles, (TZL), and required that their removal equipment be of a two–stage type. He argues that such a requirement is legally not called for, and that a two–stage removal process with textile filters is unsuitable for this type of equipment as shown by filter burn out. In support of his argument, he presents the results of TZL and CO emissions measurements downstream of a mechanical separator (multi – cyclone) that proved the possibility to reach the tighter emission limits for ZTL by using only a single–stage removal process by a mechanical separator.