Issue 3/2004

For many commercial and industrial plants, maintaining required ventilation rates can result in a significant operating cost. Fortunately, passive (i.e. enthalpy exchangers) and active (dehumidifying) desiccant systems can be used to reduce the load on the HVAC equipment and reduce its operating cost. The potential cost savings and return on investments have to be assessed individually for each application and solved on an hourly basis. It was found that using average conditions of climate and energy costs data and simplified load characteristics for such an evaluation can lead to a false application conclusion.

The article deals with artificial lighting of offices from the point of view of the air conditioning designer. The basic requirements concerning the artificial lighting of offices are here summed up and the light sources and lighting fittings usually used in practice for this purpose are described. In the form of examples the specific heat loads of offices are presented under use of different variations of artificial lighting.

The article specifies the optimum methodology of floor connvectors thermal output measuring on the basis of experimental work and compares thermal outputs with regard to floor convector individual systems of installation at the measuring point.

The author informs the readers about ČSN EN 12171 and at the same time he takes a stand of an expert connected with everyday design and operational practice on these standards.

The contributions brings information about cooling of warmaluminium pressings by air flow. A practical example of calculation is indicated including verification on model, subsequent implementation and also the final operational tests.

The author describes the proved method of flow velocity change determination in the main exhausting piping depending on the number and type of exhausting network connections being closed and on the characteristic of the used fan. It concerns the quality tool for checking the design of equipment for exhausting air from a number of sources of pollution by solid particles.

The very high ammonia concentration levels were observed in some new buildings in Slovakia not long ago. These cases relate to the special antifreeze ingredient addition into the concrete mixture. This paper presents the review of ammonia occurrence elimination methods as well as the case study of one succeful ammonia elimination.

The authoresses carried out measurements of ions concentration and thermal-humidity microclimate inside a new air conditioned building. They encountered complaints about insufficient comfort environment. They think about causes of these frequent complaints at the new air conditioned workplaces.

In a comprehensible way the author acquaints the readers with the level of our legislation and the state of putting the cost of heat energy for heating on individual accounts. The author warns about difficulties connected with the unfulfilled harmonisation of our regulations with EU regulations.

This article points out on the fact that there are two definitions of PM10 particles in the two governments papers (both from the year 2002). It is the Government Decree Nr. 350 and the Ministry of Environment Decree Nr. 356. It is shown that the results gained in accordance with this definitions may be very different.

The article deals with the principle of thermovision displaying. The introduction describes fundamental concepts and laws connected with heat transfer by radiation, informs about displaying technique design and at the same time brings nearer the present-day possibilities of thermovision utilisation in practice.