Issue 3/1996

The paper deals with evaluation of next 12 fíltration apparatuses determinated for indoor air cleanness and IAQ improvement. Dust collection efficiences of the air cleaners have been evaluated. Air flows (air capacities), noise levels and for some cleaners ozone con­centrations and líght negative ions concentrations in the air have been measured too.

The relationship between air ionization and 31 different building, fumishing and decorating materials used indoors was assessed from 170 experiments. The effect of material ageing and the change of material properties were evaluated.

The paper compares kitchen ventilation hoods of different types. Airflow rate calculations are based on the instruction VDI which is used in Switzerland. Favourable induction effect of additional nozzles on the exhaustion of harmful substances is noticed.

Thermal model of a show hall roofed with skylight is described. A mathematical model has been set up for the thermal balance between two adjacent spaces - hall and skylight ­separated by double milk glass. The model was used to research the suppression of the extemal heat gains to the hall by means of the skylight ventilation. Boundary conditions for the mathematical solution were adjusted on the basis of experimental data. A significant result of the study is the possibility to reduce the heat ga ins down to 50 % by forced venti­lation of the skylight above the show hall. The model facilitates the evaluation of thermal conditions in ventilated industrial halls with different skylight configurations.

The paper deals with possibilities of rain water utilisation in housing and civic buildings. Basic hydrological information about the rate of precipitation in the Czech Republic is presented. Various technical solutions are described and many problems which attend the use of rain water are noticed.

Temperature data measured on the surface of heating bodies are presented. Obtained results are confronted with the issue of heat consumption indicators used on heating bodi­es. The paper - without any ambition to give a comprehensive survey of the subject - inclu­des some information about different groups of indicators.

A number of successful projects prove that the horizontal single pipe heating system with low-resistance fittings and copper pipes with capillary soldered joints is suitable for recon­structions as well as for new buildings. The advantage of this system is mainly in hydraulic characteristics and lower price.

The paper deals with the history of the standard for building heat loss calculation. Individual parts of the standard are described and argued, giving suggestions for further discussion.

The results of author's many-years design work in the area of heating systems are summa­rised in the three-part paper. It is focused on the vertical double-pipe branched systems. A new approach to the function of heating systems is applied in so-ca/led thermodynamic method of analysing and designing of these systems. The method includes algorithms for calculating the heat transfer from heat source to heated rooms with maximum possible accuracy.

Information about the seminar focused on hot air welding of plastics. The paper points out that it is necessary to modify the certification procedure of workers and organisations in vol­ved in this area. The setting up of professional-Ievel checks can prevent serious accidents at handling with dangerous substances.

An application of methane-fired combined heat-power system is presented. The contribution of the paper consist in detai/ed description of the device configuration. CHP systems are more and more applied even in bui/dings which were formerly on principle equipped with tra­ditional heat sources. Possible utilisation of heat in absorption cooling units in summer raises the advantage of CHP systems.