Issue 4/1993

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The paper deals with an analysis of dependence of water density, specific enthalpy and specific thermal capacity on pressure and temperature in the range of parameters occuring in the secondary circuit of the water heating system. Values of the thermodynamic variables are calculated on the basis of The 1967' IFC Formulation for Industrial Use, indicated as IFC-1967 [1 ­3]. Dne of the authors exploits his experience from the membership in the International association for water and steam properties in the paper there.

The paper deals with evaluation of function of the 12 abroad and Czech made filtration apparatus determinated for indoor air cleaness and IAQ improvement. Dust collection efficiencies of the apparatus have been evaluated in the same and reciprocally comparable experimental conditions. Air flows (capacities) and noise level of the apparatus have been investigated too.

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The autor informs in the paper about sources of radon indoors and she presents the set of the effective measures for suppression of the adverse effects of radon and daughters' products of its decay there. Excepting building design the possibilities of forced ventilation are presented there.

The expansion possibility of a plastic piping for hot water distribution and the basic relatios for calculation of the expansion joints are discussed in the paper.

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ln the present tíme when one spends most of the time indoor the choice of optimum and economical ventilating method of the room for peaple is very important. The VVT air condítíoning system is one of the possible solutions how to pro vide the optimum state.

The paper deals with problems concerning design, assembly and operation of radiant-heat boilers. The author indicates the distinctness following from the specific construction and type of burning. He explains the origin of the problem of cooling down of the radiant-heat boilers and he presents the solution of this problem there. Water quality for heating is mentioned from the operating point of view there.

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