Issue 2/2014

Authors are aiming at the analysis of the heat loss calculation methods according to both the new and old standard and compare calculated values with respect to a family house in three variants of the construction implementation, in their article. The solution of the first variant is a two storey brick house with a cellar; second variant solves the identical brick house excluding the cellar and the third variant solves the house dimensionally identical as the previous two, excluding the cellar, but designed as the wooden house.

This paper deals with the problem of small combustion sources in terms of the Czech Clean Air Act. It presents the applicable emission requirements for small stationary combustion sources in the marketing of products and minimum requirements for their operation under the new Clean Air Act No. 201/2012 Coll. These legislative requirements are compared with the emission requirements according to European standards for boilers for central heating CS N EN 303-5:2013.

When arithmetic solution of technical problems associated with the heat-insulated flat walls or pipes is a value of the thermal conductivity important. In the calculation is commonly taken a value determined through mean temperature of both surfaces of the wall. Consequences of the simplification are not unequivocal. To avoid errors, which can reach tens of percent, should be given special attention in option and use of this most important characteristics of insulating materials.

Information and education of owners of domestic distribution systems of drinking and hot water has been neglected, which mirrors in increasing problems with water quality in consumer´s taps, even in new premises. The article summarizes legal obligations of water suppliers towards domestic distribution systems and stresses the need of continuous and adequate education. The National Institute of Public Health contributes to education by publication of ten basic rules of proper maintenance of domestic distribution system and informational brochure on health aspects of such systems.

Authors warn of the current problem, which the Hygiene Service deals with during the recent years; i.e. the problem of noise from heat pumps of the air/water type, in their article. They submit pieces of knowledge from the experience of employees of the Regional Hygiene Station in the Moravian-Silesian Region and point out to the importance of prevention at the designing the heating system, already. To take account of the noise parameter during the technical parameters option not only heat pumps, in particular for outside units of heat pumps in relationship to the environment.

The paper informs about principles and ways of standardization development both on the national and international level. Close attention is paid to currently effective National and European Standards in the field of HVAC systems. Their overview is published in the paper.

Paper deals with the condensation risk concerning high-temperature air-conditioning systems using the extreme climatic data for the Czech Republic. Different ventilation systems, ventilation rate for a person as well as properties of real air coolers used in air handling units are taken into consideration in contemplations. Recommendations for designing of similar systems are specified.

Authors are engaged in the description and modeling of stagnancy situations in solar collectors when the possible output of heat from collectors cannot be utilized due to the excess of the produced heat, in their contribution. One of possibilities in such events is to shut the flow of the heat transfer medium and to let collectors in the stagnation when the energy balance between collector heat gains and their losses occur; eventually heat losses of the system pipelines linked directly to the collector field. In this situation in most of cases in systems equipped with quality solar collectors occurs the evaporation of the heat transfer medium. Used anti-freeze mixtures established on the basis of water solution of propylene glycol fall to so called zeotropic mixtures that have the evaporation temperature process different from the evaporation process of pure water or other pure matters. Authors describe both individual phases of this stagnation and behavior analysis of systems with the different ratio of the capacity of collectors and the expansion vessel, in their contribution.