Issue 4/2011

This article deals with the conjuction of heat quality and quantity control. There is written all over the electronic speed control of circulating pumps there being in custody with the outside temperature supply control and the main aim, i.e. saving of operating costs.

The author deals with characteristics of refrigerant compressors and focuses on the definition of their working area and explanations of reasons due to which a compressor cannot be operated outside the working area limits, in his article. There is specified the reaction as concerns the refrigerating system and in particular heat pumps that the aforementioned fact is not resulting from the technical documentation anyhow, in his article. So we become witnesses, e.g. that the documentation of the heat pump includes the maximal temperature of the heated water without any warning that such a temperature cannot be reached under lower evaporation temperatures, e.g. at temperatures of the evaporation lower approximately than –5 °C in accordance with Picture 2.

The author states in her contribution a fragment of problem as concerns testing and assessment of heat pumps in the heating mode. She chose independent testing roomsWärmepumpen-Testzentrum Buchs, Eurovent, technical regulations of the Decision of the Commission no. 2007/742/ES and Standard ČSN EN 14511, by which heat pumps are tested, assessed, and classified in different categories for the most frequently used heat pumps using air/water, water/water and antifreeze/water mediums. The aim of the contribution is to highlight the diversity and the disunity of the methodology of testing, assessment, and the classification of heat pumps in categories according to independent testing rooms and technical regulations, above all.

The author describes individual mathematic and physical accesses to the solution of heat transfer at large-area heating systems. He issues from the most simplified 0D and 1D models used in practice, over 2D model up to CFD methods (3D model) used at universities and evaluates their advantages and disadvantages. So he provides the comprehensive summary of methods for calculation of heat and technical behavior of large-area systems, mainly radiation systems.

The author deals with the substitution of two-position action regulation by the modulating PI control for the solid fuel boilers. The access is demonstrated on experimentally obtained results for the automatic grate (stoker) boiler with thermal output 25 kW in which wooden pallets are burnt. Research results bring optimization of the boiler operation from the viewpoint of emissions and efficiency, without affecting the essential regulation of the output water temperature.

The author informs of new modern boiler structures with automatic supply of fuel on the basis of the factual situation with lack of qualitative wooden pellets serving as the bio-fuel for local combustion chambers. The achievement of emission factors of solid pollutants, CO and total organic carbon in so called automatic boilers burning lumpy lignite (brown coal) is at substantially lower values than in boilers of obsolete structure using the method of burning away or burning through. The author demonstrates by way of the calculation of what annual reduction of atmospheric pollution can be achieved with use of automatic boilers. The only one negative factor in use of these boilers remains the price, which is not subsidized on contrary to biomass boilers.

The building assessments become permanently one of tools focusing to the building quality increases, which concurrently affect the building commercial values. In addition to assessing systems stipulated by law (e.g. the assessment of the building energy demandingness), we meet different methods based on a multi-criteria assessment of a specific building. One of them, originally used for the Czech Republic conditions, is the method called SBToolCZ, developed by the expert team from Faculty of Civil Engineering of the Czech Technical University.

The author presents a new pneumatic system FLOW-OFF serving for discharging dust particles from discharge hoppers of filters and electric separators in his article. The described system eliminates the most of disadvantages of existing methods of the dust discharging. It is energy saving, very resistant against abrasion and environmentally and labor friendly, as well.

The paper present up-to-date possibilities of utilization and mutual combinations of renewable resources of the energy, in their contribution. They chose existing installed applications utilizing renewable resources of energy both for heating and preparation of warmservice water in a building. Above all, they refer to examples of combinations of heat pumps and solar systems. There was chosen the building of the primary school and the kindergarten in a municipality of Lukavec, where two heat pumps (ground/water type) connected to 24 underground deep wells serve as the primary resource of energy. Solar panels in the building are the other energy resources serving for preparation of warm service water, the additional heating and regeneration of one half of deep wells. An atypical combination of the solar system with the seasonal accumulative reservoir connected to the existing heat pump (ground/water type) equipped with the ground flat collector was solved in the second shown installation. In this case, the solar system is used for both preparation of warm service water and additional heating in the building, and charging (heating) the long-term accumulative reservoir 30 m3. The last example is the plant of the firm Regulus situated in the Prague district of Komořany. In this building there has been used the combination of the solar system and heat pumps (air/water type). Buildings possessed by the firm are supplied with the energy gained; if the gained energy is overpowered, heat is to be redistributed in the adjacent building of another operator.

The paper describes in detail the specific utilization of technical means regarding the information and communication technologies for the upgraded system of control and monitoring the thermal and energy economy in town of Trencin (Slovak Republic), in his article. It deals with the construction of specific systems beginning at heat resources, over heat transfer stations up to heat consumption points, and describes system functions and their attributes. Information, included in the article can usefully serve both for designers of similar systems and their operators particularly in cases, in which the reconstruction and modernization of systems for district heating are considered.

The author informs of the commissioning, the HVAC measurement and the operational balancing concerning fan APH 4850 installed as the drive in the wind tunnel at the University in Canadian Oshawa, in his article

The ventilation rate in residential buildings presents a very disputable quantity (value) as concerns the actual energy saving trends in living. The situation was complicated by missing and inaccurate requirements in legal regulations and technical standards. The National Supplement of Standard ČSN EN 15 665 came into effect in the form of the Amendment Z1 on February 2011, which defines requirements for the ventilation of residential buildings and recommends the suitable ventilation systems. Authors briefly informin their article of the contents of the National Supplement and confront the designed requirements towards foreign regulations of a similar form. Requirements for securing the ventilation air supply, which are often forgotten after the installation of tight windows, make a very significant part of the National Supplement.