Issue 5/2009

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The paper generally discusses biomass as a fuel, which is well suitable to be used in district heating plants. First there are defined various forms of biomass best available for district heating systems and their approximate annual production in the Czech Republic. In the paper are discussed ecological benefits of biomass, particularly positive effect on CO2 production. There are presented biomass properties and conditions relevant to utilization for heat production. In the end of the paper is shown an example of biomass boiler and discussed possible choices of boilers according to fuel moisture.

Recently, ever increasing effort is paid to the utilization of renewable resources of energy with respect to the utilization of geothermal energy not only for heating but for production of electric energy, as well.

Author summarizes the application conclusions arisen from the academic dissertation on optimization of radiation geometry of heaters with the radiant medium intensity. The dissertation was successfully defended in the Institute of Environmental Engineering at the Faculty of Mechanical Engineering Czech Technical University in Prague at the end of 2008. The part of the task was analyzed in detail, i.e. the case study reflecting the application of the generated mathematical model for formulation of specific conclusions in practice. It appears that the effect of reflective enclosures (shields) is overestimated in the standard methodology design. Radiant heaters including the angle of setting reflective enclosures over 45° can, in reality, be designed in bigger distance apart and vice-versa. The heater can be considered approximately as a point source.

The concept of use the ceiling radiant cooling with accumulation in the building structure (so called concrete activation, or slab cooling) in the newly built National Technical Library is presented in the article. There were verified temperatures in the library under different modes of operation of the concrete activation with use of the computer simulation. The process of simulation is specified on the basis of the model construction, solution of glazing parameters, indoor heat gains and the model of the ceiling cooling structure. There are presented results of the simulation and recommended operation modes. The article is briefly supplemented with first results ensued from the building commissioning.

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