The research is focused on energy sorrel as a fuel for local low-power heating systems with output up to 100 kW. Sorrel is perennial plant surviving in its location nearly 18 years which is very good from the point of crop expenses. It is a robust plant with height of about 2 m in second year of plantation. Dry phytomass is energetically rich fuel with total heating value 17.5 – 18.0 MJ*kg-1 at the average yield of 10 tons per hectare. An experimental combustion of pure sorrel and its blends were done with boiler VERNER A25 – a hot water boiler for pellets. 11 different sorrel fuels consisting of 5 primary kinds were tested during the experiment: sorrel (Rumex tianshanicus x Rumex patientia), Phalaroides arundinacea, Canabis sativa, pine-bark, sorrel (Rumex tianshanicus x Rumex patientia), brown coal. Based on collected data it is possible to obtain an overview of these fuels and their emission properties. Satisfactory values of CO concentration are possible to gain partly by choosing appropriate combustion device and its settings and partly by mixing with other types of fuel. In the case of sorrel the combination of both has been shown very useful. It is very hard to ...
Biomass contains chemical energy which is a transformed Sun radiation. This energy can be used in many different ways. One of these is a direct combustion which is the most popular. The direct combustion of biomass is a technology which is well proven in large-scale heat and power generation. However, the situation in the small-scale heat generation is not so good. This paper describes results from the experimental combustion with various kinds of biomass in three different combustion devices. Saw dust is used in the experiment described below. The aim is to choose the best biofuel modification and the best way for its combustion from the point of view of power and emission parameters. As for the so far reached results of the experiment, the best in case of saw dust is the combustion with gasification of saw dust briquettes on stable grate without primary air or pellets in bottom supplied burner. ...
This paper deals with the determination of several efficiency types of a cross-current recovery exchanger which is a part of the air venting system in the swimming pool hall on the premises of the Czech University of Life Sciences (CULS) in Prague. The product is a cross-current plate exchanger with a heat-exchanging surface of antirust aluminium. According to the manufacturer, the exchanger is fit for temperatures common in air ventilation systems. The air is forced in by fans at a flow quantity of 16,000 m3, maximum speed 2000 rpm, electric motor output 7.5 kW, filters for the air coming from the outside – grade G4, pressure loss from 42 to 200 Pa, filters for the air coming from the inside – grade G3, pressure loss from 46 to 200 Pa. The results presented are derived from in-process measurements taken on 31 January 2007 and 7 February 2007, from 9.15 to 11.30 on both days. Air temperature and air humidity were measured with 9636-51B-type sensors by Ahlborn, connected to the AHLBORN ALMEMO 5990-2 centre. These sensors were placed into each of the four input/output channels, very close to the exchanger itself (Fig. 2). The data measured were saved in the centre ...
The installation of an energy-saving facility must be preceded by analysisof its financial effectiveness. Among methods enabling such evaluation is thebasic net profit calculation method. For this, the annual consumption of electricityfor ventilation or of thermal energy for heating must be determined. The calculationformula uses the sum of energies for temperatures within the range fromthe calculation temperature for the area in question to the long-term average ofthe maximum temperature at the site, or to the temperature at which the heatingpower is zero. It is necessary to know the summary time of occurrence of a giventemperature during a year. The site data can only be assessed based on long-termmeteorological information. In fact, data used by current national standards todescribe climatic conditions in the Czech Republic are from the years 1901 to1950.The dependence of the average yearly temperature on altitude is shown inFig. 1 for the 1961 1990 and 1991 2000 periods. It is evident that the averagetemperatures for the latter period are nearly 0.6 K higher than those for the formerperiod, irrespective of the altitude.In this paper the climatic conditions are assessed based on daily datameasured throughout the period from 1 January 1991 to 31 December 2000.Weather stations were ...
