Piotr Sołowiej

Dynamics of Temperature Changes in Thermophille Phase of Composting Process in The Aspect of Sanitary Condition of Obtained Material

Abstract A condition of obtaining compost with proper sanitary parameters is achieving the organic recycling process temperature which exceeds 7°C. The objective of the paper was to determine the temperature course in the compost tank for organic recycling of dead poultry in relation to the applied structure forming material. Wheat, oat, barley, rapeseed and corn straw were used as a structure-forming material. A measuring system was equipped with a probe with a temperature sensor with precision of ±0.15°C, transducer and data recorder. Results were prepared with the use of the analysis of variance at the level of significance of α=0.05. Statistically significant differences of the temperature value in the thermophille phase of the composting process between combinations of the experiment were indicated. In all investigated combinations of the experiment, achievement (or exceeding) the temperature value of 70°C of the compost mass was reported.

The Influence of Weather Conditions and Operating Parameters on the Efficiency of Solar Power Collectors Based on Empirical Evidence

The influence of solar irradiance, ambient temperature and buffer tank temperature on the efficiency of solar collectors was evaluated in the climatic conditions of north-eastern Poland (climatic zone IV) characterized by relatively low irradiance (annual average of 900 kWh/m2). Two types of solar power collectors (flat-plate and evacuated tube collectors) were compared in terms of energy gains, collector efficiency and glycol temperature between May and September 2016. The collectors were mounted on the roof of a building on the campus of the University of Warmia and Mazury in Olsztyn. The roof had a pitch of 45°, the collectors had a tilt angle of 30°, and they faced west of true south. Measurements were performed separately for the analyzed solar collector systems operating simultaneously in identical weather conditions. The combined absorber surface was 4.64 m2 in flat-plate collectors and 3.23 m2 in the evacuated tube collector. Both systems were connected to a water buffer tank. Empirical data were recorded with a controller and were processed and stored in a computer. The factors responsible for differences in the efficiency of the examined collectors are discussed in the paper.

A Fuzzy Model of the Composting Process with Simultaneous Heat Recovery and Aeration Rate Control

Composting is an effective method of managing biomass waste from agricultural crops and food processing. This exothermic reaction produces high-quality humus. Heat generated during composting can be evacuated from the compost pile and used effectively for other purposes. Effective methods are needed to control prism aeration and the evacuation of heat from the compost prism to maximize heat gain without compromising the composting process. A preliminary examination of fuzzy logic systems revealed that the terms of input and output variables and sharpening methods have to be adapted to specific compost materials. This approach also delivers immediate results without the need for lengthy research. The composting process lasts several weeks, therefore, models which illustrate the responses of control systems save time and support the selection of the optimal solutions for changing the aeration rate and heat consumption in feedstock. Fuzzy models of the control system developed in the LabVIEW programs are effective tools which can be directly implemented in a programmable logic controller (PLC).

Impact of Coffee Grounds Addition on the Calorific Value of the Selected Biological Materials

Abstract The objective of the paper was, inter alia, to determine the impact of coffee grounds on the heat of combustion of their combination with other biological materials. Research on the heat of combustion and calculations of the calorific value were carried out with the use of a KL-12 Mn calorimeter according to the technical specifications and standards PN-81/G–04513 i PN-ISO 1928:2002. Coffee grounds, tea grounds, pine wood and yellow wheat straw were used in the research. The heat of combustion of particular substrates was determined and then their mixtures with coffee grounds in the following proportion were prepared: 75% substrate – 25% coffee grounds, 50% substrate – 50% coffee grounds, 25% substrate – 75% coffee grounds. Calorific value of particular substrates was increasing with the amount of added coffee grounds. Their biggest flow was reported in the mixture of 50%/50% of coffee grounds and wheat straw and the smallest in case of coffee grounds and wood on account of a similar calorific value of both substrates.