The study presents technical-economic basis for the investment and sustainable decision making about technologies and types of the exploitation of the renewable energy sources in Slovenia. It represents a unique document, which may serve as the important basis for the policy in the field of energy.
F.17 Transfer of existing technologies, know-how, methods and procedures into practice
COBISS.SI-ID: 12113179A piston prover determines the gas flow rate by measuring the time interval that a movable piston inside a cylinder needs to pass a known volume of gas at a defined pressure and temperature. This paper deals with the dynamic effects related to the operation of a high-speed, clearance-sealed realization of the piston prover concept. Its dynamic characteristics are analysed by means of pressure-response measurements and lumped-element mathematical modelling. The experimental results show that the pressure oscillations during the timing cycle increase significantly above a certain flow rate and have multiple frequency components. They could be related to the resonance effects of the piston oscillator, which is excited by the flow instabilities of the gas flowing in the cylinder below the piston. The simulations show that the sensitivity to the dynamic pressure effects depends on the properties of the thermodynamic gas processes being adiabatic, polytropic or isothermal. A new, modified flow equation of the piston prover, which considers the polytropic index as an input variable, is proposed.
F.01 Acquisition of new practical knowledge, information and skills
COBISS.SI-ID: 11756315Prefabricated, lightweight building elements are widely used in the building construction sector. Such elements consist of fibrous thermal insulation encapsulated between two metal sheets. Under various circumstances, moisture can appear in the insulation matrix. Since the temperature of the boundarz metal sheets changes dynamically with meteorological conditions, heat andy mass transfer between boundaries appear in this case. This paper presents a transient model of the heat and mass transfer, including the sorption and condensation processes. A numerical model considers the dynamical changing of the boundary temperatures. A parametric study considering different amplitudes of temperature change, different moisture masses and different thicknesses of the insulation matrix was made. It was found that a relatively small mass of water in the insulation matrix can result in a significantly increased average heat flux during a periodic cycle. The numerical code was verified with experiments, which showed good agreement with the numerics.
F.02 Acquisition of new scientific knowledge
COBISS.SI-ID: 11903003