G. Oliveti

Data bank Experimental data of the Linke Turbidity factor and estimates of the Ångström turbidity coefficient for two Italian localities

Experimental data of the Linke turbidity factor and estimations of the dngstrom turbidity coefficient are presented. This data has been obtained starting from beam solar radiation measurements performed at Arcavacata di Rende (Cosenza) and at Casaccia (Rome). Comparisons have also been carried out with some calculation methods.

Prototype experimental plant for the interseasonal storage of solar energy for the winter heating of buildings: Description of plant and its functions

The definitive version of an experimental heating plant for buildings which uses thermal energy extracted from an underground water tank heated solely by the sun with interseasonal storage is presented. The entire plant was planned and its functions simulated using calculus codes established at the University of Calabria. The prototype, now in use, consists of a solar radiation collecting field of 91.2 m2, a storage tank of 500 m3, and a building of 1750 m3 which has a thermal requirement of 111 GJ for winter heating. This article describes the constructed prototype of the plant, the procedures carried out that allow the plant to function automatically, and the use, instrumentation, acquisition of experimental data.

First experimental results from a prototype plant for the interseasonal storage of solar energy for the winter heating of buildings

The first experimental results are presented regarding the workings of a plant which uses interseasonal heat stored solely from the sun as an energy source. The results obtained over one year concern radiation collection, the behaviour of the storage system and the satisfaction of the thermal requirements of a building to be heated. The comparison of performance obtained with those predicted by a plant simulation model provided a confirmation of the reliability of the models used for collection and storage tank accumulation. For the latter, the validity of the method used for calculation of heat losses that is the basis for the design of this kind of plant is shown.

Experimental investigation on thermal radiation exchange of horizontal outdoor surfaces

The results of an experimental investigation on thermal radiation exchange between a horizontal surface and the sky are presented. The surface under consideration is the horizontal roof of an air-conditioned room, built for the study of the energy behaviour of buildings. The roof is insulated to create an almost adiabatic boundary condition. The measurement of infrared and solar radiation, together with temperature measurement, was used to determine the net infrared flow, the solar flow absorbed and, by means of the surface thermal balance equation, the convection flow. The experimental investigations allowed the patterns of the surface thermal exchange forming at variation of the boundary conditions to be identified and the problem of evaluating the radiation exchange coefficient and the heat flow rate exchanged in the infrared to be addressed.

Effect of climatic variability on the performance of solar plants with interseasonal storage

A calculation method of the accumulated probability curves from the solar fraction provided by plants with interseasonal solar energy storage is proposed. The variability of the insolation sequences was achieved by randomly generating the monthly clearness indices according to normal distribution, and subsequently, the values of daily available energy by means of Markov’s matrix library [5]. The results obtained from simulations of the generated sequences of collected energy were subjected to experimental verification.

Solar radiation utilisability method in heat pipe panels

In this article the validity of the utilisability method for evacuated heat pipe solar panels was tested, through a comparison of expected useful energy and that measured in an experimental plant. The panels used are distinctive for the working of the heat pipes, which for collection, require a threshold irradiance value higher than the critical, used in quantification of heat losses. Working limits were identified and the basal utilisability calculation hypotheses tested by using a calculation code that simulates heat pipe behaviour. Dynamic phenomena linked to inertia during collection were studied with a mathematical model constructed from results provided by the collectors field at stepped variation to solar irradiance. The numerical and experimental results enable a critical comparison between calculated and measured energy.

Technical data of a grid-connected photovoltaic/wind hybrid system with and without storage battery for residential buildings located in a warm area

Electric production data of a grid-connected hybrid system are presented. The system consists of a photovoltaic generator, a wind micro-generator in the presence (HPWBS) or absence (HPWS) of an electric storage system. In such a system, the power generated by RES (renewable energy sources) is sent directly to balance the load. A residential use has been analysed in warm climate. The analysis has been carried out by TRNSYS 17 (Transient System Simulation) software and the mathematical modelling and the energy balance of the system have been shown in Mazzeo et al. (2018). The annual energy performance has been evaluated, in terms of dimensionless balance of the generated energy and dimensionless balance of the energy required by the load, for 375 hybrid system configurations. These configurations were obtained by varying the photovoltaic power, the wind power and the battery storage capacity, considering different hourly average daily values of the load.

Data demonstrating the influence of the latent storage efficiency on the dynamic thermal characteristics of a PCM layer

Dynamic thermal characteristics, for each month of the year, of PCM layers with different melting temperatures and thermophysical properties, in a steady periodic regime, were determined (Mazzeo et al., 2017 [1]). The layer is subjected to climatic conditions characterizing two locations, one with a continental climate and the second one with a Mediterranean climate. This data article provides detailed numerical data, as a function of the latent storage efficiency, including monthly average daily values: of the latent energy fraction, of the decrement factors of the temperature, of the heat flux and of the energy, and of the time lags of the maximum and minimum peaks of the temperature and of the heat flux.