A Thermo-Economic Model for Aiding Solar Collector Choice and Optimal Sizing for a Solar Water Heating System

Abstract

The choice of solar collector type to employ and the number of chosen collectors to subsequently deploy, are important planning decisions, which can greatly influence the economic attractiveness of solar water heating systems. In this paper, a thermo-economic model is developed for the computation of a suitable metric that can aid in choosing the most cost-effective collector to use in a solar water heating system and to determine the optimal sizing of the solar water heater components once the choice collector has been picked. The energy-per-dollar comparison metric, calculated as the annual heat energy output of the collector in an average year, at the so-called "sweet-spot" size of the collector array, divided by the annualized life-cycle cost, based on warranty life and collector initial cost, was recommended as instructive for comparing cost-effectiveness of different solar collectors. For the determination of the sweet-spot size of collector to use in a particular solar water heating system, at which the energy-per-dollar is calculated, the Net Present Value of Solar Savings was used as the objective function to maximize. Ten (10) different models of liquid solar thermal collectors (5 flat plate and 5 evacuated tube type), which are rated by the Solar Ratings & Certification Corporation (SRCC), were ranked according to the energy-per-dollar criterion through the thermo-economic model described in this study. At the sweet-spot collector area for the solar water heating system, the corresponding volume of hot water storage tank and the optimal solar fraction are also simultaneously determined. The required hot water storage volume decreases as the deployed collector area increases while the solar fraction increases, with diminishing marginal increase, until it saturates at a value of unity. For the present case study where the required load temperature is 50°C and the solar water heating system is located in central Zimbabwe (latitude 19°S and longitude 30°E), the selected collector model happened to be a flat-plate type, which achieved the highest energy-per-dollar score

Marine Online Platforms of Services to Public End-Users—The Innovation of the ODYSSEA Project

“…EONs provide an excellent opportunity to deliver the required derivative marine information by increasing environmental parameter estimates and a combined accuracy assessment using geographic and demographic data [7]. Spatial planning information that can fulfil the parameters required by marine studies collected and the collection of spatial planning information have been facilitated by the analysis of free data (open-source and unlimited policy) obtained through an analysis of land and ocean observation tools [8,9].…”