Evaluación de un sistema de energía solar térmica para suministro de agua caliente en industrias cárnicas

Abstract

The sustainable development, the economic, clean and universal energy access and the safety energy, are the keys to get the planet equality and the prosperity. The objective set by the Plan of Renewable energies 2011-2020, was to obtain the 20% of the energy from renewable, and Spain is not meeting the goal, in spite of having the renewable and high energy solar potential. Focused on the food and agricultural sector, the meat industries have a high production rate, therefore are an important sector industry in this country. The heat water used in these kind of industries used in the productive process is the key in cleaning process, boiling… that uses a high energy consumption. The demand of warm water is not very seasonal, this is why it is an interesting kind of industry where install these Solar Thermal Systems. Nevertheless, the number of installations is limited, because of the hourly variability and different temperatures needed. The rate of temperatures in food industry is higher than the one used in sanitary water. This dissertation pretends to contribute to the promotion and utilization of renewable energies in the agro-industrial sector across the study of SST, using vacuum tube collectors to supply part of the demand in the meat industries. To make it, demand heat water standards have been taken in some industries (Volume and temperature water demand and the timing when is required) installing an experimental prototype, the potential energy production has been defined in these kind of solar systems, over the year. The useful energy the solar system can produce, has been calculated during the year, in different industries and stages. Finally, the profitability has been determined, having the solar system as a complementary to the current energy system. There have been calculated 3600 scenarios. The results are optimistic to install these kind of solar systems. Cities which have a high irradiation level over 1.700kWh/year (Madrid, Barcelona, Seville & Murcia) obtain energy form the SST improved between 29% and 73% from the total of the energy demand. The annual energetic spend is reduced between the 25% and 68%. These indexes of profitability are positive, including the payback from 8 to 19 years, depending on the kind of complementary energy system and the concrete characteristics of the water demanded in the industry. On the other hand, cities that have low irradiation level like La Coruña & Bilbao, the energy obtained is lower, growing the payback in the suppositions that the installation is profitable. Some cases, the investment is not recommendable, that means how important is the situation and the complementary system used in the installation. Clearly all profitability rates show that swag the electricity energy is more rentable than swag petrol energy. The main reason is the different energy price between both. Under the baseline scenarios, a sensitivity analysis has been carried out, determining the threshold of profitability with changes in defined parameters; specifically: change in investment cost, energy prices, useful life of the installation and discount rate. As an example, this analysis allows quantify the profitability in case the useful life is increased or reduced, if the available investment price was different… this study can provide high qualified additional information which allow the investors to take the decision. The results of this dissertation could be used to increase the number of solar system installation in meat industries, whose goal is get an agro-industrial sector more sustainable and competitive.