Quantitative assessment of hybrid systems of heating domestic water based on solar energy in andean zones of Ecuador

摘要

The domestic hot water systems (DHW) used in Ecuador work with electrical energy and liquefied petroleum gas (LPG). Nowadays, Ecuador is in a process of changing its energy matrix, which involves the elimination of LPG in the residential sector. In this context, gas cooker will be replaced by induction cookers and also the gas water heaters by electrical heaters. This will cause a significant problem: high peaks in the power demand curve in the country. This work shows a quantitative assessment of different hybrid solar systems used for DHW to mitigate the electric energy consumption and LPG, showing the economic and environmental benefits. This paper presents a simulation of a solar thermal system and a photovoltaic system, each one of them supported by an auxiliary heating system. Demand for hot water is considered for a typical family of 4 members in Ecuador. TRNSYS software was used to evaluate the behavior of the systems in a whole year, whereas an analytical method was used to contrast the results. The results suggest that the solar thermal systems are more profitable due to their greater efficiency with respect to photovoltaic systems. On the other hand, the costs of solar collectors and photovoltaic panels influence in a great way in the economic survey. In regard to the auxiliary systems, economic analysis shows that a system based on LPG is more profitable than an electrical auxiliary system because it presents a saving of 17.04 % of the total expenditure required. The study also shows the economic and environmental benefits for the user and the Ecuadorian government.