sustainability Article Economic and Environmental Analysis of Investing in Solar Water Heating Systems Alexandru ¸Serban 1, Nicoleta B˘arbu¸t˘a-Mi¸su 2, Nicoleta Ciucescu 3, Simona Paraschiv 4 and Spiru Paraschiv 4,* 1 Faculty of Civil Engineering, Transilvania University of Brasov, 500152 Brasov, Romania;
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[email protected] 3 Faculty of Economics, Vasile Alecsandri University of Bacau, 157 Marasesti Street, 600115 Bacau, Romania;
[email protected] 4 Faculty of Engineering, Dunarea de Jos University of Galati, 47 Domneasca Street, 800008 Galati, Romania;
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[email protected]; Tel.: +40-721-320-403 Academic Editor: Francesco Asdrubali Received: 26 August 2016; Accepted: 2 December 2016; Published: 8 December 2016 Abstract: Solar water heating (SWH) systems can provide a significant part of the heat energy that is required in the residential sector. The use of SWH systems is motivated by the desire to reduce energy consumption and especially to reduce a major source of greenhouse gas (GHG) emissions. The purposes of the present paper consist in: assessing the solar potential; analysing the possibility of using solar energy to heat water for residential applications in Romania; investigating the economic potential of SWH systems; and their contribution to saving energy and reducing CO2 emissions. The results showed that if solar systems are used, the annual energy savings amount to approximately 71%, and the reduction of GHG emissions into the atmosphere are of 18.5 tonnes of CO2 over the lifespan of the system, with a discounted payback period of 6.8–8.6 years, in accordance with the savings achieved depending on system characteristics, the solar radiation available, ambient air temperature and on heating load characteristics.