Design of the installation providing with DHW and radiant floor heating using solar energy and biomass

Abstract: In the last decades terms like Global Warming and Sustainable development have arisen. The anthropogenic green house gases emissions have raised the concentration of CO2 in the atmosphere to levels that might lead to a high increase in the average temperature in Earth. One of the most effective ways to fight against this phenomenon is to promote clean renewable energies. Among them, solar energy has the biggest developing potential and has proved to be an efficient and cost-effective energy source for different applications; one of them being the production of Domestic Hot Water and Space Heating. The aim of this Thesis is to study the possibilities to provide a single family house with hot water and space heating in an environmental friendly way. To do so, a solar system with biomass support will be designed for a single family house in northern Spain. The building has total energy demand of 20.5 MWh a year, of which 18 MWh correspond to space heating and 2.5 MWh to domestic hot water. The chosen solution for the building includes 12 solar collectors with a total area of 23.4 m2, a biomass boiler with a nominal power of 30 kW and a 32 kW oil boiler. Additionally, a radiant floor system was used as it perfectly adapts to the low temperature of the solar system. The result is an installation working with an 85% of renewable energies. This high share of renewable energy entails savings of 2,000 liters of oil a year, avoiding the emission of 4.5 tones of CO2 to the atmosphere every year. The economic calculations show that the pay back of the investment is 10 years with a Internal Rate of Return of 13%. Therefore, it can be said that, for this particular building and due to the governmental subsidies granted, solar energy is a cost effective alternative to provide the basic energy needs of a house.