Heating houses by using vacuum-tube solar collectors and a small aboveground water tank: a cost-effective solution for maritime climates

ABSTRACT This work presents a simple dynamical solar-thermal modelling and cost-optimized solution for heating houses in maritime climates by using many vacuum-tube solar collectors together with one small well-insulated aboveground water tank and the underfloor hot-water heating system. This was performed for a single house in the cold-maritime climate of Bariloche (13,000 kWh/y), which could be fully satisfied by using ten collectors on 70°-inclined roof and 4.6 m3 tank, costing €12,900. This cost is noticeably lower than for previous large projects in cold-continental climates, what is supported by four key factors: (1) solar resource and heating demand in maritime climates are more distributed than in continental climates; (2) small aboveground tanks can get noticeably higher efficiencies and lower costs that huge underground tanks; (3) vacuum-tube collectors get higher performances than flat collectors during winters; (4) high winter solar yield is achieved by installing collectors on high tilt angles (or half on low-inclined roofs and half on walls). These four factors will be discussed by solar-thermal and cost analyses, by comparing the system performance for climatic conditions of Bariloche and Okotoks.