Analysis of a Hybrid Solar-Assisted Trigeneration System

A hybrid solar-assisted trigeneration system is analyzed in this paper. The system iscomposed of a 20 m2 solar field of evacuated tube collectors, a natural gas fired micro combinedheat and power system delivering 12.5 kW of thermal power, an absorption heat pump (AHP) witha nominal cooling power of 17.6 kW, two storage tanks (hot and cold) and an electric auxiliaryheater (AH). The plant satisfies the energy demand of an office building located in Naples (SouthernItaly). The electric energy of the cogenerator is used to meet the load and auxiliaries electric demand;the interactions with the grid are considered in cases of excess or over requests. This hybrid solutionis interesting for buildings located in cities or historical centers with limited usable roof surface toinstall a conventional solar heating and cooling (SHC) system able to achieve high solar fraction (SF).The results of dynamic simulation show that a tilt angle of 30◦ maximizes the SF of the system onannual basis achieving about 53.5%. The influence on the performance of proposed system of the hotwater storage tank (HST) characteristics (volume, insulation) is also studied. It is highlighted that theSF improves when better insulated and bigger HSTs are considered. A maximum SF of about 58.2%is obtained with a 2000 L storage, whereas the lower thermal losses take place with a better insulated1000 L tank.