Title : Solar Combined System, SCS, integrated in Tunisian residential applications: Energetic and exergoeconomic investigations
Abstract:
Nowadays the cheaper and simple kinds of these converting solar energy system systems is the Solar Combisystem (SCS) which use thermal part of solar energy to provide domestic hot water and hot water for space heating. The primary energy source of a SCS is solar energy while the auxiliary energy source can be fuel, natural gas or electricity. Many researchers have treated the SCS potential and performances to cover buildings thermal needs. The endeavor of this paper is to study the potential offered by the expenditure of a Solar Combined System, SCS, integrated in Tunisian buildings for the heating load of dwellings and domestic hot water supply. The analyses are based an experimental and simulation studies according to a typical climatic condition of Tunis. The developed system was evaluated based on the steady-state conditions at different temperatures. The study of the energetic and the economic potential given by the employ of SCS is achieved by using a TRNSYS simulation model according to a Tunisian scenario. The model includes component models for the PV/T solar collector, storage tanks, heat exchangers auxiliary heating units, heating, control units and thermostat, and makes use of the appropriate weather data files. Simulations are conducted for Tunisian houses in the four climate conditions to study energy savings possible with solar combisystems. The annual performances investigation includes: energy extracted and delivered to the user from the PV/T system, heat loss, auxiliary energy and electric and thermal efficiencies. It has been observed that the proposed SCS system can meet the daily requirement of domestic hot water as well as air heating space during great periods of the year. It has been concluded that in terms of energy saving the SSC offers a greater potential compared to other conventional systems (gas boiler, PAC…). The results showed that the maximum instantaneous thermal and electric energy efficiency in active mode are about 50 and 15 %, respectively. It was found also that the maximum thermal and electric exergy efficiencies were about 50 and 14.8%, respectively. The results showed that the optimized SCS covert the major part of the hot water and the electric needs of Tunisian household’s with an expected annual average gain of about 14.60 and 5.33 %, respectively. An economic appraisal was also achieved to appraise the SCS feasibility compared to conventional systems by the evaluation of the savings, the financial viability, the payback times and the environmental aspects of the SCS system.
Keywords: Solar Combined System, Renewable energy, PV/T, buildings, energy, exergy, TRNSYS simulation
