Numerical investigation of a new combined energy system includes parabolic dish solar collector, Stirling engine and thermoelectric device

According to new findings, the use of clean energy sources such as solar energy to supply energy (both electricity and heat) to human societies is essential. On the other hand, choosing the appropriate technology to convert solar energy into useful energy in the form of individual or combined systems is a fundamental issue. Individual solar energy systems have inherently low performance. However, their use in hybrid energy systems with other energy generation devices is key solution and shows high performance. The present work provides the performance of a new combined energy system composed of the parabolic dish solar collector (PDC), Stirling engine (SE) and thermoelectric device (TD) under various parameters. Sun is the main source of energy in this system, where, sunlight is focused on the PDC focal point by the parabolic shaped mirrors. Thus, the useful thermal power is produced by PDC and then feeds to the SE. The operating fluid of the engine is heated by this heat and converted into mechanical energy. Then, the mechanical energy is converted into electricity by a generator connected to the SE and the excess heat is lost from the engine. The exhaust of the SE transferred to the TEG hot end and produces further electricity. In addition, the TEC module absorbs the cooled environment heat and produces cooling energy (by consuming electricity from the TEG). Therefore, the proposed combined process provides the electricity, heat and cooling. The paper is based on the following three scenarios: (1) the system performance is evaluated under constant climatic conditions, (2) climate data from five various cities in Europe and Asia are used for system operation and (3) this scenario presents the general comparison between the two different hybrid energy systems driven by PDC and linear Fresnel reflector (LFR). In addition, multi-objective optimization is provided to obtain the optimal performance of the developed hybrid system. The optimization results showed that, the optimum total output electricity and overall efficiency were 26.21 kW and 39.17%, respectively. It was also found that, average daily useful power generated by PDC in Moscow on 14-June is 373.97 W/m(2), which is about 11.1%, 1.55%, 33.3% and 14.23% more than Tehran, Beijing, Geneva and Kiev, respectively. Furthermore, increasing the temperature of PDC absorber improves the performance of SE and TD and subsequently improves the overall operation. Also, in terms of the PDC numbers, the system in the cities of Tehran, Beijing and Moscow has a better justification compared to the other two cities (Geneva and Kiev).