Journal of Renewable Energy and Environment
Volume:4 Issue: 4, Autumn 2017

In recent decades, excessive using fossil fuels has been resulted in emitting greenhouse gases such as CO2, consequently, environmental pollution. In this study, the techno-economic analysis of the CCHP/PV hybrid system application for a sample building was examined to reduce the environmental pollution and primary energy consumption of the buildings. The life-cycle cost analysis was utilized as a robust economic criterion. To investigate the effect of climate conditions on the system performance, five cities of Bandar Abbas, Ahvaz, Tehran, Bandar Anzali, and Ardebil were considered and evaluated. The results showed that the pollution emission rate and primary energy consumption of the building were declined by the CCHP/PV system up to 10.14 % and 26.52 % for the coldest climates, respectively. Moreover, an increase of 33.33 % was observed compared to the conventional system due to its high initial investment. However, the sensitivity analysis of energy tariffs, as well as equipment prices indicated favorable results and a bright horizon for these systems.

The present study aimed at ranking and selecting the superior geothermal project for hydrogen production in 14 provinces of Iran using a multi-objective optimization fuzzy hybrid approach through analyzing the ratio (fuzzy Moora) and expanded entropy weighting method. In this research, the extended entropy weighing method and the Fuzzy-Moora approach were utilized to weigh the criteria and project the ranking, respectively. In this research, 13 criteria for ranking the geothermal projects in Iran have been selected for hydrogen production. At first, the technical-economic feasibility of the projects was carried out in Homer software, and then the ranking process was performed with the proposed hybrid approach. The results showed that among 14 studied provinces using geothermal energy, the provinces of Bushehr, Hormozgan, Isfahan, Mazandaran, East Azarbaijan, Fars, Qazvin, Zanjan, Ardebil, Khorasan Razavi, Kerman, Sistan and Baluchestan, South Khorasan and West Azarbaijan were ranked in that order in terms of hydrogen production.

In this paper, the absorbent carryover effect in a designed counter-flow enthalpy exchanger is investigated. In a built prototype of the liquid desiccant dehumidifier, air and the absorbent solution are in contact and flow through a packed multi-channel polymer tower in a counter-flow pattern. To avoid the absorbent carryover, the tower is equipped with an eliminator. Experimental measurements show that applying wick of hydrophilic type material to the channels' surfaces of the eliminator and the enthalpy exchanger, while increasing the rate of dehumidification, reduces the solution carryover effect, however, it does not eliminate it. To eliminate the effect, pumping the solution into the tower is interrupted periodically. It was found that by adjusting the pump switching frequency, the carryover effect can be eliminated. The best result is achieved when the period of switching on state is about a quarter of the off state one and the total period is about 25 seconds. Since the solution pump is turned off frequently, the cost of electrical power is reduced significantly. Also, the measurements show that while the dehumidification ability of the tower is improved in a steady state operation its regeneration performance is not.

This paper focuses on improving the active and reactive power control of Wind Energy Conversion System (WECS) by employing the Battery Energy Storage System (BESS) and controlling the frequency and voltage regulation instantaneously. The proposed power control scheme is composed of two control loops so that they are implemented and designed for active power control and controlling the reactive power, respectively, which both are equipped with PI type controllers. In addition, two control loops were utilized to control the frequency and voltage on the rotor side converter under balance and unbalance grid conditions. In this paper, the presented control strategy optimally tuned all the parameters of controllers at the same time by utilizing a mixed integer nonlinear optimization programming and solved by the ICA algorithm. Moreover, in order to demonstrate the effectiveness of the proposed strategy, non-linear time domain simulations were carried out in MATLAB software. The obtained simulation results verified that the proposed control scheme efficiently utilize BESS to control the active and reactive power control and confirm the effectiveness of the proposed strategy under the balanced and unbalanced grid conditions.

Nowadays, the replacement of renewable energies such as biofuels is one of the main priorities in environmental programming and investments. This study is based on sustainable strategy towards integrating algal biomass generation as a green feedstock with wastewater treatment, CO2 bio-fixation, and bioenergy production. Therefore, the performance of Trichormus variabilis in biomass production together with ammonium and phosphate removal from an actual effluent obtained from a mixed wastewater streams has been investigated using two mixing methods under aeration and agitation conditions. Dilutions of 10 %, 20 %, 40 %, 60 %, 90 % and 100 % (v/v) were used for growth evaluation. The results showed that the bubbled air effectively enhances the biomass productivity. However, the agitation system was suggested to cultivate the algae in the wastewater due to the elimination of possible mechanical stimulation stress on cells. Moreover, high pH levels (pH>8) indicated a negative inhibitory effect on growth. Thus, unexpected inhibitory impacts were removed through providing the wastewater dilutions mixed with BG11 culture medium, which contains essential required nutrients, to support the algal growth in the wastewater, adjust pH and remove the mechanical stress induced by bubbling compressed air. The results with respect to investigating the effect of the inoculums and wastewater concentrations on the biomass production suggested that the highest biomass generates with 30 mg.mL-1 inoculum in 40 % mixed wastewater diluted by the BG11 medium having the highest potential in CO2 bio-fixation of 9.19±0.64 g.L-1. The results of the wastewater analysis demonstrated the removal potential of ~43 % and ~75 % for NH4+ and PO43−, respectively. The generated biomass after phycoremediation and CO2 bio-fixation can be effectively utilized in different types of biofuel production.

Ducted wind turbines are a kind of small wind turbine having a diffuser or any other shape around the rotor which increases the air flow through the blades and absorbs more power. In the present study, a small wind turbine was ducted with a relatively simple ring and its performance was investigated in a wind tunnel. The duct is shaped using rolling steel sheets on a sloping surface and finally fabricated in double-glazed surfaces. The turbine utilizes polyester resin glass fiber-armed composite hollow blades. Bare turbine produces 165 watts in its highest power generation mode which can reach 282 watts when it is ducted. The evaluation of the system in the wind tunnel showed that the power generation of the ducted system compared to a conventional turbine was 14 % higher on average. Furthermore, the rotor speed of the ducted turbine was 45 % higher than the bare one which increases the tip speed ratio (TSR). In this study, TSR increment raised the absorbed power in the developed wind turbine.