ENERGY EQUIPMENT AND SYSTEMS
Year:2024 | Volume:12 | Issue:2|Papers Count:6

Cooling system is in charge of a high percent of total energy consumption in buildings. Different cooling systems and devices have different effects on the cooling load and energy consumption. The main objective of this paper is to study the effects of floor and ceiling temperature in comparison with other parameters including location of air diffusers and application of insulation and sealant. On the other hand, hospitals are huge buildings with high energy requirements and systems compared to other buildings such as universities, schools and offices. In this paper the impacts of these different cooling parameters on the temperature and cooling load in a room of a hospital are studied using Design of Experiments (DOE) and the Taguchi method. The experiments are simulated in Energy Plus to achieve the comfort temperature in one hospital’s room in Iran during six months of spring and summer. Using different cooling systems such as chilled floor (during night to decrease the peak load during day) and ceiling in combination with air handling unit can provide people satisfaction while optimizing energy consumption. The results show that the location of inlet and outlet diffusers has the most effect while the chilled floor (when the other systems are off) has the less impact on reaching comfort temperature. The ranking of parameters and their interactions has been discussed through the paper.

Growing worldwide energy demands, the drawbacks of fossil fuels, and global climate change have prompted the creation of sustainable, clean power. One of the viable alternatives to the consumption of fossil fuels is the use of solar energy. Solar photovoltaics (PV) and solar thermal are the most widely accessible solar technology. Hybrid solar systems that make use of Concentrated PV Thermal (CPV/T) technology give an alluring option for the generation of both electrical and thermal energy at the same time. CPV reduces the area of PV receivers while capturing the same amount of solar energy through the use of solar radiation that has been Concentrated on PV cells. However, a notable concern associated with CPV is the elevated temperature of the PV surface, often necessitating the implementation of cooling measures. This problem can be resolved by the implementation of a CPV/T system. Conditions for modeling a novel CPV/T hybrid system embedded Multi Junction Photovoltaic cells (MJPV) and based on Fresnel Lens (FL) have been presented in this research. The Python programming language was utilized to simulate the functioning of a linear concentrated Photovoltaic System (LCPVS). In addition, the influence of cooling fluid and its impact on the efficiency of MJ cells (MJC) were assessed. The findings indicate that the proposed system's average thermal and electrical energy were 7.259 and 3.737 (kWh) respectively. Moreover, the average efficiency of the new design was 34.713% and the amount of potable and hot water has more optimum outcomes.

Energy efficiency is a matter of immense importance for a wide variety of sectors, and especially industry as the driver of economic growth. Ceramic tile manufacturing is a basic industry that has turned into a nucleus of industrial development in some countries. However, this industry is extremely energy-intensive. Iran has a strong ceramic tile industry consisting of a significant number of manufactories with notably high production output and export. Given the energy-intensity of this industry, it can considerably benefit from energy efficiency improvement measures. In this study, first, a number of potential solutions for improving energy efficiency in Iran’s ceramic tile industry were identified by reviewing the subject literature and surveying a group of experts. The fuzzy Delphi method was then used to identify and ultimately prioritize 22 appropriate solutions from technical, managerial and production process standpoints for the said purpose. The results showed that the highest-priority solutions for energy efficiency improvement in the ceramic tile industry are Implementation of regular maintenance program of facilities and equipment, Adjusting the air in the kilns and burners, and Replacing electro motors according to the load of slurry mixers, and the lowest-priority solutions for this purpose are Insulation of transmission and distribution routes (steam and hot water pipes), Implementation of lighting management system in the factory, and Installation of heat exchangers to recover wasted heat (exhaust gases and the kiln’s cooling system).

Solar heat transfer fluid (HTF) plays a crucial role in the performance of parabolic trough solar collectors (PTSC) and the energy systems integrated with them. In this study, a multi-attribute decision-making (MADM) analysis is employed to prioritize the HTFs for three solar-driven multi-generation energy systems. These systems are based on a direct-fed organic Rankine cycle (ORC) and bottom-cycle arrangement of a double-effect absorption refrigeration cycle and a Kalina cycle system. The ORC configurations include simple, regenerative, and ORC integrated with an internal heat exchanger. The MADM analysis shows that the optimal HTF for all systems is Therminol 66 for which ORC based system demonstrates the best performance in both energy (80.17 %) and exergy (33.21 %) viewpoints. Additionally, this system exhibits the highest performance in terms of net present value (82.6 M$), dynamic payback period (2.19 years), and cost of energy (0.018 $/kWh).

Combined Heat and Power (CHP) systems have attracted substantial interest in the past decades as they offer higher thermal efficiency than single power generation systems. Various parameters affect the performance of a cogeneration system, including environmental and operating conditions of gas turbine and Heat Recovery Steam Generator (HRSG) system. In this study, the effects of 15 substantial parameters on the performance of a CHP system are investigated using Thermoflow software. The most influential parameters are identified by performing a comprehensive parametric study and sensitivity analysis. The results indicate that only 3 parameters, including the percentage of gas turbine load, ambient temperature, and ambient pressure, affect the gross output power, i.e., increasing ambient temperature from -20 to 50 oC leads to an 8% increase in efficiency of the CHP system. In contrast, moving from the highest elevation in Iran to a beach can result in a 20% reduction in the output power of the cogeneration system. This is while 8 parameters significantly affect the efficiency of the cogeneration system. For instance, changing gas turbine load from 100% to 25% leads to a 25% reduction in the efficiency of the cogeneration system. Furthermore, the correlations between important input and output parameters are presented, which can be easily used for different environmental and working conditions of cogeneration systems and are, in fact, a roadmap for the feasibility of using this type of system in various regions and working conditions.

This study aims to evaluate the performance of a simple cycle gas turbine power plant by analysing the effect of different operating parameters. These operating parameters include compressor pressure ratio and compressor & turbine isentropic efficiencies. The study quantitatively assesses the exergetic efficiency and the exergy destruction of each unit in the cycle, as well as the power used or produced by the cycle. Any change in these parameters can significantly impact the power plant's overall performance through a specific unit in the cycle. For instance, increasing the compressor pressure ratio can reduce the temperature difference across the combustor, lessening the exergy destruction and improving the cycle’s overall performance. However, any decline in the compressor or the turbine isentropic efficiency results in an increase in the exergy destruction of the affected unit and can result in a decrease in the overall cycle performance. This is due to either an increase in power required by the compressor or a decrease in power produced by the turbine. The analysis suggests that the turbine isentropic efficiency has a greater impact on the net power generated than the compressor isentropic efficiency. Additionally, the turbine inlet temperature is a dependent variable as operating at different compressor pressure ratios and compressor isentropic efficiencies lead to varying turbine inlet temperatures. Therefore, increasing the turbine inlet temperature does not always lead to improved performance.