بهره وری انرژی

Increasing concern about the reduction of fossil fuel resources in today's societies has led to a greater tendency towards renewable energies. Therefore, solar energy is the most available renewable source. Most of the solar cells do not have the optimal efficiency. The most effective solution to solve this problem is to increase the efficiency of solar modules by combining them with other systems. One of these systems is the two-shell facade. By combining this system with solar panels, a new technology called photovoltaic systems integrated with the facade of the two building shells is introduced. The purpose of this research is to analyze several types of photovoltaic systems integrated with the facade of two building shells to observe its effect on the air conditioning load of the building and to optimize the parameters involved in this system for a hot and semi-arid climate. The results show that the temperature inside the building using the two-shell facade is two degrees Celsius lower than the simple case on average every month due to the greater heat transfer of the two-shell facade. The amount of cooling consumed inside the building is lower in the case of using the two-shell facade than in the simple case. In the summer, due to the intensity of solar radiation suitable for the city of Tehran and the lighting of the facade of two skins, the temperature inside the building rises and the need for more cooling is needed for proper air conditioning inside the building.

In this article, a new framework has been developed based on the modeling of the energy system and related greenhouse gas emissions, which aims to predict and provide a perspective of energy and environment correlation for economic sub-sectors under possible scenarios. Nexus modeling has been done by the bottom-up method using the Long-range Energy Alternative Planning (LEAP) software from 2016 to 2040. Demographic and economic data of Urmia watershed, which is one of the drivers of energy demand, was collected and used as a case study. The results based on the analysis of energy and greenhouse gas emissions under different scenarios have shown that the greatest potential for saving energy and reducing emissions is 27.76 million barrels of crude oil equivalent and 11.3 million tons of carbon dioxide equivalents respectively under the scenario of integrated policies. Analysis of the sensitivity of the total energy demand to social and economic changes shows an average increase of 3 and 2 percent per unit of increase in population and GDP. A cost-benefit analysis for productive measures under the mentioned scenario results in the maximum net present value if the interest rate remains below 8%.

This article has been investigated the effect of natural light and appropriate skylights on improving daylight performance and reducing energy consumption in classrooms.In order to implement the country’s general environmental policies and reduce school costs with the optimal use of energy, daylighting is a factor for participation in reducing energy consumption and a step towards achieving the goal of 1404. This article’s purpose is to evaluate daylighting performance and provide solutions to improve visual comfort. In order to achieve this goal, Shahid Mahdavi preschool in the northwest of Tehran was selected as a case study due to its special physical characteristics such as light shelf, trombe wall, light shelves, geometric designs on the roof and diagonal atrium. Based on the quantitative research method, a case sample was selected and light metering was performed using light measuring instruments in the two southern classes of Mahdavi preschool with and without light shelves on January 12, 2021 with sunny sky conditions and at specific times. Climate Studio software was used to simulate and analyze the results. Brightness rating was used by the rating indicator in green buildings (4.1 LEED). The qualitative method is also based on inductive reasoning and using extensive library studies. Finally, the results of field information and software analysis were reviewed and the useful daylight illuminance factor was evaluated in all 4 models, which was in the acceptable range. Therefore, a combination of south windows and light shelves, along with semi-transparent moving curtains, causes a uniform distribution of daylight. Using atrium in the north side of the classroom will increase lighting performance and its uniformity. Suggestions for improving visual comfort are presented in this study.

The use of telecommunication systems with high energy efficiency and high data rates along with the desired quality of services is the infrastructure of a command and control system (C4I) that should be used with the best quality of communication in times of crisis. The use of such a structure has a special place in modern defense systems. Therefore, the design of such systems has become a major challenge and a very important research field in the field of telecommunications. The increasing growth of wireless telecommunications and the high speed of multimedia data traffic and the presence of multiple users are associated with energy consumption, which has focused on energy efficiency and the optimal use of energy and power in telecommunications. Energy efficiency is considered as one of the major goals of wireless telecommunication systems design due to environmental and economic issues. . Multi-user multi-input multi-output systems are one of the new methods of telecommunications. In these systems, the use of hundreds of antennas in the base station improves energy efficiency. Increasing the number of system antennas increases the rate of information exchange, energy consumption and hardware, the introduction of a power selection model in multi-input multi-output multi-user systems increases energy efficiency. Important factors affecting energy efficiency are actual transmission power and power consumption in transmitter and receiver circuits, number of antennas, number of users and spatial correlation between antennas. In this paper, the algorithm for selecting the farthest antenna is proposed (antenna correlation), which leads to a significant improvement in energy efficiency compared to the conventional state.

All energy scenarios show that the energy supply approach is shifting to renewable energy, in particular energy from biofuels. On the other hand, in the context of this type of energy, water which is a limiting factor in the discussion of agricultural products, arises. In this research, using the water footprint index, the amount of water consumed for the production of each energy unit was calculated from wheat biomass. In this regard, six provinces of the country with the highest production value were selected. The purpose of this study was to determine the most desirable province for producing bioenergy from wheat biomass from the perspective of the water footprint index. The results of this study showed that Golestan, Kermanshah, Ardebil, Khuzestan, Fars and Khorasan Razavi provinces devoted 25.1, 33, 35.5, 39.4, 43.9 and 83.7 cubic meter of water per GJ, respectively and this values showed the priority to produce bioenergy from wheat biomass. In other words, from the perspective of the water footprint, the productivity of bioenergy production in Golestan province is more than other provinces. Therefore, this situation has created an advantage for the use of wheat biomass in the province.