• Energy Research

One of the most effective measures for building energy conservation is the implementation of energy codes. The building energy codes introduction in Iran started two decades after the first oil crisis in the early 1970s by establishing the building energy conservation regulation called Issue 19. Nowadays, due to some financial and executive barriers, the implementation of Issue 19 is faced with some difficulties. The most critical obstacle is the low price of energy carriers, which lead to high subsidies of energy and the reluctance of the building owners to implement the regulation. The main goal of this paper is the introduction of an innovative financial and executive mechanism for implementation of Issue 19 in both new and existing buildings to achieve sustainability and resiliency. The cost–benefit analysis approach, along with SWOT technique and a comprehensive review of global experiences, was applied to introduce proper financial and executive mechanisms to determine the economic and social aspects of energy conservation programs for implementation of energy saving in buildings. The presented mechanism indicates the role of all different related parties, such as the government, banking system, energy-saving companies, building owners, and municipality, to achieve this goal. The results indicated that with a cost of $10 million, the benefits of implementation of the introduced mechanism are over 5.78 billion dollars.

One of the most effective measures for building energy conservation is the implementation of energy codes. The building energy codes introduction in Iran started two decades after the first oil crisis in the early 1970s by establishing the building energy conservation regulation called Issue 19. Nowadays, due to some financial and executive barriers, the implementation of Issue 19 is faced with some difficulties. The most critical obstacle is the low price of energy carriers, which lead to high subsidies of energy and the reluctance of the building owners to implement the regulation. The main goal of this paper is the introduction of an innovative financial and executive mechanism for implementation of Issue 19 in both new and existing buildings to achieve sustainability and resiliency. The cost–benefit analysis approach, along with SWOT technique and a comprehensive review of global experiences, was applied to introduce proper financial and executive mechanisms to determine the economic and social aspects of energy conservation programs for implementation of energy saving in buildings. The presented mechanism indicates the role of all different related parties, such as the government, banking system, energy-saving companies, building owners, and municipality, to achieve this goal. The results indicated that with a cost of $10 million, the benefits of implementation of the introduced mechanism are over 5.78 billion dollars.

In the present study, the thermal load of a residential building is determined in two sample cities. Karadj and Hamedan. Then, the suitable solar combi-system and the underfloor healing system are designed for the units of the buildings. Furthermore, in response to the building energy demand and also by studying the expense-efficiency diagram, the efficiency of solar combi-system and the number of flat-plate solar collectors are determined. In continue, regarding the effect of the shade of the collector rows and the restriction of the roof space, a hybrid system is suggested. Finally, the annual energy saving in fuel consumption and reduction in social costs are studied and the payback period is determined. © 2009 Asian Network for Scientific Information.

In the present study, the thermal load of a residential building is determined in two sample cities. Karadj and Hamedan. Then, the suitable solar combi-system and the underfloor healing system are designed for the units of the buildings. Furthermore, in response to the building energy demand and also by studying the expense-efficiency diagram, the efficiency of solar combi-system and the number of flat-plate solar collectors are determined. In continue, regarding the effect of the shade of the collector rows and the restriction of the roof space, a hybrid system is suggested. Finally, the annual energy saving in fuel consumption and reduction in social costs are studied and the payback period is determined. © 2009 Asian Network for Scientific Information.

Abstract Small-scale concentrated solar powers (CSP) integrated with micro gas turbines can be mentioned as an effective way to power off-grid and rural areas. One of the most important challenges of using such no fuel-assisted systems is the intermittent nature of solar radiation and unavailability at nights. To overcome this issue, in this research new design for a high temperature solar receiver combined with a triple (sensible, latent, and chemical) storage was presented. In the first part, solutions to increase heat transfer to reach higher outlet temperature of the solar receiver to integrate with the thermochemical reactor are presented. For this purpose, three new pipe models including sinusoidal, triangular, and trapezoidal tubes are proposed instead of straight tubes. Based on the results, Corrugated tubes have significantly higher heat transfer as well as more pumping power compared to straight tubes and the sinusoidal model has the best thermal–hydraulic performance. In the second part, numerical modeling of a thermochemical reactor with honeycomb structure, which uses Co3O4/CoO as a redox pair, is performed and the results of the developed model are validated against the experimental results and two important parameters in the reactor design including cell density and channel wall thickness of the honeycomb structure is investigated. In the last section, the designed solar receiver is integrated with a thermochemical heat storage, and the performance evaluation of solar receiver integrated with triple storage are presented. The results delighted that the designed solar receiver hybrid with thermochemical energy storage, with the solar receiver efficiency of 68% and energy storage capacity of 137 MJ is capable to provide the required inlet temperature of turbine (1073 K) about 100 min in off-sun condition. In addition, the new design, by meeting the main constraints provided by the micro-gas turbine, has the ability to store up to three times more energy than the latent heat storage alone.

Abstract Small-scale concentrated solar powers (CSP) integrated with micro gas turbines can be mentioned as an effective way to power off-grid and rural areas. One of the most important challenges of using such no fuel-assisted systems is the intermittent nature of solar radiation and unavailability at nights. To overcome this issue, in this research new design for a high temperature solar receiver combined with a triple (sensible, latent, and chemical) storage was presented. In the first part, solutions to increase heat transfer to reach higher outlet temperature of the solar receiver to integrate with the thermochemical reactor are presented. For this purpose, three new pipe models including sinusoidal, triangular, and trapezoidal tubes are proposed instead of straight tubes. Based on the results, Corrugated tubes have significantly higher heat transfer as well as more pumping power compared to straight tubes and the sinusoidal model has the best thermal–hydraulic performance. In the second part, numerical modeling of a thermochemical reactor with honeycomb structure, which uses Co3O4/CoO as a redox pair, is performed and the results of the developed model are validated against the experimental results and two important parameters in the reactor design including cell density and channel wall thickness of the honeycomb structure is investigated. In the last section, the designed solar receiver is integrated with a thermochemical heat storage, and the performance evaluation of solar receiver integrated with triple storage are presented. The results delighted that the designed solar receiver hybrid with thermochemical energy storage, with the solar receiver efficiency of 68% and energy storage capacity of 137 MJ is capable to provide the required inlet temperature of turbine (1073 K) about 100 min in off-sun condition. In addition, the new design, by meeting the main constraints provided by the micro-gas turbine, has the ability to store up to three times more energy than the latent heat storage alone.

Abstract This paper attempts to study the demand function of natural gas in Iran using smooth transition regression model (STR). To this end, gross domestic productions (GDP), real price of natural gas and temperature have been employed as variables explaining the natural gas demand from 1971 to 2009. The results indicate that natural gas demand follows an LSTR1 nonlinear two-regime model if the real price of natural gas is considered as the transition variable. Estimation results also indicate that the slope parameter approximately equals the high value of 10 and the threshold value is 31.82 Rials 1 per one cubic meter consumption of natural gas. The results strongly suggest that natural gas demand follows the gross domestic production during the last years, but temperature has no significant impact on natural gas demand in Iran.

Abstract This paper attempts to study the demand function of natural gas in Iran using smooth transition regression model (STR). To this end, gross domestic productions (GDP), real price of natural gas and temperature have been employed as variables explaining the natural gas demand from 1971 to 2009. The results indicate that natural gas demand follows an LSTR1 nonlinear two-regime model if the real price of natural gas is considered as the transition variable. Estimation results also indicate that the slope parameter approximately equals the high value of 10 and the threshold value is 31.82 Rials 1 per one cubic meter consumption of natural gas. The results strongly suggest that natural gas demand follows the gross domestic production during the last years, but temperature has no significant impact on natural gas demand in Iran.