Performance assessment of a horizontal-coil geothermal heat pump

This paper evaluates the performance of a geothermal heat pump in Iran. An air-to-air 5.275 kW heat pump has been changed and redesigned to a geothermal heat pump system for the first time in Iran. Air-to-air condenser has been replaced by a tube-in-tube heat exchanger and assembled system has been tested under ARI-325 standard at the national energy lab of Iran and the results have been compared with the original system. Then, local weather conditions and soil properties of Tabriz (located at the north-west of Iran) have been applied and geothermal coil has been designed. Coil has been connected to the heat pump and the average coefficient of performance (COP) of rather more than three has been recorded in cooling mode. Results obtained from experimental measurements show that horizontal GSHP systems can be used for Tabriz-like climates in Iran. Copyright © 2006 John Wiley & Sons, Ltd.     

Photocrosslinking of styrene–isoprene–styrene; effect of benzoin and ethylene glycol dimethacrylate on physical properties

Crosslinking reaction of polymer by ultraviolet (UV) irradiation has been important in industries. In this work, photocrosslinking of styrene–isoprene–styrene (SIS) triblock copolymer in the presence of benzoin photoinitiator and a dimethacrylate monomer as crosslinking agent was investigated. Curing of samples was initiated under UV irradiation. Benzoin was used as photoinitiator because it contains chromophore group that could absorb UV irradiation. Ethylene glycol dimethacrylate (EGDMA) was used as crosslinking agent, since it has alkene functional groups that could react with the alkene group of SIS. ATR-FTIR spectra of samples show that absorption band of double bond at 1500–1600?cm^?1 decreases after UV exposure. Increasing the concentration of benzoin (0.1–1?phr) and EGDMA (1–10?phr) leads to an increase in gel content and hardness, while swelling ratio decreases. After 5?min heating at 150?°C, about 20%wt of the unirradiated compound became insoluble, because heating of compound at 150?°C causes crosslinking reaction without any irradiation.     

Path-Based Dynamic User Equilibrium Model with Applications to Strategic Transportation Planning

Networks and Spatial Economics - This study proposes an analytical capacity constrained dynamic traffic assignment (DTA) model along with an efficient path-based algorithm. The model can be applied...     

Application of a ground source heat pump system with PCM‐embedded radiant wall heating for buildings

This paper deals with the utilization of a renewable energy‐based integrated system with the latent heat storage option for building thermal management systems. Both energy and exergy‐based assessments of the current combined system are conducted. For this purpose, phase change material (PCM)‐embedded radiant wall heating system using solar heating and ground source heat pump (GSHP) is studied thermodynamically. Heat is essentially stored within the PCMs as used in the panels to increase the effectiveness. The stored heat is released when the solar energy is not available. In the thermal energy storage analyses, four different PCMs are considered. The present results show that the overall first ‐ law (energy) and second ‐ law (exergy) efficiencies of the PCM‐free radiant heating system are much lower than the case with the PCM‐embedded radiant heating system. Therefore, it is confirmed that the energy efficiency increases from 62% to 87% while the exergy efficiency rises from 14% to 56% with the option where SP26E PCM is employed accordingly.     

Three dimensional modelling of non-local ductile damage: element technology

This paper presents an engineering scale numerical analysis framework of ductile damage and focusses on the three dimensional element technology required for it. A three dimensional low-order tetrahedral element is developed which is free from locking and efficient from the calculation time point of view. The element is tested using a well known benchmark problem and the results show that the new element performs better compared to the standard element.     

Hydrogen production via supercritical water gasification of almond shell over algal and agricultural hydrochars as catalysts

Almond shell is one of the most abundant agricultural wastes in Kurdistan province of Iran. Conversion of almond shell into hydrogen-rich gas via supercritical water gasification (SCWG) was investigated in this study using a tubular batch micro-reactor system. Non-catalytic tests were carried out in different conditions to determine the optimum condition for H₂ production. Maximum hydrogen yield of 7.85 mmol/g, was observed in the temperature of 460 °C, residence time (RT) of 10 min and feed/water ratio (F/W) of 0.01. Catalytic experiments were performed using hydrochars as solid residues remained after SCWG of Cladophora glomerata (C. glomerata) macroalgae and wheat straw. Hydrochars were characterized by ICP-OES, FESEM and BET methods. For catalytic experiments, hydrochars were added to the almond shell by the weight ratio of 0.4. Conversion of almond shell and hydrogen production, were more influenced by the presence of inorganic compounds in the hydrochars rather than the surface area and pore volume. The maximum hydrogen yields of 10.77 and 11.63 mmol/g, were observed for catalytic experiments in the presence of wheat straw and C. glomerata hydrochars, respectively.     

Application of Seismic Attribute Technique to estimate the 3D model of Hydraulic Flow Units: A case study of a gas field in Iran

One of the most important steps in evaluation and development of hydrocarbon reservoirs is the mapping of their characteristics. Nowadays, Seismic Attribute Technique is used to build parameters of hydrocarbon reservoirs in inter-well spaces. One of these parameters is the Flow Zone Index (FZI) that has a significant effect on different stages of evaluation, completion, primary and secondary production, reservoir modeling and reservoir management. The aim of this study is to introduce an equation using seismic attribute and FZI log in wells and then generalize it to predict FZI throughout the reservoir. For this purpose, acoustic impedance (AI) volume as an external attribute was created while internal attributes were computed from seismic data. After that, The best set of attributes was determined using stepwise regression after which seismic attributes were applied to multi-attribute analysis to predict FZI. Then, the attribute map resulted from multi-attribute analysis was used to interpret the spatial distribution of the gas bearing carbonate layers. Finally, the optimum number of Hydraulic Flow Units (HFU) was determined by analyzing the break point in the plot of cumulative frequency of FZI for wells and was generalized all over the reservoir by using the 3D HFU model. The results demonstrated that multi-attribute analysis was a striking technique for HFU estimation in hydrocarbon reservoirs that reduces cost and increases rate of success in hydrocarbon exploration. Distribution of producible hydrocarbon zones along with the seismic lines around the reservoir was characterized by studying this model which can help us in choosing the location of new wells and more economical drilling operations.     

Exergoeconomic analysis and multi objective optimization of a solar based integrated energy system for hydrogen production

In the current study, an integrated renewable based energy system consisting of a solar flat plate collector is employed to generate electricity while providing cooling load and hydrogen. A parametric study is carried out in order to determine the main design parameters and their effects on the objective functions of the system. The outlet temperature of generator, inlet temperature to organic Rankine cycle turbine, solar irradiation intensity $\left(I\right)$, collector mass flow rate $\left({\dot{m}}_{col}\right)$ and flat plate collector area $\left(A_P\right)$ are considered as five decision variables. The results of parametric study show that the variation of collector mass flow rate between 3 kg/s and 8 kg/s has different effects on exergy efficiency and total cost rate of the system. In addition, the result shows that increment of inlet temperature to the ORC evaporator has a negative effect on cooling capacity of the system. It can lead to a decrease the cooling capacity from 44.29 kW to 22.6 kW, while the electricity generation and hydrogen production rate of the system increase. Therefore, a multi objective optimization is performed in order to introduce the optimal design conditions based on an evolutionary genetic algorithm. Optimization results show that exergy efficiency of the system can be enhanced from 1.72% to 3.2% and simultaneously the cost of the system can increase from 19.59 $/h to 22.28 $/h in optimal states.