In this research for the aim of optimizing the gas consumption, increasing the thermal efficiency of a Household gas water heater has been investigated numerically. The optimal design and configuration of the baffles in the middle tube of the gas water heater prevents the quick exit of the exhaust gases and consequently increases the retention time of the hot gases inside the middle tube and reduces the wasting of their thermal energy. The combustion process in the gas water heater is a chain process and completing this process occurs along its path in the middle tube. Therefore for obtaining the maximum thermal efficiency, the numerical analysis of the combustion process and designing and configuration of the baffles inside the middle tube have been carried out and conducted simultaneously. The Ansys Fluent computational fluid dynamics code has been employed for the computational simulation of the combustion of the gas, the heat transfer from the contents of the middle tube into the water tank and distribution of the velocity of the exhaust gases along their path inside the middle tube and around the baffles. Computational simulation of the problem under investigation has been carried out by considering different geometries and configurations of the baffles along the path of the exhaust gases. Numerical results show that the mass fraction of the methane gas and the carbon dioxide in the exhaust gases is negligible and consequently all of the methane gas has been consumed. The numerical results have been verified by the experimental results.

Canadian researchers are now trying to exploit much more energy from solar sources, hydropower, wind, and biomass. Given the fact that reducing the carbon pollutant level is a political priority in Canada, this paper studies the feasibility of providing sanitary hot water and space heating demands of a four-member family in 10 provinces in this country. The feasibility analysis was performed by T*SOL Pro 5. 5 software, and radiation data were obtained by MeteoSyn software. Results indicated that the most suitable station in terms of using solar water heater was Regina, which supplied 35 % of the total heat load for space heating and sanitary hot water purposes. This accounted for 5074 kWh of heat for space heating (25 % of demand) and 3112 kWh energy for sanitary hot water (94 % of demand) using a 40 m2 solar collector. In addition, results are indicative of an annual amount of saving up to 2080 kg of CO2 in the Regina station and an annual reduction of 984 m3 in natural gas for this station. In conclusion, Canada has a potentially alluring market to utilize solar water heaters for providing sanitary hot water for the residential sector.

Influence of a vent hood at the exit of exhaust flue gas and flue baffles in the fire tube on the temperature and flow fields of a gas tank water heater, as well as the structure and amount of heat transferred to the water tank has been studied numerically using two-dimensional steady state finite element simulation. Observations show that without a vent hood, there is a downward gas flow in the flue and a strong vortex in the lower burner chamber. Using a vent hood prevents the gas back flow into the flue, and placing the flue baffles increases the heat delivered to the water.

According to the iran’s economic situation. Single-product economy, the high dependence to oil revenue, the ends of oil and gas resources and the need to exchange, iran needs to become Industrial countries especially because of the the suitable markets in the Middle East and Central Asia to attract Iran's gas production. In these Thesis we study the economic evaluation of smart gas heater, by Comfar software, and we reach net present value (NPV) 15 and 20% at rates equivalent to 1.486 million toman and 822 million toman Rate of return on investment= 31.65% (IRR) .The Findings in these Thesis show that the producting of these good has high economic justification, and it can attract investor.To conclude, by producting these good we can prevent to send out the exchange, we can reach Self-sufficiency increase GDP and create jobs and reduce mortality that died with gas.

Domestic immersion heaters used for heating cold water are characterized by an electrical resistance heating element, which is encased in a tube and directly placed in it. The most common method for heating cold water is the use of portable immersion rod water heater in an open bucket operating in operator control without a controller unit (thermostat). This paper performs an experimental evaluation of portable modifed conventional buckets of 10 l capacity. Out of ten portable modifed storages, the best three cases are discussed: non-insulated Open Plastic Bucket (OPB), non-insulated plastic bucket top surface covered with a transparent cover (CPB), and insulated plastic bucket closed with a transparent cover (ICPB). Maximum temperatures arising after two hours during OPB, CPB, and ICPB are 29. 82%, 47. 36%, and 21. 49%, respectively, compared to the initial temperatures (22. 8 C). At 14: 45 hour, CPB temperature reaches 35. 6 C, which is 17. 88% and 23. 61% higher than OPB and ICPB units. Due to the application of solar energy in CPB at 35{50 C, net saving increased by 12. 34%, 25. 76%, 40. 73%, 57. 93%, 76. 45%, and 97. 18% from 2017 to 2022 as compared to the saving in 2016.

The efficiency of a Household thermostat solar water heater model with two flat panel collectors and a double-glazed storage tank of 200 liters capacity was investigated experimentally. water and glycol (antifreeze) are used as operating fluid in the water heater to be transformed into thermosyphon with free movement and increase the temperature of consumed water. water is not discharged during the test period. Flow temperatures of collector input and output, city water temperature, water temperatures at different points in the reservoir and ambient temperature for sunny days in the autumn in Tehran. Measurement and flow rate of the thermosyphon, thermal energy of the water consumed and total water efficiency The aforementioned heater has been calculated and the corresponding graphs are given over time. The results show that the highest water temperature is 60 °C on sunny days and 50 °C on cloudy days. The overall efficiency of the thermostat solar thermal heater will be around 45درصد during the month of November 1396. The highest photovoltaic panel efficiency in the sunny days is 13.5% in the autumn and 11.6% in the cloudy days, which is due to the decrease in efficiency compared to the ideal conditions. The surface temperature of the panel is high.

In the present work, a double-pass solar air-water heater has been designed for the first time to provide both hot air and hot water for using in many engineering applications. The proposed solar collector can be a useful device for the purpose of heating spaces and providing domestic hot water, simultaneously. It is like a conventional solar air heater but five water tubes are installed under the absorber plate with a large common surface area with the heated surface. The two-dimensional numerical simulation with the assumption of quasi-steady condition was done on a rectangular-shaped collector with a length of 1 m and a height of 0.128 m including five water tubes by solving the continuity, momentum, and energy equations for the turbulent airflow by the COMSOL Multi-physics. The effect of forced convection water flow inside the parallel tubes installed below the absorber plate is employed as a convection boundary condition in solving the air energy equation. Also, the convection boundary condition was employed on the boundary surfaces of the glass cover and insulation layer adjacent to the surroundings. Numerical simulations are carried out for the air and water mass flow rates of 0.01 kg/s and 0.03 kg/s, respectively. While the solar heat flux lies in the range of 5001100 W/m2. In several test cases, high thermal efficiencies (69% to 74%) are computed for the proposed collector, whose value is much higher than a smooth duct solar air heater operating under the same condition. A comparison is also made between the performances of double-pass and single-pass solar air-water heaters and a percentage of efficiency increase about 6% was found. This value reached to 75% when this solar collector is compared with a conventional solar air heater.

In common natural gas pressure reducing stations, gas heaters and throttle valves are used for pre-heating and pressure reducing. The gas heaters are used to prevent the hydrate formation after the station because of temperature reduction. In this work, in addition to study the existence of gas heaters in common stations, four substitute methods are presented and together with the commonly used method are simulated for 5 hot-climate cities in Fars province, i. e., Darab, Lar, Lamerd, Mohr and Farashband. These four methods are comprised of: 1-Use of an expansion turbine in place for the throttle valve, 2-Use of an expansion turbine for pressure reduction and an electric heater instead of the gas-burning heater, 3-Use of a vortex tube for the throttle valve, 4-Use of an evaporation-condensation cycle instead for the gas-burning heater. Heating loads and gas consumption for the commonly used method and suggestive methods are compared. Furthermore, the work gained through the use of the expansion turbine was calculated and reported. The expansion turbine and vortex tube need most and least heating loads and gas consumptions for preheating, respectively. The expansioncondensation cycle need lower heating load because of its higher efficiency in comparison of the direct gasburning heater.

heaters are one of the central parts of natural gas reduction stations using turboexpanders to prevent the formation of hydrate and corrosion failure. This study intends to design a fired heater by applying a combustion sub-model to derive an optimal model for this kind of application. This model is developed to accurately consider all subsections of the fired heater namely radiation, convection, and shield sections, as well as flue gas composition, and its volume. Within this context, a multi-objective optimization is employed to identify the optimal design of the gas-fired heater in the natural gas reduction station for the Ramin power plant case study. The total economic and environmental costs, together with modified exergy efficiency, are selected as objective functions. Multi-criteria-decision-making-method is employed on Pareto frontiers optimal curve to suggest the optimal solution. Results show that the developed model can outperform previous models in thermal efficiency with relatively similar costs. Besides, the optimal point in Pareto suggested by the decision-making-method accounts for a higher modified exergy efficiency (1.3%) than the counterpart, which thermal efficiency is regarded as an objective function. At the same time, its total cost remained almost constant. The effects of changes in each of the design parameters on the objective functions are also evaluated.