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This study presents the thermal analysis of a solar flat plate water heater working under real operating conditions in a hot sub-humid region, in the city of Merida, Yucatan, Mexico. This water heater was evaluated under thermosyphon conditions and, with the use of a submersible pump, under forced flow conditions. In both cases the thermal performance of the collector was studied in order to determine the impact of flow on the working temperature and efficiency of the collector. A comparison of the temperature values registered for both thermosyphon and forced flow regimes showed that there were significant reductions both in the temperature registered at the outlet of the collector, and in the temperature differential between the inlet and the outlet of the collector. Moreover, greater efficiency values were found when the water heater was working under forced flow. These results suggest that the use of a submersible pump in a solar flat plate water heater could be an efficient way to control the maximum working temperature in a solar collector in the region, while also providing a positive effect on the daily efficiency.

This volume contains the proceedings of the SUMO Conference 2017 which was held from 8th to 10th May 2017 with a focus on autonomous mobility. In the current transition process traffic simulation is the only tool which can give us insights in the mechanisms of traffic in largely automatized traffic scenarios. SUMO as an open source tool provides a wide range of traffic planning and simulation functionalities to support the scientific community. The conference proceedings offer an overview of the applicability of the SUMO tool suite as well as its universal extensibility due to the availability of the source code. The major topic of this fifth edition of the SUMO conference is the calibration of simulation to real world or handbook data as well as communicating networks of intelligent vehicles. A number of contributions cover heterogeneous traffic networks, junction control and new traffic model extensions to the simulation. Subsequent specialized issues such as emission modelling and personal rapid transit simulation are targeted as well. At the conference the international user community exchanged their experiences in using SUMO. With this volume we provide an insight to these experiences as inspiration for further projects with the SUMO suite.

The introduction of hybrid electric vehicle (HEV) technology in the private car fleet of Mexico City is evaluated in terms of private costs, energy, public health and CO2 emission benefits. In addition to constructing plausible scenarios for urban expansion, emission, car fleet, and fuel consumption for year 2026 and comparing them with a 2004 base case, a time series is built to obtain accumulated economic benefits. Experimental techniques were used to build a vehicle library for a car simulator that included a Prius 2002, chosen as the HEV technology representative for this work. The simulator is used to estimate the emissions and fuel consumption of the car fleet scenarios. In the context of an urban scenario for year 2026, a complex air quality model obtains the concentrations of criterion pollutants corresponding to these scenarios. Using a technology penetration model, the hybridized fleet starts unfolding in year 2009 reaching to 20% in 2026. In this year, the hybridized fleet resulted in reductions of about 10% of CO2 emissions, and yielded reductions in daytime mean concentrations of up to 7% in ozone and 3.4% in PM2.5 compared to the 2004 base case. These reductions are concentrated in the densely populated areas of Mexico City. By building a time series of costs and benefits it is shown that, depending on fuel prices and using a 5% return rate, positive accumulated benefits (CO2 benefits + energy benefits + public health benefits − private costs) will start generating in year 2015 reaching between 2.8 and 4.5 billion US Dlls in 2026. Another modernized private fleet consisting exclusively of Tier I and II cars did not yield appreciable results, signaling that a change in private car technology towards HEV's is needed to obtain significant accumulated benefits.

Compound parabolic concentrators are relevant systems used in solar thermal technology. With adequate tailoring, they can be used as an efficient and low-cost alternative in residential water heating applications. This work presents a simulation study using a ray tracing analysis. With this technique, we simulate the interaction between solar rays and solar concentrator to quantify the amount of energy that impinges on the receiver at a particular time. Energy availability is evaluated in a comparison of two configurations throughout the year: static setup at 21° and multi-position setup; tilted with respect to the horizontal, depending on three seasonal positions: 0° for summer, 16° for spring/autumn, and 32° for winter, with the aim to evaluate the amount of available energy in each season. The fact that a tracking system can be dispensed with also represents an economical option for the proposed application. The results showed that at 21°, the proposed solar Compound Parabolic Concentrator (CPC) works satisfactorily; however, by carrying out the selected angular adjustments, the overall energy availability increased by 22%, resulting in a more efficient option. The most effective design was also built and analyzed outdoors. The obtained thermal efficiency was of ~43%. The optical design and its evaluation developed herein proved to be a valuable tool for prototype design and performance evaluation.

A methodology for estimating vehicular emissions comprising a car simulator, a basic traffic model, and a geographical information system is capable of estimating vehicle emissions with high time and space resolution. Because of the extent of the work conducted, this article comprises two sections: In Part 1 of this work, we describe the system and its components and use examples for testing it. In Part 2 we will study in more detail the emissions of the sample fleet using the system and will make comparisons with another emission model. The experimental data for the car simulator is obtained using on-board measuring equipment and laboratory Fourier transform IR (FTIR) measurements with a dynamometer following typical driving cycles. The car simulator uses this data to generate emission factors every second. These emission factors, together with information on car activity and velocity profiles of highways and residential and arterial roads in Mexico City in conjunction with a basic traffic model, provide emissions per second of a sample fleet. A geographical information system is used to localize these road emissions.

Currently, there is limited information regarding the performance of solar heaters in a round-year period under real weather conditions and the determination of their characteristic equation following standard methods. Therefore, this study presents a methodology to determine the characteristic equation of the annual thermal performance under real conditions based on uncertainty and linear regression analysis estimation. With this methodology, it is possible to analyze daily experimental data in a collector that has not been restricted to any particular requirement of evaluation standards. This methodology was applied to evaluate a flat plate solar heater operating in Mexico over a period of one year in two operating modes: thermosyphon and forced circulation. In the case of forced circulation, a small submersible pump was implemented, the activation of which was controlled by using a thermostat, thereby providing an effective control of the flow and temperature of the collector. The results indicated tha...