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Fuel cell based trigeneration plants, that utilize absorption chillers to convert waste heat into cooling energy, are a promising technology to satisfy heat, power, and cooling demand in warm climates. Polymer electrolyte membrane fuel cells, that operate at low temperature (< 100 • C), are the most technologically mature among the several types of fuel cells. Thermally activated cooling technologies are widely utilized in trigeneration plants to improve their efficiency. However, absorption chillers require relatively high grade thermal energy and their coupling with low temperature fuel cells is relatively untapped.Herein, we perform a techno-economic analysis of a trigeneration plant based on low temperature polymer electrolyte membrane fuel cells and half-effect absorption chillers. A thermo-chemical model is developed to estimate the performance of a cogeneration plant based on low temperature fuel cells and of the half-effect absorption chiller. The behavior of such combined heat, cooling, and power plant is also analyzed within real energy management scenarios, considering different energy demands, climatic conditions, energy costs, and plant layouts. The control strategy of the power plant is optimized through a graph-based methodology previously developed and validated by the authors. Total energy cost and CO 2 emissions are then compared to those of a reference scenario where electricity is acquired from the distribution grid, thermal energy is produced through a natural gas boiler, and a mechanical chiller is used for cooling.The results show that the utilization of half-effect absorption chillers boosts the environmental and economic benefits for all the considered scenarios. We also demonstrate that the utilization of the absorption chiller reduces the imbalance between the results obtained for the different scenarios (i.e. climates), although economic and environmental benefits associated to distributed generation are strongly influenced by the energy context.

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The energy crisis in Pakistan has crippled the country’s economy with an energy shortfall reaching up to 6000 MW. Fortunately, Pakistan lies close to the Sun Belt and therefore receives very high irradiation. To this end, in the beginning of 2014 the Pakistani government sanctioned a solar photovoltaic project namely Quaid-e-Azam Solar Park which was rated at 1000 MW. In this study, a cost benefit analysis for the Quaid-e-Azam Solar Park has been developed. The model uses RETScreen software. In fact, a literature review pointed out that most of the previous research work with reference to cost benefit analysis for solar projects has been mainly carried out on smaller power plants. The outcome of the study shows promising results with the simple payback period coming out at 5.6 years. Furthermore, this analysis can serve as guideline for future solar photovoltaic projects in Pakistan and can help in the development and utilization of the huge solar potential of the country, thus aiding in the reduction of energy shortage. In its proposal, our research is unique and innovative in the Pakistani context. The results aim to serve as a guideline for decision makers and researchers interested in this topic.

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One of the most important functions of air conditioning systems in operating rooms is to protect occupants against pathogenic agents transported by air. This protection is done by simultaneously controlling the air distribution, temperature, humidity, filtration and infiltration from other areas etc. Due to their low price, simple installation, operation and maintenance, window/wall air conditioning system have largely been used in operating rooms in Brazil, even if these types of equipment only recirculate the air inside the room without appropriate filtration and renovation with outdoor air. In this context, this work aims to analyse the performance of the window/wall air conditioning systems on indoor air ventilation in operating rooms by measuring particle number concentrations and carbon dioxide concentrations during different surgical procedures, in a single surgical room and in the nearby areas (corridor) for two cases: single surgery and two subsequent surgeries. In addition, the efficiency of the analysed air conditioning system was evaluated by comparing the ventilation level calculated in the surgical room with the ventilation required in order to maintain the carbon dioxide concentration within acceptable levels. The results showed that this type of air conditioning system is not appropriate for use in operating rooms since it cannot provide an adequate level of ventilation. The CO2 concentrations during surgeries, in fact, significantly exceeded acceptable values and a simultaneous increase in particle number concentration was observed. The results also showed that there is a high risk of contamination between subsequent surgeries in the same surgical room, due to residues of contaminants transported by the particles emitted during the surgeries that were not removed from the operating room by the air conditioning system. The particle number concentration measured in the second surgery, in fact, was approximately six times higher than in the first surgery.

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Several researches in the scientific, industrial and commercial fields are supporting the reduction of traditional combustion carsâ\u80\u99 use. The main purpose is to increase the quality of life into the metropolitan cities through the reduction of CO2 emissions and global warming. Accordingly, one of the most successful models is the carpooling system. Currently, people are investigating the sustainability and durability of carpooling business model from both economic and organizational point of view. The present research aims to develop a Multicriteria Decision Support System (MDSS) in order to offer a carpooling systemâ\u80\u99s platform based on different criteria. The MDSS is developed from driverâ\u80\u99s point of view and settled on two levels of optimization. Firstly, a genetic algorithm is proposed to solve an orienteering problem that optimizes the total revenue of driver based on the carâ\u80\u99s capability and the time schedule. Secondly, the best optimization solutions are compared with multicriteria analysis respect to other criteria not included in the first optimization. The outcome of MDSS is a schedule for drivers, which gives maximum satisfaction in terms of profitability, punctuality and comfort of the travel