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Saving energy in greenhouses is an important issue for growers. Here, we present a method to minimize the total energy that is required to heat and cool a greenhouse. Using this method, the grower can define bounds for temperature, humidity, CO2 concentration, and the maximum amount of CO2 available. Given these settings, optimal control techniques can be used to minimize energy input. To do this, an existing greenhouse climate model for temperature and humidity was expanded to include a CO2 balance. Heating, cooling, the amount of natural ventilation, and the injection of industrial CO2 were used as control variables.Standard optimization settings were defined in order to compare the grower's strategy with the optimal solution. This optimization resulted in a theoretical 47% reduction in heating, 15% reduction in cooling, and 10% reduction in CO2 injection for the year 2012. The optimal control does not need to maintain a minimum pipe temperature, in contrast to current practice. When the minimum pipe temperature strategy of the grower was implemented, heating and CO2 were reduced by 28% and 10% respectively.We also analyzed the effect of different bounds on optimal energy input. We found that as more freedom is given to the climate variables, the higher the potential energy savings. However, in practice the grower is in charge of defining the bounds. Thus, the potential energy savings critically depend on the choice of these bounds. This effect was analyzed by varying the bounds. However, because the effect can be demonstrated to the grower, the outcome has value to the grower with respect to decision making, an option that is not currently available in practice today.

Saving energy in greenhouses is an important issue for growers. Here, we present a method to minimize the total energy that is required to heat and cool a greenhouse. Using this method, the grower can define bounds for temperature, humidity, CO2 concentration, and the maximum amount of CO2 available. Given these settings, optimal control techniques can be used to minimize energy input. To do this, an existing greenhouse climate model for temperature and humidity was expanded to include a CO2 balance. Heating, cooling, the amount of natural ventilation, and the injection of industrial CO2 were used as control variables.Standard optimization settings were defined in order to compare the grower's strategy with the optimal solution. This optimization resulted in a theoretical 47% reduction in heating, 15% reduction in cooling, and 10% reduction in CO2 injection for the year 2012. The optimal control does not need to maintain a minimum pipe temperature, in contrast to current practice. When the minimum pipe temperature strategy of the grower was implemented, heating and CO2 were reduced by 28% and 10% respectively.We also analyzed the effect of different bounds on optimal energy input. We found that as more freedom is given to the climate variables, the higher the potential energy savings. However, in practice the grower is in charge of defining the bounds. Thus, the potential energy savings critically depend on the choice of these bounds. This effect was analyzed by varying the bounds. However, because the effect can be demonstrated to the grower, the outcome has value to the grower with respect to decision making, an option that is not currently available in practice today.

<div class="section abstract"><div class="htmlview paragraph">The introduction of new light-duty vehicle emission limits to comply under real driving conditions (RDE) is pushing the diesel engine manufacturers to identify and improve the technologies and strategies for further emission reduction. The latest technology advancements on the after-treatment systems have permitted to achieve very low emission conformity factors over the RDE, and therefore, the biggest challenge of the diesel engine development is maintaining its competitiveness in the trade-off “CO₂-system cost” in comparison to other propulsion systems. In this regard, diesel engines can continue to play an important role, in the short-medium term, to enable cost-effective compliance of CO₂-fleet emission targets, either in conventional or hybrid propulsion systems configuration. This is especially true for large-size cars, SUVs and light commercial vehicles.</div><div class="htmlview paragraph">In this framework, a comprehensive approach covering the whole powertrain is of primary importance in order to simultaneously meet the performance, efficiency, noise and emission targets, and therefore, further development of the combustion system design and injection system represent important levers for additional improvements. For this purpose, a dedicated 0.5 dm³ single-cylinder engine has been developed and equipped with, a state-of-the-art Euro 6 combustion system, and an advanced common rail fuel injection system (FIS) offering higher flexibility in terms of injection strategy and higher quantity accuracy. Three injector nozzles with different hydraulic flow rates (HF) have been selected and employed for the overall combustion process optimization.</div><div class="htmlview paragraph">The optimization has been performed by means of an extensive DoE-based test campaign in which the engine and FIS operating parameters have been parametrized with the aim to carry out a proper combination in terms of HF and injection strategy. The results at partial load conditions evidence significant advantages in applying an advanced injection pattern, while the HF reduction can significantly improve the smoke emission and combustion noise without fuel consumption penalties. Therefore, a proper combination and optimization of the HF and injection strategy can provide low noise and engine-out smoke while maintaining the rated power performance targets.</div></div>

<div class="section abstract"><div class="htmlview paragraph">The introduction of new light-duty vehicle emission limits to comply under real driving conditions (RDE) is pushing the diesel engine manufacturers to identify and improve the technologies and strategies for further emission reduction. The latest technology advancements on the after-treatment systems have permitted to achieve very low emission conformity factors over the RDE, and therefore, the biggest challenge of the diesel engine development is maintaining its competitiveness in the trade-off “CO₂-system cost” in comparison to other propulsion systems. In this regard, diesel engines can continue to play an important role, in the short-medium term, to enable cost-effective compliance of CO₂-fleet emission targets, either in conventional or hybrid propulsion systems configuration. This is especially true for large-size cars, SUVs and light commercial vehicles.</div><div class="htmlview paragraph">In this framework, a comprehensive approach covering the whole powertrain is of primary importance in order to simultaneously meet the performance, efficiency, noise and emission targets, and therefore, further development of the combustion system design and injection system represent important levers for additional improvements. For this purpose, a dedicated 0.5 dm³ single-cylinder engine has been developed and equipped with, a state-of-the-art Euro 6 combustion system, and an advanced common rail fuel injection system (FIS) offering higher flexibility in terms of injection strategy and higher quantity accuracy. Three injector nozzles with different hydraulic flow rates (HF) have been selected and employed for the overall combustion process optimization.</div><div class="htmlview paragraph">The optimization has been performed by means of an extensive DoE-based test campaign in which the engine and FIS operating parameters have been parametrized with the aim to carry out a proper combination in terms of HF and injection strategy. The results at partial load conditions evidence significant advantages in applying an advanced injection pattern, while the HF reduction can significantly improve the smoke emission and combustion noise without fuel consumption penalties. Therefore, a proper combination and optimization of the HF and injection strategy can provide low noise and engine-out smoke while maintaining the rated power performance targets.</div></div>

The aim of the paper is to study the influence of the power transformer on signal transmission in the case of a power line communication (PLC) system in a overhead Medium Voltage (MV) power network. A model of the PLC system was carried out by means of the Simulink® software. A distributed parameter MV overhead line, two power transformers, the signal coupling interface of a ST7540 FSK powerline transceiver were included in the model. The performances of the complete PLC communication system are evaluated for different line lengths by means of the attenuation computed as ratio between the received and transmitted voltage signals. © 2011 IEEE.

The aim of the paper is to study the influence of the power transformer on signal transmission in the case of a power line communication (PLC) system in a overhead Medium Voltage (MV) power network. A model of the PLC system was carried out by means of the Simulink® software. A distributed parameter MV overhead line, two power transformers, the signal coupling interface of a ST7540 FSK powerline transceiver were included in the model. The performances of the complete PLC communication system are evaluated for different line lengths by means of the attenuation computed as ratio between the received and transmitted voltage signals. © 2011 IEEE.