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Faulty operations of Heating, Ventilation and Air Conditioning (HVAC) chiller systems can lead to discomfort for the users, energy wastage, system unreliability and shorter equipment life. Faults need to be early diagnosed to prevent further deterioration of the system behaviour and energy losses. Since it is not a common practice to collect historical data regarding unforeseen phenomena and abnormal...
In this paper, Artificial Neural Networks (ANNs) are used to achieve cooling load forecasting in HVAC (Heating, Ventilating, and Air Conditioning) systems. Load forecasting is crucial in plant configurations making use of thermal storage technologies, where, during the nighttime, part or most of the energy required during daytime is produced at lower cost by cooling or icing water. Load forecasting...
In HVAC plants of medium-high cooling capacity, multiple chiller systems are often employed. The performance of the system is evaluated in terms of user comfort, energy use, and financial costs. In this paper a two-layer control structure is proposed for control and optimization of a multiple chiller system. Set points and operating modes for cooling plant equipment can be set by the supervisor to...
In this paper, we report some results of a research project aimed at deriving simple, high-performance, adaptive and robust control algorithms for evaporator control by means of EEV (Electronic Expansion Valve). Control design is performed by resorting to a detailed, virtual prototyping environment described in. The proposed control scheme has two nested loops. The inner loop consists of the process...
In HVAC plants of medium-high cooling capacity, multiple-chiller systems are often employed. In such systems, chillers are independent of each other to provide standby capacity, operational flexibility, and less disruption maintenance. However, the problem of efficiently managing multiple-chiller systems is complex in many respects. In particular, the electrical energy consumption in the chiller plant...
In this paper we report some results of a research project aimed at deriving high-performance, adaptive control algorithms for electronic expansion valves (EEVs) to be used in finned-coiled, dry-expansion evaporators for refrigeration systems. The approach we use in the design is that of virtual prototyping, with the aim of developing a software environment that can be used for controller design,...
In this paper we address the problem of designing advanced control systems for increasing the performances of one of the key elements of an HVAC system, the chiller unit. In particular, we present a simulation environment based on Matlab/Simulink that has been validated on a state-of-the-art experimental facility and used to design an adaptive controller for single scroll compressor, packaged air-cooled...
There is no need to stress the importance of telecommunication industry in the global economy. Web hotel applications pose a peculiar problem for compensating very high thermal power inside rather restricted spaces. Distinctive features of this refrigerating installations are high evaporation temperature and high flow rate of cooling air, whereas latent heat load is absent. The typical system used...
We report the photoluminescence (PL) properties of a new class of highly regioregular methoxy substituted polythiophenes which display good electroluminescence properties. The thermal dependence of the photoluminescence is studied in detail and compared to the differential scanning calorimetry analysis of polymers with different alkyl-side chain length. The thermochromism of the PL is discussed in...
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