A review and analysis of control techniques in HVAC systems

Heating Ventilating and Air Conditioning (HVAC) systems are the core energy-absorbing equipment in buildings. Building HVAC system with effective control technique can greatly reduce energy consumption. The high demand for HVAC system Placing in buildings, using an effective control technique to decrease the energy absorbing of the equipment while meeting the thermal comfort demands in buildings are the most important goals of control designers. The different control methods for HVAC systems. This paper defines control techniques used in HVAC systems, MATLAB/simulation design and implementation of controller’s technique with the transfer function for the HVAC system. Keywords-HVAC, PID controller, MPC Controller, Adaptive Controller, Fuzzy Controller

Incentive Stackelberg Mean-payoff Games

We introduce and study incentive equilibria for multi-player meanpayoff games. Incentive equilibria generalise well-studied solution concepts such as Nash equilibria and leader equilibria (also known as Stackelberg equilibria). Recall that a strategy profile is a Nash equilibrium if no player can improve his payoff by changing his strategy unilaterally. In the setting of incentive and leader equilibria, there is a distinguished player called the leader who can assign strategies to all other players, referred to as her followers. A strategy profile is a leader strategy profile if no player, except for the leader, can improve his payoff by changing his strategy unilaterally, and a leader equilibrium is a leader strategy profile with a maximal return for the leader. In the proposed case of incentive equilibria, the leader can additionally influence the behaviour of her followers by transferring parts of her payoff to her followers. The ability to incentivise her followers provides the leader with more freedom in selecting strategy profiles, and we show that this can indeed improve the payoff for the leader in such games. The key fundamental result of the paper is the existence of incentive equilibria in mean-payoff games. We further show that the decision problem related to constructing incentive equilibria is NP-complete. On a positive note, we show that, when the number of players is fixed, the complexity of the problem falls in the same class as two-player mean-payoff games. We also present an implementation of the proposed algorithms, and discuss experimental results that demonstrate the feasibility of the analysis of medium sized games.Comment: 15 pages, references, appendix, 5 figure

Thermal Management Of Electronics Experiencing Large Power Dissipation Transients.

Recent developments with micro-porous surfaces have led to the introduction of very high heat flux boiling surfaces. For example, Wirtz and coworkers have introduced a structured porous surface that achieves in excess of 1.5MW/m2 in saturated pool boiling of water at 0.2atm (Tsat = 60°C); and, this increases to 2.1MW/m2 at 1.0atm (Tsat = 100°C). In this case, onset of nucleate boiling (ONB) occurs at approximately 2K superheat, and the high heat flux noted occurs at 9K superheat, so the boiling curve slope is very high, approximately 0.3MW/m2 per Kelvin superheat. This suggests that a viable thermal management approach to systems that experience large transient heat loading would be to design the heat sink so that the heat sink-to-coolant heat transfer surface would “ride” its boiling curve. At baseline power dissipation levels, boiling would occur at near ONB; and, the heat transfer surface would climb the (very steep) boiling curve as the power dissipation level rises, so that there would be only a moderate electronics temperature excursion. Vented (constant pressure), sealed and hybrid immersion cooled electronics systems are considered. A thermal response model, based on boiling curves having differing ONB and CHF points (boiling curve slopes) and boiling correlation calculates the thermal response of the system. Response time constants and maximum temperature excursions are correlated with boiling curve characteristics, and system geometric and thermo physical properties. We have obtained the temperature response with respect to time were obtained with different system parameters and have been compared with each other

Topology and Size Optimization of Composite Ply Cargo Door

Structural optimization has seen accelerated deployment throughout all industries in the past decade, largely due to the recognition that tremendous efficiency gain can be achieved at concept design stage through topology optimization. For composite laminate design a three-phase optimization process is used. The target of the first phase is the material distribution in terms of orientation and thickness. This is achieved through topology optimization where thickness of each 'super-ply' of a unique fiber direction is allowed to change freely throughout the structure. As a result thickness contour of each fiber orientation is obtained. A discrete interpretation of the thickness contour results in concept design of ply layout and thickness. Then in Phase-II the interpreted ply-based structural model is further optimized under all design constraints with discrete design variables representing the number of plies of each ply patch. During Phase-III, ply stacking optimization is performed to refine the design according to detailed manufacturing constraints. All manufacturing constraints are considered throughout all three optimization phases. Such requirement would translate into percentage requirement during Phase-I and II so that a balanced distribution of fiber orientation is achieved to allow feasible stacking during Phase-III. The three-phase optimization process is illustrated in this paper. A unique modeling technique developed in conjunction with the optimization process is the ply-based finite element analysis model where ply entities are defined as sets of elements. Then ply layup is specified by a stack definition. In the following sections the procedure is demonstrated for one of the preliminary configurations developed for the composite cargo door