Wideband mixer exploiting  and  compensation technique

Abstract. Under certain conditions, a HVAC system may consume less energy, provided that the initial response to the increasing heat gains is the increase in the airflow, while cooling is delayed. This ensures that the energy for cooling and reheat is reduced, while the fan power increases. Note that it is difficult to develop the following approach in the standard sequential control algorithms. On the other hand, the use of more complex algorithms than standard sequential algorithms is generally not encouraged because of the increase in the complexity of the control system and its resistance to respond to the varying parameters of a HVAC system. In this work, therefore, to avoid the following complications, the Intake Power Optimization algorithm is proposed. The Intake Power optimization algorithm is compared to the two sequential algorithms: Air conditioning and Airflow priority. To create the reference point enabling comparisons of the three strategies, the optimal control was established using the Nelder-Mead method. It is shown that the Intake power optimization algorithm provides a better control than the sequential algorithms and almost exclusively performs the optimal control actions. As an aside, the results indicate that the same heat gains, however, evenly distributed between rooms may contribute to the significant reduction of the energy demand.

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“…The fan power PF is calculated using Eq. (2). The thermal power of each air treatment process in the air handling unit is calculated using Eq.…”

Section: E = P · Tmentioning

confidence: 99%

“…The setpoint is usually selected, based on the peak-load, even though the majority of operation is under lower loads [2]. For this reason, all algorithms (Air conditioning priority, Airflow priority and Intake power optimization) have the duct static pressure reset.…”

Section: Control Algorithmsmentioning

confidence: 99%

Intake power measurement as a criterion for control of HVAC systems

2017

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“…-[ * ] Corresponding author, fxchen_qjy@hotmail.com Broadly speaking, there are various methods to remove the excess heat from PEMFC and keep the its temperature as desired; for example, liquid cooling [12,13], air cooling [14,15], edge-cooling [16], phase change cooling [17], combined oxidant and coolant flow [18], and natural convection cooling [19]. Among these thermal management methods, water cooling of higher heat transfer coefficient is most widely used in high power PEMFC systems, especially for a power output of 80 kW or higher [20].…”

Section: Introductionmentioning

confidence: 99%

Temperature Control for Proton Exchange Membrane Fuel Cell based on Current Constraint with Consideration of Limited Cooling Capacity

Chen

Gao

2017

Fuel Cells

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Temperature is one of the key factors to ensure reliable and efficient performance of proton exchange membrane fuel cells. Whereas, due to the limited cooling capacity in automotive application, conventional strategies may fail to remove the excessive heat when the cooling actuator saturates. Hence, three temperature control strategies based on current constraint are developed in this study. Firstly, a dynamic thermal model based on energy conservation is presented. Then a duty ratio split control strategy is proposed to calculate the reduced current from the excess of duty ratio of radiator, yet spike behavior occurs. Hence, a current governor control strategy and a constrained model predictive control strategy are derived to trade off the power demand and cooling capacity, where the maximum load current is calculated by current governor in real time and optimized under the physical constraints of duty ratio and current change rate, respectively. The performances of all the strategies are demonstrated. The current governor control strategy is easy to implement with less computational burden. The constrained model predictive control strategy has fast response and can take into account various constraints explicitly. Both of them have satisfying control performances regardless of limited cooling capacity.

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“…It has been reported that a three-component aza-Wittig reaction was used to synthesize quinolinone [10], thienopyrimidinone [11], triazolopyrimidinone [12], which have good biological activities. However, the attempt to obtain a series of chromenopyrimidione by this mean has not been reported.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Novel 2‐Aryloxy‐3‐(4‐chlorophenyl)‐8‐substituted‐5‐aryl‐8,9‐dihydro‐3H‐chromeno[2,3‐d]pyrimidine‐4,6(5H,7H)‐dione Derivatives

Wang

Chen

Wang

et al. 2014

Journal of Heterocyclic Chem

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in Wiley Online Library (wileyonlinelibrary.com).Twenty-one novel 2-aryloxy-3-(4-chlorophenyl)-8-substituted-5-aryl-8,9-dihydro-3H-chromeno[2,3-d] pyrimidine-4,6(5H,7H)-diones 5a-5u were designed and easily synthesized via a tandem aza-Wittig reaction. Treatment of iminophosphorane 3 with 4-chlorophenyl iso-cyanate gave carbodiimide 4, which reacted with phenols to provide the title compounds in 50-73% isolated yields. All compounds 3 and 5 were confirmed by infrared, 1 H-NMR, mass spectra, and elemental analysis, and compound 5a was further analyzed by single-crystal X-ray diffraction, and the title compounds were synthesized with the purpose of bringing in some new chemical and biological interests.

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Wideband mixer exploiting and compensation technique

Cited by 11 publications

References 7 publications

Intake power measurement as a criterion for control of HVAC systems

Intake power measurement as a criterion for control of HVAC systems

Temperature Control for Proton Exchange Membrane Fuel Cell based on Current Constraint with Consideration of Limited Cooling Capacity

Synthesis of Novel 2‐Aryloxy‐3‐(4‐chlorophenyl)‐8‐substituted‐5‐aryl‐8,9‐dihydro‐3H‐chromeno[2,3‐d]pyrimidine‐4,6(5H,7H)‐dione Derivatives

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