Optimal Design of Renewable Energy Systems in Low/Zero Energy Buildings

Low energy building and zero energy building have attracted increasing attention in both academic and professional fields following the ambitions of many governments in reducing building energy consumption and carbon emission. This paper presents an investigation on the optimal design of renewable energy systems in two types of buildings: Low Energy Buildings and Zero Energy Buildings. The first zero energy building in Hong Kong, namely Hong Kong Zero Carbon Building (ZCB), is taken as a reference building in this study. The TRNSYS building model is used to generate the annual cooling load profile of the building. Simplified models are developed to simulate the building energy systems including the air-conditioning systems and the renewable energy systems in Matlab while the building annual cooling load profile is taken as the input. GA (Genetic Algorithm) method and NSGA-? (Non-dominated Sorting Genetic Algorithm) approach are implemented for single objective optimization and multi-objectives optimization respectively in Matlab. Three most important design parameters, i.e., sizes of PV, wind turbine and bio-diesel generator, are chosen as the variables to be optimized. Three objectives (total cost, CO2 emission and grid stress factor) are adopted in the multi-objective optimization. They also form the objective function in the case of single objective optimization. The performances of buildings with different combinations of renewable system sizes are compared and evaluated. The effects of the two types of buildings on the design decisions of renewable energy system sizes are studied and compared. Furthermore, the uses of single objective and multi-objective optimization methods and their advantages/disadvantages in system optimization applications are discussed

Quantifying the Influence of Component Failure Probability on Cascading Blackout Risk

The risk of cascading blackouts greatly relies on failure probabilities of individual components in power grids. To quantify how component failure probabilities (CFP) influences blackout risk (BR), this paper proposes a sample-induced semi-analytic approach to characterize the relationship between CFP and BR. To this end, we first give a generic component failure probability function (CoFPF) to describe CFP with varying parameters or forms. Then the exact relationship between BR and CoFPFs is built on the abstract Markov-sequence model of cascading outages. Leveraging a set of samples generated by blackout simulations, we further establish a sample-induced semi-analytic mapping between the unbiased estimation of BR and CoFPFs. Finally, we derive an efficient algorithm that can directly calculate the unbiased estimation of BR when the CoFPFs change. Since no additional simulations are required, the algorithm is computationally scalable and efficient. Numerical experiments well confirm the theory and the algorithm

Control strategies for variable speed pumps in super high-rise building

The article discusses the proposed alternative control strategy to test and simulate chilled water pumps energy in the building. The chilled water pipelines and terminal units are associated with condenser water pump and primary chilled water pump to transfer the cooling energy from low zones to high zones to avoid high water static pressure. Moreover, the original control strategy generates 12.02% to 16.01% of energy to heat exchangers and improve control strategy in practical applications. Two control strategies for variable speed pumps were tested in a super high-rise building in Hong Kong. (1) The 1,608 ft (490 m) high building has a floor area of 3.4 million [ft.sup.2] (321 000 [m.sup.2]). The basement is four floors, a block building is six floors and a tower building is 98 floors

Ayuda, Inc. v. Thornburgh: Did Congress Give the Executive Branch Free Rein to Define the Scope of Legislation

The Note argues that the Ayuda decision is inconsistent with the congressional intent behind IRCA and prior case law. The Note further argues that the purposes underlying IRCA will best be served by prompt judicial resolution of policy disputes about legalization