The optimization of the cogeneration systems (CGS) with the gas engine generator is studied by using the Hamiltonian algorithm (HA). The HA, invented from the study on dynamical systems, is efficient to optimize to design and control the complex systems. The results show that the HA enable us to design the optimal CGS under the objective function about the investment of the plants and the equipment. The HA is also found to be effective to control the optimal CGS operations.
The optimal supervisory control strategy for a central chilled water facility has been determined. A quadratic linear regression relation for the total system power in terms of the controlled and uncontrolled variables was developed using simulated data. The supply air, chilled water, and condenser water temperatures that minimize energy consumption are determined as functions of load, ambient wet bulb temperature, and sensible heat ratio. The use of the quadratic expression to ine optimal control is demonstrated.
A reduction in the emissions arising from urban activities demands a combination of energy efficiency measures and a move away from fossil fuel sources. Progress may be enabled by the use of advanced materials and control systems and the adoption, where possible, of renewable energy conversion technologies. A major challenge is the incorporation of such systems in a manner which preserves the architectural heritage of the district. This paper describes the modelling approach used when assessing the renewable energy systems to be deployed within a demonstration project in Glasgow, UK.
Simulation of visual context in architecture, the environment that surrounds both building and observer, is an essential but problematic feature of realistic imagery. The complexity and detail of typical environments pose serious difficulties for computer modelling and photomontage techniques. The results are often simplistic, potentially misleading and incapable of representing many of the physical and perceptual relationships involved. This paper describes an alternative methodology using imagery for the whole optic array at a specific location.
In order to evaluate the air conditioning system performance in terms of control, comfort and energy conservation, this paper presents an approach to modeling automatic control process in a typical conditioned space of an office building. As air- conditioning system, constant volume single-duct system is adopted for interior zone and FCU system for perimeter zone. As for simulation model, we adopted dynamic calculation model expanded by state transition method [1].
In order to evaluate energy efficiency of solar hot water systems, a calculation method was developed in this paper that models the unsteady flow and temperature distribution in heat storage tank utilizing Computational Fluid Dynamics (CFD). Compared to actual measurements, adequate calculated results were obtained that agree during both heat storage and supplying hot water. These calculation results can not be easily replicated in actual measurements. Applying these results to a block model that reduces the time required for calculation will be the subject of future study.
The Simulation Problem Analysis and Research Kernel (SPARK) uses graph-theoretic techniques to match equations to variables and build computational graphs, yielding solution sequences indicated by needed data flow. Additionally, the problem graph is decomposed into strongly connected components, thus reducing the size of simultaneous equation sets, and small cut sets are determined, thereby reducing the number of iteration variables needed to solve each equation set.
This paper describes a method to calculate cool and warm exergies stored by building envelopes and the result of a case study in terms of passive cooling strategy using the building envelope heat capacity. The concept of exergy enables us to show explicitly the cooling potential of a substance that is colder than its ambient. We call the cooling potential “cool exergy” and the heating potential “warm exergy”. The value of either cool or warm exergy is positive without exception.
In this paper a new method called TSM was presented to analyze wind effect on high-density building areas. With TSM, a software named WEATHER is developed based on STACH-3. The wind effect on a simple building is simulated to validate STACH-3 for outdoor airflow. The wind effect to a real zone with 9 buildings is analyzed with WEATHER. It shows that TSM is an effective method to deal with high-density building areas. It takes an acceptable CPU time to get convergence.
The purpose of this study is to show explicitly a series of exergy input, output, and consumption for daylighting, electric-lighting, and space heating/cooling system and hence to reveal how daylighting system consumes solar exergy and how electric-lighting, and heating, and cooling systems consume exergy originally contained by fossil fuel. The merit of exergy calculation is that we can explicitly and thoroughly show how different types of energy are used as a series of exergy consumption at different parts of a system.
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