IBPSA1999

The LESCOM program using the Response Factor Method developed by the authors was applied to the direct gain system and calculation of fluctuations in room temperature. Regarding the solar water collector, the efficiency straight line was obtained from the measured values. The one-dimensional thermal stratification was applied to the water storage tank. It was discovered from the measured values that relations between the amount of solar radiation on the solar cells and the amount of power generation in photovoltaic power generation could be formulated in the linear equation.

The operation of technical building devices demands a lot of heating, cooling and electric energy. This also causes monetary costs and pollutant emission as well. Optimization investigations are very useful to make the running of plants more efficient. This paper shows two optimization methods. Some practical applications clearly demonstrate the profits of an optimized operation of  technical building installation.

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.