English

A set of statistical regression equations was developed to predict relative heating and cooling loads of external zones of commercial buildings. The equations were derived from the coil loads predicted by several thousand DOE-2 simulations.

The topic of this paper is the use of low temperature air (40 F or 5 C) for room cooling. Cold air systems can offer energy and space savings relative to higher temperature cooling systems. As the supply temperature and flowrate are reduced, considerations such as adequate flowrate, jet dumping or separation, condensation on duct walls, and decreased relative humidity become increasingly important. Cold air jet separation from the ceiling can be a problem resulting in unacceptable thermal discomfort in the occupied zone.

In this paper, we develop a discrete approach to describe the transport of condensible vapors through a microporous substance. We consider only isothermal water migration under uniform atmospheric air pressure, at temperature lower than 100C with negligible gravity. The pore-structure which is supposed to be representative of the material is built on a 2D random network of tubes. The basic phenomena (adsorption/desorption, diffusion, condensation) that occur during the water vapor transport in a single cylindrical pore at the steady state are taken into account.

With the accelerating use of building performance prediction models in a design context, the need for comprehensive program accreditation procedures is becoming more pressing. This paper recognises the importance of the validation component of such a procedure and makes a case for containing much of the present knowledge about validation within an interactive facility centred on test cells.

A "detailed" model of a heat emitter in hot water circulation has been developed considering, two phases (liquid and metal), the non linear heat transfer and the enthalpy transport by the fluid. A reduced order state model ( order two or three) has been then formed, linearising the initial "detailed" model and using a model reduction technique developed in our laboratory which is especially based on modal analysis. The simulated results from both the models for a step input of the inlet temperature have been presented and discussed.

Currently, building energy analysis programs employ models of fluorescent lighting systems which are much oversimplified and potentially inaccurate. One important factor neglected by all whole-building programs is the variation of lamp power and light output with lamp wall temperature. This means that the lighting component of zone load and artificial lighting levels are both calculated incorrectly. Additionally, the latter implies that the predicted energy saving for systems that automatically reduce artificial lighting when daylight is available is also incorrect.

Over the past decade developments in the building simulation field have given rise to the prospect of a new generation of design tool which has the potential to allow rigorous hypothesis testing at the design stage. While powerful at their core, simulation based design tools suffer from several user interface limitations. This paper describes an attempt to solve some of these problems by developing an Intelligent Front End authoring environment for building performance appraisal in general.

The limited development potential of current building simulation programs has spurred the design of a new generation of tools: object oriented simulation environments, where the latest in software technology and numerical methods is employed to provide users with a framework for more flexible, and thereby more appropriate, simulation models. Some of these tools provide the sophisticated user with a rich graphical environment for interactive model design. We call these model-lab simulation environments.

The efficacy of dynamic thermal simulation tools in practice is dependent not only on the facilities offered by the tools and the rigour of the underlying calculations but also on the skills of the user vis-a-vis abstracting the essence of the problem into a model, choosing appropriate boundary conditions, setting up simulations and interpreting their results.

The application, design, and sizing of commercial water heating systems has been hampered by the lack of an accessible tool for evaluating long-term performance and operating energy costs. This lack of resources has limited the application of high-efficiency alternative water heating systems such as heat pump water heaters, refrigeration heat reclaim units or desuperheaters, and waste heat recovery systems. The Electric PowerResearch Institute and the Empire State Electric Energy Research Corporation have developed the HOTCALC microcomputer software to fill that need.