IBPSA1989

A new computer program has been written for comparing the annual energy and economic performances of different window systems in non-residential buildings. The program, called CSHADE, performs a sideby-side hourly energy performance simulation of a test window system compared to a reference one. A comprehensive report is printed out at the completion of each simulation. The program is much simpler and easier to use than large building simulation programs such as DOE-2 or BLAST, and has relatively more modest computer requirements.

Today energy saving rates due to retrofits in residential housing are either measured by experiment on site or predicted by system simulation. In the latter case mathematical models of the components are developed, verified by laboratory tests and combined to represent the thermal characteristics of the investigated system. Then energy demand is calculated before and after adopting the investigated retrofit. There still remains the question, are energy savings precalculated by system simulation: obtained in fact, in other words do they agree with results of field experiments.

Experimental studies during the 1940S concluded that heat loss from slab-on-grade floors is proportional to floor perimeter length. More recent numerical investigations, however, indicate that area and shape are also important parameters. Furthermore, results of three-dimensional modelling differ significantly from those of supposedly equivalent two dimensional analysis. Earth-coupled heat transfer processes are increasingly important contributors to building energy consumption, but continue to be poorly understood by most designers.

This paper describes results from a larger project [1] which investigated the sizing of Thermal EnergyStorage (TES) systems used as part of the cooling system in buildings. The study was based on DOE-2simulations; daily integrated cooling coil energy requirements for office and retail buildings in theChicago, Fort Worth, and Miami climates were examined in relation to climate and operational parameters.

COMBINE is a file utility program developed by Jeff Hirsch of Lawrence Berkeley Laboratories for use with the DOE2.1C building energy simulation program. COMBINE merges the data arrays that are passed from the SYSTEMS simulation subprogram to the PLANTS simulation subprogram in DOE2.1C. To date, it has not received extensive publicity but it is a program that expands the applications and power of DOE2.1C and it deserves recognition as one of the most practical building energy simulation innovations of the past several years.

This paper describes a recently developed, multi-chromatic lighting simulation model, known by the acronym DIM (Digital Illumination Model). DIM accepts a description of a zones geometry, surface finishes, contents and natural and artificial light sources. A multi-chromatic raytracking scheme is then employed to obtain the surface spectral luminance distribution corresponding to each light source. Outputs from the model include data on planar illuminance and coloured perspective images.

Over the past 5 years, Dubin-Bloome Associates (DBA) and Ross & Baruzzini, Inc. (R&B) have jointly been working on a project to determine the relationship of the air conditioning load caused by building lighting with time. Our effort has been funded by the Electric Power Research Institute. An initial literature search determined that the basis of existing calculation methods was data generated by Mitalas in the 1950's for a very limited set of experiments.

The present American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE) standard 62-1981 "Ventilation for Acceptable Indoor Air Quality" is being revised. The recommended ventilation rate will be increased four-fold from 2.5 I/s/person to 10.0 I/s/person. The immediate response to this proposal is that the energy consumption and costs will parallel this increase and rise dramatically. It is the intent of this paper to provide a better understanding of the actual effect of the changes to the ASHRAE standard.

The task is for COMIS to develop a reliable and well running multizone infiltration model on a modular base. This model does not only take crack flow into account, but also covers flow through large openings, single sided ventilation, cross ventilation and HVAC-systems. The model contains a large number of modules, which are peripheral to a steering program. COMIS can be used as a basis for future expansions in order to increase the capabilities of simulating buildings or their type of construction, in the field of ventilation, heat flow and spread of pollutants.