Cooling Load Of Building Research Articles

SOMBRERO: A PC-tool to calculate shadows on arbitrarily oriented surfaces

Shaded areas of windows, solar thermal collectors or photovoltaic modules are of major importance for the calculation of solar heating- and cooling-loads of buildings as well as for the determination of thermal or electrical output of corresponding solar equipment. SOMBRERO, a PC-program written in Turbo-Pascal, calculates the GSC (geometrical shading coefficient), the proportion of shaded area of an arbitrarily oriented surface surrounded by shading elements as a function of time and location. Shading elements are treated as polygons (not necessarily rectangles) located in a plane and can be combined to bodies such as buildings or trees. They may also represent overhangs and side-wings of the building under consideration. Elements which are far away from the receiver area are treated as horizontal shading profiles. The reduction of (isotropic) diffuse radiation caused by different kinds of obstacles is calculated by means of view-factors. Calculated results of the GSC are stored in ASCII-format and can be used as an input for dynamic solar system simulation programs. This is demonstrated in two illustrative examples showing the coupling of SOMBRERO with SUNCODE and TRNSYS in order to calculate the effects of shading on passive solar heating and passive cooling, respectively.

The Potential of Vegetation in Reducing Summer Cooling Loads in Residential Buildings

The potential of trees and other vegetation to reduce building cooling loads has been recorded in a number of studies but the meso- and microclimate changes producing such savings are not well understood. This paper describes a preliminary attempt to model the effects of landscaping on temperature, humidity, windspeed and solar gain in urban climates using information from existing agricultural and meteorological studies, with particular attention placed on quantifying the effects of plant evapotranspiration. The climate model is then used in conjunction with the DOE-2.1C building simulation program to calculate the net reductions in air-conditioning requirements due to trees and other vegetation. Preliminary results show that an additional 25% increase in the urban tree cover can save 40% of the annual cooling energy use of an average house in Sacramento, and 25% in Phoenix and Lake Charles. If this additional tree cover is located to optimize summer shading, the savings are further increased to more dun 50% in Sacramento and 33% in the other two cities. The calculated savings are minimal for Los Angeles because the base case cooling energy use is small (65 hours) on the assumption that window venting is used whenever possible in lieu of mechanical cooling. There are additional benefits in lowering peak power consumption, where the savings are as much as 34% in Sacramento, 18% in Phoenix, 22% in Lake Charles, and 44% in Los Angeles. Parametric analysis reveals that most of the savings can be attributed to the effects of increased plant evapotranspiration, and only 10% to 30% to shading. The energy penalties of reduced windspeeds are found to be small in all four locations. The preliminary results suggest that while the conservation benefits of planting trees are appreciable at the individual house level, equally dramatic savings can be realized at the urban level through modifications of the urban climate by increasing the total amount of vegetative cover. Such a conservation strategy may be elective in counteracting the summer heat island evident in cities and may improve ambient conditions as well as reduce summertime air-conditioning requirements.

Geomathematics, Mathematical Background and Geoscience Applications. F. P. Agterberg

Previous articleNext article No AccessReviewsGeomathematics, Mathematical Background and Geoscience Applications. F. P. Agterberg Felix ChayesFelix Chayes Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The Journal of Geology Volume 83, Number 5Sep., 1975 Article DOIhttps://doi.org/10.1086/628152 Views: 1Total views on this site Citations: 1Citations are reported from Crossref Copyright 1975 University of ChicagoPDF download Crossref reports the following articles citing this article:L. Goliatt, P. V. Z. Capriles, G. R. Duarte Modeling Heating and Cooling Loads in Buildings Using Gaussian Processes, (Jul 2018): 1–6.https://doi.org/10.1109/CEC.2018.8477767