While Calculating the Cooling Load, how to consider shading of other buildings on glass and skylight of the building you are working on ?

For shading effect of shades and over hang of same building please note that this option is present in HAP to give the exact size and dimensions of shade and by the hap orientation it will detect the shading effect during load calculations.

Regarding the shades by tress and other shurbs as per the experts experience and my senior design engineers say it will cause maximum 20% reduction of load and it totally depends on the orientation and shade cause by the trees. If they are ever green tress than we can reduce the expose wall to 15% based on the shadow cause by the tree. These things can be best finalized by visiting the site.

The shadow caused by the other tall buildings if applicable can be checked throughout the day if there is no sun light direct on the small building or its exposed wall than it can be considered as a partition wall with outdoor temperature difference and if it has shadow sometime and no shadow other time then it is better to ignore that shadow

All the above means it is a specific scenario and should be handled as per the exact actual conditions and engineer's own judgement

Hope this will work

The usual shading effect that i know is the internal and external shading for windows as indicated HAP.

considering shading of adjacent building is not familiar to me

after search i found the next data:

2013 ASHRAE Handbook—Fundamentals (SI) F-18

DATA ASSEMBLY

Configuration.

Determine building location, orientation, and external shading from building plans and specifications. Shading from adjacent buildings can be determined from a site plan or by visiting the proposed site, but its probable permanence should be carefully evaluated before it is included in the calculation. The possibility

of abnormally high ground-reflected solar radiation (e.g., from adjacent water, sand, or parking lots) or solar load from adjacent reflective buildings should not be overlooked.

EXTERIOR SHADING

Nonuniform exterior shading, caused by roof overhangs, side fins, or building projections, requires separate hourly calculations for the externally shaded and unshaded areas of the window in question, with the indoor shading SHGC still used to account for any internal shading devices. The areas, shaded and unshaded, depend on the location of the shadow line on a surface in the plane of the glass. Sun (1968) developed fundamental algorithms for analysis of shade patterns. McQuiston and Spitler (1992) provide graphical data to facilitate shadow line calculation. Equations for calculating shade angles [Chapter 15, Equations (34) to (37)] can be used to determine the shape and area of a moving shadow falling across a given window from external shading elements during the course of a design day. Thus, a subprofile of heat gain for that window can be created by separating its sunlit and

shaded areas for each hour.

 2013 ASHRAE Handbook—FENESTRATION (SI) F-15

SHADING AND FENESTRATION ATTACHMENTS

 Example 7.

A window facing 30° south of west (wall azimuth  = +60°) in a building at 33.65°N latitude, and 84.42°W longitude is 1841.5 mm wide and 6286.5 mm high. The depth of the horizontal projection is 2438 mm. At 3:00 PM on July 21, it is calculated that the hour angle H = 15  (13.27 – 12) = 19.03°; and the declination  = 20.60°.

The solar altitude  is calculated to be: sin  = cos(33.65) cos(20.60) cos(19.03) + sin(33.65) sin(20.60) so  = 68.7°

The solar azimuth  is cos  = [sin(68.68) sin(33.65) – sin(20.60)]/[cos(68.68) cos(33.65)] so  = 57.1°

Thus, the wall solar azimuth is  = 57.1 – 60 = –2.9°.

(a) Find the sunlit and shaded area of the window.

(b) Find the depth of the projections necessary to fully shade the window.

Solution:

(a) Using Equation (34), the width of the vertical projection shadow is

SW = 0 |tan(–2.9)| = 0 mm

Using Equation (33), the profile angle for the horizontal projection is

tan  = tan(68.7)/cos(2.9)

 = 68.7°

Using Equation (35), the height of the horizontal projection shadow is

SH = 96 tan(68.7) = 6255 mm

Using Equations (36) and (37), the sunlit and shaded areas of the window

are now

ASL = [1841.5 – (0 – 0)][6286.5 – (6255 – 0)]/106 = 0.058 m2

ASH = (1841.5  6286.5)/106 – 0.058 = 11.519 m2

(b) The shadow length necessary to fully shade the given window SH( fs)

and SW( fs) from the horizontal and vertical projection are given by (see

Figure 16)

SH( fs) = 6286.5 + 0 = 6286.5 mm

SW( fs) = 1841.5 + 0 = 1841.5 mm

Thus, using Equations (34) and (35),

PH( fs) = 6286.5 cot(68.7) = 2453.5 mm

For software-based or multiple calculations, McCluney (1990) describes an algorithm that can be used to calculate the unshaded fraction of a window equipped with overhangs, awnings, or side fins.

Proceedings: Building Simulation 2007

- 223 – EFFECTS OF TREES ON THE ROOM TEMPERATURE AND HEAT LOAD OF RESIDENTIAL BUILDING

Yoshiki Higuchi1 and Mitsuhiro Udagawa

Department of Architecture, Kogakuin University, Tokyo, Japan

In summer, the shady planting is expected for providing shadow on building envelope and reducing reflected solar radiation from the front yard. The heat load simulation program which can take into consideration the shadow effects caused by trees including the effect of the long wave radiation exchange is developed by the authors. The program used to examine the effects of trees on the room thermal environment as well as heating and cooling loads of a model house. In the simulation, two kinds of trees, evergreen broad-leaved tree and deciduous broad-leaved tree were assumed. The simulation results for several cases of tree arrangements around the house showed that the cooling load was reduced by 15% - 20%. While the difference in cooling load was small, the heating load increased by 26% and 8.5% in case of the evergreen broad-leaved tree and the deciduous broad-leaved tree, respectively.

REFERENCE

*Higuchi, Udagawa, Sato, Kimura: Calculation model of solar radiation and long wave radiation in for external environment - Study on heat load simulation considering thermal effects of external environment Part1, J. Archit. Plan. Environ. Eng., Architecture Institute of Japan (AIJ), No.544,9-15,Jun,2001 (in Japanese).

* Higuchi, Udagawa, Sato, Kimura: Study on effect of housing placement on annual space heating and cooling loads of the house - Study on heat load simulation considering thermal effects of external environment Part2, J.Environ. Eng., Architecture Institute of Japan (AIJ),No.612,31- 38,Feb,2007 (in Japanese).

* Asawa, Hoyano: Development of heat transmission simulation of building considering the effects of spatial form and material in outdoor space, J.Environ. Eng., Architecture Institute of Japan (AIJ), No.578,47-54,Apr,2004 (in Japanese).

* Hong Chen et al : Study on Robust Optimum Design Method for Pleasant Outdoor Environment(Part1) – Robust Optimum Design for Optimum Arrangement of Tree Using Genetic Algorithms(GAs), Summaries of technical papers of annual meeting Architecture Institute of Japan(AIJ), 647-648, Sep, 2000 (in Japanese).

that's all the data i found and i hope to make open discussion about that subject  

to be calculating the heat load in hap we usually neglect shading in order to be on safe side since the shading will cause drop in temperature and demand this is covered up by the vfd present in the pump feeding the fcu and ahu so in my opinion we can neglect this