Plan Drawings With Solar Exposure

By analysing the impact of the sun on a site, besides every bit the building�s location, the spatial system, orientation, window placement, daylight access and other blueprint features, the designer can take total advantage of passive solar design features and increase the free energy efficiency, condolement and fiscal value of the building.

On this page:

• assessing a site for lord's day
• Lord's day paths
• distance and azimuth
• solar radiation
• building material durability
• shade
• sites with limited solar access
• sunlight adds dollar value to a house
• locating information.

Assessing a site for sun

When assessing a site for lord's day, consider:

• the time during the 24-hour interval that the site receives sunlight
• the dominicus'due south path at different times of the mean solar day and year
• how the site�s shape, slope and orientation affect solar access
• how obstructions such as adjacent buildings, trees and landforms will touch on the site and the potential blueprint
• the owners' lifestyle � for instance, when they want to have sun or shade.

Ideally a site should have excellent solar access for almost of the day and be of a shape/size to permit a home to be congenital with the living areas facing northward, requiring minimal purchased energy for space heating. By dissimilarity, a house on a site that sees little sun, or where living areas cannot face northward, will typically require college amounts of purchased energy, and therefore have a bigger carbon footprint.

Sun paths

Assessing the passage of sun across a site is important. In that location are a number of locally-produced tools that tin can help, but a site visit is still necessary to identify site-specific conditions such every bit the impact of a large tree.

Dominicus path diagrams provide a broader overview of sunday on a site as they map the path of the dominicus across the sky at dissimilar times during the day throughout the year. They can assist establish the position of the lord's day relative to a site and can exist used to determine the outcome of shadows bandage by buildings, trees and landforms on and effectually the site.

NIWA�due south online tool SolarView tin provide data quickly and accurately. However, it only accounts for geographic (state) features. Foliage and fences may likewise need to be considered. Be enlightened that if the site is shaded for more than than forty% of the time compared to a clear site, then this has significant implications for the thermal performance of the house.

SketchUp�s shading feature can also assistance with establishing shadow length.

Altitude and azimuth

The position of the sunday with respect to an observer is normally represented by two angles � distance and azimuth.

Altitude is the angle of the sun�southward rays compared with the horizon. At sunrise and sunset, the altitude is null, and in the southern hemisphere, the maximum altitude of the sun at any specific location occurs at solar noon on 21/22 December (longest days of the year).

Azimuth (sometimes known equally bearing) is the direction of the sun equally shown on a compass. Dominicus bearings at sunrise and sunset at dissimilar New Zealand latitudes are available from Land Information NZ�s astronomical information.

Solar radiation

Solar or ultraviolet (UV) radiation is the energy from the sun. The amount of solar radiation available on a site depends on the latitude and the sunlight hours received.

Information nearly UV levels can be obtained from NIWA�s UV Atlas which provides information about UV levels around New Zealand since 1960.

BRANZ also has a photovoltaic generation calculator that indicates the boilerplate yearly electricity generation capability of a PV arrangement at a given location.

Building textile durability

UV radiations affects the durability of many materials. Colours fade, plastic-based materials may become breakable, timber moves and twists, and expansion and wrinkle from heating and cooling places stress on many materials, so the effect of UV radiation over a edifice�s lifetime must be considered.

Materials such as paint on the n or west side of a building may not last as long every bit those on the due south side because the north and west sides receive much more UV calorie-free. BRANZ found that for a exam building in Wellington, the daily average UVA irradiation on the north wall was approximately half-dozen times higher than that on the south wall.

Select materials with a higher UV index number (when available) as they are more than resistant to UV degradation (such as fading).

Shade

Shade is frequently required in the summer, simply in near parts of the country, winter sunday is desirable. Obstructions on a site may block sunlight access at times when information technology is required.

When considering sunlight and edifice design, appraise the impact of obstructions in the future equally well as the present. For example, a modest tree on an side by side site may abound into a big ane that blocks sun, a building may be erected on a currently vacant site or an existing building may exist demolished and replaced by a larger 1.

Alternatively, existing trees may be retained for summer shade.

Sites with limited solar admission

South and east-facing, sloping sites have limited solar admission. It is difficult to utilise effective passive solar design features on these sites, and they should generally exist avoided. Where it is not possible to avoid or the site is an otherwise desirable one (east.g. if it has excellent views), conscientious consideration of design including building location (e.one thousand. locate every bit high as possible on the site), orientation and employ of skylights/clerestories can maximise the benefits of solar access.

Sunlight adds dollar value to a house

A New Zealand study by Motu Economic and Public Policy Research Trust, Valuing Sunshine, looked at the value buyers place on the amount of sunshine houses receive. They found that each additional hour of direct sunlight exposure for a house per twenty-four hours, averaged across the yr, added two.4% to its market value.

Locating information

The National Plant of Water and Atmospheric Enquiry (NIWA) provides climate station data for its thirty climate stations throughout New Zealand, including information about sunshine hours and hateful temperatures.

Aerial photographs tin can provide information about the buildings and vegetation on adjacent sites and may provide some limited information near the impact of sun on a site. This will depend on the age of the photo equally in older photos, trees may have grown. Aeriform images can be obtained from local councils, Google World and Terranet.

Sun touch information is likewise available:

• by carrying out an on-site survey to establish levels of adjacent buildings and site features.
• obtaining plans of neighbouring buildings from local councils.

Updated: 11 March 2021

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Source: https://www.level.org.nz/site-analysis/sun/

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