Definitions - p


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Parallel Strand Lumber

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Parallel Wiring

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Passive House

A Passive House is a house designed to use Passive Solar Design principals to drastically reduce its energy demands by making full use of the energy supplied by the Sun, this thereby reduces ecological footprint of the building.

This can include its orientation, window placement, Trombe Walls, ventilation, thermal mass and living space placement. It also include the adoption of standards on energy efficiency to further reduce energy demands.

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Passive Solar

Passive solar design refers to the use of the sun's energy for the heating and cooling of living spaces. With this approach, the building itself or some element of it takes advantage of natural energy characteristics in materials and air created by exposure to the sun.

Passive systems are simple, have few moving parts, and require minimal maintenance and require no mechanical systems. Often the thermal characteristics of materials are extensively used, often termed as Thermal Mass design.

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Passive Solar Design

Passive Solar Design is undergoing a resurgence as more people not only recognise the comfort benefits and lower energy bills of solar architecture, but now see a way of helping reduce the polluting effects of green house gases through less reliance on fossil fuels for heating and cooling.

Basic house design principles include:
  • Orientation of the main living areas towards the North (or South if in the Northern hemisphere)
  • Glazing used to trap the warmth of the Sun.
  • Thermal mass to store the heat from the Sun.
  • Insulation to reduce heat loss or heat gain.
  • Ventilation to capture cooling breezes.
A well designed solar home should remain within 18 degrees C to 28 degrees C throughout the year and save 60% to 70% in average household heating costs.

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Passive Solar Energy

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Passive Solar Heating

Passive solar heating is one of several design approaches collectively called passive solar design. When properly combined, these strategies contribute to the heating, cooling, and day lighting of nearly any building. The types of buildings that benefit from the application of passive solar heating range from houses to large office facilities.

Passive solar heating typically involves:
  • Solar energy collection through properly-oriented, south-facing windows.
  • Storage of this energy by "thermal mass," which are building materials with high heat capacity such as concrete slabs, brick walls, or tile floors.
  • Distribution of the stored solar energy back to the living space, as required, via the mechanisms of natural convection and radiation.
  • Window specifications to allow higher solar heat gain coefficient for Solar facing glazing.
Passive solar heating systems do not have a high initial cost or long-term payback periods, both common with many active solar heating systems. 

Another benefit to passive solar heating is increased comfort: if properly designed, passive solar buildings are bright and sunny and in tune with climate and nature. As a result, there are fewer fluctuations in temperature, resulting in a higher degree of temperature stability and thermal comfort.

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Passive Ventilation

Passive ventilation is a natural ventilation system that makes use of natural forces, such as wind and thermal buoyancy, to circulate fresh air to and from an indoor space. 

Such passive ventilation systems work to regulate the internal air temperature as well as bring fresh air in and send stale air out.

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Peak Sun Hours

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Perfluorooctanic Acid

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Persistent Pesticides

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Phantom Load

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Photochemical Smog

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Photovoltaic relates to the production of electric current at the junction of two substances exposed to light.

Must often used with photovoltaic cells, i.e. solar panels. Where the cells are connected together to make a solar panel.

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Physiographic Region

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Planned Obsolesence

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Plant Association

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Plate Tectonics

Geologic theory that the bending (folding) and breaking (faulting) of the solid surface of the earth results from the slow movement of large sections (plates) of that surface.

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Plug-in Hybrid

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Polar Air Mass

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Substance, especially man-made, that pollutes or contaminates an environment.

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Pollution Prevention

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Polybrominated Diphenyl Ethers

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Post Consumer Waste

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Postmodern Science

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Power Conversion Efficiency

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Power Pool

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Precambrian Rock

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Precautionary Approach

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Prescribed Burning

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Prevailing Wind

The wind direction most frequently observed during a given period.

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Price Preference

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Primary Consumer

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Primary Energy

Energy embodied in natural resources (e.g. coal, crude oil, sunlight, uranium) that has not undergone any anthropogenic conversions or transformations.

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Primary Sector

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Proxy Climate Indicators

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PV Module

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This is the process used to create biochar.

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Click on a letter to see all the terms and definitions that begin with that letter.

A free Android app containing all these definitions is now available, called the Green Dictionary. Click here to see the entry on the Android market; or click here if on an Android phone.