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Determining the Actual Power Output of Photovoltaic (PV) Panels For Green Homes

PV solar panels mounted to a pitched metal roof of a straw bale house. The “real world” output of a PV module can be much lower than what is stated by the manufacturer. Photovoltaic panels generate clean power by converting sunlight into electricity. This article will talk about the actual—verses the rated—power output of photovoltaic panels. Do not assume that a PV panel rated at 170 watts of power will actually give you that amount. It will probably be closer to 150 watts per panel. Because of the difference, care must be used when sizing the system for your electrical needs. Otherwise, you may find that you are generating less power than you need. Designing a photovoltaic system for your green home starts with using energy efficient appliances and lighting inside the house. My rule of thumb is that it is cheaper to buy a new EnergyStar-rated refrigerator for under $1,000 than to spend an extra $2,000 on photovoltaic (PV) panels to power an old, inefficient refrigerator. The same goes for other appliances—particularly those that get a lot of daily use such as televisions. The photovoltaic system for my small straw bale home (featured on the BuildingWithAwareness.com website and DVD video) cost around $12,000 in equipment. Without carefully choosing the most efficient appliances and lighting, the cost would have been dramatically higher.

Looking At Design, Part 2: Aesthetics and Form As A Part Of Green Building

The Zen garden at the Ryoan-ji in Kyoto, Japan. Photo Thomas Guignard This Japanese structure is very simple, yet very elegent in its simplicity. Even without the details of windows and doors, there is a warmth to the building. The earth plaster walls have aged to a watercolor-like patina. The patterns come from mud that was mixed with rapeseed oil (a vegetable oil more commonly known as canola oil). Materials such as this are in beautiful contrast to the monolithic look of stucco or paint in that they create harmonious variations in color and texture. The design principles used in this structure can be incorporated into home design. They are not hard rules, but something that can be drawn upon to add visual interest. By being able to evaluate what works and what does not work in a particular design, it will be easier to make the changes that are required to fix the problem. The owner/builder should be very involved in the structure’s design, instead of just turning it over to a “professional”. This goes for both green building design principles (for overall energy efficiency) and the aesthetic design. Being aware in all of the various design options is what I call ‘building with awareness” (hence the title of my book and DVD). For simplicity, I will break the visual design of of a building into two parts. First, there is the overall physical form which is the shape of the building. The second part would be the color, texture, and surface…

How To Mount Photovoltaic (PV) Solar Panels To A Corrugated Metal Roof

mounting pv solar panels to pitched metal roof

This article will show how to attach commercially available solar panel mounting brackets to a corrugated metal roof that lacked flat surfaces. In the photo above, a ladder was used to slide the PV panels to the roof. Photovoltaic (PV) panels produce all of the electricity for this straw bale hybrid home from sunlight. All of the PV panels are permanently attached to the south facing pitched roof. Standing-seam metal roofs are partially flat, so mounting a rack is not a problem. The roof on my house is corrugated metal and therefore has no flat surfaces for the aluminum mounting brackets to seat. A stout connection is essential for the photovoltaic panels to survive high wind loads and to create a waterproof seal where the bolts penetrate the roof surface. What we needed was a mounting platform that both comformed to the convolutions of the metal roof and also had a flat surface for the foot bracket to contact. Here is how we solved the problem.

Product Review: ShurFlo Diaphragm Pump For A Rainwater Cistern

Product Tested: ShurFlo Deluxe 24 volt DC model 2088-474-144 on-demand diaphragm pump, 3 gallons per minute output, with built-in 45psi pressure demand switch. Suggested retail price: $172.00 Ideally, a water pump for a rainwater cistern will use very little electricity, be durable and rugged, and be as maintenance free as possible. The model being reviewed was in daily use for 8 years in a small straw bale house. Water from the cistern delivers naturally soft water to the washing machine, the toilet, and a hose bib. A 24 volt model was chosen so that it could run directly off a 24 volt photovoltaic (PV) electrical system for this off-the-grid green home. Although the PV system included a 120 volt AC inverter, it was desired to have the pump run off the DC side as this would guarantee that the pump would have power even if the inverter was not operational. The DC pump would also be more energy efficient as some efficiency is lost by the inverter. This same pump model is also available in 24 volt and 120 volt configurations. The advantage of a rubber diaphragm pump is that they are very immune to damage from grit and debris in the water. This is important as water is collected off the roof with only a simple sand filter.

Shaping Nature Into Our Own Vision

The terraced gardens at the Chateau de Gourdon in France The balance between what we make, and what nature makes, is a play of contrasts. Hitting a balance is the goal. The dramatic mountain setting is set apart from the terrace with a segmented stone wall. The formality of the garden is in total contrast to the surroundings. Taking the vegetation to a level of whimsey makes it all work. Having fun is part of the process. photo: Pierre Metivier

Creating A Place Within The Space

Do you want a hole in the wall for a window, or a place within the room to relax? Literally and figuratively, this decision is an opportunity for adding depth to your living space. Straw bale walls are thick, something that would be prohibitively expensive to achieve with most other building materials. Thick walls have the capacity to create spaces that are both separate from, and part of, the larger room. This window space is not in a straw bale house, although the effect would be the same. Iford Manor was the home of English architect and garden designer Harold Peto (1854-1933). This window has become a place within the larger room, defined by its own walls, floor, and ceiling. The depth of the side walls reflect a soft warm glow deep within the room—something that does not happen with a typical 6-inch-thick wood frame wall. Honey-colored walls, which are probably a lime plaster, have a subtlety of hues and values that wall paint can only dream of. It is the window detailing itself that truly makes the space. The woodwork continues the plane and boundary of the room, thus making a soft divide between the inside and outside. Solid glass alone would be harsh as the interior would just fall into a bright void. The dappled pattern softens the contrast ratio between the indoors and outdoors while still permitting a view. The opening is divided both vertically and horizontally, and those spaces are further subdivided into circular patterns of light and dark.…

Natural Building In Harmony With Nature

The simplicity of stepping stones across a pond in a Japanese garden. By observing the natural form of the world around us, and combining it with the human-envisioned form of our creativity, we get what I would consider the essence of natural building and green design. It is knowing when to throw the level and steel tape to the side and create strictly from our intuition. It is taking inspiration from nature while inserting a more formalized pattern upon it. This balance, when done with care, is what makes something beautiful. article by Ted Owens photo: Simon Bisson

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