All About Solar Cookers 2



How Solar Cookers Work

In 1764, French inventor Horace de Saussure produced temperatures of 225 degrees Fahrenheit in glass-covered boxes lined with black cork. Another Frenchman, Augustin Muchot, designed a solar cooker in the 1870’s that was used for many years by the French Foreign Legion.

These solar cookers operated on the same principles as cookers of today. An insulated box is covered with a clear window allowing access to light. The light rays are absorbed by the cooker’s inside surface and are transformed into heat energy. Heat radiates out from the surface and collects inside the cooker. Some of it escapes back through the window or “cracks” in the cooker, but not as quickly as additional light enters.

This process is similar to the greenhouse effect heard about so often in the news today. On a global scale, sunlight is absorbed by the earth and is transformed to heat. The heat radiates into the atmosphere. It either escapes or is reflected back toward earth by carbon dioxide and water vapor in the air. More carbon dioxide in the air means that heat is more likely to build-up around the planet.

Unlike the earth, solar cookers are deliberately designed to keep hot air inside. The cooking area is well insulated and the opening is often surrounded by rubber to seal it when the window is closed. 

These simple cookers also encompass a collector, storage and controls. The collector is a glass or heat-resistant plastic cover that lets sunlight inside. Storage occurs because insulation prevents heat from escaping. Storage is also provided by the food itself, which absorbs heat. 

Controls for a solar cooker are the reflectors. Reflectors help control the temperature by concentrating the sun’s rays onto the cooking area. Temperatures can also be adjusted by repositioning a solar cooker in relation to the sun. If lower temperatures are needed, the cooker can merely be pointed a bit away from the sun’s direct rays.


Next Article: All About Solar Cookers 3 - Costs: Cooking while reducing summer cooling bills

All About Solar Cookers 1



The delicious way to save energy and money

As many as 500 people gather each year for an annual potluck near Tucson. They eat vegetables, bread, pie and lasagna – typical foods at many such gatherings. This potluck, however, is vastly different from most because all the food, even the pizza, is cooked on-location by the sun

The group Citizens for Solar sponsors this cookoff each year to focus attention on one device: the solar cooker. These cookers use no electricity or natural gas, consume no firewood, and produce no smoke or pollutants. In the meantime, they gently cook almost any food to tasty, juicy perfection.

Some solar chefs setout their cookers in the morning and return in the evening to a well-cooked meal. Tiny “backpack” solar cookers have been provided Himalayan mountain climbers with hot food among the snowdrifts – it’s the amount of sunshine that counts, not the outside temperature.

To some people in developing nations, Solar cookers have become important to their very survival. Solar energy cooks food where firewood is scarce, and purifies water where bacteria and dangerous diseases are rampant. Solar cookers are used in Bolivia, Guatemala, South Africa, West Africa, Haiti, the Dominican Republic and many other developing countries. 

In Arizona’s abundant sunshine, solar cookers cook meals year-round without heating up the kitchen or the cook.


Next Article: All About Solar Cookers 2 - How Solar Cookers Work

What's cooking? A Comprehensive Look at Solar Cooking

WHAT'S COOKING - SLIDE 01 Cooking - the event that occurs every day in every home (except for fast food runs or special dinners out) and is taken totally for granted as a part of daily life. We cook breakfast, lunch and a dinner (unless you are on a cold salad kick). We outfit our kitchens with the latest in appliances, from microwaves to double convection oven, to stovetops with a multitude of tradable tops for grilling, broiling and deep frying.




Did you know that a kitchen is one of the primary rooms for remodeling - both for owner desire and investment?

WHAT'S COOKING - SLIDE 05Cooking shows fill public TV on Saturdays with Jaques and Julia and America's Test Kitchen, and store racks are full of monthly magazines like Good Housekeeping, Bon Appetit and Food & Wine and we take our love affair with cooking and the equipment it comes with to our backyards with bar-b-cues.

Cooking equipment, just like other types of equipment in the house, uses energy resources to operate and with energy use comes consumption of resources (oil and gas) and costs.


WHAT'S COOKING - SLIDE 11 In the summer, Arizonans know that cooking outdoors is "the thing to do" - men return to their primal selves, and women know that it keeps the heat out of the kitchen thereby keeping it comfortable (and an additional benefit is that it helps keep summer utility bills down). WHAT'S COOKING - SLIDE 12In Arizona, we are blessed with an abundance of sunshine. There is actually more energy in the sunlight that falls upon a house than the total energy that whole house uses over the course of a day. There it is - a resource untapped, underutilized, and available to anyone who wants it.

How about cooking? 





We know about cooking with the sun - you've all heard, and probably used, the phrase "it was so hot you could fry an egg on the sidewalk". There is a great history and record of solar cooking ranging from the Age of Inquiry to the present.

WHAT'S COOKING - SLIDE 19During the 18th Century, scientific investigation was in full bloom, looking at natural phenomena and developing an understanding regarding how and why things work. The understanding of natural phenomenon applied to technology was in the forefront of scientific and industrial activity and the utilization of created materials, like glass, was a source of creativity, invention and observation. 

WHAT'S COOKING - SLIDE 20There was great fascination with the sun - its composition, its relationship to the weather and cycles, and its impact upon plants, animals and people. Experiments abounded, from the development of magnifying lenses to the creation of highly polished specially shaped mirrors used to focus the sun's rays to melt metals and set distant objects on fire, to creating steam to run a printing press to the development of cooking devices using the sun.

WHAT'S COOKING - SLIDE 21In the late 1700's, experiments with glass and trapped solar heat by French-Swiss naturalist Horace deSaussure lay the foundation for not only solar cooking but also for passive solar heating of buildings and active heating of water by use of solar collector boxes. Le Journal de Paris received from deSaussure descriptions of experiments and observations.

WHAT'S COOKING - SLIDE 22"It is a known fact, and a fact that has been know for a long time, that a room, a carriage, or any other place, is hotter when the rays of the sun pass through glass"

WHAT'S COOKING - SLIDE 23At the time there was little empirical research regarding temperatures and glass covered heat traps, so in 1767 deSaussure executed a series of experiments to determine the nature of this phenomena by constructing a miniature greenhouse - a series of bottomless glass boxes, nesting within the other with air between, and all sitting on a black base. 

WHAT'S COOKING - SLIDE 24He then aimed it to the sun, and measured the temperature inside each concentric box. He discovered that the outermost box registered the lowest of t the temperatures (which was still higher than the outside air temperature) while the innermost box registered the highest at 185 degrees F.

WHAT'S COOKING - SLIDE 25With a little inventiveness, a lot of inquisitiveness, and further experimenting he observed that "fruits... exposed to this heat were cooked and became juicy, "

WHAT'S COOKING - SLIDE 26deSaussure continued his inquiries by insulating the "hot box" sides with black cork and leaving the glass top, which resulted in increased captured heat, and increasing internal temperatures.

WHAT'S COOKING - SLIDE 27He tried the apparatus in the plains and in the mountains, and found that while external temperatures were significantly different, the internal temperature of the box remained generally the same. This reinforced deSaussure's idea that while the same amount of solar energy struck the earth, both at the plains and the Alps, the cooler mountain conditions had more to do with qualities of the air and atmosphere, than a difference in solar radiation. Similar to many of today's modern cookers, deSaussure's unit allowed the sunlight to pass through the glass cover which was then captured as heat, within a sturdy, insulated box. The captured thermal energy heated the contents of the box - in this case, food which became cooked.

WHAT'S COOKING - SLIDE 28British astronomer Sir John Herschel, while in Africa, experimented with the "hot box", so called because of the heat it retained. Herschel was able to cook numerous kinds of food while in various African locations, much to the delight of his guests and colleagues, on who was Samuel Pierpoint Langley, who later became head of the Smithsonian Institute; the American astrophysicist who became intrigued with Herschel's demonstrations and joyfully built hot boxes of his own.

Frenchman Augustine Mouchot combined the "hot box" with the intriguing mirror experiments of the time. he developed an over - made of a tall blackened copper cylinder surrounded by a cylinder of glass, capturing a 1" airspace between the two. Then he used a solar mirror to reflect and concentrate the sun's energy onto the cooker. The solar mirror reflected sunlight onto the oven cylinder, heating the contents inside to such a rapid degree that the food was cooked in a very short time. Improvement of his "vertical oven" into a 20 x 20 inch box weighing less than 30 pounds that could bake a pound of bread in 45 minutes, and a stew in 3 hours, led to its use by the French Foreign Legion.

WHAT'S COOKING - SLIDE 32W. A. Adams, developed a solar cooking unit very similar to today's popular contemporary ovens. A glass fronted box mounted on a small tiltable platform, and using an eight sided mirror to focus the sun's energy to the center of the cooker, this design reached temperatures high enough to cook a four pound turkey within 4 hours.

The early 1900's saw scientists, and backyard tinkerers alike, developing designs that improved upon deSaussure's original "hot box", and that development continues to present day and Arizona has a very significant role in that development.

WHAT'S COOKING - SLIDE 33The First National Solar Cook-off in Phoenix, Arizona on September 19, 1981, sponsored by the Arizona Solar Energy Association was the first event of its kind in the world. held at the Phoenix Civic Center Plaza, it showcased designs from throughout the nation and worlds, from the largest to the smallest of cookers. The largest cooked 60 pounds of food at a tine; the smallest was used by backpackers in the Himalayas. 

Today the solar cooking tradition continues in grand style at Arizona's Annual Solar Potluck, an annual Tucson event put on by Citizens for Solar, a not for profit organization of solar cooking enthusiasts. Hundreds of people, cooking enthusiasts, and the curious alike, get together preparing and eating breads, vegetables, lasagna, chickens and meats and even pizza. Cookers of all shapes and sizes are set up and through the day provide tasty food is shared with all attendees. The Potluck shows just how easy and effective solar cooking is in preparing delicious foods, and the public sees first hand just how this natural no-cost-energy cooking approach provides for a more comfortable kitchen environment and lowers home energy costs in the intense Arizona summers.

Today's solar cookers function much as the early predecessors, but with the advantages of past experience and contemporary materials. The components are the same. An insulated container with a transparent top to allow sunlight to the interior. The light rays impact the interior surface, are transformed to heat energy, which is absorbed by the cooker interior and its contents. While a little heat escapes back through the glass most is contained within the box and/or the cooking utensil. Additional sunlight can be directed to interior by the use of reflectors or winged additions which provide additional area of sunlight gathering potential. These reflectors serve a dual purpose in allowing the regulation of the sun's energy that travels to the box thereby allowing for some temperature control.

Solar cookers come in all sorts of sizes, shapes, and construction. There are commercial products and there are home made ovens. The simplicity of a solar cooker reflects the simplicity of its use and designs fall into some basic categories.

WHAT'S COOKING - SLIDE 34Box cookers, are simple, insulated boxes with a heat resistant transparent cover which can be a removable lid as the oven "door". The interior is black, for fuller solar absorption. 

The box container can be made of virtually any material, from high tech polymers to simple plywood to extremely low cost and light cardboard construction, and the solar face is transparent, usually glass but can be other comparable materials.

WHAT'S COOKING - SLIDE 35It provides slow, even cooking of large amounts of food, with temperatures 140 - 225 degrees depending on construction. Addition of reflectors achieve the higher temperatures.

WHAT'S COOKING - SLIDE 36Slant faced cookers. With the slanted face pointed directly at the sun, this type of cooker puts the collector glass in a more perpendicular orientation to the sun's rays while maintaining a level interior. 

WHAT'S COOKING - SLIDE 37These are usually highly efficient and the addition of reflectors will increase performance. These cookers can be made to be portable with collapsible reflectors of aluminum or mirrored foil glued to a sturdy backing, folding onto the cooker for easy transport.

WHAT'S COOKING - SLIDE 38Multi-faceted, cone shaped cookers. A faceted conical shaped interior covered with many small mirrors, this cooker brings more reflected light directly to upon the cooking pots reaching temperatures of 300 - 450 degrees F, and operates the same as a conventional kitchen oven. The larger size (generally 4' in diameter), it is large enough to roast a turkey.

WHAT'S COOKING - SLIDE 39Instead of a totally contained oven and cooking utensils, this cooker, developed in France, has reflector panels, separate from the cooking utensils, directing sunlight directly onto a dark colored pot inside a plastic bag or under a glass bowl. These cookers are extremely portable and easy to assemble and use.

WHAT'S COOKING - SLIDE 40Concentrating cookers. A curved, sometimes concave, reflective surface (aluminum foil, etc.) that focuses the sun's energy to a single focal point at which is placed a pot sitting on a separate stand. Temperatures exceeding 600 degrees F have been attained. This cooker requires more continuous attention in order to keep the focal point on the cooking utensil at all times since the sun angle is continuously changing as the sun moves across the sky.

WHAT'S COOKING - SLIDE 41These cookers can be complicated to make and because of the high heat generated at the focal point, can cause burns and eye injury if not used correctly.

WHAT'S COOKING - SLIDE 42The variety of cookers shows that there is choice for the user - depending on situation, costs, and desire. All work and the common question regarding which is best gains this response from solar cooking enthusiasts. 

WHAT'S COOKING - SLIDE 43Today, solar cookers are growing in use, not only in technological, energy rich countries, but also in countries where there is no energy for cooking and depleted resources for even a fundamental cooking fire. Whether motivated by need or by choice, solar cooking is finding its way into the lives and lifestyles of peoples around the world. Community kitchens outfitted with solar cookers provide prepared food for large groups of people, and cookers are used in Arizona backyards net to, and in place of, the American barbeque, and are even being designed as a permanent component of existing and new housing.

Arizona has an abundance of sun; a treasure of solar experience and knowledge, and an affinity for outdoor cooking. Solar cooking is natural fit - not only for celebrating the summer but for year round use, and it can be a significant aspect of keeping summer cooling bills down. 

Solar cookers come in a variety of configurations and constructions; are commercially available or can be self-constructed, but have a commonality ---

they are effective


fun to use


reduce energy demands and associated costs


and according to solar enthusiasts, they are healthier. 




This presentation was constructed by the Arizona Solar Energy Association for the Arizona Solar Center, Inc. under contract with the Arizona Dept. of Commerce Energy Office, funded by the Dept. of Energy Million Solar Roofs program. Materials and information were provided by a number of sources.

Financial support for this presentation has been provided by the Arizona Department of Commerce (Energy Office) and the U.S. Department of Energy through (DOE) Grant No. DE-FG51-01R021250. However, any opinions, findings, conclusions, or recommendations expressed herein are those of the author(s) and do not necessarily reflect the views of the Energy Office or U.S. DOE. The State of Arizona and U.S. DOE assume no liability for damages arising from errors, omissions or representations contained in this presentation.


Solar Application & Integration

APPLICATION - IMAGE 01Active and passive solar systems equipment - that hardware and elements which capture the sun’s energy for heating bath and wash water; heating swimming pools for extended season use; generating electricity to power devices; cooking food; warming and cooling buildings, etc. Solar equipment use is growing in Arizona neighborhoods, cities and towns.APPLICATION - IMAGE 02 Buildings are incorporating solar as part of the basic equipment package. People want to use solar equipment because it is cost effective, resource saving, simple to use and understand, and there is a logical, direct and unencumbered energy resource in the sun as it moves across the sky.

Solar equipment which provides for a building’s performance and the residents needs, is no longer some “future” thing - Today, solar elements and panels are part of the mainstream with other element of in the building equipment palette - electric service and distribution; gas meters and pipes; water meters and piping, water heaters, fire sprinkler systems; waste water pipes and vent stacks; air conditioners; evaporative coolers; heating systems; television receivers and connections; phone lines and junction boxes; etc. All these systems are integral elements of a buildings’ operation in meeting human needs as well as comforts. To this list, and in many cases, replacing some items on the list, Arizonans are incorporating solar devices, equipment, and design elements. Reasons for this incorporation may vary - from saving money to saving the environment, and the applications range from use of a solar hot water heater to photovoltaic panels to cool towers.


Just as in the use of any other type of equipment, the use of solar can have a direct impact upon a building - its’ performance, its’ look, even its’ form and shape. At the same time, the building also has an impact upon the optimal use of solar strategies and equipment used - affecting both placement and performance. To assist Arizonans in the use of the sun as another element of the citizen’s energy mix, the State of Arizona has enacted legislation that clearly stipulates that there can be no prohibition to the use of solar energy. This legislation has the intent and effect of both encouraging as well as protecting Arizonan citizens right to solar utilization.

ISSUES: (top)

Codes, Covenants, and Restrictions

APPLICATION - IMAGE 05 As Arizona’s population and economy grow, there is also growth in the building market. Increasing numbers of people means more buildings, and meeting the need for more buildings results in developments and subdivisions. These developments reflect the public’s desire and demand for neighborhood identity and integrity, and to this end developments often have defined conditions of building and site appropriateness, identified as Covenants, Conditions and Restrictions.

Historically, CC&Rs were drafted to mitigate, among other things, unsightly installations of roof-mounted equipment of television aerials, evaporative coolers and heating/air conditioning equipment and unkempt yards and properties. Definitive CC&R’s established an aesthetic standard in order to maintain visual integrity, which was believed to be a primary element in maintaining property value. Some of todays CC&Rs have precise definitions down to building style, materials, and even color. Unfortunately overly restrictive CC&Rs promote situations where all buildings look alike and there is no visual interest and disallowance for variation, reducing a neighborhood “look” to one of sameness and boring homogeneity.




Today, subdivision requirements have a common restriction - generally, no equipment visible on a building, most notably the roof. In order to maintain an aesthetic of clean lines and building form, equipment such as coolers, air conditioners, and television aerials must be located elsewhere or be visually screened. This prohibition accomplished its’ original purpose in screening or removing unsightly mechanical equipment from the skyline and placing it out of view.

Unfortunately, this “no equipment on the roof” restriction comes into conflict with optimal conditions of solar equipment placement, effective solar equipment utilization, good solar design, and sometimes is even in direct conflict with Arizona law encouraging use of solar energy. Ideally, the installation of solar equipment should be achieve optimum performance for the Owner, but restrictive CC&Rs have negatively impacted performance by forcing placement of equipment in situations of limited exposure to the sun; locations that require longer runs (of piping, wiring, etc.) than necessary; locations which require restrictive, and sometimes costly, screens; and/or placement of equipment in less than optimum exposure angle to the sun, each and all of which provide less than optimal results for the building owner.

APPLICATION - IMAGE 08 Recently, in litigation involving a Home Owner Association’s (HOA) attempt to restrict residents use of solar equipment on building rooftops (the only, and most effective, place it could be used), Arizona courts ruled against the restriction, and reinforced the solar rights of Arizona citizens. Additionally, the Arizona Solar Energy Industries Association (AriSEIA), has initiated workshops and activities with HOAs throughout Arizona to provide effective and appropriate definitions and implementation of solar equipment incorporation standards, in order mitigate future conflicts between homeowners and HOAs, and to meet State legislative intent. To this end, the Az. Department of Commerce Energy Office has supported AriSEIA in this endeavor, and continues to be a resource for Arizona citizens.

Design and Aesthetics

APPLICATION - IMAGE 09 The desire for optimum equipment performance of equipment often results in the need to mitigate site specific conditions through additional structure - mounting solar panels on racks for proper tilt angles and exposure. These racks, placed on roofs for optimum exposure, have come under fire and rejection from Homeowner Associations committed to maintaining the aesthetic qualities of the neighborhood. While effective in establishing proper orientation and attitude of solar panels toward the sun, these installations project a discontinuity with the building design and are perceived by many as ugly and unsightly appendages to otherwise attractive buildings.

Today’s subdivisions have fallen into stylistic characterizations (Santa Fe style, California tile roofs, etc.) instead of evolving from appropriate environmental response which would result in a truly Arizona style. Subdivisions are laid out with numerous considerations - density, views, circulation, etc. with little or no consideration is for basic tenets of good energy, solar and environmental design.



Energy issues are met by adding insulation and efficient mechanical systems without consideration of using positive aspects, or mitigating negative impacts of the site and the climate to reduce both the amount of equipment used, and the amount of energy required to run it. Effective energy benefiting actions involving orientation, building shape, space planning, amount of glass, and/or incorporation of active and passive solar and energy efficient equipment as part of the building shell are overlooked. Desert houses face west into the intense sun; roofs are flat in snow country; inordinate areas of glass wrap buildings forcing residents to take defensive measures; and building forms and structure do not readily allow for integration of solar equipment as part of the building’s fabric.

APPLICATION - IMAGE 12While the idea and ideal of maintaining a neighborhood character and quality is desirable, current design and construction practices make integration of solar strategies and equipment problematic, and when coupled with CC&R restrictions regarding solar equipment, provide conditions for conflict, penalties, litigation and unhappiness - all which are counter to the heart of a neighborhood environment and value - one of belonging and being a part of shared community, and being able to use Arizona’s most prevalent resource - the sun.

APPLICATION - IMAGE 13Solar integration is easily implemented in the design and construction of a new building - equipment and element incorporation can be executed to make the project a seamless and integrated “whole”. Proper building orientation and siting can be determined. Appropriate building form can simplify the incorporation of equipment into the structure. Proper space planning can optimize the distribution systems related to solar equipment use (piping, wiring, etc.).

APPLICATION - IMAGE 14More problematic is the integration of solar devices and elements into the existing Arizona building stock. 

Existing buildings come in an array of orientations, forms, roof shapes, construction and materials - some very compatible with use of solar strategies and integration of equipment, and others contrary to good solar design posing problematic conditions for the building owner wishing to use solar. Even award winning Arizona architecture suffers from this poor consideration, with glass walled boxes in the dessert. Sites may not have any appropriate location for a solar installation. Building roofs may not have appropriate angle or orientation to the sun. Restrictive CC&Rs may prohibit the placement of equipment on a effective south facing roof, or require screening that may effectively reduce equipment performance, or force placement of equipment in locations which effect performance.

APPLICATION - IMAGE 15Whether it be new or old buildings, Arizonans respond positively to the idea of an integrated “whole”. Additions and renovations that provide a visual continuity are more readily received and enjoyed than those projects which have additions are perceived as unsightly because of their incompatibility of form or integration. What is needed is a result which meets both the functional requirements of the equipment and aesthetic sensibilities of the people, providing the best for Arizonans and Arizona architecture.

Of course site and situation, and type of system play a role in where equipment winds up. A passive thermosiphon hot water system with separate storage may have a lower location for panels than a hot water heating system which uses pumps, which would allow for panels to be placed on the roof. Photovoltaic panels may be fixed systems integrated into a sun struck roof, or be ground mounted for ease of access or for use with a tracking system.


APPLICATION - IMAGE 16 The sun’s movement is in a predictable pattern. As the earth makes its annual elliptical trip around the sun, its axial tilt provides for the seasonal changes in the northern hemisphere. The summer sun is high overhead and its appearance and impact are longer in duration and more intense during summers, whereas the sun’s appearance is shorter in duration and lower in the horizon as it traverses the winter sky. Like all applications that use the sun’s energy, exposure is a primary and critical element. While simple direct exposure will get results, ideal positioning provides the optimum performance of any piece of solar equipment, whether it is a solar water heater, a photovoltaic panel, a solar cooker or even a passive solar heated building.


The 3 primary aspects of optimizing performance of solar equipment are uninterrupted exposure to the sun through orientation; appropriate angle to the sun (tilt angle); and effective placement. 


APPLICATION - IMAGE 18Maximum performance of solar equipment and passive heating strategies is based on continued exposure to the sun. Outputs are optimized when there is clear connection to the sun for the entirety of daylight hours - the more exposure to the sun, the more water can be heated, the more electricity generate, and the more heat can be generated for comfort. Collector locations must be face the sun’s path as it traverses the south sky, free of shade, for the entirety of daylight hours.

Tilt Angle

APPLICATION - IMAGE 19Solar water heating is most effective when it can provide hot water under coldest conditions - i.e. winter. The winter sun is lower on the horizon so the ideal angle of a collector should more vertical (to 45 degrees). Solar pool heating is more in demand in the colder parts of the year so this angle of exposure can be equally important. Solar cooking in the winter is more effective. This tilt angle is a very necessary condition for optimizing solar equipment use.

Positioning and orientation have significant impact upon the performance of any system. For example an array of PV panels tilted to the sun produces over 50% more electricity than one, which is simply vertical. 


APPLICATION - IMAGE 20Location of equipment is a critical consideration. Placement optimizes conditions by having short runs of delivery - water heated by a solar collector should have as short a run to the storage and/or use as possible to minimize transfer heat losses. Electrical installations benefit from short delivery systems. Reduced runs mean less material, less labor and materials for installation, less maintenance in the future, and less overall cost.

An additional benefit of solar equipment placement is one that directly impacts the shape and form of a building, adding visual interest as a byproduct of the solar functionality. Passive solar buildings take their form and shape from the direct relationship in using nature’s resources. Axial elongation along the East/West axis to provide more southern exposure and minimize unwanted east and west exposures to intense summer sun; roof forms and/or elements which incorporate solar equipment and strategies; specifically calculated overhangs to protect from summer sun high in the sky while allowing for the access of lower angle winter sun; vertical forms of cooling tower projections; recessed windows and doorways for thermal tempering; and colors and textures which enhance taking advantage or mitigating conditions.



Implementation of solar equipment and solar strategies have a range of options, from integration on site to integration as part of a building. Currently, there are 2 major pieces of solar equipment - solar water heater systems (panels, piping, storage) and photovoltaic panels (electricity generation from sunlight, wiring, electrical equipment, electrical “storage” for off grid installation) , with a number of other pieces of solar applications like cookers, roof ponds, thermal chimneys, cool towers, etc.

water heater


roof pond

cool tower

Arizonans have been resourceful, creative and ingenious in the incorporation of solar equipment and strategies into their lives and their sites. Rural Arizona, in particular, has less governmental and subdivision restrictions regarding codes and CC&Rs, more sense of rootedness, and more commitment to using solar and renewables. The variations of solar integration range across the State from urban areas to rural sites, and they all are responses to conditions, type of equipment and application, and needs of their Owners. Integration may result in the following applications:

1) Equipment placement adjacent to the building

* Ground mounting

In some cases, if there is appropriate access to the sun, ground mounting has been used successfully in Arizona for fixed photovoltaic panel arrays as well as individual panels on trackers, which follow the course of the sun to optimize operation. Panels mounted in open areas on a site allow for freedom of operation and movement necessary for a tracking system, and/or for ease of installation, access for maintenance and adjustment for both tracking and fixed systems.


This may also be an appropriate integration strategy for passive hot water heating systems, which use non-mechanical thermosiphon circulation methods for heating water for personal use, or for use in radiant heating of floors. Since hot water rises, and cold water settles, the thermosiphon water heating system has water, heated by the sun at the collector, naturally rising to a storage tank or through radiant heating pipes embedded in floors, and the colder water from the storage tank or the floor system, is circulated back to the panel. This convective loop runs continuously as the sun shines and works well as long as the collector panel heating the water is below the level of the delivery or storage system. Some applications with south sloping sites, place collector panels below the floor level of the house to capitalize on the thermosiphon effect of this passive approach.

Prescott house
Wright house

APPLICATION - IMAGE 32In these ground-mounting applications, solar equipment is located in response to the ease of location, ease of access, and direct and easy maintenance or in response to the terrain, type of equipment, and end use - sloped site integrating a passive thermosiphon water heater with end use being heating of a building and/or for domestic purposes. Some such installations have integrated equipment as part of a building element such as a porch or deck.

In all cases, proper orientation as well proper tilt angles can be easily achieved, thereby having equipment operate at its optimum in providing electricity and/or hot water.

* Separate structure mounting - 

APPLICATION - IMAGE 33Sometimes, equipment is mounted on, an adjacent structure. Photovoltaic systems that are completely off-grid and provide for the entirety of electrical service of a house require an extensive amount of batteries in order to store enough electricity for nighttime and overcast day usage. Use of batteries entail the need for an extensive amount of space as well as an area that is well ventilated in order to dissipate the hydrogen gas that is formed. Some applications provide a dedicated structure for this purpose and incorporate the photovoltaic panels and equipment such as inverters into the structure, thereby minimizing runs between panels, inverters, and storage.

Solar water heating systems used for heating pool water in order to extend the swimming season, can be incorporated into trellis and shading structures that are part of a patio and pool area. Since there is no necessity for storage (the pool water is heated directly) this provides a direct connection with short runs and minimal line loss inefficiencies. 

2. Equipment placement as additions to the building (top)

APPLICATION - IMAGE 34Equipment can be mounted directly on the building as a separate element or appendage. While solar elements can be attached to any part of a building that has good southern exposure to the sun, the most advantageous location at the roof. Roofs generally provide a condition of unencumbered and unshaded access to the sun’s path, and the location puts equipment out of the way. Additionally, a roof application can allow for placement of equipment directly above other elements of a system (hot water tank, mechanical room for photovoltaic equipment, etc.) thereby reducing runs which may reduce commensurate installation and materials costs, and reduce transfer losses.


APPLICATION - IMAGE 35Ideal exposure of photovoltaic and solar water heating panels is to the south and at an angle which maximizes the performance of the panels. Since the winter sun is available for a shorter time than in the summer, and is lower to the horizon, equipment performance is optimized when tilted at an angle that puts it perpendicular to the sun’s rays. This tilt angle has a direct impact on the output of the system. Summertime conditions are less a factor, primarily because there is so much sun for a longer period of time.

Many existing and new buildings are not properly sited for optimum south sun exposure, nor have roofs designed and constructed with proper tilt angle orientation to the sun. Some have no tilt at all, incorporating the prevalent Santa Fe flat roof style. These conditions force owners to live with, or mitigate negative conditions.

* Rack installations

APPLICATION - IMAGE 36 Equipment can be placed on roof-mounted racks which place panels at the correct orientation and angle to the sun. Rack mounted panels can be used to mitigate conditions of poorly oriented roofs; roofs with improper tilt angles, and flat roofs. While effective in providing proper conditions for equipment performance these installations are perceived as unsightly and incomputable with the building design, and have been the crux of recent conflicts between homeowners and their Home Owner Associations (HOA). While Arizona courts have made judgment in favor of the homeowner in this conflict, the fact still remains that some rooftop solar installations still have the issue of visual incompatibility with the building form and design.

* Screening

In order to address the issue of visual discontinuity and intrusion, some installations have incorporated screen elements which prevent viewing the equipment and racks. While screening can be executed in a manner to blend with the building architecture in flat roof situations, it is much more problematic in pitched roof and poor orientation conditions. Screening and other such visual barriers must be large enough and spaced from the equipment sufficiently in order to minimize shading which negatively impacts performance. The addition of visual screening also adds cost to the solar installation.

* Flush Mounting

Equipment can be placed flush to existing roof slopes in order to provide a compatible installation with the building’s architecture. These installations can incorporate trim, which visually integrates the equipment into the roof structure. Arizona owners and contractors have successfully installed solar equipment that is visually compatible with existing roof pitches and materials, and having the aesthetic impact equivalent to a skylight. 



While effectively providing visual compatibility, such placements result in less than optimal performance of equipment due to less than ideal orientations and exposure to the sun. 

3. Integrated Installations (top)

APPLICATION - IMAGE 39 Combining building form and optimal functional requirements of solar strategies and equipment, this approach integrates solar equipment and strategies as a part of the building fabric and architectural expression and design, sometimes coupling multiple energy and resource efficiency strategies. The building planning, design and construction provide appropriate conditions for energy efficient operations and integration of active and passive solar equipment.

* Solar Integrated Buildings


An integrated solar energy building incorporates ideal conditions for both passive and active solar applications, from space heating and cooling to power generation to incorporation of solar hot water systems. Integrated energy buildings, and building elements, are correctly located in terms of orientation, and exposure to the sun and correctly structured to provide appropriately angled roofs and elements for optimal solar equipment performance. Additionally, an integrated solar energy building is one that evolves its design and expression - its character and style - from the attributes of its solar (active and passive) and energy characteristics.


Integrated systems solar buildings vary in execution and expression, even while maintaining common attributes and premises related to environmental conditions and resources in both passive and active solar applications.

Orientation to the south allows for use of the sun for passive heating purposes in cold climes and for mitigation of negative west and east sun heat in dessert conditions. This is also an ideal condition for solar equipment performance. In some projects, south facing roofs are angled to appropriate tilt angles and equipment is mounted directly as another “skin” to the building fabric. It is known that an array of PV panels tilted to the sun produces over 50% more electricity than one which is simply vertical. Collectors, whether water heating or photovoltaic, become one with the building form and expression.


solar integrated south facing roofs

* Building Integrated Photovoltaic Systems

New developments in photovoltaic systems are bringing panels that both generate electricity and are part of the roofing system. This dual function application easily incorporates to solar building design and construction that provides appropriate roof pitches for optimum solar exposure. The photovoltaic system, a solid state semiconductor technology converting the sun’s energy directly to electricity, without moving parts, making noise or making emissions, is developed as a Building Integrated PV system which integrates this technology into the building construction, sometimes replacing or integrating with existing construction materials that form the building’s exterior “skin” - i.e. the roof or wall system. The PV system then becomes a dual-purpose element, not only generating electricity for the inhabitants but also acting as the roof and/or wall of segment thereof, of the building.

Appropriately oriented and pitched roofs are also compatible for inclusion of solar hot water panels that benefit from ideal exposure and placement and benefit the building design with integrated design elements much like skylights add visual interest to roof lines.



Integrated Solar/Energy Building Elements (top)

Not all integrated energy applications must encompass entire roofs on a monolithic building block. Buildings derive aesthetic interest from their component elements like clerestorey windows, chimney structures, overhangs and facia designs, and from building massing and variations in wall planes.


The integrated solar energy building incorporates solar equipment and applications into this scale of building element. A north facing rooftop clerestorey windows can provide the structure for south facing solar equipment on the back side, thereby combining two functions - one of introducing daylight - the other of producing hot water and/or electricity, within the same structural element.


APPLICATION - IMAGE 51This solar/day lighting element can also include openable windows and glazing to facilitate building natural ventilation exhaust of unwanted interior heat. Now there are four functions for the one building element...

it provides natural illumination

it provides for natural ventilation and building cooling

it provides a place for solar water or photovoltaic panels, and...

it provides an interesting and dramatic building design element.

Examples of element/solar integration is the placement of photovoltaic panels as a part of the building eave system, and the integration of water heating solar panels into a south wall. 


Multiple functional building elements is a strategy that lends itself to solar installations in existing buildings. While it may not be desirable to incorporate a solar device into an existing building fabric because of renovation costs, it may be quite feasible and desirable to do a single modifying action that has multiple applications including solar. Besides improving functionality to a building, the multiple energy/solar modification pays for itself with savings that is realized in energy efficiencies, and in savings realized in the use of solar equipment. It is a modification that will pay for itself in energy saved and in the increase in property value. 

Solar applications are a growing reality in the building landscape. Traditional perceptions of aesthetics, appropriateness, and value are changing in response to the realities of energy and environmental considerations, need for energy security, and desire for energy stability and self-sufficiency. Buildings are incorporating environmental design strategies in response to site conditions, and available natural resources, and are incorporating solar equipment and devices, which impact building design and construction. Buildings that integrate solar attributes and equipment define themselves in a form and expression that reflects local conditions and resources. The careful and considerate integration of solar, energy and environmental elements into the building, whether existing or new, is a benefit that manifests itself as the basis of a truly indigenous and local architecture (images below are examples).


This presentation was constructed by the Arizona Solar Energy Association for the Arizona Solar Center, Inc. under contract with the Arizona Dept. of Commerce Energy Office, funded by the Dept. of Energy Million Solar Roofs program. Materials and information were provided by a number of sources.

Financial support for this presentation has been provided by the Arizona Department of Commerce (Energy Office) and the U.S. Department of Energy through (DOE) Grant No. DE-FG51-01R021250. However, any opinions, findings, conclusions, or recommendations expressed herein are those of the author(s) and do not necessarily reflect the views of the Energy Office or U.S. DOE. The State of Arizona and U.S. DOE assume no liability for damages arising from errors, omissions or representations contained in this presentation.