One of our most active commenters let me know about this interesting idea below. After a bit of a back-and-forth with the man behind it, Futura Solar’s founder Patrick O’Leary, I solicited this guest post from him on it. Check it out:
by Patrick O’Leary
Every building standing today is a solar collector anyway. Whether we intend it to be, design it to be, build it to be, or equip it to be. If we sit it in the broad daylight, it will catch some rays.
Do we put that energy to good use, or do we let it go counter-productive? This idea below is about productivity and rework. The least expensive way to do anything is to do it right the first time. It does cost money to harvest all that free solar energy, but it costs more to use fossil fuels to get rid of it and also to replace it. Standard roofing had better be as cheap as possible — it is running up electric bills over the 20-year life of the roof!
If we let it go counter-productive, we will end up using fossil energy to get rid of solar energy that comes through in the form of heat. Flat built-up deck roofing collects solar energy — put your hand on it during the day to test that idea. That heat is energy, and we routinely pay good money for that.
Every roof intecepts solar gain, but how many put it to good use? How many can put it to good use? Sawtooth roofing harvests some and delivers it to the business inside in a usable form. Our computer printers now scan, fax and copy in addition to printing. Why doesn’t our air conditioning equipment heat domestic water? Why dump useful heat into the atmosphere and then pay to replace it? We are all in the solar energy business and solar is part of all of our budgets. Whether we acknowledge it or not, whether we accept it or not.
The Futura Solar Roofing System
The Futura Solar system (see images above) harnesses solar loading to heat air while taking advantage of the tendency of hot air to rise and move air to draft air behind itself, thereby powering the system. The hot air generated can be used for process air (for heating, drying, or cooking), for space conditioning, or simply dumped back into the atmosphere with no net thermal pollution. Daylighting the business beneath the roof immediately reduces facility lighting costs. Solar water heating (SWH) and photovoltaic electricity (PV) are then available as add-on options. Excess PV can be net metered or even put in a dedicated building circuit.
Sawtooth Solar Daylighter prototypes have proven the utility of the Futura Solar design and have established system baseline performance. This system will handle all of the solar loading on a building roof — of any size.
The Futura system prevents internal temperatures from rising by drafting warm air from the ceiling through the roof into the air heater. This design allows the system to cope with infiltration and internal heat loads, whether from people or machines.
The patented design integrates known technologies in a new way. The Sawtooth represents ‘game changing’ technology when applied to ‘zero net energy’ growth policies, or mandates connected to greenhouse gas emission reductions. This system’s energy efficiency / renewable energy capability represents a significant reduction in energy demand for low profile, commercial, industrial, institutional, or agricultural buildings.
The sawtooth design combines existing SWH and PV technology with building space framing technology. This allows bright diffused daylight to enter the building, offsetting the costs of electric lighting and immediately reducing a building’s energy cost. The use of SWH and/or PV means that additional building cost reductions occur by allowing the sun to do what it does best. Excess PV can even contribute to grid demand if net metering is allowed in the region.
Building end-use efficiency, especially for existing structures, is of importance in terms of reducing energy demand and improving energy utilization. Offering a new alternative technology concept to building end users will effectively restructure the market. This creates an ‘eco-advantage’, a term coined by Esty & Winston of Yale University. The technologies comprising the SISRS are all proven, ‘recovered’ technologies, integrated into a structurally holistic system.
The most cost-effective way to gather this rooftop energy is to do it right the first time — when a building is built from the ground up. Buildings undergoing re-roofing are another way to improve the built infrastructure. This means there are opportunities to bring efficient, cost-effective solutions to problems of expensive lighting, process air, heating and cooling or electric energy by rethinking rooftop energy capture and utilization. Helping regional markets to reduce both peak electric demand and natural gas demand directly addresses fuel consumption, and indirectly addresses energy cost, whether for electricity generation, heating, or transportation. This also permits continued economic growth within infrastructure constraints. The Sawtooth technology will contribute towards reduction of air pollution by directly reducing fossil fuel consumption in commercial buildings.
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