For many years I can remember riding in the back seat of my
family’s car through downtown Los Angeles going to pick up my mother and
passing several glass buildings. I remember thinking to myself "that's a lot of
glass", and asking my father what type of building is that. My father replied in
a hesitant voice and said “It’s an office building”, then I asked “why is it so
shinny”, and he said because the “windows have tint on them”. Of course I knew
that my dad had a two question limit and I better not ask another question, so
I grew up thinking that the glass on office buildings was special glass. Well that answer from my dad was not all that
bad, in fact who would think 25 years later, I would develop a love for Commercial
Real Estate, and pursue a career as a Real Estate Developer and the inception
of my entire career would hinge on me having a more elaborate answer to
familiar question of “What is Building
Integrated Photovoltaics”? Now I
must admit, it’s not as simple as that glass has tint on the windows, but the
principle is the same. This blog will explore some methods, solutions, and
economic feasibility of implementing Building Integrated Photovoltaics (BIPV) systems in your construction plans.
During the design
phase of constructing a new building the process of substituting traditional
building materials used for rooftops, windows, or curtain walls (façade) with a
Photovoltaics material known as Building Integrated Photovoltaics (BIPV). To
understand this process even more we must define Photovoltaics (PV). Photovoltaics is loosely defined as the
transformation of light into electricity in laymen terms it’s a series of crystalline solar
cells which reminds you of honeycombs where Bees live. These thin cells are connected together and
enclosed in a metal panel casing that absorbs solar energy to produce electricity.
BIPV Rooftop
The rooftops of a building has the most exposure to heat
transfer, I’m sure it’s has something to do with the sun beaming its rays down
onto it. The easiest way to reduce this heat exposure is to paint the
roof white; however if you would like to reduce the heat exposure, reduce
the carbon footprint of the building, and store the energy for later use BIPV materials may be the way to go.
One of the most common use for BIPV is on the rooftops of buildings. To install the BIPV materials on a flat roof, first you must instruct your GC to build the roof traditionally with metal decking, thermal installation, vapor barriers, roof membrane, and of course drainage. The extra steps will come in to play after the adhesive membrane has been applied. The next step is similar to putting in a drop down ceiling inside a building; however in reverse, and on top of the roof. To install BIPV first you must attach mounting racks to the roof’s membrane to support the BIPV without attaching the panels directly on to the roof.
One of the most common use for BIPV is on the rooftops of buildings. To install the BIPV materials on a flat roof, first you must instruct your GC to build the roof traditionally with metal decking, thermal installation, vapor barriers, roof membrane, and of course drainage. The extra steps will come in to play after the adhesive membrane has been applied. The next step is similar to putting in a drop down ceiling inside a building; however in reverse, and on top of the roof. To install BIPV first you must attach mounting racks to the roof’s membrane to support the BIPV without attaching the panels directly on to the roof.
http://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwjCtszqnsHOAhUCVh4KHSX-ClIQjB0IBg&url=http%3A%2F%2Fwww.pv-magazine.com%2Fnews%2Fdetails%2Fbeitrag%2Fsolarcentury-report-lifts-lid-on-uk-commercial-solar-potential_100016905%2F&bvm=bv.129422649,d.dmo&psig=AFQjCNEtsGhxLhpn_6GOvCOaLb4a-p2Xzg&ust=1471275581035383
Once these panels are in place and all the electric wiring has been properly connected and now the roof is ready to generate solar energy hopefully for the next 20 to 25 years before any service is needed or baring major storm damage. The cost for standard BIPV materials can range from $18-$22psf for a 1000kw system. The process to install BIPV materials can take up to 3 weeks, or even as long as one month. This wait time will be well worth it. When this system has been fully integrated you will be allowed to apply for LEED certification and your building will be considered a Green Rated Building which will translate to a higher market rent per Sf. You can also market the building as a cost saving to any future tenants because they will save up to 65% off their electric bill(NNN lease), and not to mention the federal tax credits that they will receive for saving the planet. After saving and producing so much energy the electric company will give you a credit for your stored electricity. If that’s not a win/ win then I don’t know what is! http://www.solarelectricsupply.com/commercial-solar-systems/flat-roof
There are some perceived disadvantages to having BIPV
materials on top of a commercial roof. One
disadvantaged would be the extra weight on top of the roof. Many in the commercial
development industry consider this extra weight from the BIPV will decrease the
life cycle of a roof, and may cause leaks throughout the roofing system. I am
happy to report there are thin flexible solar cell panels that can be applied with adhesive on top of the membrane
without using mounting racks. Another real concern deals with the warrantee from
the roof manufactures. Most if not all manufacturers will void the roof warranty if you've
used BIPV materials after the roof has been complete, so if the roof springs a
leak the owner will have to pay out of their pockets to fix the roof. Retro fitting an existing
roof with BIPV materials may cause a problem if the life cycle of the roof only has 10 years left before it will need replacing and the BIPV materials has
a 20-25 year life cycle, so basically if you need to perform any maintenance,
or replace the roof, you will have to uninstall all of the BIPV materials to fix
the roof, and reinstall BIPV system when your done. Is it worth it?
The installation of curtain walls is another innovative way
to harness energy, and “Go Green”. A
curtain wall is a term originated during the medieval times to describe the
wall outside of the castle. This wall usually has a ditch or small body of
water that separates the castle from any potential threat. Today we use the term curtain wall to describe
the outer skin or façade of a high-rise building, and it is design to protect the
occupants of the building from the outside elements. BIPV system are tested in the factory to resist
hurricane forced winds. Curtain walls are not load bearing walls and it does
not support the building’s weight in any way. In fact it hangs onto the side of
the building like curtains or drapes would in your home. When using Building Integrated Photovoltaics
materials as a substitute, the traditional curtain walls allow the owner of the
building an opportunity to harness solar electricity through solar rays. There are two basic BIPVs used for curtain walls:
thick crystal which uses silicon cells, and thin film which is incase by a
metal frame and gives a building a glazed crystal facade. BIPV materials are pre-fabricated, and delivered
to the jobsite and put on the building by a crane, and each panel can weigh typically
over 500lbs each. https://www.youtube.com/watch?v=xnjx73K18pk
. To install this type of curtain wall, you will have to set aside a few extra weeks for installation. The average construction team can only install around 40 to 50 panels per day. Some engineers can actually design the BIPV
between the floors during the construction stage of a building, this process is
known as window- walls and this option offers a smooth inline look to the
building.
The thermal energy from the side of a building has a direct effect on the building’s occupants. Similar to rain screens using BIPV materials as your curtain wall will offer your building’s tenants shade, and confront from the sun while storing thermal energy from the sun. There is a tremendous amount of cost savings associated with this application, such as cost savings on labor cost, and not to mention the building materials cost. The estimated cost for installing BIPV is around $200psf.
