Exteriors: Green Roof in Bloom
[nggallery id=”24980″ template=galleryview] Last year, a Park Slope couple sent us the skinny on the green roof they’d installed. They’d found the design firm, Prospect Architecture, through our very own forum, who created a green roof, photovoltaic array (solar power) and roof deck, making it feel like “a small meadow.” Here’s the update from the…
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Last year, a Park Slope couple sent us the skinny on the green roof they’d installed. They’d found the design firm, Prospect Architecture, through our very own forum, who created a green roof, photovoltaic array (solar power) and roof deck, making it feel like “a small meadow.” Here’s the update from the architects: “We (and the clients) were thrilled by how well the plants have grown and filled in the space. The garden has required little to no maintenance. The most exciting part has been that the solar panels have provided for about 60% of the clients’ energy needs!”
Here are energy use numbers before and after solar installation:
– 2007 6/11-7/12 2081 kwh (before solar installation)
– 2008 6/10-7/10 958 kwh (after solar installation)
Pretty garden!!! It really turned out swell! Congratulations!
LISA,
I have a feeling you need to correct: “The most exciting part has been that the solar panels have provided for about 60% of the clients’ energy needs!”
Can we assume the house also has a gas or oil furnace, hot water heater and gas stoves? If so, then the solar panels would not provide “60% of the clients’ energy needs” but rather the 60% of their *electricity needs*. One sees gas heating, hot water and cooking much more than one sees these run on electric in NYC.
Now, if the owners could seriously reduce their energy consumption and maximize solar heat gain in during the heating season and add a domestic hot water panel, more PV panels and possible a heat pump, they might be able to reduce their main fossil fuel use significantly. Some of the steps:
–Super-insulating the house (very, very hard on brick and brownstone rowhouses for many reasons)and keeping decent interior high mass (i.e. insulate the exterior while keeping the brick within the insulated envelope…hard because these walls are continuous with neighboring houses and they do not have a damp-proof course)
–Installing all triple-pane windows, pref’bly high engineered with insulated sashes. If heat gain is necessary, care should be taken to specify no IR films/coatings on those windows.
–Switching to very high efficiency appliances (preferably having a 12V fridge/freezer); installing an electric ring cooktop instead of plaques or induction or halogen cooktop; using Kuhn-Rikon insulated cookware; maximizing washing machine use (and cold water washing only); drying cabinet instead of tumble dryer; no dishwasher use; switches to turn off all electronics and appliances that sit in stand by mode (large ghost load on the system).
–Changing out all lighting to LEDs
–again, installing more PV panels and a domestic hot water solar collector, using insulated window treatments indoors and awnings in summer if necessary,
One thing that might help during the heating season would be a high mass masonry oven or even a soapstone stove. Aside from providing heat, they can also help heat water for a circulating heating system and/or domestic hot water use. The wood to supply the stove should be sustainable and as local as possible to reduce the fuel expended to bring it to the home.
They just *might* manage to reduce their energy usage and up their passive and active solar systems to have the two meet.
Snarkslope:
No, this system will likely NOT provide electricity to the house if/when there is a blackout. The system is grid-tied which means it probably does not have any battery back-up. It can cost quite a bit extra, but a battery back-up might allow the house to run an essential circuit in the event of a blackout. A 12V fridge, an oxygen concentrator or other necessary medical equipment and LED lights might be connected to that circuit in the event of a blackout or run off a dedicated circuit so there is no interruption. The problem with the batteries is that they would probably be lead acid batteries.
Hey — looks amazing! If the owners or designers are watching this post still, could you comment on which plants you chose and which have done well, which survived the winter best, etc? And am I right in remembering that you have an irrigation system installed under the growing medium? We have our own green roof in progress, and would love more info on getting it looking like yours….
Rooftop Gardening!
Also check http://www.insideurbangreen.org. See the “Rooftop Garden†links in the right side “Categories†list. This writer is an inspiring urban gardener (Brooklyn). I plan to try his prophetic sub-irrigation methods at my home – besides roofs, also fire escapes, front stairs, sides of buildings, etc. He makes it look easy for a gardening-challenged person such as I.
Combustiblegirl, may I ask who is doing your roof? We would like to put one in, for the exact same reasons you listed, and I’m curious who is out there. Also… can we have a price idea? Thank you!
I shouldn’t have made the snarky 22nd century payoff remark — you wouldn’t save the the cost of the entire expensive roof any time soon but could on just the solar piece. I’m all for green roofs / green energy and I’d like to know what the cost of just the solar panels was (and also what could be done on a peaked roof in victorian flatbash).
Looking back at the old post, from Prospect Architecture “…
SOLAR POWER – The PV system is a 4800 watt (dc) Sunwize standard grid-tie system consisting of 24 Sanyo 200 watt high efficiency modules. The PV array will be split between the deck roof (9 modules), the bulkhead (5 modules) and an angled array at the front of the roof (8 modules). The efficiency of the technology does not lessen the benefit of solar power. The efficiency of a coal plant matters because its energy source is polluting the environment and destroying ecosystems; the efficiency of solar power relates only to the amount of solar radiation on a particular area that is absorbed by the panels. No harm or true loss occurs if 80% of the solar radiation hitting that panel is not converted to electricity. The government rebate programs for NY State pay just over 50% of the project costs for all systems up to 10KW, which calculated at current electrical prices pays for itself in 11-12 years. The actual payback will likely be closer to 7-8 years due to the continuing cost increases in electricity.”
Well also, don’t forget that as part of ROI there’s more to it than the monthly electric bill — there’s the fact that the resale value of the entire building is increased from having this amenity.
Dittoburg’s comment above is funny and speaks to the complexity of being “purely” green on a project like this. Ipe’s a bit problematic, sure, but balanced by what a showcase this is, and a cool place that’s created here, I think it’s a pass.
If you have solar panels, does that mean you’ll have electricity during the next blackout?
Not all ROI are measured in monetary terms.
PS: The whole project looks fantastic.