Boston Properties Office Tower | 888 Boylston Street | Back Bay

[citylover94]

But they aren't using that style of turbine so you can't compare those to the more compact style being used at 888 Boylston. I'm not saying they will produce huge amounts but they aren't completely useless either.

 

[whighlander]

But they aren't using that style of turbine so you can't compare those to the more compact style being used at 888 Boylston. I'm not saying they will produce huge amounts but they aren't completely useless either.

City -- True the details are different -- but the fundamentals are the same -- take the area exposed to the wind -- the output power scales directly with that area

There are efficiency factors which can range over more than 2 but less than 10 -- so the conclusions are still the same

If you want the details -- see the following MIT web site
http://web.mit.edu/windenergy/windweek/Presentations/Wind Energy 101.pdf

key content:

P [units of Watts] = ½ *ρ * A * v^3 * Cp
where ρ is the density of the air in kg/m^3
A is the "rotor swept area" in m^2
v is the wind speed in m*2/s -- it enters in as the cube
Cp is the Power Coefficient == ratio of power extracted by the turbine compared to the total power contained in the wind resource
Note: The Betz Limit is the maximal possible Cp = 16/27 === 59% efficiency
this 59% is the best that a conventional wind turbine can do in a extracting power from the wind -- all real wind turbines will have a Cp < 0.59

Finally to get to the real output you need to know how the turbine performs over some interval -- typically one year
CF == Capacity Factor == The fraction of the year the turbine generator is operating at
rated (peak) power === Average Output / Peak Output typically about ≈ 30%

Note that CF is based on both the characteristics of the turbine and the site characteristics (typically 0.3 or above for a good site)

Finally the efficiency is related to optimizing the Tip Speed Ratio [TSR]
see for example
http://www.slideshare.net/Jupiter276/windturbinetechnology-kid-wind

Tip-Speed Ratio == the ratio of the speed of the rotating blade tip to the speed of the free stream wind. For an airfoil [turbine blade] there is an optimum angle of attack which creates the highest lift to drag ratio.
Because angle of attack is dependant on wind speed, there is an optimum tip-speed ratio TSR == optimum = ΩR / V
Where, Ω = rotational speed in radians /sec
R = Rotor Radius
V = Wind “Free Stream” Velocity

For a small wind turbine a typical curve of output versus wind speed is given below

and a comparison of output for a given wind with increasing rotor diameter

Note that a wind of 10 m/s is as fast as an Olympic sprinter runs and its about twice the Boston average wind speed at ground level of 5.5 m/s

So like I said earlier -- the majority of the value for the 888 Boylston wind turbiines is PR output

 

[cca]

EEEEk! My eyes are bleeding.

cca

 

[whighlander]

EEEEk! My eyes are bleeding.

cca

CCA -- try some "Bag Balm" it does wonders on most everything else that's been irritated

 

[F-Line to Dudley]

So...after 2 years, dozens of charts, and that lovely little sidebar on climate change denialism back on Pages 24-26...has anyone ever actually pinned down the answer in the form of a concise sentence:

"These turbines will generate ___ kWH of power on average for the building."

 

[whighlander]

So...after 2 years, dozens of charts, and that lovely little sidebar on climate change denialism back on Pages 24-26...has anyone ever actually pinned down the answer in the form of a concise sentence:

"These turbines will generate ___ kWH of power on average for the building."

F-Line if you look at the graphic showing output vs diameter -- it looks as if each turbine will be in the 3 to 5 kW name plate rating Unfortunately, because of locally generated turbulence placing several turbines next to each other reduces the efficiency of each so that the whole is less than the sum of the parts

In short I will guess the total installation is going to have a name plate rating of about 10 to 20 kW and on an average achieve something of the order of 20 - 30 % of the name plate rating for a Capacity Factor [on an annual basis]

Thus the overall annual energy output is the product of the average power output of 2kW to 6 kW x 8000 hrs / yr == about 16,000 to 48,000 KWh per year

 

[FenwayResident]

F-Line if you look at the graphic showing output vs diameter -- it looks as if each turbine will be in the 3 to 5 kW name plate rating Unfortunately, because of locally generated turbulence placing several turbines next to each other reduces the efficiency of each so that the whole is less than the sum of the parts

In short I will guess the total installation is going to have a name plate rating of about 10 to 20 kW and on an average achieve something of the order of 20 - 30 % of the name plate rating for a Capacity Factor [on an annual basis]

Thus the overall annual energy output is the product of the average power output of 2kW to 6 kW x 8000 hrs / yr == about 16,000 to 48,000 KWh per year

The average US home uses around 10,000 KWh/year. So even giving +100% margin on the high end of Whigh's estimate, those turbines will generate enough power for ten homes on average. That seems like a fairly insignificant number for a large office building. I suppose it's better than nothing, though.

 

[timsox6]

The average US home uses around 10,000 KWh/year. So even giving +100% margin on the high end of Whigh's estimate, those turbines will generate enough power for ten homes on average. That seems like a fairly insignificant number for a large office building. I suppose it's better than nothing, though.

Right. While I don't know what the numbers will be, it seems to me like Boston Properties is merely saying, "Hey, look what can be done on top of a building. Look how green we can be."

And this one office building will now be producing more power than the whole of the rest of the Prudential center complex combined, right? So it's a start.

 

[F-Line to Dudley]

"These turbines will generate. . .

F-Line if you look at the graphic showing output vs diameter -- it looks as if each turbine will be in the 3 to 5 kW name plate rating Unfortunately, because of locally generated turbulence placing several turbines next to each other reduces the efficiency of each so that the whole is less than the sum of the parts

In short I will guess the total installation is going to have a name plate rating of about 10 to 20 kW and on an average achieve something of the order of 20 - 30 % of the name plate rating for a Capacity Factor [on an annual basis]

Thus the overall annual energy output is the product of the average power output of 2kW to 6 kW x 8000 hrs / yr == about 16,000 to 48,000 KWh per year

. . .kWH of power on average for the building."



We're getting there. Only another 138 words and one cross-referenced Figure left to cut from the game blank before we're ready to play Mad Libs "for reals" this time. Practice makes perfect.

 

[shmessy]

"These turbines will generate. . .
. . .kWH of power on average for the building."



We're getting there. Only another 138 words and one cross-referenced Figure left to cut from the game blank before we're ready to play Mad Libs "for reals" this time. Practice makes perfect.

Why are you even engaging that Gasbag? All he does is Whighjack threads with digressions that his own family has, over the years, learned to tune out - - that's why he comes here to post his regurgitations.

Post #765 is the epitome of a lack of self awareness.

 

[stick n move]

 

[DigitalSciGuy]

With the Boylston Street entrance reopened and approaching completion, I'm starting to get antsy about the retail on that corridor. Do we know how far from completion we are on the retail podium?

Do we also know if the Boylston Street entrance is going to stay white while they re-paint the rest of the arcade or is that just primer? The reconstructed part is very different from the existing arcade and fairly jarring.

 

[whighlander]

Why are you even engaging that Gasbag? All he does is Whighjack threads with digressions that his own family has, over the years, learned to tune out - - that's why he comes here to post his regurgitations.

Post #765 is the epitome of a lack of self awareness.

Shmessy -- a well chosen moniker -- you and you're "ilk" do much more to derail and deviate these threads by your constant carping and supposed clever connections to Howie Carr, etc.

My postings may not be fully appreciated by all -- but I never post gratuitously [well OK I think I did in approaching some numerical milestone]

My posts are always either in direct response to someone addressing my previous posting or based on new information relevant to the discussion which is on-going

So my postings relative to the output of the turbines was to provide a framework for the discussion which was on-going about the "value" of such a feature to the 888 Boylston building

 

[FK4]

Sadly, it is a natural element of human group dynamics to seek a scapegoat... Even worse, usually, on online forums...

Some people are given to take umbrage... Well, take umbrage they will...

 

[tobyjug]

Wiggy doesn't deserve to be bullied. He is usually good natured and he seldom uses snarkiness as a substitute for content. He puts great effort into his posts. If challenged by their volume and/or content, or if you don't have time to read them, you can skip over them. I think you can even block them? But if you do this, you'll miss some interesting, even if occasionally obtuse or abstruse, thinking.

 

[BeeLine]

^^^ +1

 

[Czervik.Construction]

Um, I thought I left physics in undergrad. Could we go back to complaining about this building?

Thanks.

-The Management team at Czervik Construction

 

[FK4]

Wiggy doesn't deserve to be bullied. He is usually good natured and he seldom uses snarkiness as a substitute for content. He puts great effort into his posts. If challenged by their volume and/or content, or if you don't have time to read them, you can skip over them. I think you can even block them? But if you do this, you'll miss some interesting, even if occasionally obtuse or abstruse, thinking.

Exactly. Some people get very rigid about rules as an excuse to crap all over someone else. It take a peripheral glance to see if a post is something you want to read or not. You scroll if the latter. End of story. I come here many times a day recognizing that each of us may have different motivations for browsing this site; for myself, I love the city, it's architecture and its history... I enjoy the posts relating a modern development to a broader context of history or science. Clearly not everyone does. Well, sometimes the angry comments are funny (I have to admit I usually chuckle at f lines) but many are getting quite nasty. Really... If you don't like what you're reading, just don't read it. There is certainly less added to the forum by angry vitriolic responses to whighlander's posts than by his posts themselves.

In a New Yorker annual press thing for young journalists they used to do (in this case with Dan Rather, Tom Brokaw, and Peter Jennings circa 2004), the conference concluded with Brokaws advice to those lamenting the rise of cnn and Fox News, and the loss of popularity of more thoughtful journalism... Brokaw's final comment was "you're the one with the remote control and if you don't like what you see, you can always change the channel".

http://youtu.be/nfWlot6h_JM

 

[AmericanFolkLegend]

Wiggy doesn't deserve to be bullied. He is usually good natured and he seldom uses snarkiness as a substitute for content. He puts great effort into his posts. If challenged by their volume and/or content, or if you don't have time to read them, you can skip over them. I think you can even block them? But if you do this, you'll miss some interesting, even if occasionally obtuse or abstruse, thinking.

Toby it's not just his posts. It's the repeated derailments his posts cause. But you're right, no one should be bullied on an architecture forum.

 

[whighlander]

Toby it's not just his posts. It's the repeated derailments his posts cause. But you're right, no one should be bullied on an architecture forum.

AmFolkLeg and the rest -- Thanks

All I'm looking for is fair consideration of what I present -- if I'm off-base on the tech, artististic details, etc., -- please enlighten us

As was pointed out above -- I do put a fair amount of work in formulating what I post and hope that it contributes something to the discussion of each thread [even if sometimes peripheral -- aka "derailment"]

As most of you I enjoy the banter -- but I also enjoy an intellectually stimulating discussion of Boston architecture / city planning and its historic context as well as some good "Arch Porn" pix of the latest cranes, etc.

to paraphrase what the Brits said during WWII -- "Relax and Carry On"

Now back to the regularly scheduled discussion of 888 Boylston's turbines