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Comment by jmharvey | Hacker News Reader

I'm a little surprised by this. The article implies that shuttered Sears stores already have the power and data capacity to function as a data center, but I can't imagine why. Compared to similar sized buildings (office buildings or factories, mostly), Sears retail locations don't seem to have a lot of power- or data-intensive needs.

Sears does have some amazing infrastructure (lots of square footage, locations at key transportation points in densely populated areas throughout the country, huge parking lots) but those aren't really the kind of features that data centers are usually optimizing for. I'm sure they're finding creative uses for this infrastructure, but I doubt it's anything like a data center as we think of one.

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The closed stores tend to be old, which means their original power requirements were based on what today would be grossly inefficient, and they are in locations with high levels of utility infrastructure and declining demand due to both the closure of other buildings and the increasing efficiency of those that remain.

Retail is actually fairly intensive from a power perspective, lighting levels are high to show off goods. The capacity of cooling systems is also high compared to office uses because the design case is a mob of shoppers [edit: think August afternoon during the tax free back to school weekend]. Unlike lighting, people generate a lot of latent heat, and unlike office workers they are moving. Also unlike office workers, feeling a little hot means they will take their business elsewhere.

Now, that's not to say that the infrastructure of a retail space is going to compare to a heavy industrial use, such as a steel mill or juice plant. But those aren't what Sears owns. And in any event, industrial sites don't offer the opportunity for redevelopment of the parking lot with smaller boxes as a means of diversifying the underlying asset. The sites aren't bad, the way in which they are developed is.

"Unlike lighting, people generate a lot of latent heat, and unlike office workers they are moving. Also unlike office workers, feeling a little hot means they will take their business elsewhere."

Excellent point. I remember when I put an HVAC system in many years ago (in a plant) the calculation was something like 2000btu per person in heat generated in terms of sizing.

I was curious so I just checked (couldn't back then) to see if that figure is anywhere near correct but can't seem to find the answer.

This seems to indicate that 600 watts is about 2k btu per hour it wouldn't surprise me if a human gave off 600 watts of heat:

http://www.rapidtables.com/convert/power/Watt_to_BTU.htm

Actually this more or less shows it is ballpark:

http://answers.yahoo.com/question/index?qid=20081206141450AA...

it wouldn't surprise me if a human gave off 600 watts of heat

Much closer to 100W sustained. I can hit 600-700W, very briefly, on a rowing machine. Wouldn't care to keep that up for more than a minute or two.

I second the "100W sustained" number. I did the math once with the assumption: 2000 kilocalories/day diet, 4.1852J/calorie, 86400 seconds/day, all input calories are eventually given off as heat.

2000 * 1000 * 4.1852 / 86400 = 97 watts

That is the problem, there is NOT enough power on site to run a datacenter. The article quoted one location with 127ksqft and 5MW. 5MW is tiny for that footprint. To give you an idea, you need to roll at least 300-400w/sqft of power/cooling to be viable, calculate in UPS and other losses, and 5MW powers around 5000sqft of datacenter space which is only a couple hundred racks of servers and storage. They're probably going to need 40-100M to retrofit that space, so I'd say the math is not on their side...

This reads like a realestate person proposing this, not a datacenter person...

Rooftoop solar is good for a mere 8 Watts / sqft [1] [2] when the sun's shining, and it's not a constant 8 Watts output over the day even if the weather is clear all day.

So repurposing a Sears building's rooftop area for solar power would not cover even the minimum requirements you cite (300-400 W/sqft -- x 24hrs/day) as necessary for a datacenter re-purpose.

But then there is that big, unused parking lot. If it's got, say, 30x the rooftop's area and can be fenced in, maybe then a ground-mounted solar system might supply some significant fraction of daytime energy.

------

[1] http://www.ehvacdesign.com/solar_system_design.htm

[2] http://www.solar-estimate.org/?page=solar-calculations

It's not whether it's already laid, but how easily it could be added.

The article mentions that the target locations are standalone buildings with good fiber and power already connected. They mention 5 megawatts for one location.

I don't know why a Sears location would need lots of power (beyond tons of lights and powerful HVAC units), but I can see the need for quality and low-latency data: retail POS generates a large amount of transactional data, and you need low latency for database syncing and credit card/loyalty card transactions.

> retail POS generates a large amount of transactional data, and you need low latency for database syncing and credit card/loyalty card transactions.

I've always been curious about what sort of infrastructure the average big-box retail store actually needs. My local Walmart can't have anything but a wireless uplink, unless they actually installed 5+ miles of fiber or something when they built the store.

This Quora answer gives a little insight in to the needs of a modern store: http://www.quora.com/What-is-the-new-instantaneous-payment-s...

Also these stores basically couldn't exist without robust inventory management systems. There is probably more technology in the average big box than we realize.

I was told that every time an item is scanned at the register at any Walmart store, it updates an inventory database in near real-time (I assume there is some sort of message queue with that kind of volume and distribution). Then their system automatically places replenishment orders with their vendors when the inventory of that item goes below a certain level. They are a well-oiled machine, focused on making sure that they almost never lose any sales due to being out-of-stock, nor waste money on carrying excess inventory in their warehouses. Mismatching inventory to sales will drive a retailer out of business very quickly.

This is also part of the reason why they are able to push "everyday low prices" instead of discounts. Discounting is what you do with the excess inventory when you messed up and ordered too much of something.

The system is Retail Link and there's quite an ecosystem around it.

Working for a regional grocery retailer from the mid-90's to the mid-2000's, I can assure you that not nearly enough consideration was given to bandwidth needs when designing and building new stores. I remember, as late as 2002, having an entire store run off of something like a 512kbps circuit.

We literally shipped register (paper) journal tapes back to the warehouse via truck mail.

Time/date/UPC. That should fit over a 9600 modem line, and that's before you add compression.

More like time/date, UPC, quantity, item description, price, coupons, sale discounts, sales tax, rebate info, clerk info, customer info, payment info, and more. Times dozens of items per receipt, times dozens of registers. All continually operating 12+ hours a day. All needing low-latency access to master databases, credit card servers, and banks.

Trust me, retail is big. Like "Big Data" big. There is more data there than you think. ;)

Sears also runs (and used to run many more that have since shut down) an auto repair shop -- Sears Auto Center. Auto shops will have some pretty hefty power requirements.

Well, my guess would be that they might have similar requirement power-wise. Keep in mind that those store need power for fixtures, refrigeration / freezing ... Someone knowledgeable around to confirm or refute ?

It probably would need some development but to me it's not as senseless as it seems.

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