Building an Energy Efficient Datacenter?

asc4 asks: "The company I work for is a webhosting and colocation company. As our power utilization grows, we have begun searching for ways to make our datacenter more efficient. The biggest hit from the utility company comes in the peak usage charge, which penalizes (rather severely) for the highest sustained burst of usage during a billing period. Due to the nature of the colocation business, we can't control how much or when client devices use power, so I'm wondering: is there's something we can do at the datacenter level to help smooth out our power consumption, over the course of a given period of time?" "In these days of hybrid cars, Energy Star devices, and in general more eco-friendly power consumption, it seems like there must be some products out there that can help make datacenters more efficient, as well. Could fuel cell technology be something to look into? Would flywheels or capacitors help? How about using more efficient AC units than what are available from the big names? What are others doing to reduce peak power consumption in high-drain datacenter environments?"

Comments

pump water uphill through generators

[rcpitt]

During off-peak time, pump water uphill to a holding reservoir - a big swimming pool on the roof might do.

Heat the water with the waste heat from the cooling units.

Sell access for swimming - nice warm water (well, here in Canada we like it warm :)

During peak hours, drain the pool back via generators to make electricity. (make sure you tell people first)

Use warm water to cool more - generate steam.

Run steam through turbines to generate electricity.

Use electricity to pump more water to pool on roof

continue as needed

Re:pump water uphill through generators

[Kitsuneymg]

This is exactly how the TVA stores extra generated power. They pump it back uphill above a dam. While hard for a small business to do, it is one of the most efficient power storage mechanisms used by the power industry.

A thought that crossed my mind: Power Factor

The power you actually benefit from is not what you are charged for. If the magnitude of real power (550 kwatts etc) is one side of a right triangle and reactive power (measured in VARS where 1 VAR= sqrt(-1) watts) is the other, you are charged based on the hypotenuse. (eg sqrt(Real^2 + Reactv^2) = Billed power. The angle between the hypotenuse and real power is controlled by the amount of impedance (reactance) in your system. This is called your power factor. To bring this towards unity in industry, special variable capacitance motors are used to counteract the inductive effect of normal motors (and PSUs and fans, and wires, etc.) Your power company should be able to tell you all about it, including if it is worth it for you to do. Just ask about power factor correcting.

The motor DOES use real power but it helps eliminate reactive power. Power companies typically charge a lot for an overabundance of reactive power consumption(ie too muich inductance) because this can seriously wear on generators.

Another thing. Make sure you have good switching power supplies. Cheapass supplies are both noisy and inefficient. ANything quoted as having Active-PFC or A-PFC already does power factor correction and the above can be ignored for it.

Wiki-links: Reactive Power, Power Factor, Power Factor Correction. The last one is what you will want to do.

Load Balancing

[redphive]

I am going to guess you have 3Phase power perhaps through more than one primary link. Do they charge
based on the peak of one phase or the average of all. If you aren't balanced on your phase input into your building, you may be able to rebalance and see some benefit there. If you have one or two large UPS systems that are pulling equally across all three phases, make sure that the output of the UPS system is also balanced, that could end up bringing your input usage down.

This of course wouldn't help with your peak usage, but something to consider anyways.

Short of that, you would be looking for something that could store power and charge that at a regular rate. But then you could end up possibly shorting your demand on the output side based on the available power in that 'system' at peak times.

I am going to guess your best bet is to look at phase and load balancing through your power distribution network and make sure you have placed your clients. If I was in a similar situation, I would set up a collection of load coils across each hot lead in your power distribution network and graph the values on a tight schedule (in order to catch peaks) and determine what is responsible for your peaks.

Don't know if any of this would help, but it is discussion, mod accordingly.

Lower Peak Demand

[RelaxedTension]

I used to work for a company where I was in charge of building automation and peak demand limiting. We used several strategies for this. 1. Use thermal storage where possible. The only real source you can control is the cooling/heating for the building, and you want to build uip as much of what you need during low periods of usage, like in the middle of the night. If you're in a cold climate, store heat, and if you're in a cold climate store cold. Use water large water tanks to achieve this. It will cost you to install them initially, but they will pay for themselves in a surprisingly short period of time. 2. Monitor the usage and trim where you can when you're hitting peak demand. Turn off lights, coooling units, etc., for the short time that it's required. Pre chill or heat the building ahead of time. 3. Run your backup generator to supplement existing power if you have seasons where usage is much greater than at other times of the year. If you have to run it every day of the year it won't help due to maintenance and fuel costs. But if you need it for short periods to chop the peak then it's well worth it. Again, it will more than pay for itself. The power company may even pay you to supplement them with it. 4. Look for alternative methods to heat or cool, or even generate power. You'd be surprised at what's available now for that.

How much do you value reliability?

[Anonymous Coward]

For smoothing out power usage, there are a number of different options -- aside from alternative energy, you could do rolling brownouts throughout your datacenter and rely on UPSes or generators to keep things going -- but you *will* take a hit in reliability. Every switchover -- one mains circuit to another, mains to battery, etc. -- carries some risk.

I've watched an entire datacenter go out on what was supposed to be a controlled switchover -- power company needed to do some work, pulled the plug (with the datacenter's consent), the backup generators start... and then die. The UPSes kicked in, but could only supply 15-20 minutes of power. Everything failed over to a backup datacenter, whose link then decided to go out to lunch.

Total cost of the outage was measured in tens of millions of dollars.

Just keep this in mind when doing the business justification calculation (cost savings from lower energy bills, minus upfront cost of equipment, minus risk of additional downtime times cost of downtime, minus cost of maintaining the equipment). Unless energy prices go *way* up -- like oil hitting $250/barrel -- I'd be surprised if this would pay for itself.