Topic: Electricity to cool the house when mining (Read 3472 times)

Agreed.  I may look back into it.  During the day or two I spent tuning the GPUs, I had some stability problems dropping the memory frequency and did not pursue that option, rather I concentrated on pushing the core clocks to the max.

You should consider lowering your memory to 200-400 range.  It will reduce your temps further.

remember that heat rises...

Go to your local Costco and buy a solar-powered roof fan for $300 (assuming you live in a house).

You should get a $100 tax credit on your federal taxes if you itemize.

The amount of work your AC in the house will have to do will drop considerably!!! resulting in lower electricity consumption due to cooling.

My rigs: 1.48 MH/s/watt + no AC cost
Your rigs: 1.60 MH/s/watt + maybe some AC cost

Clearly your rigs are more efficient.  My GPUs are overclocked, perhaps yours is not.  In any case, I had limited choices when purchasing my rigs and chose the Sapphire HD 5770 because of their low purchase cost for the MH/sec produced - by then the 5830's were gone.

you have to reconsider your setup. 860W producing 1272 MHash/s, that's not very efficient. my current system draws 240W and produces 385 MHash/s. it's not some cheap low power consumption cpu, either. it's an overclocked 2600k. in addition to that i use a 2nd video card for gaming etc, which is (of course in low power state) included in the 240W.


i'm not too sure about that. i didn't have thermodynamics in theoretical physics yet, but reading some wikipedia article about it, it seems that the reverse of a carnot process apply here, so the efficiency is the inverse of that of the carnot process. and iirc the carnot efficiency is not <0.5, but <1. the actual efficiency depends on the delta value of the 2 different temperatures.

Right now the humidity in Austin, Texas is 45%.  My house is pier and beam construction which elevates it 4 feet above the rocky soil under the house.  Because the house is on top a ridge, the crawl space has been bone dry for years. Dust might eventually be an issue but the CPU and GPU fans seem to keep their respective radiators clean enough.  As purpose-built mining rigs, I chose a conservative configuration with respect to heat dissipation.   There are only two GPUs per mother board, and there is sufficient space between the cards for unobstructed airflow.  I chose Radeon HD 5770 CPUs that draw somewhat over 100 watts when overclocked.  Likewise I chose the least power consuming CPUs for the motherboards. The three rigs have six 5770 cards and in total draw 860 watts from the socket.  

Some may not be aware that recently Intel has been conducting research on whether datacenter air conditioning could be relaxed a bit.  This article: http://www.datacenterknowledge.com/archives/2008/09/18/intel-servers-do-fine-with-outside-air/ gives details.

I'm not ignoring a possible fire danger with six overclocked GPUs.  I have the power supplies sitting on pieces of floor ceramic tile, and the case-less motherboards elevated a bit off the small sheet of plywood that supports them.

Here are temperature and clock readings from one of the rigs, that I control from my home office via ssh.  Note that the outside air temperature is 38 C (100 F), the crawl space is a steady 30 C (86 F).  The rig produces 424 MH/sec using poclbm.

user@linuxcoin02:~$ DISPLAY=:0.0 aticonfig --odgt --adapter=all

Adapter 0 - ATI Radeon HD 5700 Series
            Sensor 0: Temperature - 65.00 C

Adapter 1 - ATI Radeon HD 5700 Series
            Sensor 0: Temperature - 56.00 C

user@linuxcoin02:~$ DISPLAY=:0.0 aticonfig --odgc --adapter=all

Adapter 0 - ATI Radeon HD 5700 Series
                            Core (MHz)    Memory (MHz)
           Current Clocks :    960           1200
             Current Peak :    960           1200
  Configurable Peak Range : [500-960]     [1200-1445]
                 GPU load :    99%

Adapter 1 - ATI Radeon HD 5700 Series
                            Core (MHz)    Memory (MHz)
           Current Clocks :    960           1200
             Current Peak :    960           1200
  Configurable Peak Range : [500-960]     [1200-1445]
                 GPU load :    99%


 

Keep in mind that these are all approximations, your mileage WILL vary, but these approximations have worked for me quite nicely:

For each watt of actual consumed power (read: go buy a kill-a-watt) from computer equipment, expect approximately 3.5 BTU/H of heat to be produced. It costs about 0.1175 watts for the least efficient air conditioner to remove 1 BTU/H of heat, or about 0.4114 watts to remove the 3.5 BTU/H of heat produced by one watt of computer equipment.

Newer air conditioning is better and there are a number of ways one can reduce this, but 0.4114 watts of cooling per watt of equipment is a good "worst-case scenario" for cost estimates. In my case, for example, one of my lower-end rigs consumes about 400 watts of electricity. 400 * 1.4114 = 564.56 watts after cooling is considered. At my local rate of $0.1128 per kW/H, that means that without AC that rig costs me about $1.08 per day. With AC it now costs $1.53 per day. If you're only interested in rough estimates, it's pretty fair to say it'll cost about 40% as much to cool the equipment as it does to actually operate it.

Again, all estimates and worst-case estimates at that, but hopefully they help.

I hope you have a dehumidifyer nearby or else that rig will be toast soon.

This is exactly what I'm planning to do. I tested a miner for 2 days outside the last weekend. No problem so far.

Here is tutorial on A/C costs for large office installations that scales well to bitcoin mining rigs. http://joule.bu.edu/~hazen/LinuxCluster/actut.pdf

A quote from that article ... "Typical air conditioning systems would require 0.5 BTUs of energy to remove 1 BTU of heat."

By the way, knowing the expense and discomfort of running an 850 watt bitcoin mining farm inside my house, I situated my three rigs outside my house.  They are in the crawl space under it where the ambient temperature is 30 C / 86 F, even when the outside air is 100 F here in Austin, Texas, USA.

This is a good point to consider.  I mine in a 2-story home and it definitely heats up the top corner where the rig is located.  Thankfully, I have 2 separate air conditioners and I can set the bottom floor to be much cooler than the top floor.  Anyone mining in a small apartment and running the air conditioner to keep the living space cool has got to be losing money on his operation.  Not to mention dealing with the noise... I know I wouldn't be able to deal with everything that comes with mining without a 2-story place...

Depends. A mining rig is about 100% efficient at heating a house. If I recall correctly, the carnot cycle, the most efficient method of converting thermal energy to work is about 50% efficient? So real world application probably below 30%.

But then again there are other factors to be remembered. For example you are not necessarily removing every bit of energy produced by your rigs via A/C. Simple convection can help you a bit. In general though A/C uses a ton of energy. In many cases your best bet would be to isolate your mining rigs into a single area, that vents hot air to the environment, while taking in a moderate flow of cooler house air, and keeping the rest of the house insulated with cool A/C air running. In this way you do not need to air condition every watt necessarily. The Mining room will be warm of course.

Depends. on your cooling eqwuipment and how stupid you set it up.

For example, why cool the house? Why not just blow all the hot air out and ler cool air come into the house? A lot more efficient than running chillers. What about water? A chiller runs more efficient with a good heat sink - if you ahve a small lake or something along the house.... bingo

We all know about the electricity we use to run our mining rig. But what is the amount of electricity we use more to cool the room or house because of the heat produce by the miners.

For example, if my miners use 1000W (8.3A at 120V). How many Amps does th AC needs to cool the house for the added heat of the miners ? Is it about the same ?

Is the AC more efficient to cool the house than computer is to heat it ? Or it's about the same.