Blower 2C782 = BAD heat & power use!

[jman311]

In my quest to cool my dual-tap 3" tower, I first ordered the 2C782 Blower recommended here. I noticed the blower itself puts out a lot of heat, not a good idea inside your fridge. So I did some tests, very disappointing!

Using a "Kill-A-Watt" (device that measures power usage on an A/C outlet), I found the baselines for my kegerator and the blower, running separately:

Kegerator - 20 kWh/month (@ $30/year)
2C782 Blower - 15 kWh/month (@ $22/year)
Added together = 35 kWh/month ($51/year) baseline power usage

That is a LOT of power usage for the blower just for the purpose of tower cooling. Anyhow, next I installed the blower inside the kegerator, using flex hose to push the air into the tower:

Kegerator w/ blower installed - 71 kWh/month (@ $102/year)

That's an additional 35 kWh/month (@ $51/year) over the baseline, which can be attributed to heat loss in the tower and the kegerator having to work harder to counter all the heat given off by the blower itself.

So ... ditching the blower for a smaller 80mm computer fan I get:

80mm PC fan (alone) - 3 kWh/month (@ $4/year)

With the fan installed in the kegerator, cooling the tower (fan -> cardboard shroud -> flex tube -> tower):

Kegerator w/ PC fan installed - 36 kWh/month (@$53/year).

That is HALF the annual cost of using the blower! The heat loss here, assumed to be mostly from the tower, is only 13 kWh/month ($19/year). Looks like my next step is to improve the tower's insulation.

Not to mention the PC fan is ~$15 or so, while the blower is ~$80 something.

Anyhow, based on the cost of the blower and the heat it gives off, I must say I recommend against the 2C782 blower, and I think Micromatic should not be selling them for this purpose. If you must use this blower, install it OUTSIDE the fridge.

[monkey710]

First...you can get the blower for much cheaper on other supplier websites.

Second, what cfm are you getting with the computer fan? Is it the same as you would with the blower?

I think that paying $70 more a year is well worth it for perfectly cooled Fat Tire!
But if you get the same results with the computer fan, great!

[cubby_swans]

Originally Posted by monkey710

First...you can get the blower for much cheaper on other supplier websites.

Second, what cfm are you getting with the computer fan? Is it the same as you would with the blower?

I think that paying $70 more a year is well worth it for perfectly cooled Fat Tire!
But if you get the same results with the computer fan, great!

The CFM is nowhere near the blower, but you don't need that much air movement. You just need air movement. The blower is better suited for commercial applications. The 80MM PC fan works fine. That's what I used. And mine was free. Took it from a PC going in the trash at work.

[Scott Zuhse]

Wow! Sounds kind of angry out there. I guess a comeback on the fact that Micro Matic offers this blower would be at least we offer something. Is it perfect? Probably not. Could we improve on this? Yes indeed and we will! We are always looking to improve how we do things in the best interest of low waste and quality dispensing.

Now that this wound has been opened, here is a question for the folks that offer kegerators with no tower cooling at all. Why? Yes, we offer these as well. We'll look at this too.

[lunkhead]

Originally Posted by jman311

Kegerator - 20 kWh/month (@ $30/year)

80mm PC fan (alone) - 3 kWh/month (@ $4/year)

Kegerator w/ PC fan installed - 36 kWh/month (@$53/year).
[/u].

Even the pc fan power consumtion has gone up 13watts installed in the kegerator. It's trying to move too much air into too small a space and may eventually burn out. This fan is also too big. With a proper sized fan there should be very little power increase. A small dc blower or fan in a box setup works the best in these smaller home kegerator units. Check the fan for a power rating and see how close it is to 16 watts or VA. That will tell you if your going to have a problem or not.

[jman311]

Monkey710 - I believe the PC fan is 30 CFM. It definitely loses some flow by the time it pushes the air up all the way up to the tower. In both cases (blower or fan), the tower was plenty cold ... as cubby_swans said you don't need much flow at all really.

Scott - I'm not angry. I was just disappointed when I noticed the blower, which is being marketed to put inside a fridge, puts off so much heat. When I first got it installed I noticed the fridge compressor ran a LOT more to keep up with it, which inspired me to check the numbers.

Lunkhead - the PC fan power consumption did not go up when installed in the kegerator. If I isolate it and check the consumption separately, it's still the same. I believe the reason the overall consumption goes up (in both cases) is the colder air is being pushed into the very-much "under-insulated" tower, which becomes very cold to the touch and loses a lot more heat than when the warmer air sits in there, stagnant. It's running the coldest air over the least-insulated part of the system. Colder air pushed to the top of the tower will push warmer air back into the kegerator. All this makes the compressor run more often.

I'm assuming the additional heat loss from the tower is relatively constant in both models. The main problem with the blower (over the fan) is ambient heat given off by the blower itself.

By the way, with no air flow, the temperature difference between the top and bottom of the inside of the kegerator is significant (6+ degrees). With the air moving through, the difference drops to a degree or so.

[lunkhead]

You might try adding some extra layers of insulation in there. I used 2 layers of foam floor underlayment with is only 1/8" thick per layer, on top of the existing insulation. Takes up room, but there's enough space for return air flow and the tower is not cold to the touch.