Jump to content

Air blower treatment plants - power consumption.


ProDave

Recommended Posts

I have just today connected and comissioned the air blower on my Conder ASP6 treatment plant.

 

According to the pump it's rated at "80W" so I am somewhat surprised and very disappointed when I measured the actual current it is drawing as 0.7 Amps, which at 240V is 168W. If that is true then that adds up to an astonishing 1471KWh per year or at £0.15 per unit, an annual running cost of £220.  That is NOT what I expected.

 

I guess the first thing I need to do is run it for exactly 24 hours, with nothing else whatsoever in use and see how many KWh the electricity meter actually clocks up. That will give a more true indication of the actual "cost"

 

Anyway that's way to high so I want to look at other options, including replacing the pump with a lower power one, and an idea that has been discussed before of running the pump only part time.

Link to comment
Share on other sites

The PF will be well off unity, as these things are near enough an inductive load, one that only draws power each half cycle, as well, because they run at 25 Hz.  There was no PF capacitor that I could see when I took ours apart to change the diaphragms, either.  A decent power meter should do a good enough job of reading true power, but it may not, as the coils are driven from diodes, so only draw power for half a cycle.   The supply meter should easily be able to read true power, though, so reading the meter should give you a fairly accurate estimate of power.  The power drawn does vary with load, which is back pressure dependent, so the tank needs to be full of liquid to the normal operating depth to get a proper reading.

Link to comment
Share on other sites

I don't have a PF meter and guessed that might be what's "wrong" hence my idea of a 24hr electricity meter test.

 

The tank is full of clean water at the moment, having had no "input" yet so it's just blowing bubbles in clean water. 

Link to comment
Share on other sites

Clean water should be fine to get the right back pressure, so with luck you should get a reasonably good reading from the meter over 24 hours.  Inside these pumps there's just a pair of coils driving a semi-linear spring-mounted, armature back and forth, and this armature drives the centre of a diaphragm.  To get power pulses at a reasonable frequency, the incoming mains is just half wave rectified, so the coils are only energised for one half of each cycle.  It makes for a fairly reliable design, as there are no bearings, commutators or what have you, but the PF is pretty dreadful from the inductance of the coils, not to mention the fact the things only draw current for one half cycle!

Link to comment
Share on other sites

Okay test started.

 

An initial indication, is that the "1000 pulses per KWH" light is flashing once every 45 seconds. So that will take 45,000 seconds to clock up 1KWh which is 750 minutes or 12.5 hours.  So that would be 2KWh per day or an average of 83 watts continuous power, which is more like I would expect.

Link to comment
Share on other sites

That sounds about right.  You can almost certainly reduce that by 1/3rd by switching the pump on and off with a timer if you want.  There are problems if the pump is off for too long, as sludge can start to settle around the holes that the air comes out of, increasing the back pressure and stressing the diaphragms, but when I looked around I found that at least one system on the market uses a 30 minutes on, 15 minutes off timer and that system uses the same sort of pump.  I've made a simple timer that fits inside a watertight single gang socket box, with a solid state relay that's timed to switch the power from the socket on and off to this time schedule.  I've yet to install it, but the hope is that it will reduce the power consumption without adversely affecting the life of the pump. 

 

 

Link to comment
Share on other sites

  • 1 month later...

Further to this. Where I was working today, they have a Graff treatment plant. That has the air blower mounted remote from the plant, in this case in the garage.  The garage was serving as the site tea hut, so during lunch, I observed the blower was running for 5 minutes on, then 10 minutes off,

Link to comment
Share on other sites

3 minutes ago, ProDave said:

Further to this. Where I was working today, they have a Graff treatment plant. That has the air blower mounted remote from the plant, in this case in the garage.  The garage was serving as the site tea hut, so during lunch, I observed the blower was running for 5 minutes on, then 10 minutes off,

 

As per @joe90 other thread which I just posted in. Our Graff unit goes in this week. I'll report back.

Sounds promising.

Link to comment
Share on other sites

I don't know if the Graff works on a timer, or pressure. The pipes from the blower pass through the control box so it may be reacting to pressure changes, or that might just be to detect blower failure.   It will be interesting to see if those timings are repeated.

Link to comment
Share on other sites

  • 1 month later...
12 minutes ago, Jimbouk said:



@prodave Just wondering on your thoughts on the Condor system? Still consuming more power than anticipated? I have to decide on my system soon...

No it's consuming exactly what it should, 2KWh per day, see the above test with nothing else on.  the measured current is greater than expected but it must be running at a lousy power factor, and the meter does a good job of measuring KWh not KVA/h

 

I anticipate later on halving that by putting the blower on a timer, but no time for little projects like that just now.

 

I can report the discharge from the plant now it's been in proper use for a few months is an odourless colourless liquid.

 

Link to comment
Share on other sites

Having seen the Condor at @ProDave, it's certainly well worth keeping in the list.  The BIG advantage this over the Biopure I have, is that there is a separate emptying point, i.e. you do not have to lift out the blower / blower housing to empty it, as I have to do with my Biopure.  

 

One of my requirements was for the blower to be housed within the unit rather than remotely.

 

My decision to go with the Biopure was based on their ability to deliver to my location without significant uplift in price.  I simply couldn't get the Condor here for anything remotely approaching a competitive price vs the Biopure.

Link to comment
Share on other sites

  • 2 weeks later...
1 hour ago, Jimbouk said:

Can any one recommend the best supplier for the Condor? We will be installing it ourselves... TIA

I got several prices on line, then the local Travis Perkins came in lower.

Link to comment
Share on other sites

Ive been going round this loop. From my experience, the smaller players cant support the installation of their product. 

 

So you always end up being offered a Klargester unit, even though your initial enquiry was for something else entirely!

 

The Vortex in particular was one i looked at as mine is serving 2x 4 bed houses with a total of 4 people living there, 2 of them almost part time. Trying to get installation, frankly was a joke. Or rather, simply impossible. And its not like im stuck out on a limb like some of you guys, im in the home counties!!!

 

 

Link to comment
Share on other sites

  • 1 year later...

Thread revival.

 

Condor all installed and now been running for last six months. All good. Can confirm it seems to use circa 2kw a day.

 

Noted that @ProDave was looking to install a timer to reduce consumption. Have you had a chance to do that? Or has anyone else?

 

If so how, as simple as a three pin plug in timer from ikea?

 

Our unit will only be used for a couple of weekends over the winter, so seems wastefully having it running the whole time, equally I don’t want to save £50 electricity only to cause it all to sludge up and fail!

 

Thoughts and advice welcomed.

  • Like 1
Link to comment
Share on other sites

I'd have thought you'd need to keep the pump running, maybe at a lower level, all of the time, not just when the unit is directly in use, in order to keep the aerobic wee beasties alive rather than have them replaced by smelly anaerobic ones.

Link to comment
Share on other sites

From what I've been able to find out, leaving the pump off for more than a few hours may well cause sludge to settle over the air outlet holes and cause blockages or increased back pressure.  The timer systems seem to pulse the pump on and off, with on times being long enough to cause any sludge to get recirculated back into suspension (so around 15 minutes to half an hour minimum I think) as well as cause enough oxygen from the pumped air to dissolve into the effluent. 

 

It seems to be an imprecise art, getting the pump on/off times right, and I've arranged for the duty cycle on the timer I've built to be programmable, so that I can change it around to see what the effect is.  Right now it's operating for 20 minutes off, 40 minutes on, but that's a pretty conservative setting, I think, as I've heard of much longer off periods with some other timed units.

 

Changing the pump flow rate isn't easy, as they all run synced to a half wave rectified mains supply.  Adding a valve to throttle the airflow stresses the pump diaphragm, much the same as high back pressure from  sludge build up.  @PeterStarck found that high back pressure from excessive sludge build up caused a pump diaphragm to fail, IIRC.  Almost all aerated units seem to massively over-aerate, because they all use pumps that were originally designed to aerate Koi carp ponds.  Over aeration errs on the side of caution, as it does no harm and ensures the output always has a pretty low BOD.  The main disadvantage of over-aeration is the higher than strictly necessary power consumption.

 

There are higher efficiency pumps available that reduce power consumption a bit.  Our unit is running on a Secoh JDK series pump, which has a lower power consumption for the same air delivery rate as the older Secoh EL series pumps.

Link to comment
Share on other sites

@ProDave quite understand! Only prompted by the other thread running this morning...

 

@Ed Davies sadly there is no option to turn down. Either on or off, keeping the aerobic bacteria alive is key objective. Especially as during the winter months it will be doing nothing for weeks then have 8 visitors for a weekend.... then nothing for a few more weeks.

 

wondering whether it is better to do 15 minute on / off cycles or 1 hour or 2 hours. Guess it is a balance of wear on pump when it starts versus settlement.

Link to comment
Share on other sites

Are we over thinking this a bit, you say to save £50 in electricity, so if you get it turned down a bit and save £25, 

how much is the timer and the faff 

i have just spent £20 on to full English breakfast and two coffees 

maybe better places to make a saving and not risk a bunged up tank. 

 

Just my view on things. 

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...