Air blower treatment plants - power consumption.

[Ian]

16 minutes ago, Jimbouk said:

 

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.

My Biopure 1 is serving a holiday home and I was advised by the manufacturer to run the blower 2 hours on/2 hours off.

its been running about 18 months now without any issues.

With the 50% reduction in time the running costs are only about £20 per year as the JDK-S-60 pump is already a low power one (27 watts I think)

Edited October 27, 2018 by Ian

[Jeremy Harris]

Thanks, that's a useful data point to add to the various different on/off times that I've heard of, and as it happens we also have a Biopure 1, and the same Secoh pump.  I'll change the duty cycle on the timer next time I have the lid open and a laptop handy to programme it and see how it goes.  Our unit will only be lightly loaded with the two of us, and I'm pretty sure that it's still over-aerating at the moment.

[Ed Davies]

42 minutes ago, Jimbouk said:

sadly there is no option to turn down. Either on or off, …

 

Sure, I meant low duty cycle.

 

34 minutes ago, Russell griffiths said:

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, 

 

Well, for the 80 watts for the less power-saving ones that's 700 kWh/year, £112/year, so a 50% saving is £56/year.

 

Off grid, though, the saving is much bigger. Roughly speaking, winter-time electricity costs upwards of £30/watt in capital cost so saving half of 80 watts would be worth £1200. That'd buy you an awful lot of little timers. Even with a low-power (27 W) pump it'd be about £400. My warrant specifies a BioPure so I was going to ask their advice on low power running closer to the time but this thread seems to have given most of the answers anyway.

 

At Hinkley Point C prices (~ £20e9 for 3.2e9 W) it's still £6.25/W so the saving between an 80 W 100% duty cycle and a 27 W 50% duty cycle is £415 in capital costs.

[dpmiller]

Looking at the manual for our Solido Smart (which uses a Hiblow Duo 80 with a built-in timer controller, and is an SBR plant) it's aeration time can be varied between 5 and 18min per 20min cycle, to cover usage from 2-10PE.

[Jeremy Harris]

@Ed Davies, your thinking mirrors mine.  Although we're not off grid, we have enough PV generation capacity to more than cover our annual electricity use, and it helps a fair bit if I can reduce our power consumption during the hours of darkness.  Even in mid-winter the PV will generate enough to power the house normal background load, and I've been gradually looking at ways to reduce this during the night.  I run the house network stuff (VDSL2 modem, router, switch, file server etc) from DC via PoE, with the DC coming from switched mode DC-DC converters running from a battery bank.  The charger for that battery bank is currently just on a dumb timer, that charges it up during the day, allowing the batteries to power everything in the evening and overnight.  The next step will be to add some intelligence to the charging system, so it only charges when there is excess solar (pretty easy to do as I have an 868 MHz RF data link from the meter cabinet that transmits instantaneous true power and direction data every 10 seconds). 

 

The borehole system doesn't draw power overnight, as it takes around 300 litres to be drawn off before the pump comes on, and water consumption in the evening and at night is fairly low.  My car charge point only normally triggers a charge when a high export power is detected, not perfect, but a reasonable compromise given the inherent limitations of the J1772 protocol.

 

Reducing the treatment plant background demand makes a worthwhile difference, especially if I can add some intelligence to it later, so that the duty cycle varies in proportion to the amount of use the unit gets.  I may well be able to do this by using the discharge pump on time as a trigger, as that operates from a float switch.  Night time operation of the discharge pump seems unlikely, and so just detecting when it's operated, waiting a set period of time with no operation and then reducing the aeration pump on time, may be a good way to reduce overnight power consumption.

 

@dpmiller, thanks for another data point on acceptable on/off cycle times.

[Gone West]

4 hours ago, JSHarris said:

 

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.

 

When I fitted my WPL Diamond DMS2 over eight years ago it came with a Secoh EL-100C rated at 110-120W. I've noticed that the latest technical information for the DMS2 states that the air pump is now rated at 80W. Whether they have changed anything else I don't know but I could probably fit a lower rated pump without problems.

[Jeremy Harris]

16 minutes ago, PeterStarck said:

When I fitted my WPL Diamond DMS2 over eight years ago it came with a Secoh EL-100C rated at 110-120W. I've noticed that the latest technical information for the DMS2 states that the air pump is now rated at 80W. Whether they have changed anything else I don't know but I could probably fit a lower rated pump without problems.

 

My guess is that they have changed the pump from the Secoh EL-100C to the Secoh JDK-S-100, which has the same air delivery rate and pressure but uses 30% less power.

[Jimbouk]

5 hours ago, Russell griffiths said:

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. 

 

Cash saving is not the driver! Main home eats 25kw a day of electricity on stuff. No electric cars and gas heating. 

 

When i I started out building this one as a holiday home, I was keen to keep as simple as possible, not putting in all the gadgets that I have at home.

 

i’m monumentally failing and scope creep has taken control with a vengeance, to the extent fibre gets installed next month.

 

Would prefer to not have another house munching power, particularly when I’m not there. Think of it as a slight twinge of environmental consciousness.

 

prefer the Cirencester prices for breakfast. My normal breakfast haunt is Jolly Nice at Frampton Mansell. Unfortunately today’s hipster version cost £45 for two and the walls were covered in OSB, bloody Marys were involved though  

 

 

Edited October 27, 2018 by Jimbouk

[Russell griffiths]

Hi @Jimbouk are we neighbours, sort of. 

Bloody hipsters. Hate em. 

[Jimbouk]

@Russell griffiths indeed, I think I learnt to windsurf 30odd years ago very close to your plot!