The good news is that in terms of reducing our use of town water, this project is definitely meeting its objectives! We've done piles of washing and started flushing the loo again with wild abandon. I even hosed off the concrete along the back of the house after doing some top-dressing of the lawn. With the weather we've been having lately (lots of showers) we've been unable to get the water level more than about 1200L below capacity, and as of this morning the tanks were full again. Makes me wish there was some way to use that water for bathing as well.
However... all this water abundance has come at the cost of increased electrical consumption. Of course I knew that some electricity would be necessary to power the pump, but I've discovered two ways in which our setup is far from optimal.
First, the pressure switch. That blue gizmo on top of the pump which monitors the pressure and decides whether the pump needs to be running or not. Courtesy of my power meter I have discovered that the cost of monitoring the pressure is apparently about 15W continuous power consumption, or the equivalent of one rather bright CF bulb shining 24x7. In most homes that would be considered negligible, but in my home that's slightly more than a 5% increase in our average daily energy use.
The obvious solution to problems of that sort is simply to switch off the device when it's not needed. And sure, the pump needs an appropriate switched outlet to plug it into. But that would only solve part of the problem.
Three out of the four taps fed by the pump are used in such a way that it makes sense to switch on the pump before use and switch it off again afterwards - doing a load of washing, filling the tub or a bucket, using the hose and so on. The toilet, though, is a different matter.
With a toilet you need the water to flow into the cistern after your, um, "activity" is completed, and then only for a relatively short time. Can you imagine being required to flush, wash hands, walk to the laundry, flick the switch on, wait 30 seconds then flick the switch off again? Can you imagine teaching young children to do that? No, a simple switch is not going to suffice here.
The next most obvious suggestion is to install a second switch in the toilet, wired up in a 2-way configuration like many light fixtures are - such that flicking either switch up or down will change the on/off status of the light, or pump in this case. It would alleviate the walking part of the problem, but you'd still be left with the waiting.
What I'm hoping to do is a variation on that idea using a logical "OR" operation and a time delay switch. This switch is normally in the "off" state. When you push it in, power is allowed to flow but only for a minute or so until the spring-loaded mechanism returns to its initial position. So you push one button on the cistern to flush the toilet and then another button on the wall to refill the cistern, then you walk away (to wash your hands, of course). Either the laundry switch OR the toilet time delay switch can be independently activated to provide power to the pump as required.
Actually both of those switches will feed into the exterior switched socket that the pump is plugged into, so the correct logical expression is: (laundry OR toilet switch turned on) AND (external switch turned on) -> (a powered pump).
I foolishly bought all three switches today without first asking about the prices. Total cost $106. Could have saved twenty bucks if I hadn't asked for the laundry switch to have one of those little red lights in it to show when it's turned on. But anyway...
At current prices of 21.455 cents per kWh (15.455c regulated tariff 11 plus 6c GreenSwitch renewable energy premium) I'm going to have to have the pump switched OFF for about 33 thousand hours - nearly four years! - to recover the cost of the switches alone. But then I'm still predicting that energy costs will rise rapidly over time, and hopefully these switches will be in use for a long time after they've paid back their cost.
The moral of the story is to carefully check the electrical requirements of the equipment you're installing in a bid to save water. Thus endeth part 2. Next time I'll look at the other, far more important aspect of the energy efficiency equation when it comes to pumping water around: the pipes.
(Got any ideas about how to design a really efficient tank/pump system for home? Please share in the comments.)
Saturday 29 December 2007
Pipes and Pumps, part 1
Can you think of a more boring-sounding subject? There wouldn't be too many, but if you care about energy and water efficiency then there are some very important things to know about pipes and pumps. As with many lessons in life, I learned these things shortly after the precise moment when it would have been most helpful to know them.
The context is, of course, that having installed tanks to capture the rain that falls on my roof I needed some way to get that water into my laundry and toilet in order to reduce my consumption of externally-supplied water. In this time and place carrying water in buckets is not an acceptable solution. Pipes, valves and a pump would be required. In this post I'll show you the solution we installed.
As I've mentioned more than once, our two tanks are situated one at each end of our house and are connected by a 25mm plastic pipe at ground level. That pipe has two functions: it allows the water level to rise evenly in both tanks regardless of how much water flows through their respective downpipes, and because it runs straight past the laundry it allows water to be drawn evenly from both tanks through a T piece inserted at the appropriate point. So far so good.
Knowing my limits, I paid a professional to supply and install the rest of the solution. We had a brief discussion about my requirements, agreed to use a pump at the low end of the price/performance curve and arranged to install four taps: one on the outside laundry wall adjacent to the pump, two just inside the laundry for the tub and the washing machine and the fourth a few meters along and through the wall for the toilet.
Stop! Camera time. In this first image you can see the inlet (low foreground) going into the pump body (red). On top of the pump is the electric pressure switch (blue) which turns on the pump whenever the outlet pressure drops below a preset level. The water flows upwards through the pressure switch and out the top.
Here you can see the new pipework (black) going up the wall to the new tap (left) and still further up then through the wall into the laundry.
Next, a shot inside the laundry with the double tap arrangement for the tub and washing machine.
Finally, our modified toilet. My original plan was to have a second tap in the toilet just as we have in the laundry so that we can connect the cistern to the appropriate one as required. The bloke we hired to do the installation explained that council regulations wouldn't allow it - something about making it too difficult for the elderly or the disabled to ensure reliable toilet operation - and so we now have a permanent dual-float configuration where we merely need to turn on the appropriate tap. The tap (and float) on the left control the existing mains water supply while the parts on the right take water from the pump.
Now I shall be the first to admit that, overall, this isn't a "pretty" job - because that really wasn't a goal. The pump gets hidden under a plastic cover that's about the same colour as the concrete, the laundry is destined for eventual renovations anyway and the whole lot is down the back side of the house where nobody goes looking for aesthetic satisfaction.
So that's what it looks like. In the next post I'll go into how well it works.
The context is, of course, that having installed tanks to capture the rain that falls on my roof I needed some way to get that water into my laundry and toilet in order to reduce my consumption of externally-supplied water. In this time and place carrying water in buckets is not an acceptable solution. Pipes, valves and a pump would be required. In this post I'll show you the solution we installed.
As I've mentioned more than once, our two tanks are situated one at each end of our house and are connected by a 25mm plastic pipe at ground level. That pipe has two functions: it allows the water level to rise evenly in both tanks regardless of how much water flows through their respective downpipes, and because it runs straight past the laundry it allows water to be drawn evenly from both tanks through a T piece inserted at the appropriate point. So far so good.
Knowing my limits, I paid a professional to supply and install the rest of the solution. We had a brief discussion about my requirements, agreed to use a pump at the low end of the price/performance curve and arranged to install four taps: one on the outside laundry wall adjacent to the pump, two just inside the laundry for the tub and the washing machine and the fourth a few meters along and through the wall for the toilet.
Stop! Camera time. In this first image you can see the inlet (low foreground) going into the pump body (red). On top of the pump is the electric pressure switch (blue) which turns on the pump whenever the outlet pressure drops below a preset level. The water flows upwards through the pressure switch and out the top.
Here you can see the new pipework (black) going up the wall to the new tap (left) and still further up then through the wall into the laundry.
Next, a shot inside the laundry with the double tap arrangement for the tub and washing machine.
Finally, our modified toilet. My original plan was to have a second tap in the toilet just as we have in the laundry so that we can connect the cistern to the appropriate one as required. The bloke we hired to do the installation explained that council regulations wouldn't allow it - something about making it too difficult for the elderly or the disabled to ensure reliable toilet operation - and so we now have a permanent dual-float configuration where we merely need to turn on the appropriate tap. The tap (and float) on the left control the existing mains water supply while the parts on the right take water from the pump.
Now I shall be the first to admit that, overall, this isn't a "pretty" job - because that really wasn't a goal. The pump gets hidden under a plastic cover that's about the same colour as the concrete, the laundry is destined for eventual renovations anyway and the whole lot is down the back side of the house where nobody goes looking for aesthetic satisfaction.
So that's what it looks like. In the next post I'll go into how well it works.
Friday 28 December 2007
It's not easy being Green (Powered)
In the past I've sung the praises of GreenSwitch as an easy and relatively economical way to source renewable energy for your household's consumption while investing in reputable Australian renewable energy projects. That's still the case, but less so than it used to be: GreenSwitch no longer allows transactions less than $75 in value. My own requirements for the previous quarter only come to about two thirds of that, so they wouldn't let me buy.
For anybody in South-East Queensland, be aware that our major electricity retailers, AGL and Origin Energy, currently don't offer 100% certified GreenPower plans to Qld customers. I can't get a straight answer out of them as to why that's so and what they are currently able to offer is pretty pathetic. It's a pity though, because their 5.5c/kWh premium is now a fraction cheaper than GreenSwitch, which has risen to 6c/kWh.
If you really want less than 1250kWh of 100% GreenPower and you want it now, try ClimateFriendly for around 6.5c/kWh.
I could hold on for the next quarterly bill and buy six months worth of green energy in one go... except that I'm predicting continually increasing energy prices. Will ponder.
For anybody in South-East Queensland, be aware that our major electricity retailers, AGL and Origin Energy, currently don't offer 100% certified GreenPower plans to Qld customers. I can't get a straight answer out of them as to why that's so and what they are currently able to offer is pretty pathetic. It's a pity though, because their 5.5c/kWh premium is now a fraction cheaper than GreenSwitch, which has risen to 6c/kWh.
If you really want less than 1250kWh of 100% GreenPower and you want it now, try ClimateFriendly for around 6.5c/kWh.
I could hold on for the next quarterly bill and buy six months worth of green energy in one go... except that I'm predicting continually increasing energy prices. Will ponder.
Stats Update (Updated)
I last read my electricity and water meters 37 days ago. Some interesting things have happened between then and now including the installation of the electric pump that enables us to use captured rainwater in our washing machine and toilet. There'll be a separate post about the pump and related matters, but I have been very curious about how much impact that system would have on our consumption of external energy and water.
Today's reading won't give the whole story. For one thing, I can't recall exactly when the pump was installed but I'm pretty sure it was after that last reading. And our whole family went away for a week's holiday during the period so our consumption was artificially low during that time - I'll do some math to compensate for it but even that won't be accurate because the fridge was running for the week and I don't know how much power it would have used when nobody was opening it.
And speaking of the fridge... it's not well. Either it has a blocked drainage channel or leaking door seals. There's too much Christmas food in it to try and fix the problem right now but I wouldn't be surprised if it's using more power than usual. (Update: only hours after I posted that, the electrical safety switch in our fuse box tripped. The fridge was the culprit - all that water building up must have short-circuited something. Emptied it out and pulled it apart a bit, found the decomposing remains of some corn kernels blocking the condensation drainage pipe. Cleaned, reassembled, tested, OK now.)
So then: Tariff 11, the standard domestic electricity supply. Over 37 days we used 265kWh, averaging about 7.15kWh per day. (Our average for the 94 days to 10 Dec, which includes our week away, was almost exactly 7kWh.) Compensating for our time away brings the figure to more like 8.8kWh per day, a fairly significant increase. I'll have to do some work here to understand where the extra power is being used. Probably I'll connect the fridge and the pump to my two power meters and find out precisely how much of a contribution they're each making.
Next up is Tariff 31: Night Rate. I'm including this one just for comparison, because since the installation of our solar water heater we've switched to a different tariff. But energy is energy, and on this bill we see that over 21 days we used 90kWh. This included a few days where we had no hot water system at all and then a few more after the solar system was installed but before the electricity company came to reconfigure our meter for the other tariff.
Tariff 33, "Controlled Supply", works similarly to the night rate system except that it's available for 16 hours each day instead of just 8. I decided that made more sense for a hot water booster because we'd likely need it in the late afternoons and evenings when night rate supply would still be unavailable. Our total consumption over the 73 days covered on the bill was...
2kWh. That's not per day, that's total. We had to flick it on for an hour or so sometime in October if I recall correctly. It hasn't been on since, so of course the consumption over the past 37 days is a flat zero. I love my solar hot water system.
OK, so on to the water. I want to put this into perspective.
For the previous 39 days (that is, prior to the last time I read the meter) we had averaged 381L per day. For the 37 days just ended our daily average is 200L per day!
Even taking out the week we weren't here gives a figure of 247L per day. Again this is something that will need some monitoring during the coming weeks to work out our ongoing rate of consumption but I'm pretty pleased about that. Tank water is now being used for all outside requirements, all laundry, and most of our toilet flushing. The Shower Saver would account for a sizeable reduction in mains water use as well.
Today's reading won't give the whole story. For one thing, I can't recall exactly when the pump was installed but I'm pretty sure it was after that last reading. And our whole family went away for a week's holiday during the period so our consumption was artificially low during that time - I'll do some math to compensate for it but even that won't be accurate because the fridge was running for the week and I don't know how much power it would have used when nobody was opening it.
And speaking of the fridge... it's not well. Either it has a blocked drainage channel or leaking door seals. There's too much Christmas food in it to try and fix the problem right now but I wouldn't be surprised if it's using more power than usual. (Update: only hours after I posted that, the electrical safety switch in our fuse box tripped. The fridge was the culprit - all that water building up must have short-circuited something. Emptied it out and pulled it apart a bit, found the decomposing remains of some corn kernels blocking the condensation drainage pipe. Cleaned, reassembled, tested, OK now.)
So then: Tariff 11, the standard domestic electricity supply. Over 37 days we used 265kWh, averaging about 7.15kWh per day. (Our average for the 94 days to 10 Dec, which includes our week away, was almost exactly 7kWh.) Compensating for our time away brings the figure to more like 8.8kWh per day, a fairly significant increase. I'll have to do some work here to understand where the extra power is being used. Probably I'll connect the fridge and the pump to my two power meters and find out precisely how much of a contribution they're each making.
Next up is Tariff 31: Night Rate. I'm including this one just for comparison, because since the installation of our solar water heater we've switched to a different tariff. But energy is energy, and on this bill we see that over 21 days we used 90kWh. This included a few days where we had no hot water system at all and then a few more after the solar system was installed but before the electricity company came to reconfigure our meter for the other tariff.
Tariff 33, "Controlled Supply", works similarly to the night rate system except that it's available for 16 hours each day instead of just 8. I decided that made more sense for a hot water booster because we'd likely need it in the late afternoons and evenings when night rate supply would still be unavailable. Our total consumption over the 73 days covered on the bill was...
2kWh. That's not per day, that's total. We had to flick it on for an hour or so sometime in October if I recall correctly. It hasn't been on since, so of course the consumption over the past 37 days is a flat zero. I love my solar hot water system.
OK, so on to the water. I want to put this into perspective.
For the previous 39 days (that is, prior to the last time I read the meter) we had averaged 381L per day. For the 37 days just ended our daily average is 200L per day!
Even taking out the week we weren't here gives a figure of 247L per day. Again this is something that will need some monitoring during the coming weeks to work out our ongoing rate of consumption but I'm pretty pleased about that. Tank water is now being used for all outside requirements, all laundry, and most of our toilet flushing. The Shower Saver would account for a sizeable reduction in mains water use as well.
A season for everything, even blogging
Last post November 18th. Hmm.
When I started this blog, I made a point of it being for "you". "You" turned out to be not that interested, or perhaps just unaware that I was doing it. Such is the world of amateur blogging as far as I can tell, and that's OK. It seems that most amateur blogging tends to be a personal, cathartic thing - certainly that's been the case for me even though I didn't expect it to be so.
Things may remain quiet around here for a while, apart from a couple of quick updates I'm thinking of posting since I'm sitting here anyway. January will continue to be really busy for me at work and the family has to take priority over blogging. If anybody has any ideas for a post or any questions about anything, drop me a line in the comments.
Cheers,
Terry
When I started this blog, I made a point of it being for "you". "You" turned out to be not that interested, or perhaps just unaware that I was doing it. Such is the world of amateur blogging as far as I can tell, and that's OK. It seems that most amateur blogging tends to be a personal, cathartic thing - certainly that's been the case for me even though I didn't expect it to be so.
Things may remain quiet around here for a while, apart from a couple of quick updates I'm thinking of posting since I'm sitting here anyway. January will continue to be really busy for me at work and the family has to take priority over blogging. If anybody has any ideas for a post or any questions about anything, drop me a line in the comments.
Cheers,
Terry
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