Browse Forums Eco Living Re: Sizing a rainwater system for self-sufficiency 2Apr 08, 2013 5:12 pm The Harder You Try - the Luckier You Get ! Web site http://www.anewhouse.com.au Informative, Amusing, and Opinionated Blog - Over 600 posts on all aspects of building a new house. Re: Sizing a rainwater system for self-sufficiency 5Apr 09, 2013 10:57 pm 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. Re: Sizing a rainwater system for self-sufficiency 7Apr 10, 2013 9:52 am 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. Re: Sizing a rainwater system for self-sufficiency 9Apr 10, 2013 2:39 pm 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. Re: Sizing a rainwater system for self-sufficiency 10Apr 10, 2013 4:38 pm TimH247 As to tank size, I'm thinking 6 months supply in storage so around 50,000L - maybe 2 x 25,000L? Don't forget to allow for a fire fighting reserve. - The council or the CFA should be able to advise you of the amount The Harder You Try - the Luckier You Get ! Web site http://www.anewhouse.com.au Informative, Amusing, and Opinionated Blog - Over 600 posts on all aspects of building a new house. Re: Sizing a rainwater system for self-sufficiency 11Apr 10, 2013 5:58 pm Thanks for all the info there H20, very useful. Most of the blocks around here are dead flat which leads to a wet system. I've read through your posts on other rainwater threads and gained some excellent insights into what's involved. I will have some questions when it comes time for an actual install At this point I'm only in the feasibility stage so just trying to work out if it's possible to be self-contained on one of these blocks. Looks promising so I'm going to push forward with some more accurate budgets... bashworth TimH247 As to tank size, I'm thinking 6 months supply in storage so around 50,000L - maybe 2 x 25,000L? Don't forget to allow for a fire fighting reserve. - The council or the CFA should be able to advise you of the amount Good point bashworth. My vision involves a small dam/large tank to store irrigation scheme water for reuse (horse water, plant nursery, garden establishment), so CFA could use that if it's ever required. Will check with them. Rainwater is just for potable water in the house. As an aside, I'm looking at an LG LD1452WFEN2 dishwasher to replace the dying F&P in my current house. Claimed water use per wash is only 11.5L! Re: Sizing a rainwater system for self-sufficiency 12Apr 10, 2013 6:47 pm Planning for water efficiency is important. More important is that you can attain that efficiency. If not all the planning goes out the window. We live in country Vic and some years ago just had tank water for everything, the garden coming off dams. Given the actual cost of tanks to hold the water are not really that expensive I would have more than you need. If you price what having to get water delivered to your house because you run out, it does not come cheap, and the cost of an extra tank will soon cross your mind. We had at that time we had about 800 sq metres of catchment area. That includes shedding as well as the house, and with good falls water was soon replenished. Our tank held 25000 gallons or about 113000 litres storage. We had one year of very low rainfall, where to keep a good margin we still had to purchase some water. Given Mildura is not the wettest environment, my advice would be similar to H20's, with a small difference, in that I would have a substantial volume in a tank or tanks, transferred to a smaller tank near the house for usage. The brand escapes me now but we had one similar to the Pioneer tanks. Also as Bashworth says access for fire use is very handy, especially if your house is burning! Perhaps an irroigated water tank could be used for this purpose. An alternative to header tanks in the roof is to go old fashioned. Place a 1000 litre tank on a stand, 6/7 metres up, to supply water to the house. This could be placed in the area where your tanks are located to "hide" it a bit. Water transfer would only occur occasionally then. Settlement 1/2/12 New Shed 23/3/12 Slab poured 27/3/12 Frame complete 4/5/12 Roof complete 1/6/12 LOCKUP 29/6/12 Our new build blog http://kareenhillsownerbuild.blogspot.com/ Re: Sizing a rainwater system for self-sufficiency 13Apr 11, 2013 7:18 am delatite13 An alternative to header tanks in the roof is to go old fashioned. Place a 1000 litre tank on a stand, 6/7 metres up, to supply water to the house I like this idea, mainly because the header tank can be filled during the day when the solar panels are at work and gravity supplies the water pressure at night, but to get reasonable pressure (say 30psi) it needs to be 21m high. 7m is only 10psi, which isn't much pressure. Enough to slowly fill a toilet plumbed to a separate grey water system, but not much else. My elderly parents have a header tank on their hot water system (for pressure relief - wood stove heated) which is only 5-6m high. Showering is absolutely painful, I don't know why they put up with it (it needs a pressure booster on the hot line). Other than the grey water toilet fill, I can't see the point in having a separate smaller tank near the house. Doesn't that mean you need to pump from the main tanks to the small tank, then pump again from the small tank when water is actually needed? It just seems like an extra capital expense that also halves water supply efficiency. Re: Sizing a rainwater system for self-sufficiency 14Apr 11, 2013 11:40 am Hi TimH247, That reminds me, are you also clued up on pump sizing and friction loss? Having a smaller but tall tank at the house as I suggested gives better pump efficiency than drawing from a remote tank. A lot of people unnecessarily buy big expensive pumps (after advice from plumbers and builders) when all they needed was a larger diameter garden hose or pipework. As an example, at 20 lpm an 18mm garden hose has 8 times less friction loss than a 12mm garden hose. It is easy to fit a couple of metres of 12mm garden hose to the end of an 18mm garden hose so that the standard 12mm fittings can be used. This info is mainly for the benefit of site visitors. Try not to use small pipes for internal plumbing (apart from a header tank to a cistern) as the friction loss kills a pump's dynamic head. Pex and compression fittings are mostly used these days. Some of the newer washing machines also have high pressure solenoids and this has to be considered when determining the dynamic head that a pump needs to deliver to the machine. Friction loss varies markedly with the flow rate. Rainwater is naturally acidic due to the CO2 in the air and this reacts against copper pipe. Many people on tank water see blue or green stains in a sink or basin but not realise what the cause is. Putting a retrievable bag of crushed limestone in a tank will help balance acidic water but it forms a protective barrier as it dissolves. The limestone chips need re-breaking every 4-6 months. The Fluidmaster 400UK063 cistern valve is very compact, costs about $20 and is available with an optional gravity feed very low pressure (red 242LP071) seal. Don't fall for the trap of gravity or pump feeding to a cistern fitted with a seal that is designed to handle mains pressures greater than 1,000 kPa. http://www.haron.com.au/fluidmaster_products.html I gravity feed my main use cistern from my main tank for about 8 months of the year and have done so for many years. I was initially very wary of switching to mains pressure during summer but there has never been a problem with the seal. Until recently, it was on mains feed for 6 months (Melbourne) as the tanks were kept for garden use during a very dry and hot period. 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. Re: Sizing a rainwater system for self-sufficiency 15Apr 11, 2013 2:55 pm Thanks for the link to the cistern valve, I assumed there would be a specific unit for low head applications. Copied and pasted into my spreadsheet of "relevant data" which is constantly growing (and changing). I'm not a plumber nor an irrigation engineer, but after 25 years as a nurseryman and orchardist, including some time working for an irrigation company as a technical manager, I've picked up a few things. I am familiar with the smell of pipe glue and know how to read a pump curve, but no substitute for the day to day hands on experience of a full time professional. I've been using a program called dp to calculate pressure loss, but lately just use an online calculator like this http://www.freecalc.com/fricfram.htm. I agree, bigger pipe is cheaper than a bigger pump (both purchase and running costs). I understand that a tank by the house has less friction loss and possibly less head loss, but I can't work out how that is overall more efficient if you have to pump the water from the main tanks to this one. Friction losses from a remote tank (eg 50m away) would be comparatively small if the appropriate sized pipe was used. In my case the ground is relatively flat, so no head loss other than friction losses. One example I can see where a second tank would benefit would be if there was a large head difference from the tank to the house, and the house was running on solar. A smaller pump (ie lower flow/pressure than required for showers etc) could run during the day topping up the house tank using solar energy, then a second small pump would supply the house needs, negating the requirement for a single larger pump to run on demand (especially valuable if running off batteries). My ideal scenario would be a house near the bottom of a hill (30-40m of head), so that a header tank on top of the hill could be filled during the day using solar power, then gravity feed the house at night. We don't have many sites like that here though. Re: Sizing a rainwater system for self-sufficiency 16Apr 11, 2013 5:01 pm TimH247 I understand that a tank by the house has less friction loss and possibly less head loss, but I can't work out how that is overall more efficient if you have to pump the water from the main tanks to this one. ..... In my case the ground is relatively flat, so no head loss other than friction losses. Flat ground allows you to gravity feed from the bigger settling tank to a smaller but often tall tank (commonly 900 or 1,000 litre poly) at the house. The pipework between the two tanks does not need to be big and the water in the balance pipe will be turned over many times every day. A remote tank also needs to be supplied with a wet system but if you don't use a vertical riser, you will have more head and the pipes regularly flushed without yield loss plus many other benefits. The link below is a currently active discussion about a low yield pumped system and an alternative low level wet flow path is discussed in part. The block slopes but the same head/efficiency principles still apply. viewtopic.php?f=19&t=63937 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. Re: Sizing a rainwater system for self-sufficiency 17Apr 11, 2013 7:16 pm SaveH2O TimH247 I understand that a tank by the house has less friction loss and possibly less head loss, but I can't work out how that is overall more efficient if you have to pump the water from the main tanks to this one. ..... In my case the ground is relatively flat, so no head loss other than friction losses. Flat ground allows you to gravity feed from the bigger settling tank to a smaller but often tall tank (commonly 900 or 1,000 litre poly) at the house. The pipework between the two tanks does not need to be big and the water in the balance pipe will be turned over many times every day. A remote tank also needs to be supplied with a wet system but if you don't use a vertical riser, you will have more head and the pipes regularly flushed without yield loss plus many other benefits. The link below is a currently active discussion about a low yield pumped system and an alternative low level wet flow path is discussed in part. The block slopes but the same head/efficiency principles still apply. viewtopic.php?f=19&t=63937 Makes sense for flat site. Thanks for the link, more reading material Hi guys, I want to do some floor levelling before laying the planks and am considering doing it with self-levelling or yellow tongue PB board. I am wondering which one… 0 7632 There is a whole lot more to know than just the answers you seek but they are a good start. Overflow outlets have a mosquito proof mesh. These… 3 9316 Grate, thank you! RexChan if thats the reason i could sleep well without thinking about additional cost. But 1st i'll need to read about NRV cleaning/replaing stuff. I… 7 32196 |