Heating Water – What I wouldn’t give for a warm shower….
About 20% of your home power consumption is for heating water. So being able to heat your water can significantly reduce your power requirements and save you some money if you are sizing an alternate power system like solar. While you can do it the old-fashioned way and boil a big kettle of water and then transfer it into a tub like they did on WestWorld (which seemed to work ok up to the point the androids starting killing all the guests – but we shouldn’t blame the bucket system for that result). This is your fall back system as long as you have a tub and large kettle, if you don’t mind lugging up to the bathroom, plus you have plenty of fuel to use for the fire. But there are plenty of ways to get how water is delivered to the faucet after the grid goes down (assuming you still have water pressure from some cistern or elevated tank or a pump on an alternate source of power).
Solar water heating – for washing and showering this is probably your best system but it may not get the water hot enough for your washing machine or dish washing machine (assuming you are still using those when the power goes out).
► Solar showers: include one in your kit - good for a hot shower on the move… as long as the sun is shining. Most units are under $25. Two-three gallons is more than enough for two people as long as you watch your water usage (wet down, turn off the nozzle and soap up, then rinse off). Check the comments before you buy and make sure you get a durable one. I got the Advanced Elements 3 Gallon model. Remember that water weighs 8 pounds per gallon so theoretically, if full, this would weigh 24 pounds.
► Solar water heaters: more permanent fixtures mounted on your house / safe-haven designed to provide sustainable heated water for years. A couple of things to consider when you are deciding which system to get: do you need to worry about the water overheating (in tropical / sunny climates) or do you need to worry about components being damaged by freezing weather? A good resource for planning your installation can be found at http://www.pasolar.ncat.org/lesson01.php
Overheating protection: If you are using a pump and drainback system, you can just set the pump to cut off when the temperature in the tank reaches a certain level. As long as you are not using evacuated tubes, you can circulate the water in the tank at night so some heat is given off. But most systems rely on some sort of pressure relief valve (in a high pressure system) or a vent (in a low pressure system).
Freeze protection: The simplest way is to use a drainback design so when the system is not in use, the fluid drains out so that expanding ice will not damage the collectors. Some indirect systems use anti-freeze fluid in the collector to avoid the problem. In a direct system when freezes are uncommon, you can drain the collector when a freeze is expected. But since this relies on the operator, it is potentially unreliable. Another option to use is to freeze tolerant silicone rubber components in construction of the collector so they can expand and contract as needed.
Sizing: You will need to get with an expert to size your system properly. You want to plan for heating during winter months when you have limited sunlight and lower ambient temperatures. Rule of thumb: 1 sqm of flat panel collector area for each family member or occupant and 20-30 gallons of tank storage per occupant.
Collectors: Flat panels or evacuated tubes that the fluid passes through to absorb the heat. The flat panels will be mounted in a box with a glass or plexiglass top facing the sun. These components are usually painted black and then covered with acrylic plastic or similar material to prevent heat loss. Evacuated tubes avoid heat loss due to convection when compared to flat panels.
Pump system: To move the fluid from the collector to the tanks and vice versa.
Tank: an insulated tank to store the heated water. If you use an indirect system, there will be a heat exchanger in the tank where the fluid circulating through the collector can transfer heat to the water stored in the tank.
You may wish to have a back-up for your solar water heater system such as an in-line gas heater (maybe use that methane from your anaerobic digestor!). You could also hook up a heat exchanger around a wood stove chimney so you can still get hot water if the weather is overcast.
You should also check out The Secret Greenhouse of Survival by Rick Austin. He installed 800 feet of black-colored 1” water pipe in his greenhouse in coils. That gave him about 30 gallons of heated water basically in-line. He augmented with an in-line heater as a back-up but with proper timing (he gets 40-60 gallons of hot water each day).
Since in a survival situation, you need redundancy, let’s look at your compost pile:
Bio-generation of Heat – Jean Pain Pile
Well actually, you need to build what is called a Jean Pain Pile which is about a ten foot radius pile of wood shavings, sawdust and some manure. A detailed explanation of the construction is included here http://www.compostpower.org/node/24. Developed in the 1970s by innovator Jean Pain, he demonstrated that you could get continuous flow of 1-4 liters per minute of hot water using the heat from decomposition of the pile of 10 parts wood chips, 10 parts saw dust and 1 part manure.
Briefly – you build a 20-22 foot diameter foundation of wood chips about 2-3 feet high with some 4” perforated pipe threaded through it (this helps aerate the pile). You then start laying in a supply line of flexible tubing in a coil or spiral keeping about 8-10 inches between rings(the external ring will be about 12-18 inches from the edge). Add another 8-10 inch layer and lay more flexible tubing and repeat. All told, you want to use about 900 feet of tubing interwoven in the pile. The pile will be about 6-9 feet tall and take about 30-40 cubic yards of mix. Wet it all down and in about 10 days, you should be able to start pushing water through the pile. Ok – sounds simple but it will be a lot of work if you don’t have a tractor and a small excavator. But theoretically, it should be able to supply you with hot water for 12-18 months. At the end of that, you break down the pile and use the remains to fertilize your garden.
How neat is that? Even if all you have is a hand pump, you could end up with running hot water even after TEOTWAWKI. In summary, after the SHTF and the grid goes down, we don’t have to revert to the hygiene of the Middle Ages. There are plenty of ways to have hot water without power (from the grid).
I am just going to finish up with a comment that you can route your hot water to help heat your home or your greenhouse. These systems are best installed during initial construction, but in turn can make your cold floor toasty warm or keep your greenhouse thriving no matter what the weather. Food for thought….
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