This project goes into the build of a passive solar thermal water heater using pex pipes and 4 X 8 plywood piece. The pex pipes are sturdy and tough , doesn’t easily leak. This passive solar heater can reach upto 120 – 150 F on a typical sunny day. Instead of pex pipes, you can use cheap irrigation pipe for this project. The pex pipes are more stronger and durable . The heater can be used for heating your domestic water, space or room heating or just heating a swimming pool.
The box that contains the pipes are made of 4 X 4 plywood . Four pieces of 2 X 4 pressure treated lumber are joined along the sides using screws to make the frame. We staple in some bubble insulation along the dimensions of the box . Since the insulation material is silver, it will reflect heat. To avoid this ,we coat it with a flat black paint to attract the solar heat.
Two holes are drilled on the sides of the frame for the inlet end of the pipe where the cold water comes in and outlet end where the hot water comes out. The inside and the outside of the heater is painted flat back using rust-oleum high heat paint to absorb maximum heat from the sun.
The first layer of half inch pex tubes or irrigation pipes are secured inside the solar heater box using half inch pex talon clamps. The clamps are installed on four sides of the box securing each loop of the pipe. The second or upper layer of pipes are secured in using zip ties. The total length of the pipe is 200ft.
The pipe comes in through the inlet hole and goes to the outside on the first layer , all the way around and work itself inside .It then goes through the top layer and all the way to the outside and then exit through the outlet hole.
The bottom layer pipes aren’t going to be exposed to the sun as much but they still will be warmed up because the whole box is covered with lexan polycarbonate sheet. The top layer with the pipe that goes outside through the outlet hole will have the highest thermal BTU.
A very inexpensive reed thermometer with a 4 inch stem is installed on the side of the heater using a half inch to three eighths bushing reducer .
A 4 X 8 Makrolon Polycarbonate Sheet is placed on top of the heater box and secured down in place using a No 8 One and one fourth sheet metal screws ,finishing washers and rubber grommets. Silicon adhesives are used to seal the gap formed between the sheet and the box frame.
The Solar thermal heater is placed at an angle of 20 degrees. This is done with the help of leg supports with dimensions 16 and 8 inches 2 X 4 pieces at both the sides. A 50 watt Renogy Solar Panel is also installed adjacent to the heater. This Solar Panel is for powering the bilge water pump.
A 500GPH 12V bilge pump is used to pump the cold water through the pipes into the heater . In order to control the flow of water through the pump , it is connected to an speed control electric circuit box which has a relay, a buck boost converter,a motor pump speed controller, potentiometer and a switch. The pump is powered by a 50W Solar Panel .The negative connection from the panel is connected to the relay, the positive goes to the switch.
The relay determines the voltage for the buck boost converter .It activates on a certain voltage we set and then powers the buck boost converter. The buck boost converter will keep a constant voltage no matter what the voltage the solar panel is putting out. It is then connected to a 15 amp motor pump speed controller and a potentiometer which is used to control the voltage of the bilge pump motor. The 12V 500GPH bilge pump is connected to the motor pump speed controller.
In order to test the unit, we place the heater near a pool to heat it. The bilge pump is submerged into the pool which is then connected to the heater with help of a PVC hose. The output pvc hose is returned with heated water back to the pool. The water reaches upto 140 F based on our test.
- How to recycle scrap metal in the backyard by building a simple Mini Metal Foundry from start to finishIn this project, we're using equal parts of sand and plaster to make a simple backyard foundry that's powerful enough to melt scrap metal in seconds. With this homemade furnace, we have the power to liquefy aluminum in the backyard and cast just about any object we can think of. You will need some big bag of play sand and some plaster of paris both of which you can find at your local hardware store for under $20. We are also going to need a 10 quart steel bucket and a tablecloth to cover anything. For this makeshift refractory lining we need One and 1/3 buckets full of plaster Paris or 21 cups, One and 3/4 buckets full of sand or 21 cups and 1 and 1/4 buckets filled with water or 15 cups. Mix everything together. It's really important to get all the dry powder wet and work out any lumps as quickly as possible. And after mixing for a couple of minutes, it should be fairly runny and roughly all the same color. Transfer the mix to the steel bucket upto 3 inches from top. We use the plastic measuring bucket to form the center of the foundry. Let the mixture dry for 3 minutes. Next step ,we turn an old steel fire extinguisher into a custom crucible. Depressurize the tank and unscrewed the valve from the top to make it safe and easy to cut in half with a hacksaw. At this point the plaster should be pretty well set. So let's dump the water from the bucket then use a pair of channel locks to pull the bucket out. Next step is make an air supply port .Using 3/8 inch hole saw and a metal cutting blade, we cut a hole to accommodate the one inch steel blower tube. The blower tube is made of one inch steep pipe ,one inch PVC coupling and one inch PVC pipe.Threads on one half of the coupling screw onto the steel pipe and the slip adapter on the other end simply pushes onto the PVC side easily. Next step is to build a lid to retain the heat.You need a couple of 4 inch U bolts.Make them stand upright into a 5 quart bucket filled with the insulating mix. To relieve pressure buildup, make a vent hole using a 3 inch hole cutting saw. This design works great for venting pressure and gives us the option to melt metal as well without even having to take the lid off the furnace. By the way, if you run out of soda cans to melt, you could try using it as a blacksmithing forge or even a barbecue for summertime grilling. We evenly place 5 charcoal briquettes at the bottom of the crucible made out of steel fire extinguisher, helps smelt the can faster once we fire it up. A hair dryer is taped to a PVC pipe and inserted a couple of one inch couplings to connect the steel tub eat one end and give the blower to a quick release feature. This way it's super easy to take apart and fits into a five gallon bucket for easy storage. The charcoal is filled it to the top and we breathe life into the steel furnace with a propane torch.The hairdryer is set to the low setting and blow a steady stream of oxygen on the charcoal to really heat things up. The lid we made keeps the heat inside so it conserves energy while it's bringing up the temperature. The coolest part is that the crucible lines up perfectly with the hole in the center. The container is three inches wide, which is the perfect size for melting standard size soda cans like these and at temperatures over 1000 degrees Fahrenheit . In order to isolate aluminium, first we remove the crucible making sure we have got a very secure grip with our tongs and slowly pour the liquid into a steel mold. The Soda cans are molded in the form of ingots.The purpose of an ingot is to keep some pure metal handy for when you want to make something cool. https://www.youtube.com/watch?v=hHD10DjxM1g https://www.youtube.com/watch?v=lSoWxG30rb0
- How to build a Super Efficient Outdoor Wood Stove Heater from an Old Propane BottleThis project goes over the build of an efficient outdoor wood burning stove heater out of an old propane bottle and some scrap metal from the scrapyard. This stove has secondary burn system that helps in combustion of any unburned smoke or fume inside .Almost little to no smoke coming from the flue pipe. The first step is to make sure that the old propane tank is empty. We take the valve at the top by removing the valve protector cage. Fill the tank with water and let it sit for a few hours before we drain the tank and start cutting top and bottom. With the help of a hole saw cutter ,we cut 100mm four inch holes at the top and bottom of the tank . The top hole is for the flue pipe to sit in and the bottom hole is for cleaning the ashes out. We also remove the bottom stand too. Next, we cut a hole for the door for the stove. This is cut as high up to the top of the bottle . The door is made of chequered plate piece . We fit a rectangular pyrex dish glass piece in the middle of the chequered plate that can withstand high temperature with couple of steel bracket pieces. The glass on the door helps us to see how the secondary burn system is working inside the chamber. The door is attached to a frame through hinges. The flue outlet on the top the tank is attached through a flange piece with holes. The door handle is made of a socket wrench. The wrench is bolted to the plate and a small metal piece is welded onto to the frame to which the wrench is pulled to close the door A deflector plate made of small holes is installed inside the stove on the top . We drill 8mm holes around the top of tank and put dome bolts across them. The deflector pipe sits on these bolts. The deflector plate stop the unburned gases exiting out the flue outlet pipe. This encourages the flame that rises, pass through the deflector plate holes into the secondary burn chamber that helps in better combustion. The secondary burn system is made of stainless steel pipes .The air intake section is long enough to get the air coming in to get super heated and move into two sections filled with holes. Since not all gases from the wood combust from the primary air intake, the secondary burn pipe ensures that the air gets super heated before exiting the pre-drilled holes and helps burn the unburned gases rising from the fire before exiting the flue pipe. The secondary air intake pipe coming out of the firebox is welded on the top of the tank with a flange piece. The primary air intake pipe that goes under the door frame is made of a two inch coupler and threaded damper disc. A small metal piece is welded to the coupler with a hole in the middle. The damper disc screws in through the hole that allows us to close and open the intake .
- DIY Video: How to build your own Water Pump From Scrap and save lots of dollars