Solar heat collectors are a good supplemental heating source that can provide homeowners with free heat for their home when the sun is shining. Solar collectors are a box like structure that capture the energy from the sun and convert it into usable energy for heating purposes. Inside the collector solar energy is simply converted into usable thermal energy.
On the front side of the solar collectors . a clear panel or glazing material typically polycarbonate sheeting, single pane glass ,double pane glass face towards the sun and allow the sunlight into the collector box. On the inside of the collector box is a heat exchanger or a absorber. The heat exchanger or absorber is responsible for transferring the heat of the sun into a usable thermal heat source. The heat exchanger is suspended or attached inside the collector box and should be coated flat black with a high heat temperature resistant paint.
The flat black paint helps to absorb the heat energy from the sun. It is very important to utilize a flat finish black paint inside the collector box. If the paint has a reflective coating, it will reflect the sun back outside of the collector, which results in lost potential energy. It assists with the entrapment of that heat energy rather than reflecting it away from the collector.
Once the sunlight has penetrated the collector box through the glazing, the heat exchanger material and the flat black paint will absorb that heat and begin to warm the air inside the collector. As the air inside the collector and around the absorber warms, it will expand and rise. The expansion of warm air will naturally create a convection current. As the air inside the collector rises, it will continue to pick up heat through friction with the absorber. The air passing over and through the absorber is given more opportunity to gain heat by rubbing against that surface which is being heated by the sun.
Now that the air is warm and picking up heat and needs a way to move through the collector box, we install two vents on the backside of the solar collector facing towards the room or space that we want to heat. Through the vent at the top of the collector, the heated air moves into the home , the vent at the bottom allows the cooler air to return back to the the collector.
Having a return event at the bottom and a supplier event at the top of the solar collector allows natural convection process. The air inside the collector is picking up heat from the absorber and is naturally wanting to rise up and out of the collector. A natural force of air rising will induce a convection current, which will pull cooler return air from the room or condition space into the bottom of the collector box.
The collector creates a convection current inside the room .It removes cooler dense air from the bottom of the room and takes it through the collector where it is warm, and then exhausts the heated air out of the supply duct back into the room.
This project goes over the build of an entirely self contained Solar Air Heater using no grid power whatsoever. The unit draws the cold air from the room and exhausts hot air into the room using a 2 5V DC brushless 7 vane case fans. This fans are powered by a 16 Watt Amorphous solar panel. Both the intake and exhaust pipes ore of 5 inch diameter.
9 rows of 17 soda pop cans , a total of 153 355ml soda cans are used for the collector. The aluminum pop cans are painted with a flat black paint to ensure all sunlight is absorbed and not reflected. Also there is a five inch intake and exhaust manifold at the bottom and top of the unit. This ensures that all air travels through the interior of the aluminum cans.
To maximize the heat transfer from the sun to air within a given space, we need to build a better heat exchanger. Solar air heating systems use air as the working fluid for absorbing and transferring solar energy. Transferring heat from one place to another by definition is a heat exchanger. When the sun heats the metal, the hot metal heats the air circulating over the metal of the heat exchanger. The job is to capture radiation from the sun and transfer this thermal energy to air via conduction heat transfer. Heat transfer output depends on the rise in temperature and the airflow.
In order to minimize heat loss through the plexiglass , we keep the absorber temperature as low as usually possible. The cooler the absorber runs, the less heat will be lost out of the glass. A way to keep the absorber cooler while extracting the same amount of energy from the sun is to increase the airflow.
To improve conduction heat transfer without significantly reducing airflow , we disturb the airflow within the solar air tubes . Four holes are put in some of the soda cans to create a baffle that increase the turbulence .These baffle cans are placed evenly across the tubes to distribute the airflow. We place the first baffle cans on the second row from the bottom with the intention of disturbing the airflow early. The second baffle will be located in the 10th can .
In order to stack the empty cans, we make an assembly tray “V” shaped support structure using leftover baseboard. The cans are glued together using PL Premium construction adhesive that is water resistant, non shrinking and paintable. The soda cans are positioned on the loading tray and slowly rotated to evenly distribute the construction adhesive.
The “V” channel made from baseboards holds the cans perfectly straight.
The box for the Solar air heater is made of 5052 aluminum alloy sheets. The dimension of the box are 91 inches tall and 24 inches wide. We use a one inch flange and a metal bending brake to bend the aluminum to make the sides of the box. The top and bottom caps are bend to fit on the top and bottom of the box . When manufacturing the bottom caps, the distance between the bends is decreased by one millimeter to allow the caps to fit inside the solar air box to facilitate drainage.
Next step is securing the aluminum box top and bottom .The procedure involves using a smaller diameter drill bit as a pilot and then drilling to final size for the rivet only after the two pieces are mated together. The pieces being held together via cleco fasteners. The function of the cleco is to temporarily hold material in the exact position during the manufacturing process.
Two five inches holes are cut at both top and bottom on the box to install the plenums. The intake and the exhaust pipes for the two solar air heaters are manufactured from a single piece of five inch HVAC plenum. These are inserted and secured into the holes using construction adhesive.
The back of the box is insulated using two sheets of half inch foam sheet. One sheet of half inch foam is installed on the sides. A pneumatic air file is used to cut the sheets.
We install a snap action thermostat in the interior of the exhaust manifold, constantly monitoring the temperature of the air being brought into the dwelling. The intake and exhaust manifolds need to ensure that all air travel through the interior of the cans therefore it is important to have a good seal to each can. This also means that the manifold itself needs to seal well against the interior of the heat box.
Nine holes are cut on a two sheets of half inch plywood to make the intake and the exhaust manifolds. These manifolds are secured in place against the cans using PL construction adhesives.
The solar air tubes are held tight inside the box using two 1/16th half inch 6063 aluminum extrudes. These lightly applying pressure on the cans holding them firmly against the back of the heat chamber.
Three separate coats of high heat black rest-o-leum paint are applied to the box , all within 60 minutes of each other.
Clear silicon adhesive will be the primary method of adhering the Plexiglas to the solar air heater. After precisely positioning the glass on top of the heat chamber, I used a 1/8 inch pilot drill to go through the plexiglass. One full tube of silicone is used around the perimeter prior to laying the glass down.
We install 2 16 Watt Sailflo Duct Exhaust fans with a capacity of moving 141 CFM (Cubic Feet per Minute) for air . These are powered by a small solar panel. One blowing air into the chamber and one sucking air out. This helps to overcome the additional internal airflow resistance built into the design.
The completed solar air collector is installed outside facing south to maximize the exposure to the sun. Once the solar air collector is installed outside , we take the temperature rise between the incoming and outgoing air while moving 141 cubic feet of air per minute from the fans . The calculate the amount of heat transfer we multiply the CFM and Temperature rise with a factor of 1.08.
- DIY Video:How to build a Super Efficient ,Multi Use Homemade Ammo Can Rocket Stove. Inexpensive,Portable and Leaves no smoke….This project goes over the build an efficient clean burn multi use ammo can portable rocket stove . Easy to build , small ,portable , leaves no smoke. The reason it is smokeless is because it uses a secondary burn system . Also can be used as a cooking stove. The first thing you need is an old NATO ammo can. Remove the rubber seal that sits around the top of the can and replace it with a stove rope. The stove rope gets compressed when you close the stove with its closing mechanism and the smoke wont escape from around there. One the top, we have the flue made out of 2 inch stainless pipe .It has two sections, upper section slides onto the lower section. In order to build the flue, we take the top of the ammo can, then place the pipe on top and draw around it that gives the circumference. Take a grinder and simply cut across the shape. In order to get a smoke tight seal, we wrap some stove rope around the flue area we just cut and then insert the pipe and use a jubilee clip around the bottom and compress it against the stove rope. Once this gets up to working temperature, it draws cold air in from down below and expels it out at the top. So all the smoke from the stove gets drawn upwards. We use 2 turnbuckles as a stove door closing mechanism. There are two closing mechanisms on this door. One is a quarter turn latch. So you rotate it, the door opens ,you close and then you rotate it and it locks the door closed. Another mechanism is using a long piece of metal. You can turn each of these a quarter turn and that locks the door extremely tight to fit these turnbuckles . The stove baffle plate is made out of 0.8mm thick thin steel. To make it, measure it up against the stove and bent the steel into that shape. The baffle helps in generating more heat as it keeps the air from escaping the burn chamber. A secondary pipe made of galvanized steel pipe comes from back of the stove and comes across the stove through a small hole. The pipe has been drilled with small holes. When the stove is in operation, this draws in cold air from outside, it gets pre-heated on the way down across the burn chamber. And then the pre-heated air rises and is expelled naturally through these holes. And since this pipe is just under the baffle plate, it reignites the smoke and the smoke is burnt on the way across the upper section of the stove. The stove is insulated using fibreglass and stainless steel from three sides inside, helps in efficient secondary burn. You just need enough insulation to get the temperature high enough to get secondary burn. If the whole stove is insulated then the heat would dissipate through the flue instead. The bottom of the stove is insulated using half inch rockwool and on top we have some chicken wire that stops the burning fuel from sitting on the bottom of the stove and being starved of oxygen. It allows the oxygen to get underneath and burn all the way around the wood efficiently. The primary air is drawn in through an air intake at the side of the stove. To attach it to the stove, bend the pipe around the side and place a jubilee clip and stove rope around to insulate it. So when the stove is in operation, you can add sticks, twigs, pellets or anything you want without opening the door. https://www.youtube.com/watch?v=BUz6Ai2yAxE Burn Video : https://www.youtube.com/watch?v=Vd7RFwyQxrI
- How to build a Large 2000W Portable Solar Power Generator at Home from scratch.The idea of a completely silent power generator that can still run large power loads, and never need gasoline is a really cool concept. This project goes over the build of a large 2000W Portable Solar Generator that can power appliances ranging from a table saw to charging your phone effortlessly. We need a large box to hold our basic components. Here we use a pelican 1620 protector case that is durable, dustproof and waterproof .This is going to be the case that we package everything into. It's got wheels on the bottom so you can roll it around ,also has heavy handles on either sides. The battery is a AGM glass mat ,coil would style, 12V optima deep cycle battery. A deep cycle battery just allows you to get a little bit deeper into the discharge before you are starting to shorten the life of that battery. This battery also has the ability to be mounted in any orientation . So it is safe whether the battery is on its side on its back or even upside down as long as we have it mounted securely so that nothing shorts against our terminals. The next major components for our build is the 2000W inverter from Krieger. This one has some large terminals on the back for our wiring. Also has a active fan here for ventilation. Also comes with a remote control switch. The 100W Solar Panel is from Renogy. It has the bus on the back for connecting in to your solar charger .It also comes with a 30A Solar Charge controller. This can run up to four of the 100 watt panels in a 12 volt system. The back of the solar panel comes pre wired with MC4 connectors, as well as a couple of MC4 pigtails. We use high quality 16 gauge speaker wire to extend the connection. These wires are highly flexible for portable use. To connect it to the MC4 pigtails we need to go ahead and strip the insulation off and use butt splice connectors to crimp them to the MC4 pigtails. In case you cant to charge the system with standard AC power ,we use a 1.5A Battery maintainer / Float or Trickle charger. This will be good for just keeping it topped off when it is in storage. Or if you just want to charge up your batteries and you really don't have a place to be setting the panels out. Next step is mounting components on the outside of the case . Before mounting any component, factor in how the internal components are going to placed inside the case. On one side of the case ,we are going to mount a small LED work lamp with toggle switch, a 12V gauge pod with 5V USB output, digital voltmeter,12V cigarette socket ,an AC input plug for using with the trickle charger, a 6pin solar panel trailer connector. These components are secured in place using a RTV silicone sealant. One the other side of the case , we are going to mount the inverter remote control switch, 350A high current plug which is used for jumper cables or to add high current loads, a GFCI AC outlet with a weatherproof cover. The GFCI outlet is connected to the inverter inside the case. We want to put the battery as close to the wheels as possible, because that will help keep the heaviest part down low when moving the case around either on the wheels or by carrying it. We place it snug into a corner of the case using battery mount and couple of pieces of 2X4. The inverter is placed inside the case in such a way that there is enough space for air ventilation and for tucking some of the wires underneath. The inverters are secured in place using mounting tabs and 10x24 machine screws. The PWM solar charge controller is also mounted in the same way near the solar panel connector input. The trickle charger / battery maintainer is placed as low into the back of the case .This is not something that will get very warm so we don't need to worry about heat dissipation or anything like that . We plug the power cord from the trickle charger into the AC input cord. Next step is the wiring. We start by connecting the power cables from the inverter to the battery. The positive and negative from the inverter is connected to the positive and negative of the battery respectively. To distribute power in our generator ,we use a six circuit fuse panel for the positives and a busbar for the grounds. We use two inexpensive battery cables to run the power to our distribution blocks as well as running the power to our high current quick connector. The positive red connection from the quick connector goes to the fuse panel and the black negative connector to the ground busbar. Both connections are further extended to connect to the positives and negatives of the battery respectively. The LED lights are connected to the 3 way connector switches. The switches are further connected to the power distribution fuse block. Similarly a single switch is connected to the USB outlet, voltmeter and the cigarette lighter ports in parallel. The positive from the switch is connected through a daisy chain mechanism to the three positives of the ports ,the negatives are similarly connected to our distribution block. At this point, we now have a power wire and a ground wire for every single one of our accessories connections . We bundle these wires and keep it neat and tidy using zip ties. Separate the positive wires from the negative wires, we are going to be rounding the negative wires to our ground busbar. After we have all of the ground wires connected, we can move on to the power wires on our distribution block. Each one of the blade connectors represents one fuse circuit. We connect the positive red wires from charge controller, battery trickle charger, usb ports,voltmeter,12V outlet to the fuse circuit. We are using a 30A fuse for the charge controller,12V socket, 20A for the LED work lights, 5A for the trickle charger. https://www.youtube.com/playlist?list=PLIorqrLdxMKZV464fFUflegLuuvLEyMrU
- DIY Video :How to build a Simple and Efficient Copper Coil Burner Stove from start to finish.Great in a emergency/disaster or while out campingThis project goes over the build of an simple and efficient copper coil tiny alcohol burner jet stove. The materials you need to make this stove are canning jar, small copper tubing, JB weld to seal up the from inside and outside , pipe to wrap the coil, couple of drill bits, a wick material, sand and Isopropyl Rubbing Alcohol as a the fuel. Fill the copper tubing with sand all the way up. Seal both ends of the tube with a cloth or a cap. With the help of a vice ,we bend the tubing around the pipe into a loop. Flatten the sides of the coil keeping the sides together. Empty the sand out of the copper coil and run water through it to get everything out. This is done so that the inside is completely open for the air and the gas to build up and burn in there. Cut a vent hole down the center of the looped coil using the smallest drill bit. Mark the canning glass jar against the copper coil so that we can cut off the extra coil legs so that the coil fits inside the jar approximately three quarters way down. Next step is to make holes for the lid of the jar . Place the coil on top of the lid and make two spots for the holes. We use a drill bit ,same size as the coil to drill two holes. The coil is placed through the two holes of the lid and sealed on both the top and bottom side using JB Weld. Allow the glue to set for an hour. Take your wick cloth material ,insert and twist them through both the holes of the coil all the way up to the top. Pour some Isopropyl Rubbing Alcohol onto the jar , place the lid with the coil on the top and tightly close the jar with the cap. Wipe the sides of the coil with rubbing alcohol. To prime the stove for its first burn , start by heating the coil using a propane torch first. The heating of the coil gets the gas going. Heat until the flame starts to appear. Burn for four to five minutes to steady the flame. https://www.youtube.com/watch?v=HFrWw5dgliQ