Building an inexpensive solar heater
manufacturing cost about $ 800 pesos MX
We are in the process of uploading images of each step to make it much easier construction.
Before deciding to begin construction of the heater, you should take into account that the principle is the same for any type of building a solar heater, ie "thermodynamics" and if you change or modify any methods of construction or arrangement should only consider the output and efficiency is not the same, however if you follow exactly the instructions could save enough money for many years.
A system like that described the construction consists of 2 parts:
collector tank.
energy calculations will add at the end because although they are a good complement, may be boring to read on the front lines.
For the construction of this collector was selected for drip irrigation hose of polyethylene with a diameter of 16 mm. This hose is very cheap because it is extremely thin and flexible and sensitive in its handling, its color is black-suited to absorb the sun's heat and There are many types of connectors for this type of hose.
Due to the material chosen to build a grid is very easy, since the hose can be cut with scissors, taking into account any that are very thin and make connections with the connectors is not complicated because you only have to enter the end we are interested in the hose connector, pressing with your hands. and because the precione is minimal, requires no glue or clamps, or any other type of fastener
Cut 8 lengths of hose and attach 2 m as shown in figures.
hose segments can be smaller but should put more segments in the same arrangement, to maintain efficiency, which is not very good input in this design, remember that design is a low-cost heating and although very functional, will not have the efficiency of a sales team. To
tank preferably use 2 tanks of plastic or galvanized steel, one of 50 to 60 liters and one a little higher, but with the same characteristics, the difference in size will ensure that by introducing one in the another is an area of \u200b\u200bapproximately 5 cm to be filled with an insulating material.
Ideally polyurethane foam is used, but would raise the cost of manufacture, but increase efficiency, but you can use Styrofoam and even crumpled newspaper as a ball.
respect to the connections, you can use PVC water pipe of 1 / 2 ", three and must be done so that the joints are properly sealed in the inner tank and sufficient length to protrude at least 2 "from the external tank.
Consider that:
1 .- The cold water inlet (to the collector) will be made at the lowest possible, 2 .- The entrance to the hot water (from the collector) is should give the highest possible consideration which should be a 1 inch below the highest water level
3 .- The output for services should make up two-thirds.
Before adding insulation we test for leaks at connections. Otherwise all the work go to waste, because if you choose to use polyurethane foam that must be removed to repair the leak if you use the wet newspaper and will not work as insulation
To connect simply collector and tank joins the output of cold water tank (on the road is a T-connector for the entry of cold water replenishment *) with the low end of the collector, while the high end of the collector is attached to the entry hot water tank.
thermosyphon effect works very well and in summer the water temperature reaches 45 ° Celsius or more tank retains heat well enough, even at midnight even need to mix with cold water to get a comfortable shower. in winter the temperature should reach 25 ° C, overnight if you use non-insulating polyurethane and about 30 degrees if you use. The type of insulation used and the way of construction of water heater will be crucial in maintaining the water temperature longer a well-built water heater will keep hot water losing only one degree every 3 hours during a winter night ambient temperature 10 °
* The makeup water is the main tank of cold water from the house, whose high level should be maintained at the same level as the solar heater tank, this is not nothing but a simple connection of communicating vessels.
calculations.
polyethylene hose that makes collector has a total of 24 meters and is 16 mm in diameter, its total external surface: 0.016 x 3.1416 x 24 = 1.2 mt2
Assuming that only half of its surface is exposed to the sun, then the absorption area is 1.2 / 2 = 0.6 m2
The sun bathes with 1 kilowatt of energy per square meter, then we will fall 0.6 Kw collector when the sun shines on it.
At this point we should calculate the energy of the day starting with the watts and hours, but before we do something more interesting parts of the results obtained in practice.
Water enters the heater in the mornings at 20 ° C and leaves at the end of the day at 45 ° C therefore has earned 25 ° C. As it is 40 to 60 liters, then the energy gained is 25 ° C x 40.000 cc = 1,000,000 calories or 1.000 Btu.
860.4 Kcal energy is equivalent to 1 kWh, therefore be 1.000 Kcal: 1000 / 860.4 = 1.16 Kwh
few paragraphs above we found that our 0.6 Kw collector receives full sun, then we have to conclude that the 1.16 kWh just calculated should be met with about 2 hours of sun . Why only 2 hours? Are not most hours of sun to have been exposed the catcher? The answer is simple: in fact, has been exposed more than 2 hours, but it is a low-efficiency construction.
With the above just confirm that this system loses power or is not making, but still gives us all the hot water needed in a house (in summer and spring) and the inefficiency goes unnoticed because the source of energy is the sun.
Next project:
'll show you how to make more efficient solar water heater, or to build a solar heater much more efficient than this, just remember that the more efficient the cost of manufacturing and design rules and construction will be stricter and more.
