Solar heater made of beer-cans

Dear Reader,

First of all look at this site, please:

I was inspired by these things which have been found here by me to build a similar one tentatively. It's a solar collector system for heating supplement which warms air. It has a quaint feature: it's built with empty aluminium beer-cans thus while we haven't found a better name I will mention it as a "beer-collector".

You can read a detailed summary about this theme and steps of the making on this Hungarian forum:

The frame of the collector has been made of timber, its front has been made of a clear polycarbonate sheet (3 mm, 0.12 inches). The absorber has been made of black-painted beer-cans. There is rock-wool insulation behind the boxes. There are distributor-collector boxes for the flowed air at the framework's roof and bottom. These have been made of aluminum sheets (1 mm, 0.04 inches). The air is streaming through a filter and a non-return valve from the room to the inlet manifold by a powerful quiet fan, then the air gets to the tubes made of glued beer-cans and if the Sun is shining it warms up the air very fast. The warmed air gets back into the room through the outlet. The room-space, the inlet manifold, the beer-cans and the outlet generate a closed system. The air can't escape from the tubes into the frame box else the inside of the cover gathers dust or mists up. Installed fins at the joins screw the air for a better efficiency.

First of all I collected empty beer cans. You need to clean boxes immediately, because those are very fetid. Attention! Beer-cans are made of aluminum generally, but there are some cans made of iron. You can test these cans by a small magnet.

When I collected enough cans I drilled each cans below and above. I used a similar tool which has shown on Picture 1 and 2. Its diameter is 44 mm, 1.75 inches. Set 45-60 revs per minute. This tool has an ingredient for the centralization but unnecessary to use that in this occasion.

Picture 1	Picture 2	Picture 3

WARNING! This operation is very dangerous because walls of the cans are very thin.
Those pieces can provoke any hand injury.

Use a hard plastic ring for own hand protection shown on Picture 3. This ring has been made by a turner. The ring fits up and down on the cans. When the drilling was finished the metal sometimes did not break off. You can use any pliers to take out the fallen scraps. .

Don't take out the scraps by hand!

Remove the grease from the cans' surface. Any synthetic stain-remover is suitable for this. Execute this operation outside or in a well ventilated room.

 WARNING! This operation is flammable and potentially explosive!

The usage of an opened flame and smoking to be neglected!!

Glue the cans by any heat-resistant adhesive. The adhesive must be heat resistant at least up to 200 °C. There are heat-resisting adhesives up to 280 °C or 300 °C too. The roof of the beer cans and they bottom adjust to each other. If you prepare a bore with 44 mm diameter, so a little edge stays on the roof. Put some adhesive onto this part round, and press the bottom of the other box into it. In this manner the adhesive don't escape from the edge. After drying the glue will be adequate elastic and stuffed. A detail of the glued cans is visible on Picture 4.

Picture 4	Picture 5

Prepare the trough which has been shown on Picture 8. Make it from nailed planed timber and the pipes will be straight by this. The pipes keep in this trough when the adhesive dries. Fasten the cans to the trough with large fruit rubbers. Hang the rubbers onto the tiny nails knocked in the rear side of the timber.

The small fins are made of the wispy disk gained from the side of the boxes. Their task to make a turbulent flow in the pipe, so the streaming air cuts more heat from the warmed box wall. Draw it with an alcoholic felt-tip pen, cut it out with a scissors, and then bend it with the help of pliers (Picture 5 and 7). Before gluing it is necessary to make the fins.

The Picture 6 and 10 show the gluing process. The cans glued together form a pipe. The Picture 11 introduces a pipe, which stays in the trough, during the drying of adhesive..

Picture 6	Picture 7	Picture 8	Picture.11
	Picture 9	Picture 10

The divisor/collector boxes have built with 1mm aluminum sheets (Picture 12); the gaps at the edges have been caulked with heat resistant adhesive. The lids of boxes have cutting with a diameter of 55 mm tool on a stand drill. The pierced roofs are visible on Picture 13. The first row of cans has been glued into the lid of the divisor. (Picture 14 and 15). The next picture shows the divisor, collector and the absorber which have been put together before painting.

The adhesive's drying is very slow. It is necessary to let it dry during at least 24 hours.

Picture 13	Picture 14	Picture 16
Picture 12
Picture 15

The absorber gets into a box which was made of timber (Picture 17). The reverse side of the box was made of chipboard, for stiffening I developed planks into cassettes. The rock-wool got into these cassettes. These all are covered by thinner chipboard. The installed insulator is visible on Picture 18. Already it has been covered on the opposite part. It is necessary to surround the holes with planks at the inlet and outlet, to fixing the insulation.

Picture 17	Picture 18

The box got preparatory timber protection, and then I painted it. I applied four ears onto his four corners to install it to the wall (Picture 19). I placed the empty frame box to designated place of the brick-wall. I used 10 mm stem screws for this operation. Finally I chiselled the brick-wall at the nominated place (Picture 20).

Picture 19	Picture 20

After that the black-painted absorber has got into the frame. The frame got a cover which has been made of polycarbonate sheet. It has been clamped with an aluminum-profile by me.

The polycarbonate sheet is slightly convex, that let him be more rigid a bit. The installed absorber is visible without cover on Picture 21. The complete solar heater on the floor is visible on Picture 22, and the eventually installed heater is visible on the Picture 23 and 24.

Picture 23	Picture 21	Picture 24
	Picture 22

Data:

width:	1238	mm
height:	2966	mm
most thickness:	180	mm
full surface:	3,67	m2
useful surface:	3,5	m2
weight:	76	kg
inlet diameter:	100	mm
outlet diameter:	125	mm
used cans:	270	pieces
installed fins:	252	pieces
position:	vertical

This system has a mistake: it isn't capable to store the produced heat. When the Sun is shining it warms but it is necessary to utilize the produced heat immediately. If the sun does not shine inhibit an air flow in him, because it cools the room otherwise. It is possible to solve it by a non-return valve with minimal heat loss.

A temperature difference switch controls the fan. It is possible to buy it in electronic shops. It has two sensors. One of these is installed into the upper effluent tube, the other one is installed into the lower inlet.

If you set temperatures correctly it will produce about 1-2 kW of heat energy. It is related to power of the sun.

The collector's dress rehearsal was in the garden before I was installing him onto his definitive place, on 26 January 2006. It was on a cloudless winter day, and the sun was radiating strongly. The air was blown by a little fan, and I measured temperatures with thermometer. A little anemometer measured the velocity of the air. I defined the mass flow in the knowledge of the cross-section and I defined the temperature's difference and then I calculated the power of the heater.

The outside temperature was -3 °C and more than half m3/min of warmed air was streaming out from the heater. Its temperature was +62 °C. I was calculating from the measured data around 700 watts. If I put the +/- 5% of tolerance into the rounding error of the displays, even the 736 W result could have been calculated.

This is precisely 1 horsepower!!!

I wrote about this in the forum, namely in this manner: "... the beer collector brought a horse from the Sun! It may be it was a beer-horse! "

The experienced results are promising, the solar heater is suitable for a heating supplement in sunny time.

(A little explanation to the understanding: The beer-collector is a pun, and the beer-horse is a pun too.
The "beer-horse" expression originates from the past when beer was delivered into the pubs in Europe by carriages towed by horses. These horses were burly animals, and they have been given a name as beer-horses by the people.)