Finally... The first results of my homemade recuperator. What makes you happy and what needs improvement?
And so, after a long time of preparation, assembly of the entire system, and after many assumptions and conjectures, like "what will happen in the end?", it's time to see the real result of my system ventilation(after all, you can say for a long time that I won’t succeed, but you can’t argue with reality).
Friends, if you are in the final of this whole epic, then come to my channel and read the background, in past articles. This will give you a better understanding of what is going on here.
When the heat exchanger was mounted in place, all the channels were assembled, and the fans were connected, I did not wait long to press the "ON" button. Ventilation for supply and exhaust has earned ...
Looking at everything, this case, I had a question: What's next?
At the first stages it was necessary to make control measurements.
Air flow rate in real conditions.
The declared air exchange of the installed fans is 450m³/hour. But in the presence of resistance of all channels (with many bends), filters, and the recuperator itself, this figure will certainly be less.
To measure the flow rate, I used the simplest anemometer ordered in China (something around 500 r. managed).
At the inlet, the speed was 4.8-5 m / s (it still shows the temperature, but something obviously attached to it).
On the hood, this figure was less. The speed was about 4.2m/sec.
It remains to perform simple calculations: πR² * V * 3600
3.14 * 0.075 * 0.075 * 4.8 * 3600 \u003d 305 m³ / hour. It's on the tributary.
3.14 * 0.075 * 0.075 * 4.2 * 3600 \u003d 267 m³ / hour. It's on the drawer.
The figures are, of course, approximate (taking into account the quality of the device and measurement errors), but the overall picture is still clear.
- Losses of 150 m³ / h suit me quite well (that's why I took the fans with a margin).
- At the same time, there is a little more inflow, which is a plus to the fact that there is a stove in the house, which means there will be no problems with it (I'm talking about reverse draft). And at the same time, the difference can be adjusted.
Now let's move on to the recuperator.
The design allows you to take measurements directly at the inputs and outputs. To do this, I took my small thermometer, and put it in turn right inside the heat exchanger, in the right channels.
We got the following results.
- Supply at the inlet to the heat exchanger: -0.9 °С (this is the temperature outside now).
- Air supply at the outlet of the heat exchanger: +7.8 °С
- Exhaust at the inlet to the heat exchanger: +15.5 °С
- Exhaust at the outlet of the heat exchanger: +6 °С
To calculate the efficiency, I found the following formula:
We get the result: (7,8-(-0,9))/(15,5-(-0,9))=0,53. Those. The efficiency of my heat exchanger at a given temperature of the outdoor and indoor air is 53%.
At the same time, I see what can and should be worked on.
✔ First, It's a balance between intake and exhaust. After all, if the supply is stronger than the exhaust (as in my case), then the efficiency of the heat exchanger is less. Therefore, you need to slightly muffle the air supply to the house (anemostats at the outlets of the channels can help here.
✔ Second, you can reduce the overall air exchange. After all, the lower the air flow rate in the heat exchanger, the better the heat exchange takes place, and, accordingly, the work of the heat exchanger is more efficient (and judging by the data obtained, there is much to reduce). To do this, you can use the fan speed controller.
In the end, I think the result will be much better.
Friends, I'm waiting for your opinion on the first tests. As always, good advice and your experience is always helpful. I'm waiting for you in the comments.
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