Automatic defrost circuit - Page 4

AC_Hacker · 12-16-12, 01:09 AM

Acuario,

Long time since I've seen one of your posts. Last time I was tuned in to your work, you were in the midst of cracking the code on an inverter technology Air Conditioner, and you were interested in converting it to a heat pump.

I was very interested in that project, because I have always thought that such a project had tremendous potential for efficiency.

Could you say a few words about how that project went? Were you successful? If so, was the converted unit significantly more efficient than the other conversions which use the older, less complicated technology?

Best,

-AC

Acuario · 12-16-12, 01:37 AM

The Daikin project is still ongoing. It's been delayed due to other projects but I'm just about to start working on it again, just need to finish the olive harvest and re-grouting the swimming pool.

Current state of play is that I can control the unit from a PC but I want to move it onto a dedicated controller.

The original controller I bought didn't have enough memory so I used it for the Greenhouse project.

I bought a Raspberry PI and thought of using that (it's still a possibility) but then came across a PIC board that has lots of memory and an onboard web server, so it opened up another chain of thought and new possibilities - controlling the machine via a web interface over a wifi connection...hummmm

AC_Hacker · 12-16-12, 09:07 AM

Quote:

Originally Posted by Acuario

...just need to finish the olive harvest and re-grouting the swimming pool...

Wow, I wish I could say that I needed to finish the olive harvest before I could get back to my projects!

Best,

-AC

Acuario · 12-16-12, 10:45 AM

We had a good harvest ourselves this year - from 50 trees we harvester 614Kg of olives and have 95 litres of extra virgin oil for the year ahead - next years harvest may be much lower as it goes in cycles. The acidity is 0.3 degrees so it's classed as Extra Virgin - a luxury!

We've just been helping some friends and in 1 1/2 days have harvested around 700Kg.

Living in Spain we have so much, particularly in southern Catalunya where I live - oranges, mandarins, clemantines, lemons - it's so sad seeing them falling from the trees and just rotting.. also almonds, olives, cherries, apricots, grapes, carobs, figs and almost any vegetable you can imagine. I also grow rhubarb and raspberries plus loads of stuff growing in thegreenhouse now - just ready are green beans (runner beans/french beans, not sure what you call them in the US) and loads of other stuff - even, surprisingly strawberries. I never thought they would grow so out of season!

AC_Hacker · 12-16-12, 11:14 AM

Quote:

Originally Posted by Acuario

Living in Spain we have so much, particularly in southern Catalunya where I live - oranges, mandarins, clemantines, lemons - it's so sad seeing them falling from the trees and just rotting.. also almonds, olives, cherries, apricots, grapes, carobs, figs and almost any vegetable you can imagine. I also grow rhubarb and raspberries plus loads of stuff growing in thegreenhouse now - just ready are green beans (runner beans/french beans, not sure what you call them in the US) and loads of other stuff - even, surprisingly strawberries. I never thought they would grow so out of season!

OK, I'm sold.

Was it difficult to relocate?

-AC

Acuario · 12-16-12, 01:50 PM

Living in Europe (UK to be precise) it was dead easy - sold the house, packed a van and moved into the new house. No problems with immigration, green cards, visas - nothing.

From the US I'm not sure although I do know of other US citizens who have moved here so I guess it's not too difficult.

Xringer · 12-16-12, 04:59 PM

Wow, I was just looking at the Street view in that area and, wow! is that a date palm?
https://maps.google.com/maps?q=Torto...292.39,,0,5.88

Looks like an old fort up on the hill.. An amazing place!

Acuario · 12-17-12, 12:19 AM

Yes it is a date palm - I've got 3 or 4 in my garden. The dates here are a bit on the small side though but they are edible. You need to go a bit further south to Valencia to get big juicy dates. I unfortunately just lost one tree to an insect called the 'Red palm weevil' that is slowly devestating the palm trees in Spain.

Tortosa has a 'Parador' - an old fort now turned into a luxury hotel - that overlooks the city. I can see it from where I live. We're also in the foothils of Mt. Caro which sometimes has snow on the top of it in winter - it did a few weeks ago when we had a cold snap - all gone now though.

It's a wonderful place to live, both for the culture, countryside, climate and more. As I write at 7:15Am the temperature outside is 15 degrees C - yesterday during the day it was in the low 20's - not bad for the middle of december!

Xringer · 12-17-12, 09:02 AM

Wow, that sounds pretty nice! (Except for the 'Red palm weevil')!

Today we've got snow, rain & ice all over the place.
Ever since the day I slipped on ice and destroyed my right ankle, ice scares me.
Now that I'm almost 67, it's even more scary..

Not a nice day here at all. I wanted to get in some part-time work at the lab today. (Need Christmas $$).
But, I'm not too keen on driving slippery roads, while so many drivers are still in the learn mode.
(Many here have to relearn winter driving skills every season).

This morning we have frost on both outdoor units.
But so far, only the main house unit has done a defrost cycle.
The den unit is still cranking out the heat..
Right after the 3.5kW TED alarm went off, my 10A / 60 second shut-down triggered.
Giving the main Sanyo a little break. Working fine right now.

Acuario · 12-17-13, 11:02 AM

It's been a while since I updated this post so I thought I would share my experience this winter.

Last winter was unusually mild, hardly any nights below 3 degrees so it seemed the defrost was 'good to go'. This year it's a lot colder and as a result it has thrown a spanner in the works as far as the defrost was concerned.

Was it a success: No, in it's current form it failed.
The problem was it was cold and low humidity, result being that the temperature dropped to and below zero but little or no frost or freezing up. So the defrost kicked in when it didn't need to dumping heat unnecessarily.

Did I learn from it's failure?
Yes of course so a bit of research, a rewrite of the code and a reposition of the sensor to the output side of the capillary and hello Version 2.

Based on some info I found hunting on the web the algorithm used to start a defrost cycle was:

When the temperature on the output side of the capillary reaches 0 degrees reverse the refrigerant flow (hot refrigerant defrosts the hx).
When the temperature on the output side of the capillary reaches 13 degrees go back to heat mode.

Did it work? No.
Again the hx wasn't frozen at 0 degrees so again I was unnecessarily dumping heat. The cap output temperature also seemed to stay pretty much at 0 degrees when running in heating at low ambient temperature.
Reducing the defrost start temperature to -1 didn't work either as when the humidity increased the cap exit temperature stayed the same but the unit then froze up.

So version 3 is now installed (but the nights have warmed up a bit so I might not know if it works for a few days).

Version 3 now has 2 sensors; 1 at the exit of the cap and one at the exit of the hx.
Now I'm measuring the difference between entry and exit of the hx and can re-program the defrost on trigger based on the temperature difference between the two (assuming that when the hx is frozen there won't be any difference or if there is it will be very small) and the defrost off is determined by the capillary exit temperature or a timer, whichever expires first.
I've also added a control for the fan to turn it off when the defrost cycle is running and removed the stopping/restarting of the compressor.

With the ambient temperature at 13C the difference across the hx is 5C (6C at the cap exit and 11C at the hx exit).

It's not due to get down to freezing here now until friday night/saturday morning (3 days from now) so it'll be a few days until I have results from the current setup.

I didn't realise a defrost cycle could be so challenging but it's fun trying to come up with a working solution.

Acuario

12-16-12, 01:09 AM	#31
AC_Hacker Supreme EcoRenovator Join Date: Mar 2009 Location: Portland, OR Posts: 4,004 Thanks: 303 Thanked 723 Times in 534 Posts	Acuario, Long time since I've seen one of your posts. Last time I was tuned in to your work, you were in the midst of cracking the code on an inverter technology Air Conditioner, and you were interested in converting it to a heat pump. I was very interested in that project, because I have always thought that such a project had tremendous potential for efficiency. Could you say a few words about how that project went? Were you successful? If so, was the converted unit significantly more efficient than the other conversions which use the older, less complicated technology? Best, -AC __________________ I'm not an HVAC technician. In fact, I'm barely even a hacker...

12-16-12, 04:59 PM	#37
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	Wow, I was just looking at the Street view in that area and, wow! is that a date palm? https://maps.google.com/maps?q=Torto...292.39,,0,5.88 Looks like an old fort up on the hill.. An amazing place! __________________ My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less..

12-17-12, 09:02 AM	#39
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	I hate weevils Wow, that sounds pretty nice! (Except for the 'Red palm weevil')! Today we've got snow, rain & ice all over the place. Ever since the day I slipped on ice and destroyed my right ankle, ice scares me. Now that I'm almost 67, it's even more scary.. Not a nice day here at all. I wanted to get in some part-time work at the lab today. (Need Christmas $$). But, I'm not too keen on driving slippery roads, while so many drivers are still in the learn mode. (Many here have to relearn winter driving skills every season). This morning we have frost on both outdoor units. But so far, only the main house unit has done a defrost cycle. The den unit is still cranking out the heat.. Right after the 3.5kW TED alarm went off, my 10A / 60 second shut-down triggered. Giving the main Sanyo a little break. Working fine right now. Attached Thumbnails __________________ My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less..

12-17-13, 11:02 AM	#40
Acuario Apprentice EcoRenovator Join Date: May 2011 Location: Tortosa, Spain Posts: 221 Thanks: 2 Thanked 81 Times in 46 Posts	It's been a while since I updated this post so I thought I would share my experience this winter. Last winter was unusually mild, hardly any nights below 3 degrees so it seemed the defrost was 'good to go'. This year it's a lot colder and as a result it has thrown a spanner in the works as far as the defrost was concerned. Was it a success: No, in it's current form it failed. The problem was it was cold and low humidity, result being that the temperature dropped to and below zero but little or no frost or freezing up. So the defrost kicked in when it didn't need to dumping heat unnecessarily. Did I learn from it's failure? Yes of course so a bit of research, a rewrite of the code and a reposition of the sensor to the output side of the capillary and hello Version 2. Based on some info I found hunting on the web the algorithm used to start a defrost cycle was: When the temperature on the output side of the capillary reaches 0 degrees reverse the refrigerant flow (hot refrigerant defrosts the hx). When the temperature on the output side of the capillary reaches 13 degrees go back to heat mode. Did it work? No. Again the hx wasn't frozen at 0 degrees so again I was unnecessarily dumping heat. The cap output temperature also seemed to stay pretty much at 0 degrees when running in heating at low ambient temperature. Reducing the defrost start temperature to -1 didn't work either as when the humidity increased the cap exit temperature stayed the same but the unit then froze up. So version 3 is now installed (but the nights have warmed up a bit so I might not know if it works for a few days). Version 3 now has 2 sensors; 1 at the exit of the cap and one at the exit of the hx. Now I'm measuring the difference between entry and exit of the hx and can re-program the defrost on trigger based on the temperature difference between the two (assuming that when the hx is frozen there won't be any difference or if there is it will be very small) and the defrost off is determined by the capillary exit temperature or a timer, whichever expires first. I've also added a control for the fan to turn it off when the defrost cycle is running and removed the stopping/restarting of the compressor. With the ambient temperature at 13C the difference across the hx is 5C (6C at the cap exit and 11C at the hx exit). It's not due to get down to freezing here now until friday night/saturday morning (3 days from now) so it'll be a few days until I have results from the current setup. I didn't realise a defrost cycle could be so challenging but it's fun trying to come up with a working solution. Acuario

12-16-12, 01:37 AM	#32
Acuario Apprentice EcoRenovator Join Date: May 2011 Location: Tortosa, Spain Posts: 221 Thanks: 2 Thanked 81 Times in 46 Posts	The Daikin project is still ongoing. It's been delayed due to other projects but I'm just about to start working on it again, just need to finish the olive harvest and re-grouting the swimming pool. Current state of play is that I can control the unit from a PC but I want to move it onto a dedicated controller. The original controller I bought didn't have enough memory so I used it for the Greenhouse project. I bought a Raspberry PI and thought of using that (it's still a possibility) but then came across a PIC board that has lots of memory and an onboard web server, so it opened up another chain of thought and new possibilities - controlling the machine via a web interface over a wifi connection...hummmm

12-16-12, 10:45 AM	#34
Acuario Apprentice EcoRenovator Join Date: May 2011 Location: Tortosa, Spain Posts: 221 Thanks: 2 Thanked 81 Times in 46 Posts	We had a good harvest ourselves this year - from 50 trees we harvester 614Kg of olives and have 95 litres of extra virgin oil for the year ahead - next years harvest may be much lower as it goes in cycles. The acidity is 0.3 degrees so it's classed as Extra Virgin - a luxury! We've just been helping some friends and in 1 1/2 days have harvested around 700Kg. Living in Spain we have so much, particularly in southern Catalunya where I live - oranges, mandarins, clemantines, lemons - it's so sad seeing them falling from the trees and just rotting.. also almonds, olives, cherries, apricots, grapes, carobs, figs and almost any vegetable you can imagine. I also grow rhubarb and raspberries plus loads of stuff growing in thegreenhouse now - just ready are green beans (runner beans/french beans, not sure what you call them in the US) and loads of other stuff - even, surprisingly strawberries. I never thought they would grow so out of season!

12-16-12, 01:50 PM	#36
Acuario Apprentice EcoRenovator Join Date: May 2011 Location: Tortosa, Spain Posts: 221 Thanks: 2 Thanked 81 Times in 46 Posts	Living in Europe (UK to be precise) it was dead easy - sold the house, packed a van and moved into the new house. No problems with immigration, green cards, visas - nothing. From the US I'm not sure although I do know of other US citizens who have moved here so I guess it's not too difficult.

12-17-12, 12:19 AM	#38
Acuario Apprentice EcoRenovator Join Date: May 2011 Location: Tortosa, Spain Posts: 221 Thanks: 2 Thanked 81 Times in 46 Posts	Yes it is a date palm - I've got 3 or 4 in my garden. The dates here are a bit on the small side though but they are edible. You need to go a bit further south to Valencia to get big juicy dates. I unfortunately just lost one tree to an insect called the 'Red palm weevil' that is slowly devestating the palm trees in Spain. Tortosa has a 'Parador' - an old fort now turned into a luxury hotel - that overlooks the city. I can see it from where I live. We're also in the foothils of Mt. Caro which sometimes has snow on the top of it in winter - it did a few weeks ago when we had a cold snap - all gone now though. It's a wonderful place to live, both for the culture, countryside, climate and more. As I write at 7:15Am the temperature outside is 15 degrees C - yesterday during the day it was in the low 20's - not bad for the middle of december!