Our 375 Gallon project
- Thread starter sidewinder770
- Start date
AcroSteve
Make my Funk a P-Funk
Re: Chiller
I have the same type of DIY chiller on my system and have a permanant temp reading at the suction side of the compressor. Meaning, I did not remove it after setting the chiller up. This is visible from my sump room. This is a great comfort to have this reading available to insure I am not overloading the chiller.
I try to keep my suction temp in the 50's as I understand if it is above 65 for very long, compressor damage can result.
I have the same type of DIY chiller on my system and have a permanant temp reading at the suction side of the compressor. Meaning, I did not remove it after setting the chiller up. This is visible from my sump room. This is a great comfort to have this reading available to insure I am not overloading the chiller.
I try to keep my suction temp in the 50's as I understand if it is above 65 for very long, compressor damage can result.
AcroSteve, grant it, I don't know the details or design of your DIY chiller system, but I don't see any problems with running suction temps even into the 80s - it would just mean that you have a very good heat exchanger (or it would indicate that your system is leaking and has a low refrigerant charge, although a suction pressure would be a better indicator there).
Low suction temps indicate that you may have a poor efficiency heat exchanger, an oversized system, fouling due to calcium buildup, or ice formation on the water side.
Low suction temps indicate that you may have a poor efficiency heat exchanger, an oversized system, fouling due to calcium buildup, or ice formation on the water side.
sidewinder770
New member
It will definately make it easier in the end but it's also a lot more work setting it up. Knowing the type of setup we wanted ruled out placing everything under the stand from the start. I must admit though- I have seen some impressive cramming of equipment into stands.NOLACLS said:
Fliger- Thank the monsoon for the temp drop at 8pm
. AcroSteve & cseeton- I messed around with the chiller last night and here is what I ended up with for temps- let me know what you think (these temps are taken from a temp guage strapped to the pipe). Chiller input temp (right after the TXV) is about 39.6-40.4. suction temp about 4 inches after the chiller- 53.4-54.6. I was suprised how much I had to dial the flow of the water back to get it that low- a very rough guess but I would say in the 800-1000gph range....but I could be way off on that. I could go lower but I think that may be about right? I am also able to get a little more temp variation between those 2 readings by adjusting the TXV a little (It has an external adjustment screw). I still need to put the gate valve on the water output instead of a ball valve so I can fine tune it a bit more but I should be able to get about 38 on the input and 54 on the suction. What kind of temps are you guys getting? Should I be concerned with temps at any other point? Unfortunately I don't have a set of gauges to hook up to the low and high pressure ports but the unit itself seems to be running nice and quiet. The way it was setup the first night the chiller input temp was about 52 degrees and the suction temp about 64 so I think it will cool even faster now and be better for the compressor. The suction line (where it goes into the condensing unit) is cool and sweating- I would say about mid 50's- does that sound about right? The pressure line coming from the condensing unit is warm- not hot but I would say 110-120. The ambient temp outside at the time was about 102. I'm just learning the whole HVAC thing so any advise anyone could give would be great.
Let's see... An evaporator temp measurement of about 40 is ok, and your superheat of about 15 degrees is a little high. Try raising your evaporator temp to about 50 and play with the TXV to keep at 15 degree temperature rise. This will allows allow your minisplit to run a little more efficiently and will increase its capacity.
There is no need to dial back your water flow. Let it stream through there and increase the LMTD (fancy way of calculating temperature difference). There is no need to have "cold" water leaving the chiller tube, water has such a high heat capacity that the heat is removed without such a big temperature difference. Obviously though it needs to be lower than your desired temp but give it a little time, your system is large and will take few minutes.
Don't worry about the compressor, it will be fine if your AC guy put the correct TXV inline (they are sized for system and work well, try not to play too much with it). The suction line should be insulated and not dripping while your liquid line (the line from the condensing unit) will be about 5-10 degrees above the outside air temp.
Oh, I just read the rest of the post.... try and get back to the original settings of 52F chiller input and 64 exit. That is a good setting and falls with what I said above...
There is no need to dial back your water flow. Let it stream through there and increase the LMTD (fancy way of calculating temperature difference). There is no need to have "cold" water leaving the chiller tube, water has such a high heat capacity that the heat is removed without such a big temperature difference. Obviously though it needs to be lower than your desired temp but give it a little time, your system is large and will take few minutes.
Don't worry about the compressor, it will be fine if your AC guy put the correct TXV inline (they are sized for system and work well, try not to play too much with it). The suction line should be insulated and not dripping while your liquid line (the line from the condensing unit) will be about 5-10 degrees above the outside air temp.
Oh, I just read the rest of the post.... try and get back to the original settings of 52F chiller input and 64 exit. That is a good setting and falls with what I said above...
AcroSteve
Make my Funk a P-Funk
This thread was a great help to me.
http://www.reefcentral.com/forums/showthread.php?s=&threadid=177020&highlight=suction+temp+damage
In regards to higher suction temps, I took the advice of someone that made a lot of sense to me at the time. Check out robthorn's post on page 9 at 06/24/2003 09:09 AM.
There are several good pages of technical stuff around there too.
Check this thread too.
http://www.reefcentral.com/forums/showthread.php?s=&threadid=308701&highlight=chiller
The way I see it is, you are overloading your compressor and shortening it's life by subjecting it to greater internal temperatures. Your way may work for a few years, mine may work for 10+. It is hard to tell, but I am playing it safe. I think I am running about 600 gph or less.
By changing my flow through my chiller, I can make my suction temp anywhere from below freezing, to whatever the tank temp is. Right now, my suction temp is aroung 55 degrees and I feel I have a very efficient chiller.
I took my suction temp readings by zip-tieing the remote probe from an indoor/outdoor thermomter to the suction line right before the compressor, and under the insulation. This is still in place today. I did not leave any gage in place.
My system has an orfice, not a TXV, so I cannot give you any real experience with adjusting it. Other than to say, the TXV is better. Get a gate valve before you spend much time adjusting things
You should consult a local HVAC tech with gages to properly set the refrigerant level. The will check the temperature at the compressor suction, and the high and low pressures. These are the minimum requred to calculate what is called "Super Heat". This value should be less than 10.
But.. before you do much else, do yourself a favor and take a few hours to read those two threads.
http://www.reefcentral.com/forums/showthread.php?s=&threadid=177020&highlight=suction+temp+damage
In regards to higher suction temps, I took the advice of someone that made a lot of sense to me at the time. Check out robthorn's post on page 9 at 06/24/2003 09:09 AM.
There are several good pages of technical stuff around there too.
Check this thread too.
http://www.reefcentral.com/forums/showthread.php?s=&threadid=308701&highlight=chiller
The way I see it is, you are overloading your compressor and shortening it's life by subjecting it to greater internal temperatures. Your way may work for a few years, mine may work for 10+. It is hard to tell, but I am playing it safe. I think I am running about 600 gph or less.
By changing my flow through my chiller, I can make my suction temp anywhere from below freezing, to whatever the tank temp is. Right now, my suction temp is aroung 55 degrees and I feel I have a very efficient chiller.
I took my suction temp readings by zip-tieing the remote probe from an indoor/outdoor thermomter to the suction line right before the compressor, and under the insulation. This is still in place today. I did not leave any gage in place.
My system has an orfice, not a TXV, so I cannot give you any real experience with adjusting it. Other than to say, the TXV is better. Get a gate valve before you spend much time adjusting things
You should consult a local HVAC tech with gages to properly set the refrigerant level. The will check the temperature at the compressor suction, and the high and low pressures. These are the minimum requred to calculate what is called "Super Heat". This value should be less than 10.
But.. before you do much else, do yourself a favor and take a few hours to read those two threads.
Acrosteve,
I would love to discuss your 65 degree problem in more detail since I think someone gave you some unclear advice on a temperature, but I do not want to tie up this tread. There are some very good tips in your first link, but for people reading this - if you want to do a DIY chiller - hire a licensed professional. You need an EPA license to work with refrigerants. This will prevent you from not correctly charging your system and possibly have it fail prematurely, sizing one of the components to cause system failure, or - worse - injuring someone due to it being overcharged to pressures near the burst of the metal lines or the compressor shell.
Chris
I would love to discuss your 65 degree problem in more detail since I think someone gave you some unclear advice on a temperature, but I do not want to tie up this tread. There are some very good tips in your first link, but for people reading this - if you want to do a DIY chiller - hire a licensed professional. You need an EPA license to work with refrigerants. This will prevent you from not correctly charging your system and possibly have it fail prematurely, sizing one of the components to cause system failure, or - worse - injuring someone due to it being overcharged to pressures near the burst of the metal lines or the compressor shell.
Chris
sidewinder770
New member
Don't worry about tying up my thread- post away all you like. I'm sure other people would like to hear the discussion about this as well. I appreciate both of you posting your knowledge and appreciate your time.
AcroSteve- I have read those two posts a few times- I probably wouldn't have even attempted this set-up if I had not read those threads as they contain some very useful information. I was doing a little different of a setup so I wanted to make sure I was on the right track- the other threads didn't use 1/2 of a mini split or a TXV so I wasn't sure if things would be different because of that. For anyone trying to do this setup I would definately check out those 2 threads.
Anyway- I got the gate valve on yesterday and probably wont fire up the chiller again till I get some saltwater in the system. I have a few smaller projects to get done here and there in the sump room and need to start on the canopy / lighting but I am currently still waiting on the skimmer which will probably be 2+ weeks from being finished still.
I'll post more pics as I get more done.....I am just ready to have water in this already and can't wait for the skimmer to get here!
AcroSteve- I have read those two posts a few times- I probably wouldn't have even attempted this set-up if I had not read those threads as they contain some very useful information. I was doing a little different of a setup so I wanted to make sure I was on the right track- the other threads didn't use 1/2 of a mini split or a TXV so I wasn't sure if things would be different because of that. For anyone trying to do this setup I would definately check out those 2 threads.
Anyway- I got the gate valve on yesterday and probably wont fire up the chiller again till I get some saltwater in the system. I have a few smaller projects to get done here and there in the sump room and need to start on the canopy / lighting but I am currently still waiting on the skimmer which will probably be 2+ weeks from being finished still.
I'll post more pics as I get more done.....I am just ready to have water in this already and can't wait for the skimmer to get here!
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I still maintain that anyone trying to DIY a chiller tube, needs to hire a professional to correctly charge the system. But, I also know that there are alot of people that will not yield my advice and do it themselves anyway.....
Since I do not want to be the one that "cseeton on reefcentral told me how to do this...", and you do it wrong and the system breaks. I will refer those interested to this online trade article:
How to Charge an Air Conditioner
I do not want to toot my own horn, but I am getting my PhD in refrigerant/lubricant properties, i.e. compressor lubrication. And I will tell you right now that the temperature fo the refrigerant entering the compressor being too high is not a concern. The concern is why is the temperature too high... Usually, high suction temps occur because the system is undercharged (has a low suction pressure, high superheat) or the evaporator is a high efficiency design (normal suction pressure and correct superheat). Now you can see that there are two different reasons (one bad, one good) for inlet temperatures and without knowing the correct suction pressure (and therefore, superheat) there is no way to know what is happening. You will never see a HVAC tech without his gauges (and if you do, get another one) to determine the superheat and operation of the system.
As far as the suction gas "cooling" the compressor... there is not enough energy left in the stream to provide much of a cooling benefit to the compressor (it is a gas with virtually no capacity). The compression process generates a great deal of heat on its own and the compressors are designed to have this heat carried away in the discharge line or have a fan cool the compressor shell.
For those still really wanting to their own DIY chiller, a TXV is the way to go. Yes, these cost a little more, but they really help the DIY person because they take one thing out of your hands... These systems are charged for subcooling since the TXV modulates the superheat. In addition, if you live in climates where the temperature drops below about 65F, then you will need to get a head pressure controller and a crankcase heater. These devices are not too expensive and will allow for year round operation of your chiller. The head pressure controller (electrical version with a 10K thermistor) and crankcase heaters are also electrical so they can be added to currently operated systems without disturbing the refrigerant lines.
So, my recommendation is to purchase all the pieces for your system - condensing unit, or window AC, TXV, chiller tube, and for those inclined, refrigerant tubing (keep it clean!!). IF you feel comfortable putting it together then go ahead, but don't make the final connections to the condensing unit. Hire a HVAC tech to make a call. He will make the final connections, pull a vacuum on the system and either release the refrigerant from the condensing unit or charge the system. At that time, if you are uncomfortable with electricity the tech can also connect the head pressure controller and crankcase heater. Be absolutely certain that you keep water out of all components if there is a time lag between the tech getting there and when you piece together your components. The number two killer of AC systems is water - right behind overcharging. Keep an eye on your system for a while, if you see your compressor "sweating" or frosting, call your tech because your system is likely overcharged or frozen and will need adjustment.
Since I do not want to be the one that "cseeton on reefcentral told me how to do this...", and you do it wrong and the system breaks. I will refer those interested to this online trade article:
How to Charge an Air Conditioner
I do not want to toot my own horn, but I am getting my PhD in refrigerant/lubricant properties, i.e. compressor lubrication. And I will tell you right now that the temperature fo the refrigerant entering the compressor being too high is not a concern. The concern is why is the temperature too high... Usually, high suction temps occur because the system is undercharged (has a low suction pressure, high superheat) or the evaporator is a high efficiency design (normal suction pressure and correct superheat). Now you can see that there are two different reasons (one bad, one good) for inlet temperatures and without knowing the correct suction pressure (and therefore, superheat) there is no way to know what is happening. You will never see a HVAC tech without his gauges (and if you do, get another one) to determine the superheat and operation of the system.
As far as the suction gas "cooling" the compressor... there is not enough energy left in the stream to provide much of a cooling benefit to the compressor (it is a gas with virtually no capacity). The compression process generates a great deal of heat on its own and the compressors are designed to have this heat carried away in the discharge line or have a fan cool the compressor shell.
For those still really wanting to their own DIY chiller, a TXV is the way to go. Yes, these cost a little more, but they really help the DIY person because they take one thing out of your hands... These systems are charged for subcooling since the TXV modulates the superheat. In addition, if you live in climates where the temperature drops below about 65F, then you will need to get a head pressure controller and a crankcase heater. These devices are not too expensive and will allow for year round operation of your chiller. The head pressure controller (electrical version with a 10K thermistor) and crankcase heaters are also electrical so they can be added to currently operated systems without disturbing the refrigerant lines.
So, my recommendation is to purchase all the pieces for your system - condensing unit, or window AC, TXV, chiller tube, and for those inclined, refrigerant tubing (keep it clean!!). IF you feel comfortable putting it together then go ahead, but don't make the final connections to the condensing unit. Hire a HVAC tech to make a call. He will make the final connections, pull a vacuum on the system and either release the refrigerant from the condensing unit or charge the system. At that time, if you are uncomfortable with electricity the tech can also connect the head pressure controller and crankcase heater. Be absolutely certain that you keep water out of all components if there is a time lag between the tech getting there and when you piece together your components. The number two killer of AC systems is water - right behind overcharging. Keep an eye on your system for a while, if you see your compressor "sweating" or frosting, call your tech because your system is likely overcharged or frozen and will need adjustment.
Oh, if you are using a window AC as you condensing unit. Do not cut the tubing. Let The HVAC tech do that for two reasons, first it is illegal to vent refrigerant (the tech will reclaim it) and, second so that water will not absorb into the lubricant during the time it is open to the atmosphere. Just bring the tubes from the chiller tube to the unit. Water will also freeze inside the system and clog the expansion device (cap tube, or TXV) so it is very important that the system stay sealed until the final connections are ready to be made.
AcroSteve
Make my Funk a P-Funk
Good information!
If we could discuss this a little more, It might help us understand it a little better. I will simplify a little bit, so as to avoid over-analyzing it.
Regarding the load on the compressor;
Let's consider that our tank water temp will be constant. I say this because for all practical purposes, and in most cases, we are working with a temp range of one degree or less. Therefore, the only way to change the load on the compressor, is by adjusting the water flow through the heat exchanger.
In my situation, I charged my system to a certain superheat value using a load that was not precicely known. I estimate it was about 600 gph, but I have no way of being sure. I do not have my notes so I cannot quote any specifics, but my high side was around 250, and the low side was around 65. As I mentioned before, I kept the sution temp in the 50's.
I have a fan cutout switch that is currently set at 200psi with a span of 70psi. I did not incorporate any heaters or head pressure controller. It has worked fine for 2 winters now, but I do cover about 80% of the condensor area in the winter.
Enough of my rambling. now a few questions for you cseeton.
Given that my compressor is a 5200btu window unit(and the source of my capillary tube) and I am using a 1/3 hp chiller barrell, should I re-connect my gages and check and or re-set my pressures and superheat? How much load should I place on my compressor for the most effecient operation? What suction temperature would you "shoot for". Would you choose different setpoints for the fan cut-out switch
Additionally, my chiller is fed from my return pump, so any increase in the flow through my chiller will come at the expense of flow to my tank. Therefore, I would be better off with the least amount of flow though my chiller that will still get the job done.
With my current level of charge and chiller water flow, my chiller is dropping the water temp of my 250 gallon system 0.5 degrees in about 15 minutes. Should I even be concerned with it? Still, answers to my previous questions will help myself and others in the future.
What made you pick this for your PhD anyway?
If we could discuss this a little more, It might help us understand it a little better. I will simplify a little bit, so as to avoid over-analyzing it.
Regarding the load on the compressor;
Let's consider that our tank water temp will be constant. I say this because for all practical purposes, and in most cases, we are working with a temp range of one degree or less. Therefore, the only way to change the load on the compressor, is by adjusting the water flow through the heat exchanger.
In my situation, I charged my system to a certain superheat value using a load that was not precicely known. I estimate it was about 600 gph, but I have no way of being sure. I do not have my notes so I cannot quote any specifics, but my high side was around 250, and the low side was around 65. As I mentioned before, I kept the sution temp in the 50's.
I have a fan cutout switch that is currently set at 200psi with a span of 70psi. I did not incorporate any heaters or head pressure controller. It has worked fine for 2 winters now, but I do cover about 80% of the condensor area in the winter.
Enough of my rambling. now a few questions for you cseeton.
Given that my compressor is a 5200btu window unit(and the source of my capillary tube) and I am using a 1/3 hp chiller barrell, should I re-connect my gages and check and or re-set my pressures and superheat? How much load should I place on my compressor for the most effecient operation? What suction temperature would you "shoot for". Would you choose different setpoints for the fan cut-out switch
Additionally, my chiller is fed from my return pump, so any increase in the flow through my chiller will come at the expense of flow to my tank. Therefore, I would be better off with the least amount of flow though my chiller that will still get the job done.
With my current level of charge and chiller water flow, my chiller is dropping the water temp of my 250 gallon system 0.5 degrees in about 15 minutes. Should I even be concerned with it? Still, answers to my previous questions will help myself and others in the future.
What made you pick this for your PhD anyway?
Boy, I wish I knew... It just kind of drew me in.... I worked for a number of years before I came back to school and I guess a quote from my old boss got me started. "image this, here we have a system that uses industrial grade solvents, mixed together with a lubricant, dirt, water, and other unspeakables... It is really a small chemical processing plant. We are limited to only to an initial oil charge, while with every other piece of industrial equipment we can filter or change the oil,. AND, we expect this system to operate for a minimum of 10 years without failure in the cold of winter and the extreme of summer. Now, if we don't get it right, or even have a hiccup, the consumer will pound on the door and demand that it is fixed now and compensate him for the losses. How is that for a tough challenge...."
Anyway, on to your question. If I remember right, in your attached thread you said that you are using a R22 system. A high side pressure of 250 corresponds to a condensing temp of about 115F (if you used a gauge set, you can read the corresponding temp from the scale corresponding to your refrigerant - green in my case). Now, a suction pressure of 65psig corresponds to a temp of about 38F and if your suction temp was in the 50s, your superheat was between 15-20 degrees. But since you measure it at the suction instead of the evaporator exit, the superheat is probably a little lower. That is ok.
Should you reconnect your gauges and try again? NO. Your system does not sound like it is far off the mark. I would try to flow as much through your chiller as you are comfortable with, the more the better. Just do not drop your flow so low as to let frost form on the exit line from the chiller tube...
Your fan cutout switch operates the same as a head pressure control, it just uses pressure as the parameter instead of temperature. These are usually a cheap alternative to the electrical control, but you have to set it up when the system is not charged. If the system is charged, I recommend the electrical control since a service call will easily cost the difference.
High suction temps are not a problem, low suction temps are a big problem. There is no maximum temperature for the suction inlet; it just depends on the system, the load on the system and it could be an indication of low charge. Find high quality gauges and use them.
sidewinder770
New member
AcroSteve & cseeton- Thanks for all the advise and help with this. Looks like I do have a little adjusting to make but I'll wait till I have saltwater flowing and all the other tanks are ready to go before making final adjustments. I did have a question- on the TXV- I noticed when I turn the adjustment screw clockwise (I'm assuming I'm closing it) The temperature of the line going to the chiller drops- then I adjust the water flow to raise the temp a bit. I assume this is because on a normal A/C system you would be adjusting the TXV based on airflow since It's probably something that isn't very adjustable with a normal evaporator. With water, the temp can be adjusted based on water flow so I would probably want to close the adjustment screw most of the way to allow more water flow correct? Hope that makes sense.
As for the rest of the tank I still have a few small details and things to do on it before it's ready to go but I am mainly waiting on the skimmer at this point and that should be in the next few weeks. I'll post some more pics when I have more updates. Once I know the skimmer is shipping I will probably start the RO/DI since it will take about 5-7 days to get it filled so it should be filled and ready when the skimmer arrives.
Thanks again for all the great information and tips- I really appreciate it.
As for the rest of the tank I still have a few small details and things to do on it before it's ready to go but I am mainly waiting on the skimmer at this point and that should be in the next few weeks. I'll post some more pics when I have more updates. Once I know the skimmer is shipping I will probably start the RO/DI since it will take about 5-7 days to get it filled so it should be filled and ready when the skimmer arrives.
Thanks again for all the great information and tips- I really appreciate it.
gobygoby
New member
Scott,
did you have to do anything special to the actuator to get it working??
I just got mine tonight and it came with the Taiwan male plug-in so I called the guys at parts express and they said it was fine to attatch the U.S. plug. When I press the buttons on the control the red LED lights up but no noise or movement in the actuator. I noticed a small screw on the actuator motor that can be adjusted, I assume this is for limiting? do you have to have the batteries hooked in to make this work? anyway, I didnt know if there is a secret to get it working. so far my doesnt do anything!
PS. mine didnt come with any instructions either.
Thanks
Goby
did you have to do anything special to the actuator to get it working??
I just got mine tonight and it came with the Taiwan male plug-in so I called the guys at parts express and they said it was fine to attatch the U.S. plug. When I press the buttons on the control the red LED lights up but no noise or movement in the actuator. I noticed a small screw on the actuator motor that can be adjusted, I assume this is for limiting? do you have to have the batteries hooked in to make this work? anyway, I didnt know if there is a secret to get it working. so far my doesnt do anything!
PS. mine didnt come with any instructions either.
Thanks
Goby
sidewinder770
New member
Goby- I didn't have to do anything to get it to work. It came with a standard 3 prong plug for 110v. I haven't put any batteries in mine and it seems to be working just fine without them. I'd have to look at mine again but I don't think it had an LED of any sort on the remote( I could be wrong about this but I'd have to look), not sure if mine came with instructions or not but I didn't need them since it was a plug it in and it worked kind of deal. Sounds like you may have gotten a different actuator than we did. Does your look like the picture I posted a few pages back in this thread? I would tell them they sent you the wrong item as it sounds like you got some type of 'non-US' model.
matt & pam
Member
Goby,
Assuming you have the same linear actuator, the remote goes into the middle connection of the power box, and the actuator motor plugs into the left connection when the connections are oriented towards the top. Mine is the same as Scott and I do not have any LEDs.
Matt
Assuming you have the same linear actuator, the remote goes into the middle connection of the power box, and the actuator motor plugs into the left connection when the connections are oriented towards the top. Mine is the same as Scott and I do not have any LEDs.
Matt
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