Hybrid Water Source Heat Pump

Reply

  #1  
Old 11-05-09, 11:26 AM
Member
Thread Starter
Join Date: Nov 2009
Location: Florida
Posts: 7
Received 0 Votes on 0 Posts
Hybrid Water Source Heat Pump

Hybrid Water Source Heat Pump

With the increasing cost of electricity and more increases on the way I'm looking to reduce consumption and since A/C and water heating are the biggest drains I'm looking for the cheapest alternatives that don't take 10 years to recoup the cost. I have 3 water wells on my property and was looking at water source heat pump A/Cs but as you know these run in excess of $2500 a ton. The Trane XE1000 (I think) 2.5 ton A/C I have now is only about 9 years old.

My hare-brain idea is to have a qualified A/C installer install a big water to refrigerant "Brazed Flat Plate Heat Exchanger" in the current A/C units' liquid line just as it exits the main cooling coils as a "Subcooler". The idea is to pump 3 to 6 GPM through it and further supercool the refrigerant about 20F. On a 90 day the air coming out in the home is about 70 and I'm hoping to lower this to 50 thereby cutting down the run time of the A/C unit. The only problem with the idea is in the winter when the heat pump reverses it's flow. I'm told the exchanger then becomes the primary cooling, the main coil becomes the subcooler and the refrig. in the exchanger may heat too much and try to freeze up. I suppose I could use two exchangers one at the input of the primary coils also and switch exchangers in the winter or just pump more water through the exchanger in the winter.
My questions are; first, will this work? Secondly, is this to complex for this forum? Is this a really dumb idea?
Any input would be appreciated.
 
Sponsored Links
  #2  
Old 11-05-09, 12:21 PM
GRIMKNOTME's Avatar
Member
Join Date: Nov 2009
Location: N.C. USA
Posts: 120
Received 0 Votes on 0 Posts
Originally Posted by u4ia2000 View Post
Hybrid Water Source Heat Pump

With the increasing cost of electricity and more increases on the way I'm looking to reduce consumption and since A/C and water heating are the biggest drains I'm looking for the cheapest alternatives that don't take 10 years to recoup the cost. I have 3 water wells on my property and was looking at water source heat pump A/Cs but as you know these run in excess of $2500 a ton. The Trane XE1000 (I think) 2.5 ton A/C I have now is only about 9 years old.

My hare-brain idea is to have a qualified A/C installer install a big water to refrigerant "Brazed Flat Plate Heat Exchanger" in the current A/C units' liquid line just as it exits the main cooling coils as a "Subcooler". The idea is to pump 3 to 6 GPM through it and further supercool the refrigerant about 20F. On a 90 day the air coming out in the home is about 70 and I'm hoping to lower this to 50 thereby cutting down the run time of the A/C unit. The only problem with the idea is in the winter when the heat pump reverses it's flow. I'm told the exchanger then becomes the primary cooling, the main coil becomes the subcooler and the refrig. in the exchanger may heat too much and try to freeze up. I suppose I could use two exchangers one at the input of the primary coils also and switch exchangers in the winter or just pump more water through the exchanger in the winter.
My questions are; first, will this work? Secondly, is this to complex for this forum? Is this a really dumb idea?
Any input would be appreciated.
-----------------------------------------------------------

My hare-brain idea is to have a qualified A/C installer install a big water to refrigerant "Brazed Flat Plate Heat Exchanger" in the current A/C units' liquid line just as it exits the main cooling coils as a "Subcooler". The idea is to pump 3 to 6 GPM through it and further supercool the refrigerant about20F.

If im reading this right you cannot mix the two together

But you can install an additional water coil with a circulator pump size and all tech stuff to be determined. And cut it off in winter , iv been to fla. in winter and my a/c broke on car ,i like 2 have died
 
  #3  
Old 11-05-09, 01:45 PM
Member
Thread Starter
Join Date: Nov 2009
Location: Florida
Posts: 7
Received 0 Votes on 0 Posts
Originally Posted by GRIMKNOTME View Post
-----------------------------------------------------------
If im reading this right you cannot mix the two together

But you can install an additional water coil with a circulator pump size and all tech stuff to be determined. And cut it off in winter , iv been to fla. in winter and my a/c broke on car ,i like 2 have died
Yeah, refrigerant can really be noxious-- I had a similar situation once but not in a closed space.

Why are you saying they can't be mixed. I hope you don't think I'm mixing water with refrigerant-- it's a heat exchanger.
 
  #4  
Old 11-05-09, 02:11 PM
Member
Join Date: Aug 2006
Location: santa fe /texas
Posts: 998
Received 0 Votes on 0 Posts
i have a similar idea, but i want to put the water to refrigerant heat exchanger at the compressor discharge-before the cooling coil-(thinking this would lower head pressure & amps required/used)
 
  #5  
Old 11-05-09, 04:17 PM
GRIMKNOTME's Avatar
Member
Join Date: Nov 2009
Location: N.C. USA
Posts: 120
Received 0 Votes on 0 Posts
Originally Posted by u4ia2000 View Post
Yeah, refrigerant can really be noxious-- I had a similar situation once but not in a closed space.

Why are you saying they can't be mixed. I hope you don't think I'm mixing water with refrigerant-- it's a heat exchanger.
Just making sure some people just dont know you dont realize what we go thru sometimes .
The cooling part i would agree with. But you can install an additional water coil with a circulator pump size and all tech stuff to be determined. And cut it off in winter.
 
  #6  
Old 11-05-09, 05:18 PM
Member
Thread Starter
Join Date: Nov 2009
Location: Florida
Posts: 7
Received 0 Votes on 0 Posts
Originally Posted by newtofta View Post
i have a similar idea, but i want to put the water to refrigerant heat exchanger at the compressor discharge-before the cooling coil-(thinking this would lower head pressure & amps required/used)
Yes, that's probably a better idea. That way would less of a problem in winter.

Do you have any idea of what size the exchanger needs to be?
 
  #7  
Old 11-06-09, 01:00 AM
GRIMKNOTME's Avatar
Member
Join Date: Nov 2009
Location: N.C. USA
Posts: 120
Received 0 Votes on 0 Posts
Originally Posted by u4ia2000 View Post
Yes, that's probably a better idea. That way would less of a problem in winter.

Do you have any idea of what size the exchanger needs to be?
I cant say , if you got a basememt you have more to work with you dont wont to use a to restrictive coil as to restrict your air flo when heating ,and cooling off heatpump , with a basement you could increase your duct (after filter ) and slide in a slab coil then decrease back to original size , definitely add 1/4 turn cutoffs at this coil , but running this at same time as your a/c (it will effect your system charge it may can be adjusted ). I would not recommend as your water temp will change i would run this off a different t-stat which can be wired into a circulator pump and fan on your air handler as that should be all you need for cooling depending on water temp.

Just my opinion as im sure you will get more.

I love the idea of this wish I had one.
 
  #8  
Old 11-06-09, 05:56 AM
Member
Thread Starter
Join Date: Nov 2009
Location: Florida
Posts: 7
Received 0 Votes on 0 Posts
Originally Posted by newtofta View Post
i have a similar idea, but i want to put the water to refrigerant heat exchanger at the compressor discharge-before the cooling coil-(thinking this would lower head pressure & amps required/used)
I first thought that was a good idea but then on second thought maybe not. Here's why, if your outside air is say 90F and the exchanger is before the main coil the exchanger water is 70 (in Florida). Then goes to the main coil and it's being warmed by the main coil instead of being cooled. Unless you're in heat cycle then it's the opposite.
 

Last edited by u4ia2000; 11-06-09 at 06:02 AM. Reason: Incomplete
  #9  
Old 11-06-09, 07:43 PM
Member
Join Date: Aug 2006
Location: santa fe /texas
Posts: 998
Received 0 Votes on 0 Posts
i understand your thinkikg.
'my' thinking- out side air temp-90/95.
high side pressures 350,(or so)in normal condensing unit.
'if' you -water-cooled the dishcarge line -pressure 'might' drop to 150?(possibly?)-there fore 'unloding' the compressor/& apms used.
so 'supose' the water cooled refrigerantwent from 300 deg. down to 100 deg through the water.
now it goes through the air to refg,coil-at 90-95 deg air.'possible'still cooler (high side refrigerant) than the -SRICTLY air to refrig. coil. could produce.
possible at mimal cost or the water circulation/or dump from the well.
? what do you think?
 
  #10  
Old 11-09-09, 07:46 AM
Member
Thread Starter
Join Date: Nov 2009
Location: Florida
Posts: 7
Received 0 Votes on 0 Posts
Sorry, for the delay in responding but I've done some research since my last post and come across a place that manufactures pretty much what we have been discussing at ; Doucette Industries
This unit installs between the compressor and the 4way valve and taps off hot water. It claims to increase efficiency 10% but if it were supplied with ground water instead of return hot water it should go to 20% or higher.

Cheers,
A penny saved is a penny earned. Ben Franklin Beer 4U2
 
  #11  
Old 11-09-09, 08:48 AM
Member
Join Date: Aug 2006
Location: santa fe /texas
Posts: 998
Received 0 Votes on 0 Posts
did you get a price quote?
 
  #12  
Old 11-10-09, 11:40 AM
Member
Thread Starter
Join Date: Nov 2009
Location: Florida
Posts: 7
Received 0 Votes on 0 Posts
Originally Posted by newtofta View Post
did you get a price quote?
I e-mailed them and they said they didn't sell retail and to contact a distributer-- didn't give distributer address either. The CXN-S 250 that they said could be used as a main coil replacement is listed on the downloadable price list as $505.00-- it's a spiral coil HE 2.5 ton. Comes with a cupo-nickel water side for ground water. But if one uses that one must take a lot precautions to prevent freezing in case of unexpected shutdown unless the A/C unit already has those precautions installed-- I don't know-- I'm not an A/C tech. I didn't see the RX6... on the price list.
 
  #13  
Old 11-20-09, 04:57 PM
Member
Thread Starter
Join Date: Nov 2009
Location: Florida
Posts: 7
Received 0 Votes on 0 Posts
Originally Posted by newtofta View Post
did you get a price quote?
A week ago they were $390. Ijust checked toady and they are $445.99 at Heat Recovery Units Beer 4U2
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: