The Homemade Heat Pump Manifesto - Page 131

AC_Hacker · 09-04-12, 11:58 PM

Quote:

Originally Posted by charlesfl

I found a free computer program that can be run in windows by Lawrence Berkley National Lab called THERM...

Good find!

It might be a good idea to duplicate your post to the 'Tools' Sub Forum located HERE.

Best,

-AC

twinkelbel · 09-09-12, 10:32 AM

Hi all,

I am new to this great forum.
Searching the web to find some info about DIY heatpumps i also found the following link about heatpump monitoring,

openenergymonitor.blogspot.co.uk/2012/03/heat-pump-monitoring.html#!/2012/03/heat-pump-monitoring.html

Also found some links about DIY microcontrolled eev valve,
new.ipfw.edu/dotAsset/239492.pdf (just copy link to your browser)

and some info about eev,
sporlanonline.com/100-9.pdf

Hope it helps somebody

Robert

AC_Hacker · 09-09-12, 12:01 PM

Quote:

Originally Posted by twinkelbel

Hi all,

I am new to this great forum...

...Robert

Robert,

Welcome to the discussion.

These are very useful links you have shared with us... Thank you.

Perhaps you could say a few words about your interest in homemade heat pumps or related interests or projects.

Best

-AC_Hacker

pachai · 09-10-12, 01:22 PM

I have a question that is similar to one I saw asked and answered with a link but the link seems outdated...so I'll ask my question...

A one-room synagogue near me is being vacated to begin construction of a big building. (I already told them to consider GEO for that, but not DIY :-)

I asked the "operations officer" if I can get the old Central A/C. He will get back to me.

Has anyone used a traditional whole house A/C and documented it?

It seems to me that this should be easier in some ways than a "unibody" air conditioner...it's more like a "maxi-split."
Because the units are separate, there may be more room to work with it. I have friends who are licensed who may help. One of them helped me with a plan for ductwork.

My only small worry is short cycling as it might be a bit big. The SF of the facility is similar to my house, but their planned load was about 100 people, mine is about 5. (Note, I have not seen the unit yet :-). (They also have 2-3 older 220V wall units. :-)

I appreciate any experience you can share.

Seth
PS All I need is TIME :-)

AC_Hacker · 09-10-12, 02:28 PM

Quote:

Originally Posted by pachai

It seems to me that this should be easier in some ways than a "unibody" air conditioner...it's more like a "maxi-split."
Because the units are separate, there may be more room to work with it. I have friends who are licensed who may help. One of them helped me with a plan for ductwork.

My only small worry is short cycling as it might be a bit big. The SF of the facility is similar to my house, but their planned load was about 100 people, mine is about 5. (Note, I have not seen the unit yet :-). (They also have 2-3 older 220V wall units. :-)

This is pretty off-topic for the Homemade Heat Pump thread... you'd do better to start another thread.

And somewhere near the start of that thread you should bring up the issue of Air Conditioning Heat Load calculation.

A central air system is a big piece of equipment and uses big energy, so even if your system hardware is free, you could end up with a big mess on your hands.

Start your new thread and your new project with calculations... it's much easier to erase numbers than to remove and dispose of improperly sized hardware.

Best,

-AC_Hacker

pachai · 09-10-12, 02:48 PM

Quote:

Originally Posted by AC_Hacker

This is pretty off-topic for the Homemade Heat Pump thread... you'd do better to start another thread.

-AC_Hacker

Sorry I wasn't clear, I am talking about converting it to ground source.
That's the connection with this thread.

randen · 09-10-12, 03:30 PM

Pachai

Yes you can convert a air-conditioner to a ground source heat pump and be very happy with the results. This thread covers all you need to know. However there is no free lunch.

The geothermal HVAC is a complete system. You will need a ground loop and a nice tight envelope to be efficient and possibly an in-floor heating system for the low temp application. One other thing is sometimes the compressors (recips.) can be a little noisy. With my application the homemade GSHP is in my shop and I can't hear it for the machines but in the office its a slight anoiance. If maybe you place it in a basement room insulated for sound could be a consideration. I'm heating and air conditioning my shop for about $350.00 worth of electricity now. I don't have the shop as warm or cool as my home but I used to pay $2800.00 for heating oil. The ground loop cost me about $2500.00 and there was some work for the landscaping afterward. My ROI should be fairly quick with the price of oil sky-rocketing. Yes it can be done but it is work.

Randen

AC_Hacker · 09-10-12, 04:01 PM

Quote:

Originally Posted by pachai

Sorry I wasn't clear, I am talking about converting it to ground source.

Well now, that is a horse of a different color...

Everything randen said is right on, and I will add something he emphasized previously, and that is to keep in mind that the heat comes from the ground... The heat pump just moves it. Too small a loop field is not so good.

So, are you going to use the GSHP for your radiant floors? Do you remember what the water feed temperature was to heat your house? GSHPs work best when the water feed temp is on the low side, like below 120F... the lower, the better.

Here's a chart to give you some idea of the relationship between COP and output temperature:

Best,

-AC

Thepprof · 09-11-12, 07:56 AM

Minisplits only have a gas tap hence normal analysis of the system cannot be done. If I suspect low gas, the process involves removing all gas and reloading by weight. I recently had occasion to reassemble a nearly new system in my shop. I spoke with the Factory rep about what pressure should I expect at the liquid line tap when the system is working as designed. He indicated 125-140 psi. I gave the system a 30 second shot and turned on the system. It started producing heat at the condenser coil immediately and the air handler started cooling. The gas pressure was low (about 80 lbs.) I noticed that the evap. coil which has many horizontal coils feeding from top to bottom was hot only on the top 3 coils. As I added gas more coils were radiating heat, the pressure increased at the tap and the output of the air handler went from 3-4 degrees to nearly 20 degrees. Is there someone out there in the AC world that has a greater understanding than I who can comment on the following. I'm thinking that if this system is low on gas the liquid line tap will show lower pressure and that the number of evaporator coils that are radiating heat will be fewer. I'm relatively new to these systems and my thoughts are that: It is much easier to take off the outer housing cover on this particular unit and read the coil temp with a IR thermometer than to evacuate the system and add the proper weight of gas to be sure. Comments. thanks Owen

MN Renovator · 09-11-12, 05:51 PM

Everything I've ever seen on tech to tech HVAC chats about inverter mini-splits is that you really need to weigh in the charge because of the variable nature of the systems hiding the correct/incorrect charge.

09-09-12, 10:32 AM	#1302
twinkelbel Lurking Renovator Join Date: Sep 2012 Location: belgium Posts: 1 Thanks: 0 Thanked 0 Times in 0 Posts	Heat pump monitoring Hi all, I am new to this great forum. Searching the web to find some info about DIY heatpumps i also found the following link about heatpump monitoring, openenergymonitor.blogspot.co.uk/2012/03/heat-pump-monitoring.html#!/2012/03/heat-pump-monitoring.html Also found some links about DIY microcontrolled eev valve, new.ipfw.edu/dotAsset/239492.pdf (just copy link to your browser) and some info about eev, sporlanonline.com/100-9.pdf Hope it helps somebody Robert

09-11-12, 07:56 AM	#1309
Thepprof Lurking Renovator Join Date: Jun 2012 Location: Virginia Posts: 28 Thanks: 0 Thanked 4 Times in 3 Posts	Minisplit Minisplits only have a gas tap hence normal analysis of the system cannot be done. If I suspect low gas, the process involves removing all gas and reloading by weight. I recently had occasion to reassemble a nearly new system in my shop. I spoke with the Factory rep about what pressure should I expect at the liquid line tap when the system is working as designed. He indicated 125-140 psi. I gave the system a 30 second shot and turned on the system. It started producing heat at the condenser coil immediately and the air handler started cooling. The gas pressure was low (about 80 lbs.) I noticed that the evap. coil which has many horizontal coils feeding from top to bottom was hot only on the top 3 coils. As I added gas more coils were radiating heat, the pressure increased at the tap and the output of the air handler went from 3-4 degrees to nearly 20 degrees. Is there someone out there in the AC world that has a greater understanding than I who can comment on the following. I'm thinking that if this system is low on gas the liquid line tap will show lower pressure and that the number of evaporator coils that are radiating heat will be fewer. I'm relatively new to these systems and my thoughts are that: It is much easier to take off the outer housing cover on this particular unit and read the coil temp with a IR thermometer than to evacuate the system and add the proper weight of gas to be sure. Comments. thanks Owen

09-10-12, 01:22 PM	#1304
pachai Renovator-in-planning Join Date: Oct 2010 Location: Northern NJ Posts: 85 Thanks: 6 Thanked 0 Times in 0 Posts	I have a question that is similar to one I saw asked and answered with a link but the link seems outdated...so I'll ask my question... A one-room synagogue near me is being vacated to begin construction of a big building. (I already told them to consider GEO for that, but not DIY :-) I asked the "operations officer" if I can get the old Central A/C. He will get back to me. Has anyone used a traditional whole house A/C and documented it? It seems to me that this should be easier in some ways than a "unibody" air conditioner...it's more like a "maxi-split." Because the units are separate, there may be more room to work with it. I have friends who are licensed who may help. One of them helped me with a plan for ductwork. My only small worry is short cycling as it might be a bit big. The SF of the facility is similar to my house, but their planned load was about 100 people, mine is about 5. (Note, I have not seen the unit yet :-). (They also have 2-3 older 220V wall units. :-) I appreciate any experience you can share. Seth PS All I need is TIME :-)

09-10-12, 03:30 PM	#1307
randen Uber EcoRenovator Join Date: Apr 2011 Location: Strathroy Ontario Canada Posts: 657 Thanks: 9 Thanked 191 Times in 129 Posts	Pachai Yes you can convert a air-conditioner to a ground source heat pump and be very happy with the results. This thread covers all you need to know. However there is no free lunch. The geothermal HVAC is a complete system. You will need a ground loop and a nice tight envelope to be efficient and possibly an in-floor heating system for the low temp application. One other thing is sometimes the compressors (recips.) can be a little noisy. With my application the homemade GSHP is in my shop and I can't hear it for the machines but in the office its a slight anoiance. If maybe you place it in a basement room insulated for sound could be a consideration. I'm heating and air conditioning my shop for about $350.00 worth of electricity now. I don't have the shop as warm or cool as my home but I used to pay $2800.00 for heating oil. The ground loop cost me about $2500.00 and there was some work for the landscaping afterward. My ROI should be fairly quick with the price of oil sky-rocketing. Yes it can be done but it is work. Randen

09-11-12, 05:51 PM	#1310
MN Renovator Less usage=Cheaper bills Join Date: Nov 2010 Location: Minneapolis, MN Posts: 939 Thanks: 41 Thanked 116 Times in 90 Posts	Everything I've ever seen on tech to tech HVAC chats about inverter mini-splits is that you really need to weigh in the charge because of the variable nature of the systems hiding the correct/incorrect charge.