TRACTOR PARTS Allis Chalmers Case & David Brown Farmall & International Ferguson Ford & New Holland John Deere Massey Ferguson Massey Harris Minneapolis Moline Oliver & Cockshutt Kubota / Yanmar

TRACTOR MANUALS

Allis Chalmers	Case	Farmall IH	Ford 8N,9N,2N	Ford
Ferguson	John Deere	Massey Ferguson	Minn. Moline	Oliver

Attention Forum Users: On the 28th of December 2023 at 9:00am Central Time, we will be taking the forums down for maintenance while we prepare the new forums for your use. Please click here for more information.

Tool Talk Discussion Forum

Shop heater AC cooler

Welcome Guest, Log in or Register

Author

Ohio D14

11-30-2007 19:35:15

Report to Moderator

I have a couple R22 condensing units laying around from other projects that I did. I was wondering if it would be possible build an efficient heat pump using the two condensing units? My thought is to set one condensor outside, and one inside, hook up the outlet of one to the inlet of the other, and vice versa for the other line. I would wire both units so that both fans always run, but only one compressor depending on if heating or cooling. I drew a diagram up, and it seems like it would work, but I think I would need a xpansion valve, possibly two somewhere in the system. On the other hand, maybe the one way valve of the non operating compressor would work as an expansion valve?

Any thoughts, or recomendations would be appreciated. I just dont want to throw away such nice pumps and heat exchangers.

[Log in to Reply] [No Email]

T_Bone

12-01-2007 13:31:30

Report to Moderator

Re: Shop heater AC cooler in reply to Ohio D14, 11-30-2007 19:35:15

Hi Ohio,

A good single book on the subject is;

Modern Refrigertion

Goodhart & Wilcox

A compressor mounted lower than the evaporator is a common installation and we don't have a problem with oil migeration with good piping designs.

Enclosed is a brief article I posted in 2005 on refrigeration theory;

Refrigeration theory:

To have a complete understanding of the refrigeration process we need to define some rules to follow as it matters to use the correct
terminology when designing or servicing heating, ventalating or refrigeration systems.

1) Cold only occurs at minus 460�R or absolute zero. Above that we only have a absence of heat or can be stated as lack of heat. This is very important to understand as it helps in understanding all refrigeration or heating processes.

2) The accepted slang term AC does not mean "cold" as the true meaning stands for "air conditioning", that is to heat, cool, clean, humidifiy or dehumidifiy common air.

3) The second Law of Thermodymanics states:

"heat flows from a higher temperature source to a lower temperature source"
This is really important to understand when dealing with refrigeration or heating as one can quickly figure direction of heat transfer at any point in a process.
4) There's several types of common heat exchangers:

a) air to air
b) air to liquid

c) liquid to liquid

5) All refrigerants have a direct relationship between temperature and pressure (called it's T & P) that is to say that a refrigerant at 100� may have a pressure of 196psig and at 0� a pressure of 24psig.
With knowing the T & P of the refrigerant I would know I'm dealing with refrigerant 22 (R22) using the above numbers.
Example #1:

A simple refrigeration process can be explained as where liquid refrigerant (from the bottom of a condensor) is fed into a small diameter orifice (capillary tube) that runs into a larger tube (evaporator). As the refrigerant enters the evaporator the refrigerant expands into saturated vapor (vaporized fluid) thus dropping pressure thus lowering it's temperature, hence the refrigerating effect has just completed.

Using the above T & P already discussed above, the condensor would have a temperature of 100� and the evaporator would be at 0� thus our evaporator would try to gain heat from it's surrounding area as stated by the 2nd Law of Thermodymanics.
Notice we never talked about the use of a compressor in the above example to obtain the refrigerating effect as only T & P was responsible for the cause of refrigeration effect as explained by the 2nd law of Thermodynamics.
Some refrigerated semi trailers and rail cars use a expendable refrigerant based upon the above example.

A typical outdoor HP uses the same above therory of refrigerating effect. A HP just adds a reversing valve for direction of refrigerant flow and a compressor for reusing the refrigerant with-in a closed loop refrigerant system. 0n a typical HP we want to use the evaporator as a condensor sometimes and the condensor as a evaporator sometimes and a reversing valve accomplishs this. The compressor pumps refrigerant from the evaporator to the condensor.
To keep this short as possible we will not address Latent heat of compression, the effect that a compressor adds to the refrigeration cycle.

Notice we never mention using any fans for the above HP unit to complete it's refrigeration cycle nor to obtain the refrigerating effect. Depending on the desired results would we add a fan.
During the time that our outdoor HP is in the heating mode, the condensor is used as a evaporator. That means were trying to refrigerate the ambient air and thus obtain heat, (see the begining of example #1). As the HP continues to run the outside eveporator begins to ice from trying to absorb heat from the surrounding air as well gathers moisture. To defrost this ice build up we momentary reverse the refrigerant flow thus melting the ice and the "swoosh" sound our HP makes when it reverses refrigerant flow.
Now to increase the heat flow to our HP evaporator during heating mode we can add a liquid to liquid heat exchanger with taking heat from a ground source hence the name geothermal. Now that ground source heat could be obtained form well water or a secondary coil located with-in water with a ground source heat sink.
There's many different ways to accomplish a ground source heat gain but a liquid to liquid heat exchanger has the highest efficiency ratio.
T_Bone

[Log in to Reply] [No Email]

T_Bone

11-30-2007 21:24:13

Report to Moderator

Re: Shop heater AC cooler in reply to CRUSADER, 11-30-2007 19:35:15

Hi Ohio D14,

Yes your idea is possible BUT:

You best have a excellent understanding of how TX valves operate as you will need to adjust it after system charging and you best understand refrigerant temperature pressure relationships and you best understand refrigeration super heat, preform clean refrigeration brazing, own a micro vaccum pump cabable of 29.925 plus HG, understand at what temperature water boils at while in a deep vaccum, have a way to measure deep vaccum, etc:, etc:, etc!

Even using store bought reversing valve for about $200, you would still need the knowledge listed above and LOTS of free time. Compressors and coils are a matched system design!

T_Bone

[Log in to Reply] [No Email]

Ohio D14

12-01-2007 05:55:07

Report to Moderator

Re: Shop heater AC cooler in reply to T_Bone, 11-30-2007 21:24:13

I was assuming that by replacing the evaporator (low pressure side) of the system with another condensing unit (pump, condensor, and fan), the condensing unit would actually add an element of safety to the system. The rest of the "knowledge" has been designed in by the engineers.

My assumption is that one would not need a reversing valve since the reversal of refrigerant flow would be done by managing the power to the respective pump, and existing fans.

The only issue that I see is that when the refrigerant passes through the "evaporator" side, the refrigerant will be a liquid, flowing through the pump check valve, through the cylinder cavity, and back through the condensor heat exchanger. This liquid can not get into the pump, or the pump will be ruined.

If both condenser units draw from the top of the heat exchanger, the liquid should set in the bottom of the heat exchanger, and go to vapor by using the fan to disipate energy.

Rethinking this, I dont think a expansion valve is possible in the system since the flow will be reversed using the pumps. The system would have to run using the check valve of the non running compressor as the expansion valve. Expansion valves usually work on temperature, or mechanical orafice sizing, so I think the check valve should suffice for this.

The major issue would be to make sure there is no liquid in the compressor that is being started. Maybe this could be done by running one or both fans until the refrigerant is at equilibrum, and the liquid is in the respective heat exchanger. Additionally, some of these units have a block heater that could be turned on to heat the compressor, which would boil out the liquid form the cylinder head.

[Log in to Reply] [No Email]

Bob

12-01-2007 08:22:41

Report to Moderator

Re: Shop heater AC cooler in reply to Ohio D14, 12-01-2007 05:55:07

Amoungst other details, you are forgetting that oil migates though the system with the refrigerant.

After a period of time, the compressor at a higher level will be devoid of oil, and the compressor at the lower level will have all the oil in it, and suck oil into the cylinder, and bang it against the cylinder head. (OUCH!).

Compressors operating in tandem are set aat the same level, often have a line between the crankcases to allow the oil levels to remain equalized.

If you intend to do this with ANY efficiency, you need to study up on expansion valves, oriface tubes, and capillary tubes.

A simple "check valve" just ain't gonna "cut it" as an expansion device!

There's all sorts of "through-the-wall" heat pumps (motels, for example) that get changed out from time to time. You'ed be FAR better off picking up a unit like that.

[Log in to Reply] [No Email]

Ohio D14

12-01-2007 09:09:50

Report to Moderator

Re: Shop heater AC cooler in reply to Bob, 12-01-2007 08:22:41

Good point, would the oil migrate even if only one compressor were working at a time? I have seen the heat pumps you are talking about, they are efficient and inexpensive, I just hate to throw stuff away (personal problem I guess). Anything else I could use the pumps for? I could use them to cool my shop in the summer, but it really does not get that hot here.

When I am finished with any of my projects, I send the remaining scrap to the recyclers, at least it does not go to the dump.

[Log in to Reply] [No Email]

[Options] [Printer Friendly] [Posting Help] [Return to Forum] [Log in to Reply]

TRACTOR PARTS	TRACTOR MANUALS

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today. [ About Us ]

Home | Forums

Copyright © 1997-2023 Yesterday's Tractor Co.
All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy

TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.

Yesterday's Tractors - Antique Tractor Headquarters

Website Accessibility Policy