Retrofitting A/C sizing components correctly

[tbirdtbird]

Interesting discussion.
Please be aware that evaps under the front seats facing forward are not likely to give you the performance you are seeking. The reason evaps are normally in the dash or under the dash blowing the cold air to the rear of the vehicle is because if the face feels the cold air the whole body thinks it is cold. If only the legs are getting cold air, then not so much.
Show me a commercial system where the evap is under the seat blowing forward.
Good luck.

[JohnHere]

i totally agree. It would be easier. But I don't want to start a second time pulling the car apart if it isn't. I just need a T piece and some aluminium pipe to go to the rear evaporators or evaporator. and those can be on whatever fan setting needed, it doesn't has to be full speed. like this my front evaporator would be quieter too (not that it matters that much in a lada niva) but the fan speed could be lower.
These evaps are cheap as chips.

Tees for standard barrier hoses and reduced barrier hoses in different sizes are available in the market. It might be easier to run reduced barrier hoses instead of aluminum tubing due to the hose's flexibility. You'll need a good crimping tool to assemble the hoses, fittings, and ferrules, though.

thank you for your educated guess.
At a cost of a few pesos per evaporator I thought it would be easier to just install a third one since the car is pulled apart, and then regulate the system through the fan speed.
It's going to be a work truck install not a Maybach masterpiece

If the vehicle doesn't already have tinted windows, I suggest having that done as well. In your location where it's hot year round, window tint will help reduce the load on the A/C and make for a more comfortable cabin.

Not a Maybach

Is that not what the accumulator is for, to protect the compressor from liquid?

Yes. The accumulator also has desiccant in it to remove any moisture in the system.

The idea was to simply play with the pulley. get it to a ratio of 1.7.
That is 4700RPM az 8000RPM and 1360 at 800RPM

The compressor's variable displacement and increase in RPM at idle should help cooling, which as I understand it, is mainly what you're looking for.

If I understand it correctly then the maximum heat load determines the amount of refrigerant?
I have to fill the system by using subcooling to make sure that there are no bubbles in front of the orifice nor the TXV's?
The refrigerant in the supply line is a vapor at the compressor due to the heat, and is (has to be) a liquid in front of the orifice.
Do we know how the control valves control the compressor, is that superheat, subcooling, suction pressure, suction temperature or what?

We don't normally talk in terms of subcooling and superheat when discussing an MVAC system because of its constantly changing operating parameters, unlike an HVAC residential system or heat pump that has a compressor running at a constant speed. Charging techniques that are used when a custom MVAC system's refrigerant capacity isn't known has been discussed at length on this Forum and elsewhere. So I won't try to repeat all of that here. But to answer your question, yes, a solid stream of refrigerant is required immediately before each metering device.

Briefly, a manual control valve (MCV), like on the VDC you're considering purchasing, varies the compressor's displacement mainly by system pressures. The MCV has no direct electrical connection to the Powertrain Control Module or Engine Control Module (PCM or ECM). On the other hand, an electronic control valve (ECV) has wires hooked up to it and works by first having the PCM or ECM analyze a number of additional operating parameters. In turn, the ECV then varies the compressor's displacement and therefore how much refrigerant the compressor sends through the system at any given instant.

[Tim]

Unless you get a response, I would not spend a lot of time on this post. They were having issues gaining access to the site. I am just mentioning that they might not be seeing any posts.

[huramentzefix]

Unless you get a response, I would not spend a lot of time on this post. They were having issues gaining access to the site. I am just mentioning that they might not be seeing any posts.

chill brother you are getting things wrong! I am here
I have explained to you that I can access the site using some back routes. I was asking if you could help getting normal access to the site and to remove the block, not to stop people from helping me.

Have you found out what the issue is yet, are you working on it? you said you had not much time to spare, but apparently enough for pushing people away that are trying to help?

i totally agree. It would be easier. But I don't want to start a second time pulling the car apart if it isn't. I just need a T piece and some aluminium pipe to go to the rear evaporators or evaporator. and those can be on whatever fan setting needed, it doesn't has to be full speed. like this my front evaporator would be quieter too (not that it matters that much in a lada niva) but the fan speed could be lower.
These evaps are cheap as chips.

Tees for standard barrier hoses and reduced barrier hoses in different sizes are available in the market. It might be easier to run reduced barrier hoses instead of aluminum tubing due to the hose's flexibility. You'll need a good crimping tool to assemble the hoses, fittings, and ferrules, though.

I considered that but the aluminium tubing is much smaller and could be routed much easier under covers and carpets? I can easily bend it with a tube bender. There are many crimping tools, can you suggest a "good" affordable crimpung tool? Would the cheap 150$ handcrimper do the trick?

thank you for your educated guess.
At a cost of a few pesos per evaporator I thought it would be easier to just install a third one since the car is pulled apart, and then regulate the system through the fan speed.
It's going to be a work truck install not a Maybach masterpiece

If the vehicle doesn't already have tinted windows, I suggest having that done as well. In your location where it's hot year round, window tint will help reduce the load on the A/C and make for a more comfortable cabin.

Not a Maybach

OK that is an excellent suggestion. I had it tinted before but it was cheap tint and has faded. there is some good 3M foil, which cost a fortune but has some high heat rejection. I will check again if it justifies the expense. 3M Ceramic IR or alike ...

The idea was to simply play with the pulley. get it to a ratio of 1.7.
That is 4700RPM az 8000RPM and 1360 at 800RPM

The compressor's variable displacement and increase in RPM at idle should help cooling, which as I understand it, is mainly what you're looking for.

Yes, I didn't need an airconditioning because I live in the country side and I am always driving with the windows open.
But when I am in the city then the car barely moves and the heat is unbarable. I stopped going to the city with my car. It's just one big traffic jam.

If I understand it correctly then the maximum heat load determines the amount of refrigerant?
I have to fill the system by using subcooling to make sure that there are no bubbles in front of the orifice nor the TXV's?
The refrigerant in the supply line is a vapor at the compressor due to the heat, and is (has to be) a liquid in front of the orifice.
Do we know how the control valves control the compressor, is that superheat, subcooling, suction pressure, suction temperature or what?

We don't normally talk in terms of subcooling and superheat when discussing an MVAC system because of its constantly changing operating parameters, unlike an HVAC residential system or heat pump that has a compressor running at a constant speed. Charging techniques that are used when a custom MVAC system's refrigerant capacity isn't known has been discussed at length on this Forum and elsewhere. So I won't try to repeat all of that here. But to answer your question, yes, a solid stream of refrigerant is required immediately before each metering device.

I will read up on charging mobile systems, thank you.

[Tim]

I see that comprehension is not your best trait. Reread the first sentence. I never pushed anyone not to answer your posts!!

After a few condescending emails, I have no interest in providing free information or wasting unappreciated effort! The issue has always been on your end. I can't help you use a blocked IP that the "server" companies have placed on a blacklist.

Now, move forward with your A/C questions. The thread will be removed if there is any more back-and-forth concerning anything else.

[tbirdtbird]

Please note that Tim has put together some of the finest/smartest AC techs here. I know him well and he has always been willing to help people.
I would strongly suggest you avoid any condescending comments. The way some servers run their version of a forum can be baffling.
I have always assumed these companies have new IT guys behind the scenes. And please remember that this site is free.