HVAC system are awesome.

Written By engineerisaac

Posted: Fri, Jun 08, 2018 at 10:24 PM - Showing 482 Views

So my air conditioner stopped getting as cold as it once did. I started doing a ton of research on how thermodynamics worked. How expansion valves worked and how the whole system worked in general. Turns out this shit is pure magic. And most air conditioners can only handle a 3 to 2 degree differential. But the amazing part of why they work is they can maintain that 3 degree shift constantly.

Meaning that if your house is on a loop, Like 99% of the homes across the US. Then if your house is at 74 and you have a constant -3 Differential then in enough time your temperature will hit 71 if the loop continues. And then can continue to drop unless some type of thermostatic system is put in place.

Lets put this into easy perspective. The most complex and expensive part with all the moving parts. Chills outside your home in the compressor and expansion coil. It is basically a sealed pump and a radiator. Its hooked to a switch that turns it on and off along with a fan. THATS IT.

Then once activated it begins to take this misty like substrate and smashes it into a compressor so that way its a liquid like format. It travels inside your home and at this point the chemical is luke warm until it hits what is called a expansion valve. Now here is where the magic happens. due to the chemical CFC in the line that is in liquid it gets forced into a small nozzle and then the moment that fluid escapes that nozzle into a larger side chamber it reacts causing a cooling effect.

The cooled liquid then travels through another radiator called the condensing coil. It then absorbs all the heat energy from your home and stores it into a ever expanding format to where it turns back into a mist and runs at higher pressures back to the outside expansion coil where it takes all that energy it absorbs and expells it outside. "This is why your outside condenser blows hot air out." And then repeats the cycle.

Now when a HVAC comes to your home they bring a manifold that they attach to your system. This device measures pressures against the 2 sides of the loop to make sure its within the nominal levels.

While we as customers cannot touch the CFC chemical unless we become EPA certified. We can however Measure the differential to be sure our device is working by putting a temperature read out in the return and exhaust of the system.

I set this up with my automation system to get a reading of whats going on.

My plan is to write a logging system that will measure this change constantly.

This Isnt Finished yet.
Leave a Comment: