It's vital to minimise the flammable refrigerant charge quantity while retaining the high energy efficiency of refrigeration and air-conditioning units. Here are the tips that I list for your suggestions and comments:
1. Select smaller tube coils for evaporator and condenser. If using 5/8", 1/2", 3/8" or 5/16" OD coils now, for example, you may try 7mm, 6mm or 5mm OD coils instead or go straight to micro channel coils.
2. Choose a compressor with less oil charge quantity and/or more viscous lubricant oil type. With the same cooling capacity and/or COP, different brand compressors may require different lubricant oil type and/or different oil charge quantity.
3. Size a suction line heat exchanger with highly enhanced and compact liquid channels to have less liquid refrigerant store and achieve adequate vapour superheat so as to reduce the refrigerant mass dissolved to compressor lubricant oil.
4. Install the filter/dryer (and receiver if required) to have a bottom/lower outlet port.
5. Use smaller liquid tubes from the condenser outlet to expansion valve or CAP tube inlet.
This is a copy of my post on LinkedIn ( https://www.linkedin.com/pulse/tips-minimizing-hydrocarbon-other-refrigerant-charge-rac-jeff-wang/ ) about the applications of cloud eTools provided by www.refriglab.com . Your additions, suggestions and comments will be much appreciated. The question is, how to minimise the refrigerant charge of refrigeration and air-conditioning units/systems?
It may be for Refrigerator. But for Airconditioning application, charge reduction is not suitable. Is there any suggestion regarding system modification for Air conditioning application with HCs.
Thank you for your comments, Saurabh!
The tips apply for both household and commercial fridges and air-conditioners.
The compliance for flammable refrigerant units, especially for electrical designs, is quite different and suggest that you check the technical requirements for HC refrigeration.
Nowadays, hydrocarbons are highly focused for research and development for refrigeration and air-conditioning, bringing the old topic of refrigerant minimisation to the new front. To my mind, using mini and micro channel heat exchangers is one of the solutions although new challenges such as coil circuiting and refrigerant distributing come up as well. The other likely solution is developing compact compressors with less lubricant oil used for the operation. Any other likely solutions?
If HC is blended with HFO, there may be effect in flammability of HCs.
Thanks Mr Wang for guidance.
Sir, if someone wants to pursue research in Hydrocarbon Airconditioning. Which area or topic, he should opt considering minimum expenses on test setup.
Hi, Saurabh
A lot of projects are interesting on HC RAC applications. The following are the topics that I am interested in and would be happy to work on for your information and comments. As R&D engineer, I am focusing on the last two projects for my Cloud eTools being available at www.refriglab.com for refrigeration and air-conditioning applications. Can you share with us what your interests?
1) minimising refrigerant charge;
2) optimising unit energy efficiency;
3) developing cost-effective mini and micro channel coils;
4) refrigerant distributing for mini and micro channel HX coils;
5) Developing CloudComputing-based eTools;
6) Developing Cloud AI-based administration system.
Thanks sir. My field of interest is related to point 1 & 2. My focus is system modification without compromising refrigerant charge and energy efficiency for HCs or HC/ HFO blends in Airconditioning application.
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