Archive for the ‘ENGINEERING’ Category

Refrigerant Piping Design Guide

Filed under: REFRIGERATION and HVAC ENGINEERING

Please click Refrigerant Piping Design Guide to download

This Application Guide was created for design engineers and service technicians to demonstrate how to size refrigerant piping.

This Guide covers R-22, R-407C, R-410A, and R-134a used in commercial air conditioning systems. It does not apply to industrial refrigeration and/or Variable Refrigerant Volume (VRV) systems.

Several HVAC systems require field refrigeration piping to be designed and installed on-site.

Examples include:

  • Condensing units
  • Direct expansion (DX) coil in air handlers
  • Remote evaporators with air-cooled chillers
  • Chiller with a remote air cooled condensers

The information contained in this Application Guide is based on Chapter 2 of ASHRAE’s Refrigeration Handbook and McQuay’s experience with this type of equipment.

A properly designed and installed refrigerant piping system should:

  • Provide adequate refrigerant flow to the evaporators, using practical refrigerant line sizes that limit pressure drop
  • Avoid trapping excessive oil so that the compressor has enough oil to operate properly at all times
  • Avoid liquid refrigerant slugging
  • Be clean and dry

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Dupont Refrigerant Piping Handbook

Filed under: REFRIGERATION and HVAC ENGINEERING

Please click Dupont Refrigerant Piping Handbook to download

This special Handbook of Refrigerant Piping that can use for design of refrigeration piping. This is consist of Engineering Data Piping Losses, Nomographs, Piping Procedures, Expansion / Contraction, Best Practices, Quick Pick Criteria, HFC Quick Pick Tables, HCFC Quick Pick Tables, CFC Quick Pick Tables.

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Haynes Techbook Automotive Heating And Air Conditioning

Filed under: REFRIGERATION and HVAC ENGINEERING

Please click Haynes Techbook Automotive Heating And Air Conditioning to download

There was a time when every good mechanic understood the basic systems of the automobile pretty well.

But that time has passed. The days of the renaissance repairman are over. As systems have become more complicated, the investment in training and tools necessary to service the entire range of automotive technology found on a typical modern vehicle has widened to the point that no one actually “fixes cars” anymore. Instead, most modern mechanics specialize. Today, we have engine builders, front end specialists, tune-up specialists, transmission specialists, etc. Unfortunately, this approach has created an aura of “black magic” around the more esoteric of these topics.

Automotive air conditioning is certainly one subject that is poorly understood by nearly all do-it-yourselfers and a lot of professionals as well. The reasons for this situation come down to motivation, money and knowledge.

Unlike performance-related topics such as degreeing a cam, rejetting a carburetor, etc., air conditioning theory, service and troubleshooting is, frankly, pretty dry stuff. A well maintained air conditioning system won’t make a vehicle faster. But it will make it more comfortable. Unfortunately, performance – not comfort – is what gets young mechanics going. Consequently, they don’t usually grow up saying “I want to be an air conditioning technician.”

Then there are the special tools. Even if you are the kind of person who is attracted to air conditioning work, the tools needed to diagnose, repair and maintain a typical system are highly specialized and expensive. They’re so specialized, in fact, that they can’t be used for much else. Only a professional who chooses the field as a career can justify the kind of investment it takes to become an air conditioning specialist.

Another reason air conditioning seems so mysterious is that little useful knowledge of the basics is readily available. Lots of books explain how to service specific systems, but few bother with the underlying principles of operation. This is unfortunate, because a good grasp of basic theory can enable a mechanic to understand any air conditioning system.

If carefully read and understood, this book should help any mechanic understand the fundamentals of air conditioning systems. It begins with a discussion of basic air conditioning theory, followed by a description of each of the components found in typical heating and air conditioning systems. Any real comprehension of what follows after that is only possible if the first two chapters are read and understood. The rest of the book is devoted to routine maintenance, service procedures, repairs and troubleshooting.

Only two things are not included in this volume:

1) Removal and installation procedures and

2) Compressor overhauls.

For specific air conditioning and heating  system component removal and installation procedures, refer to the Haynes Automotive Repair Manual for the vehicle in question. If – after using this book to troubleshoot an air conditioning system – you conclude that the compressor is malfunctioning, we recommend that you remove it and install a rebuilt unit. There are several reasons for this.

First, time is money.

The money you will save by rebuilding the compressor yourself is more than offset by the money you will have to invest in specialized tools that may not work on other compressors. In this day of rebuilt components, it doesn’t make much sense to rebuild a critical component like the compressor when you can obtain a rebuilt one for a few dollars more. Second, there simply is not enough space in this volume to include the overhaul procedure for every air conditioning compressor available.

Other than these two items, however, you will find most everything you need to know about how air conditioning systems work, how to maintain them, service them, troubleshoot them and repair them in this manual.

One final note: The astute reader will notice that little mention has been made so far of heating systems.

That’s because- aside from heater core replacement (covered in Haynes Automotive Repair Manuals when possible) – heating systems are pretty easy to maintain and fix. Because heating and air conditioning systems are so interrelated, it’s impossible to discuss one without the other.

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