HVAC System

Must be a new semester in college. Another homework question.

Please do the research yourself. That is part of the learning process.

Go to your College Library pick up any book on HVAC and you will find it.

Do your own homework.

Visit couple of HVAC installations in your area and make Sketch your self thats how we learnt the same way &you would never forget the subject in your life time.

crm

You can refer through wikimedia dictionary or colledge book.

Good luck.

Dear, How did you imagine that you can get your homework done at CR4?

This is Elementary Watson! There are other important cases to be answered.

I suggest you get a copy of the Product Safety Standard for HVAC. In the US, it's UL 1995, or a number of other Standards and guidelines available. Go to www.techstreet.com and type in HVAC.

Many designers start without considering electrical safety, then later have to go back and re-design.

Good luck!

A typical system -- there are many variations. Not shown are secondary equipment such as tower and chilled water make-up, tower blowdown, water treatment, the chilled water expansion tank, air separator, primary chilled water pump balancing valve, tower water balancing valve, air relief valves and configuration of the air handers -- which can be blow through or draw through, etc.

The cooling tower rejects the heat of the building and heat of the chiller by evaporation. Shown is a crossflow tower with large propeller fan on top.

A typical chilled water system will provide a ton-hour of cooling using .8 kwh of electricity and about 18 lbs of water (including blowdown). A ton-hour is 12,000 btus. Coefficience of performance is therefore around 4.4. 1 btu of energy produces 4.4 btu's of cooling.

The chiller "pumps" the heat from the air handler coils from the chilled water loop to the warmer tower water loop. The tower water loop and the chilled water loop are separate. The chilled water loop is considered a closed loop and the tower water loop an open loop. Water treatment for the two loops is different.

A primary secondary flow system is shown. The primary system has a relatively low hp pump and keeps constant flow through the chiller. A Chiller needs a certain minimum flow to prevent freezing within the tube bundle heat exchanger and an expensive repair. The secondary pump of larger horsepower pumps chilled water through the building(s) as needed by the air handlers. Other configurations are possible including constant flow and variable primary flow systems. Multiple chiller systems can be installed in parallel or in series or a combination.

A reverse return piping system is shown, but may not be necessary for a variable flow system. It uses more pipe and costs more, but the chilled water coils and control valves would tend to see the same pressure drop across them regardless where they are on the loop.

The secondary pump variable frequency drive is controlled by monitoring the pressure drop across the supply and return piping. It may be desirable to have a bypass in the line at the last AHU to insure some flow is always occuring in the pipe to keep the chilled water line cold under light load.

Could you also send a link to the graphic suitable for plotting on D size paper just for clarification of course.

Where you work in HVAC

HOPE WE DO NOT FIND ANY OF MY STUDENTS ASKING SUCH QUESTIONS /

as the other posts said there are MANY variables as to hvac design /

end result to move heat to where not objectionable /
we have been doing hvac werk for 35 years , still finding and seeing new ideas /