Functionalities of Buffer and Expansion Tanks in an HVAC System?

bijumohan,

An expansion tank is typically used in a closed loop HVAC system. When the liquid (e.g., water, glycol, refrigerant, etc.) in the system is heated, the liquid will expand and the tank provides a place for the expanded liquid to go without allowing the resultant pressures to exceed the design of the system.

(Chilled Water) Buffer Tanks are designed for chilled water systems with insufficient water volume capacity, in relation to the chiller capacity. Relatively low water volume systems require additional "buffer" capacity for the system to eliminate problems such as excessive chiller cycling, poor temperature control , and erratic system operation.

Dear JMAN

Many thanks for the prompt reply. This is the first time I am using this site and let me tell you we are more than excited to have a dais to address and clear our technical doubts.

Once again many many thanks

Regards

Biju Mohan

UAE

Hi,

May I add some to Jman's comments

RGS

Ediri

Please go ahead Mr. Ediri69

Hi

As Jman Said, expansion tank will protect the system when liquid pressure trying to rise (above design pressures) due to high liquid temperature.

Not only that!!!!! Problems can occur when pumps are starting, stopping, valves closing and opening (specially ball valve). So all this liquid hammers and system piping jerk will eliminate by the expansion tank.

There are two type of Buffer tanks

1. Close type
2. Open type.

Close type buffer tank is typically use in a insufficient water volume close loop Chill water system. In the same system there will be a Expansion tank also.

Open type buffer tanks refer Mr Jman's explanation.

Thanks and regards,

Ediri

Many thanks Mr. Ediri

can you cast some light on two kind of fire dampers (fusible and motorized).

I posted this query in the forum before but the reply was not clear fully. Cud u please explain to me what is the criteria to decide whether to go for fusible or motorized dampers. which is more expensive and more reliable?

hope u can come up with an answer

rgds

biju

You are learning HVAC through the forum. welcome

Should do some course on HVAC and also read more about hvac components

the fire damper

function of the fire dampers are to cutoff the air flow in a closed loop typically.

Fusible fire dampers:- The damper closes when the fuse is blown due to high temp of the air passing through this damper. Usually this happens when fire accident happens and the AHU is running. spring with a fuse is holding the open possition of the damper.

motorised dampers: Usually takes the input signal (digital/analogue) through a divice..... could be directly from sensors/ fire alarm system and cause to start a motor attached to the damper and make an effor to close the damper. there should be BAS (building automation system ) in place for use of such dampers or

may work with a stand alone controller

I hope you have got the answer.

sivabala