i have some problem choosing Refrigerant for building...

[go1f]

i was assigned from my teacher to design a building with 48 floors and i have no idea what to do because all he gave me is these informations,



· Problem statement
Design the chilled water air conditioning system with heat exchanger and pumping system of the chilled water side of the system.
· Identification of customer need
§ Each floor need cooling capacity of 75 ton(900,000 BTUH).
§ Chilled water capacity be 2.4GPM for 1 refrigeration ton.
§ The chilled water temperature shall be 44-54degree fahrenheit.
§ Pressure drop on the air handling unit or fancoil unit shall be no more than 15 ft WG.
· Problem defination
§ Building with 48 storeys of 3.5 meter height.
§ Each floor has an area of 1350 square meter.
§ Each floor has core area 140 square meter.
§ Total using area each floor has 1350 square meter.
§ Basement floor of 1200 square meter with 4.5 meter height excluding the 48 storeys for using as the back of the house.
§ Specify all necessary accessories needs for th system such as valves,strainer,check valves , control valves,expansion tank and /or balancing valves.



so far now i've designed my piping system, AHU and now i have some problems with choosing what refrigerant should be used in this building.

It would be great if some of you can give me differences between each refrigerant that are commonly used in present.

Thx for every answer and sorry for my poor English. :D

[TXiceman]

Your refrigerant choise is somewhat driven by the compressor (chiller) manufacturer and refrigerants available in his product line.

Your total load is 3600 tons. Are you trying to do this in one chiller package, or are you going with 2 or 3 packages?

You need to talk to some chiller manufacturers and get an idea of waht size ranges they have and the refrigerants they use.

Ken

[Brian_UK]

Are you actually required to select the water chiller?


· Problem statement
Design the chilled water air conditioning system with heat exchanger and pumping system of the chilled water side of the system.Are you to just select a heat exchanger and design the chilled water pipework circuit?

[Gary]

The interesting part is getting the water up 48 stories.

[US Iceman]

I don't see where you need to select the refrigerant. The problem as stated appears to be requesting the design of the chilled water system. Once you have that completed, it is simply a matter of deciding how to fit the respective manufacturers chillers into your problem.

The real issue with this problem is properly designing the chilled water circuit for hydraulic issues in 48 floors!:eek:

[go1f]

Your refrigerant choise is somewhat driven by the compressor (chiller) manufacturer and refrigerants available in his product line.

Your total load is 3600 tons. Are you trying to do this in one chiller package, or are you going with 2 or 3 packages?

You need to talk to some chiller manufacturers and get an idea of waht size ranges they have and the refrigerants they use.

Ken

so what i have to do now is to choose heat exchanger then design the piping system and searching for some catalog of water chiller to see how much it can give a load of 3600 tons right?

if you have to do this problem, how much packages will you choose to solve this,,, i really have no idea what to do with it. Thx for every answers

[US Iceman]

I don't think I would spend to much time worrying about the quantity of chillers. You could simply say; I have preliminarily selected three chillers of 1200 Tons each to account for part-load effects of the building response to the cooling loads. If this building is to be erected, then I reserve the right to re-evaluate the building loads during less than peak demands. Or, something to that effect.

It is one way of letting the instructor know you realize there may be other work required, but you have immediately answered the requested question. And, that you investigated the project in greater detail than was requested. That should be sufficient.

Good luck.

[go1f]

Thank you for your answers, US Iceman and everyone.

good luck too

[BobTheBull]

At this date I would assume you have finished your project, so this is parenthetical.

I assume you are an ME student.

In the real world, you would exactly what has been suggested, but I will refine that a little. You will design the piping system, pumps, fan coil units, etc. You, as the ME, will specify the requirements of the chiller/s for the contractors to bid on. You let them choose what chiller package/s they want to submit and this includes the choice of refrigerant. They will do this based on what they have access to and cost of same. And as Iceman pointed out, you want to reserve the right to re-evaluate on the basis of what they preserve.

Or, to put it another way, trying to pick the specific refrigerant for a large chilled water system in the design stage is putting the cart before the horse. Design the system and specify the chiller requirements. What specific chiller configurations, including refrigerants, will be dictated by what is available in your area.