2 replies to this topic

[steven12]

Hi guys, this is gona be a short question that doesn't require a technical answer.

I am doing some work experience at the moment, the maintenance manager wants to see if he can hook up the current chiller we have, to the rest of the equipments (6mills, 2 mixings tanks)in the manufacturing area so we can make the cooling tower, which handles the cooling redundant.(saves cost).

Now the maintenance manager believes there are extra cooling capacity in the chiller, which I have some doubts be because it is rated at 50kW for cooling, which converts to about 15 tons of cooling.

I want to know if this chiller is considered as a Small,Medium, or Large chiller in terms of its cooling capacity. Because I read it on the wikipedia page(I know its NOT the most reliable source) that a chiller ranges from 50-1500kW in cooling capacity, which will make our chiller at the moment at very small when compared.

50 kW can only chill 3 L/s of water by only 4 Kelvin (3*4*4.18)

Thanks people

[Art Montemayor]

Steven:

15 tons of refrigeration is equal to 180,000 Btu/hr. You really don’t need to know whether this size is “considered” small, medium, or large size. You already know specifically what size it is: it is capable of cooling water at a rate of 180,000 Btu/hr.

Putting this capability in laymen’s terms, if we try to cool 3 liters/sec of water, we obtain:

Q = W * Cp (T2 – T1)

(T2 – T1) = Q /(W * Cp)

where,
(T2 – T1) = temperature drop of water, ^oF
Q = heat transferred = 180,000 Btu/hr
Cp = heat capacity of water = 1.0 Btu/lb -^oF
W = water flow rate = 3 lt/s =23,823 lb/hr

Therefore, (T2 – T1) = 180,000/23,823 = 7.6 ^oF = 4.2 ^oC

This checks out your estimate of 4 degrees Kelvin – which is not very much cooling, in my opinion. Therefore, I would consider this a small chiller.

[steven12]

Thank Art, by the way, I was working though the Cranes fluid problems you uploaded. I am working through very slowly because of the imperial unit. It very hard for my brain to work in imperial units .