كيف تصمم تشيللر للتبريد بالمياه والهواء

Why use water chiller?

مجموعة تكنولاب البهاء جروب

عميد دكتور

بهاء بدر الدين محمود

استشارى معالجة المياه

01063793775

As you know, cooling time plays an important role in cycle time.

Practically speaking, to use water chiller instead of (or with) cooling water tower may reduce cooling time obviously, and improve output by 20% or more.

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Why choose air cooled water chiller?

Easy startup; No need to work with extra cooling water tower.

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Why choose water cooled water chiller?

Lower cost; Better heat transfer efficiency.

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How to know real chilling capacity?

Real chilling capacity = (theoretic chilling capacity) * (heat transfer efficiency);

For water cooled water chiller, heat transfer efficiency is 75%;

For air cooled water chiller, heat transfer efficiency is 60%.

But circumstance temperature, temperature of cooling water (for water cooled water chiller), etc. may influence heat transfer efficiency.

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Why series water chiller is better than others'?

The difference is heat transfer efficiency;

For water cooled water chiller, 75% (Kenplas') vs <=65% (others');

For air cooled water chiller, 60% (Kenplas') vs <=50% (others').

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How to choose water chiller for my machine?

Material Real chilling capacity (per Refrigerant Ton, i.e. 3000Kcal/h, or 12000BTU/h)
Injection Molding

(kg) Extrusion Molding

(kg) Blow Molding

(kg) Machine

Name Power (kw)

HDPE 13.6 22.7 - Air Compressor (no after cooler) 4.7

LDPE, PP 15.9 22.7 - Air Compressor (with after cooler) 3.7

Nylon 18.2 - - Vacuum Pump 7.5

PS 22.7 34.1 - Hydraulic Cooling 7.5

ABS 22.7 - - Hot Runner Mold 10.5

PVC 29.5 36.3 - Water Pump in Circuit 3.7

PC 29.5 - - Feed Throat - 400 Ton up machine 1 set

PET 31.8 - - Feed Throat - 400 Ton below machine 2 sets

Polyolefins - - 15.9 Extrusion -- Gear Box Cooling 74.6

Extrusion -- Feed Throat (screw<=3") 1 set

Extrusion -- Feed Throat (screw>3") 0.5 set

Extrusion -- Barrel or Screw Cooling 1 inch (screw dia)

Remark: 1 Kw = 860 Kcal/h = 1.34 Hp.

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What flow rate of chilled water is the best?

Generally speaking, the temperature differential between chilled water and back water should be within 3~50C (sometimes 1-20C).

Please note this equation:

(Real chilling capacity in Kcal/h) =

(temperature differential in 0C) * (flow rate of chilled water in L/min) * 60min/h.

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Any requirement to water?

For sure, the water should be clean. Moreover, be care for PH value of water.

It is the best to have PH=7.

If PH>7, terrible corrosion may happen, which leads to scale (dirt) gathers inside evaporator or mold, thus may reduce heat transfer efficiency by 30%.

In such case, an water softening device (or discale additives) is needed in the water circulation to lower the PH of water.

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What should be the diameter of pipeline?

Dia. 3/8" 1/2" 3/4" 1" 1-1/4" 1-1/2" 2" 3"
Flow (L/min.) 12 20 35 60 90 130 230 560

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Cooling for hydraulic oil, inlet of barrel?

Generally, just normal gap water is OK.

Better not use water chiller unless especially low temperature is required.

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Heat preservation for pipelines of chilled water?

Action on heat preservation must be taken not only to prevent heat loss, but also to prevent dew on pipelines.

e.g. using metal pipeline (length 25m, surface area 25m2), chilled water -- 100C, circumstance temperature 300C, heat loss may goes up to 750Kcal/h, i.e. 10% of nominal chilling capacity of 3Hp water chiller.

Another solution is to use enhanced rubber tube instead of metal pipelines.