chiller evap size for daikin 37kw compressor

[ah fai]

hallo friend....
can anyone help me how to calculate evap and water cooler condensor size for chiller....

secondary fluid (water) details.
inlet water temp=25degc
outlet water temp=15degc
water flow rate=22 lpm

it is possible 1 unit 37kw daikin compressor can handle this???
thanks...

[Aik]

hallo friend....
can anyone help me how to calculate evap and water cooler condensor size for chiller....

secondary fluid (water) details.
inlet water temp=25degc
outlet water temp=15degc
water flow rate=22 lpm

it is possible 1 unit 37kw daikin compressor can handle this???
thanks...

If water flow rate = 22 lpm (litre per minute) then:
G=22 l/m=0.37*10^(-3) m^3/s=0.37 kg/s (density of water is 1000 kg/m^3)
Q=c*G*(Tin-Tout)=4200 J/(kg*degc)*0.37 kg/s * (25 degc- 15degc)= 15.54 kJ/s=15.54 kW

[ah fai]

thanks for reply. 15.54kw means cooling capacity??
one more question is if i have a 37kw daikin compressor, the cooling capacity??

[Aik]

thanks for reply. 15.54kw means cooling capacity??
one more question is if i have a 37kw daikin compressor, the cooling capacity??

Yes, it's a cooling capacity.
Really, I don't understand the 2-nd part of your question. What mark of compressor, evaporating/condensing temperature, type of refrigerant? Capacity of compressor depends on thise parameters...

[nike123]

Chiller water Δt should be 5K for proper chiller operation and best heat transfer at water to refrigerant heat exchanger.
Therefore, for your 37kW cooling capacity, water flow at evaporator should be ~106L/min or 6,4 m^3/hr.
If your process require higher Δt and different flow rate, you should use mixing valve or hydraulic separator.

Where and how did you got these data you present us here?
With flow and capacity what you posted, Δt would be 24K.

[Aik]

If you need to chill water from 25 C to 15 C you must take compressor with proper capacity ( 15.54 kW or no much more). Evaporating temperature would be near 7-10 C.
If you have compressor with capacity of 37 kW at 7-10 C evaporating temperature it would be done capacity regulation, otherwise evaporating temperature would be much lower and would be big problems...

[ah fai]

ok....thanks both of u..
i put wrong people on design and installation chiller in my work place, now i have to pay the price to study and correct it... actually i m electrical automation specialist.

[ah fai]

or i can unload the compressor maybe 50% or 25% load when reach the set point.

[nike123]

or i can unload the compressor maybe 50% or 25% load when reach the set point.

Running unloaded for long periods mean bad oil return and inefficient work.

Install buffer tank/hydraulic separator in one tank
http://www.cemline.com/products/steeltank/sebmenu.asp


and use dedicated pumps for primary and secondary circuit.
Also, you could calculate tank capacity here according to minimal running time of 10 min for chiller.

[Aik]

If use tank capacity, then you may use compressor of 37 kW capacity and system will work without any problems (compressor's working time will be shorter).

[ah fai]

any idea from ur if i just install copper pipe after expansion device as evap in the chill water tank, the calculation for evap piping surface for my 37kw compressor.....thanks again...

[nike123]

any idea from ur if i just install copper pipe after expansion device as evap in the chill water tank, the calculation for evap piping surface for my 37kw compressor.....thanks again...

Not good. One pipe mean big pressure drop. Also, liquid in tank need to be moved or you could freeze it quickly. You need BPHE (brazed plate heat exchanger ) and correct pump for right flow.

Why don't you find some contractor to do proper job for you?

[ah fai]

ok,i can put a lot of pipe, make it paraller circuit, like water chiller evap. of course the water in tank move all the time. i have interest in this field.this is my 2nd project. the 1st project i had completed very successfully to installation ***** r22 bitzer osn7471-k with eco,the result is -45degc...

[Aik]

ok,i can put a lot of pipe, make it paraller circuit, like water chiller evap. of course the water in tank move all the time. i have interest in this field.

You can do it and your's the next post will be: how calculate evaporator capacity of pipe situated in tank in which continually move water.

[ah fai]

sure, can u find me a solution???