How to measure COP (evaporative condenser)

Hey,

Sorry I am new to this specific field and I need to do COP test methodology for an Evaporative Condenser.

Is it enough to measure only the following:

• Temperature of the refrigerant entering condenser (steam under 80 Celsius)
• Temperature of the refrigerant leaving condenser (liquid over 0 Celsius)
• Refrigerant flow (liquid)
• Power consumptions (condenser's fan and condenser's pump)?

I don't understand why I should also need to measure:

• Wet bulb temperature (outside air entering condenser)
• Dry temperature (outside air)
• Pressure of refrigerant entering/leaving compressor and condenser (under 30 bar).
• Power consumptions (compressor)?

Is there something else I need to measure?
And what measuring equipments should I use and how to do the measurements.

Designing system
I also have a problem choosing the compressor. The smallest evaporative condenser is almost 200% too big. Do I also need to choose a bigger compressor because of the big condenser and does the too big condenser affect badly the compressor and other devices?

Thank you very much for your help in advance!

Isn't the rejected heat: m*c*(he-hl)=q*c*p*(te-tl)

m=mass flow
q=refrigerant flow
h=enthalpy
t=temperature
p=density
c=specific heat

e=entering
l=leaving

That is why I was thinking isn't it enough to measure only temperature and flow to get rejected heat?

Why do I need pressure or wet bulb temperature and other values?

Hi Juho
What you are measuring at the end of the day is efficiency which is output over input (energy).
You need to measure enthalpy (total energy) which with refrigerant needs pressure and with air needs to include moisture content or pressure. so don't be lazy and go a little further - find out where these formulas come from.
We don't really consider it as COP for what you are measuring - just efficiency. COP is generally reserved for the total refrigeration cycle or total system performance.
Measurement will/should require direct refrigerant temp and press (search this forum). Check out pressure enthalpy diagram for refrigerant and psychometric chart for air along with basic Q=AUdT and Q=MShcdT

You are speeding ahead without first having a good understanding of the basics. This will only add confusion.

The AHRI standard specifies that the outdoor should be maintained at 35°C and indoor should be maintained at 27°C dry bulb and 19°C wet bulb. To calculate EER or COP, the a/c equipment has to be tested in a psychometric room as per the AHRI standard.

So can I even measure COP on-site?

COP is different at different conditions, the manufacturers COP is calculated at prescribed conditions. Calculating COP with on site conditions will give you COP for that window in time.
You have not listened to what Telsa has said or taken his GOOD!! advice.