Evaporating / condensing temperatures

[US Iceman]

The values you reference for 1%, 3% & 5% were revised sometime ago by ASHRAE. The new occurence values are 0.4%, 1%, & 2% and account for the percentage of annual hours where that value is exceeded.

So, this equates to:

0.4% X 8760 hours = 35.4 hours
1.0% X 8760 hours = 87.6 hours
2.0% X 8760 hours = 175.2 hours

In some locations the dry bulb temperature may not vary much, in other locations it will.

I'm late to this discussion, but I'm sure it has been lively with lana participating.

[lana]

Thank you US Iceman for clarifying the percentages.

Cheers

[mohamed khamis]

The values you reference for 1%, 3% & 5% were revised sometime ago by ASHRAE. The new occurence values are 0.4%, 1%, & 2% and account for the percentage of annual hours where that value is exceeded.

So, this equates to:

0.4% X 8760 hours = 35.4 hours
1.0% X 8760 hours = 87.6 hours
2.0% X 8760 hours = 175.2 hours

In some locations the dry bulb temperature may not vary much, in other locations it will.

I'm late to this discussion, but I'm sure it has been lively with lana participating.

Ok thank you for this data, i have seen it on http://www.microcool.com/cooling/bro...PreCooling.pdf.
However, i am so happy that i was a reason of correcting the common perception of the fellows for using maximum ambient temperature occurred in the year as the design temperature for the condenser without looking to something named the frequency occurrence. Regardless of these new values i do believe as u mentioned each location has its specifications.

Cheers

[lana]

Hi there,

In Persian Gulf area we have minimum of three months extreme temperatures between 45 to 55°C.

3 months x 30 days x 24 hrs = 2160 hrs

This is way more than 1% occurrence.

Cheers