Issue:
Evaporator Approach Rule of Thumb
Resolution:
Approach temperatures are affected by many different factors including Water Flow, Glycol Type, Glycol Concentration, Refrigerant Charge, Oil Charge, System Impurities (both water and refrigerant), Evaporator Setpoint, etc. Therefore, it is very difficult to pinpoint an expected approach temperature.
For Pueblo DX evaporators, a very general rule of thumb for evaporator approach is 5 degrees (based on 45 degree evap leaving water temp). In addition, for every 10% of glycol added, the approach temperature increases 1 deg.
Example, a chiller running 45 degree ELWT and containing 25% glycol would have an expected approach:
= 5 + (25/10)
= 5 + 2.5
= 7.5 deg
Notes:
Changes:
Other Question/Problem/Cause Statements:
- Evaporator Approach Rule of Thumb
Facts:
- RTAA 130-400 Ton (Pueblo)
- RTAA 70-125 Ton (Pueblo)
- RTUA
- RTWA
Document Identifier: DOC-77145
Document Identifier: 77145
WARNING:
Information in this article is intended for use by individuals possessing adequate backgrounds of electrical and mechanical experience and who comply with all federal, state, and local laws, rules, orders, or regulations related to the installation, service, or repair of a heating or central air conditioning product. Any attempt to install, service, or repair a heating or central air conditioning product may result in personal injury and/or property damage. The manufacturer or seller cannot be responsible for the interpretation of the information contained herein, nor can it assume any liability in connection with its use.