Tek-Tips is the largest IT community on the Internet today!

Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!

  • Congratulations TugboatEng on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Effectivenss Calculations

Status
Not open for further replies.

jrrocks

Mechanical
Joined
Aug 13, 2018
Messages
58
Location
IN
Effectiveness of heat exchanger can be calculated as (Tin - Tout)/Max Differential Temperature. I have Energy wheel to extract heat from outside air. OAT=46°C, after energy recovery it drop down to 30°C. Exhaust air Temperature EAT=24°C. so, Effectivess = (46-30)/(46-23), it gives 70% effectiveness which is matching with the manufacturer data. Flow rate is same. OA supply airflow rate is equal to exhaust flow rate.

But when I put Heat Pipe in series with energy wheel, I am getting relatively lower temperature of outside temperature after energy wheel i.e. 26°C. So overall heat recovery system effectiveness is (46-26)/(46-23) = 87%.
In some AHUs the OA temperature drop is even low, i.e. after Heat pipe - Energy wheel OAT is less than 26°C. But i think, in any case my OA temperature will not go below 24°C (EAT temp). So my effectivess of Heat recovery system may come to Unity.

Someone please confirm, if I am on the right track?
 
Status
Not open for further replies.

Part and Inventory Search

Sponsor

Back
Top