[TRNSYS-users] Immersed heat exchangers

[fdominguezm at uma.es]

Dear TRNSYS users,

I am modelling a small solar heating system with an immersed heat
exchanger in the solar side. I am wondering about the best way to model
this heat exchanger. The aim is to make an easy to use TRNEDIT program.

While TYPE534 (TESS) is very robust and fast, it asks for many physical
and geometric parameters that are not usually available in the catalogs
and that, anyway, I can not ask to the user. My first question is: does
somebody know a set of "typical" values for these parameters?, i.e.,
values that apply for most of the small tanks (lets say <500 liters) in
the market.

A second option is to use a constant UA-value. I think that the French
program "SimSol" solves the immersed heat exchangers in this way. In the
manual of the program, a value of 1000 W/m2K is recommended. Does somebody
know the impact of the constant-UA hypothesis on the result?, and How to
choose a particular UA for a given heat exchanger?

Thank you in advance for any comment

Greetings

Fernando Domínguez Muñoz
ETS Ingenieros Industriales
Plaza El Ejido s/n
29013 Málaga (SPAIN)