Hi,
I wish to know how to estimate size and cost of a storage tank/mixing heat exchanger. Is there a good and precise reference for the estimation of a mixing heat exchanger with two inlet and single outlet. Just for single phase and water.
There are many types of storage tank and many types of heater. There are two basic issues to calculate:
1. The steady state heat requirement when the system is in steady operation, which is simply the balance between incoming and outgoing energy; and,
2. The heat input required when charging the tank.
Depending upon the use of the tank either of these could dominate the calculation. A tank with a small capacity relative to throughflow will be defined using the steady steady approach where Q= F.Cp.DT1 = U.A.DT2. where F is the average flowrate, Cp the specific heat of the fluid, DT1 the temperature change of the fluid, U the overall htc, A the heat transfer area and DT2 the mean temperature difference between the heating medium and the fluid used.
In large capacity (storage type) tanks (as in oil stores) the heat requirements for heating while filling can far exceed the steady state values.
To perform a simple analysis there are packages for the heat exchanger rating such as those from HTRI and HTFS but this does assume that you have a design duty. Please advise the design duty required, the temperature ranges required and any fluid properties that you have, the exchanger configuration both in terms of its nozzle locations and its application. For example, are you taking liquid from the tank, sending it to the exchanger, warming it and returning it to the tank or are you taking the liquid from the tank, warming it and then sending it elsewhere? If the exchanger exists, its nameplate will give you information. I suspect that it is a fixed tubesheet design but additional data is required. You may also advise any fouling information you posses.
Stephen
- Badges
- Science topic
- Similar topics
- Social Psychology
- Attitude