E-CodeHeat exchanger, effectiveness-NTU — a TI-84 Plus CE program
HXNTU is a TI-BASIC program for the TI-84 Plus CE. Counterflow, parallel-flow or one-shell-pass exchanger: effectiveness, duty, outlet temperatures, and the LMTD cross-check with its correction factor.
What it asks for and what it shows
It asks for 5 values at its prompts, after you pick option 1 from its menu. In the example below it shows EFF, Q W, TH OUT, TC OUT, NTU, LMTD C, F.
Example run
One of its oracle test cases: “counterflow”. The inputs are typed in order, and the results are the values the case expects on the screen.
| Step | Value |
|---|---|
| You enter | |
| Menu | option 1 |
| Input 1 | 4000 |
| Input 2 | 2500 |
| Input 3 | 150 |
| Input 4 | 30 |
| Input 5 | 3000 |
| The screen shows | |
EFF= | 0.6024645862 |
Q W= | 180739.3759 |
TH OUT= | 104.815156 |
TC OUT= | 102.2957503 |
NTU= | 1.2 |
LMTD C= | 60.24645862 |
F= | 1 |
How it's checked
5 test cases, each checked against an independent method. Replayed key by key on a virtual TI-84 Plus CE, they make 39 checks.
How E-Code checks every program
Run it or put it on your calculator
- Open the library in the TI-84 Plus CE calculator and pick “Heat exchanger, effectiveness-NTU” (HXNTU).
- Put it on your own calculator with a computer and a USB cable, or type it in by hand.
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All TI-84 Plus CE engineering programs · All TI-84 Plus CE programs