ScilabTEC

A new toolbox to optimize nonlinear objective functions by solving

combinatorial problems in industrial applications

A. Bassi, M. Venturin

www.openeering.com

May 16th , 2014

A NEW TOOLBOX: Scilab Heat Engine Design Optimizer

A. Bassi, M. Venturin

www.openeering.com

May 16th , 2014

ScilabTec 2014 - Copyright © 2014 EnginSoft SpA, all rights reserved

Tutorials and applications


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5 14/05/2014

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HEAT ENGINES EFFICIENCIES


Energy Efficiency Ratio (EER)

CHILLER COOLED

SPACE

Required work =

Required Power * time

QL

(Desired effect )

QH

HOT

ENVIRONMENT

W

𝐸𝐸𝑅 = η = 𝐷𝑒𝑠𝑖𝑟𝑒𝑑 𝑒𝑓𝑓𝑒𝑐𝑡

𝑅𝑒𝑞𝑢𝑖𝑟𝑒𝑑 𝑤𝑜𝑟𝑘=

|𝑄𝐿|

𝑊


Coefficient Of Performance (COP)

HEAT

PUMP HEATED

SPACE QL

COLD

ENVIRONMENT

W

𝐶𝑂𝑃 = η = 𝐷𝑒𝑠𝑖𝑟𝑒𝑑 𝑒𝑓𝑓𝑒𝑐𝑡

𝑅𝑒𝑞𝑢𝑖𝑟𝑒𝑑 𝑤𝑜𝑟𝑘=

|𝑄𝐻|

𝑊

QH

(Desired effect)

Required work =

Required Power * time

Efficiency depends on power!

Pf [kW] 0 50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850 900 950 1000

EER 1.466667 1.825 2.16 2.471667 2.76 3.025 3.266667 3.485 3.68 3.851667 4 4.125 4.226667 4.305 4.36 4.391667 4.4 4.385 4.346667 4.285 4.2


𝜂 = 𝜂(𝑃)

W1

QL1 QH1

QL2

QL3

COOLED

SPACE

HOT

ENVIRONMENT

CHILLER

1

QH3

QH2

W2

CHILLER

2

W3

CHILLER

3

Goal: maximize the efficiency in parallel configurations


The mathematical problem


max 𝜂𝑡𝑜𝑡(P1, P2, P3)

𝑃𝑟 = required power

We maximize the efficiency of the overall system:

Subject to:

𝑃1 + 𝑃2 + 𝑃3 = 𝑃𝑟

Solution strategy


0 50 20 10 30 40

0 50 20 10 30 40

0 50 20 10 30 40

Approximate efficiencies with piecewise linearized curves

Given a required power (𝑃𝑟), analyze all possible combinations that satisfy the requirement

Find the optimal solutions and rank the suboptimal ones

THE SHEDO TOOLBOX: SCILAB HEAT ENGINE DESIGN OPTIMIZER

The toolbox


1. Settings


It allows to set the paths and the files to be used during the analysis

The default settings are loaded from the previous run

2. Pre-processing


In this phase the user can choose the .csv file containing the powers and efficiencies of the heat engines

Adding new heat engines configurations is very easy!

2. Pre-processing


3. Analysis


Single analysis: fixed power requirement

Full analysis: solutions for all the powers between Pt_min and Pt_max with step Delta Pt

3. Analysis


3. Analysis


4. Post-processing


SHEDO main technical features


Scilab 5.5 and JIMS module JIMS module (Java Interaction Mechanism in Scilab) allows Scilab to instantiate Java objects.

.csv files as input and output arguments

SHEDO is a user-friendly program!

Conclusions


Automated search of the optimal solution

Scalability of the problem in many different plant and machinery

Time to search for a solution reduced to a few seconds of computation

Average energy saving of 15% compared to the manual solution with significant cost savings

+15%

BEFORE

AFTER

THANK YOU FOR YOUR ATTENTION

Documents

ScilabTEC