ipu refrigeration software

IPU Refrigeration

SoftwareJorrit Wronski

2021/02/23

Who are IPU?

• A small company that bridges the gap between research and business since 1956.

• We are located on the campus of the Technical University of Denmark (DTU).

• IPU work with 5 key areas:

• Advanced Materials & Surfaces Technology

• Thermodynamics and Energy Technology

• Autonomous Systems and Robotics

• Modelling of Physical Systems

• Product- and Process Technology Development

• IPU have a long history in developing software solutions for refrigeration engineers.

2021-02-23 IPU Refrigeration Software, Jorrit Wronski ([email protected]) 2

Refrigeration Software Overview

• Custom development of product selection software like: Danfoss Coolselector2, Emerson

CO2 Booster Tool, Nilan Calculator, …

• Delivering high performance utility libraries for fluid properties and heat transfer (ASEREP,

CoolProp, ExternalMedia) compatible MS Excel, EES, Modelica, …)

• User-oriented software available from IPU:

• Pack Calculation Pro (annual performance of refrigeration systems)

• CoolTools (simplified simulation models with new refrigerants)

• CoolPack (simplified simulation models for refrigeration engineers and students)

• SecCool (properties of secondary refrigerants and heat transfer media)

• Simple one-stage CO2 (educational program for transcritical CO2 cycle)

• Get them all at: https://www.ipu.dk/products/


https://www.ipu.dk/products/

Pack Calculation Pro

• Minimum required input data (customization is still possible).

• Calculate performance each hour of the year (= 8760 operating

points)

• Weather data for more than 3700 cities around the world

• 11 commonly used cycles (including parallel compression and

transcritical cycles)

• Choose from 10000 commercially available compressor to build your

system

• Calculate Life Cycle Costs and payback time

• Get an overview of both energy consumption and carbon footprint

• Create reports and export plots and data

• And much more!


EU-project “SuperSmart Supermarket”

concludes:

… it [Pack Calculation Pro] is one of the

most useful tools for planning the

refrigeration system, since it includes

many desired features (component

database, user-friendly interface,

automatic report generation) and also

recent refrigeration system layouts.

CoolTools

• Free to use – also for commercial purposes.

• Written in the Python programming language.

• Makes use of the Qt-framework.

• Built-in fluid properties using CoolProp,

REFPROP interface planned.

• Still under development – looking for more

funding.


• Partly funded by the Danish Environmental Protection Agency:MST-626-00257 – Rådgivnings- og informationsaktiviteter om klimavenlige kølemidler

• Additional funds provided by IPU

SecCool Properties

• A software to calculate the properties of

secondary refrigerants

• Estimate all properties needed to dimension

a heat transfer circuit:

• Calculate flow rate from cooling demand

• Determine pressure drop and flow velocities

• Calculate concentration and freezing point


Simple one-stage CO2

• 2 simple CO2 system configurations

• Immediately visualize the effect of changing

parameters

• Designed to illustrate the interrelation of

different parameters

• Made for educational purposes – important

state points and diagram only

• No distraction details about the calculations

or the results


Motivation and overview

• There is a need for simple calculation tool for basic refrigeration calculations.

• Many people contacted us, asking for a new version of CoolPack with new refrigerants.

• CoolTools started as a clone of the old EES CoolTools package from CoolPack.

• Future development is going to divert from this path and include other features.


Agenda

• Basic features

• Calculation examples

• Next steps


Currently included calculations

• Cycle Analysis

• One stage with DX evaporator

• One stage with flooded evaporator


• Auxiliary

• Compressor

• Evaporator

• Air cooler

• Gas and liquid pipe flow

• Moist air

Cycle Analysis – One stage cycle with DX evaporator


7

2

5 4

6

8 1

3

35.0 [°C]

-10.0 [°C]

55.3 [°C]

-4.0 [°C]

32.6 [°C]

CYCLE ANALYSIS : ONE-STAGE CYCLE

T5 :

T1 :

T2 :

TE :

TC :

0.36 [kg/kg]X6 :

QE :

QC : 187.3 [kW]

139.8 [kW]

W : 46.41 [kW]

QSGHX : 0 [kW]

3.036COP* :COP : 3.012

1.2 [kg/s]m :

T4 : 32.6 [°C]

Department of

Mechanical Engineering

55.3 [°C]T3 :

REFRIGERANT : R404A

-5.0 [°C]T7 :

-4.0 [°C]T8 :

> DX EVAPORATOR

Technical Univ ersity

SUB-DIAGRAM

WINDOWS

CARNOT : 0.519TOOL C.1

CoolPack

© 1999 - 2001

of Denmark

Version 1.48

LOG(p),h-DIAGRAM


Cycle Analysis – One stage cycle with DX evaporator

Cycle Analysis – One stage cycle with Flooded Evaporator


Comparison of results

• Dry expansion • Flooded evaporator


CoolTools CoolPack

T2 [⁰C] 131.1 131.2

QC [kW] 12.74 12.8

m [kg/s] 0.00931 0009

W [kW] 3.01 3

COP 3.32 3.296

CoolTools CoolPack

T2 [⁰C] 56.05 55.3

T4 [⁰C] 33.15 32.6

x6 0.36 0.36

QC [kW] 187.87 187.3

QE [kW] 139.95 139.8

W [kW] 46.8 46.1

COP 2.99 3.012• Noticeable differences:

• Instant processing – no calculation button.

• Real pressure-enthalpy diagram, no sketch.

Auxiliary – Compressor


Auxiliary – Gas Pipes



• Compressor calculation • Gas pipe flow


CoolTools CoolPack

Mean velocity [m/s] 11.76 11.76

Volume flow [m3/s] 13.6 13.55

Mass flow [kg/s] 0.08035 0.08041

Heat ingress [W] 71.55 70.14

TOUTLET [⁰C] -4.045 -4.31

Surface

temperature [⁰C]

15.33 15.43

CoolTools CoolPack

T2 [⁰C] 124.9 124.1

p2 [Pa] 1829.5 1817

nVOl [-] 0.774 0.765

QE [kW] 4.14 4.08

W [kW] 3.697 3.666

COP 1.12 1.113

What’s next?

• More funding needed for further

development.

• All suggestions are welcome!

https://www.ipu.dk/products/cooltools/

Link: Questionnaire

• Pipeline of planned features:

• REFPROP interface

• Moody diagram and standard pipe flow


http://app.ipu.dk/ext/form/entry.php?m=324408a1489da5b49114c2c05dfc0e96e07695f&Origin=Direct

Purpose of calculations

• Dimensioning / design

• Optimization

• Fault detection



Jorrit Wronski

Thermodynamic Modelling Specialist

Diplomvej 376, 2800 Kgs. Lyngby, Denmark

[email protected] / www.ipu.dk

Dir. +45 45 16 04 26

mailto:[email protected]

https://www.ipu.dk/

Auxiliary – Air cooler


AIR COOLER

INLET CONDITION OUTLET CONDITION

x1

h1

RH1 [%]

TDEW,1

20.00

70.0

46.05 [kJ/kg]

0.01022 [kg/kg]

14.37 [°C]

T2 [°C]

x2

h2

RH2

TDEW,2

6.00

0.005691 [kg/kg]

20.33 [kJ/kg]

98.2 [%]

5.74 [°C]

Cooling demand

Sensible load

Latent load

Latent load (frost)

16.93 [kW]

9.479 [kW]

7.449 [kW]

56.0 [%]SHR

10.72 [kg/h]

Volume flow [m3/h]

MOIST AIR DRY AIR

Mass flow (mixture)

Mass flow

101.33 0.0

2000

0.665 [kg/s]

0.658 [kg/s]

Mass flow (water) 0.006724 [kg/s]

Dehumidification rate

5684 [kJ/kg]

PROCESS PARAMETERS

Air pressure [kPa] : Cooler surface temperature [°C] :

TWET,1 16.44 [°C] TWET,2 5.87 [°C]

T1 [°C]

Inlet and outlet properties are stated per kg dry air

Process: Cooling and dehumidification

AIR FLOW

dh/dx

0.000 [kW]

CoolPack

Department of

Mechanical Engineering

Technical Univ ersity

TOOL A.2

© 1999 - 2001

of Denmark

Version 1.48

> COOLING AND DEHUMIDIFICATION OF MOIST AIR

Auxiliary – Moist Air



Comparison of results – Air cooler

CoolTools CoolPack

TDEW1 [⁰C] 14.37 14.37

x1 [kg/kg] 0.01025 0.01022

h1 [kJ/kg] 46.144 46.05

x2 [kg/kg] 0.00575 0.005691

RH2 [%] 98.85 98.2

Mass flow

(mixture) [kg/s]

0.6583 0.665

Mass flow (water)

[kg/s]

0.00675 0.006724

Sensible load

[kW]

9.451 9.479

Latent load [kW] 7.28 7.449

Comparison of results – Moist air


CoolTools CoolPack

TDEW [⁰C] 13.23 13.23

Humidity Ratio 0.00951 0.009478

Specific

enthalpy

[kJ/kgda]

44.18 44.259

Auxiliary – Evaporator UA




CoolTools CoolPack

UASENSIBLE [kW/K] 0.04138 0.04081

UATOTAL [kW/K] 0.06897 0.068

LTMD[K] 14.499 14.7

ipu refrigeration software

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