Transcript Diapositiva 1

Development and
Implementation of
Educational Portable
Equipment for Artificial Cold
Production Subjects
Daniel Sánchez García-Vacas
Ramón Cabello López
Enrique Torrella Alcaraz
Jorge Patíño Pérez
Rodrigo Llopis Doménech
Carlos Sanz Kock
David Conesa Sorolla
Hugo Negre Gómez
Carlos Rodríguez Rodrigo
Josep San Mateo Sanahuja
Barcelona 7th – 9th July, 2014
INDEX
1
Introduction
2
Experimental facility
3
Results
Educational Context
1
Introduction
• The European educational framework based on ECTS credits system pretends;
 A teaching process focused mainly on student learning.
 A quantification of student workload: class attendance, seminars, practice sessions…
 Development of students’ skills, abilities and competencies.
• How to achieve students’ skills and abilities?  using practice sessions, because…





Students can be in touch with “intangible” concepts showed in class: radiation.
Consolidating new theoretical concepts.
Developing of new skills and abilities.
Students change its theoretical mind into a practical one.
Sometimes it introduces a completely “new World”.
1
Introduction
Thermal Machines and Engine Area
• Our particular case:
• Department of Mechanical Engineering and Construction. Jaume I University
• Mechanical degree, Master degree.
• Subjects related with heat transfer:









Thermal Engineering.
Design of heat exchangers.
Thermoelectric Power Plants.
Air Conditioning.
Combustion
Infrared Thermography
Cogeneration.
Refrigerating technology
…. etc.
Practice Sessions
1
Introduction
• All subjects have several practice sessions given in the same laboratory.
Heat
Energetic
Air
Refrigerating
conditioning
transfer
demand
plants
through
and
inbased
Combustion
buildings
plane
onsurfaces
vapour
(LIDER)
and
compression
and
extended
radiation
technology
surfaces
heat transfer
• Some examples: Cogeneration
Practice Sessions
1
Introduction
• Regarding to artificial cold production subjects:
 In some cases research plants or facilities are used to teach students.
 It has some advantages and disadvantages:
 Advantages
- Main variables (temperature, pressure, mass flow…) are measured.
- Very close (or similar) to the real one.
- Since the refrigerating facility has been studied previously, is totally known.
 Disadvantages
- High electrical energy consumption.
- Secondary loops are necessary  heat transfer rejection and/or heating.
- They are very expensive and heavy.
- They can be modified continuously.
- Can be difficult to understand for students.
Main Objectives
1
Introduction
• OBJECTIVS:
 Development a portable and lightweight educational equipment based on vapour
compression simple… in order to be used in theoretical classes and practice sessions.
• REQUIREMENTS:






Inexpensive.
Powered by 240 VAC and 50 Hz
Portable and lightweight.
Vapour compression cycle without internal heat exchanger (IHX).
Easy to use.
Transparent heat exchangers  condensation and evaporation processes must be
visible.
 All the main variables (temperature, pressure…etc.) must be registered.
INDEX
1
Introduction
2
Experimental facility
3
Results
2
Experimental facility
Structure
• Portable and lightweight
• The structure has been assembled with 25 x 25 x 1.5 mm square steel profile.
• Moreover, pine wood panels has been bolted to square steel profile to reduce weight.
Dimensions
Hight: 645 mm
Wide: 670 mm
Thin: 250 mm
Refrigerating Diagram
2
Experimental facility
• Vapour compression cycle:










[1] Hermetic compressor
[2] Oil separator
[3] Transparent condensator
[4] Sight glasses
[5] Liquid receiver
[6] Filter-drier
[7] Micrometric valve
[8] Transparent evaporator
[9] Pressure transducers
[10] High and low pressure gauge
2
Experimental facility
Main Components
• Transparent heat exchangers  glass and ground glass
• Maximum operating pressure 12 bar with Nitrogen
• Accordingly we choose a low pressure refrigerant  R600a (isobutene)
• Hermetic compressor form EMBRACO Model: EMT30CDP, with a cooling capacity of [130 ÷
409 W] working at [-5 ÷ 15 ºC] (evaporating) [35 ÷ 65 ºC] (condensing).
2
Experimental facility
Main Components
• Two DC fans are installed in order to modify easily the condensing and evaporating
temperature. Both have a voltage regulator to modify its flow.
2
Experimental facility
Data Acquisition System
• The DAQ system have to be inexpensive and flexible to be modified in the future.
• Accordingly we use the open hardware platform ARDUINO. Model MEGA 2560 with 54
digital i/o, 16 analog inputs, 256 kB internal memory and a clock speed of 16 MHz.
• Supply voltage of 7 – 12 VDC via USB or with a
power supply, depends on the number of transducers.
Data Acquisition System
2
Experimental facility
• Transducers:
Number
Measured variable
Measured range
Supply voltage
Accuracy
Output signal
5
Temperature (ºC)
-10 ÷ 85 ºC
5 VDC
± 0.5 ºC
Digital
4
Temperature (ºC)
Relative humidity (%)
2
Pressure (bar)
0 ÷ 100 %
-40 ÷ 125 ºC
0 – 8 bar
0 – 15 bar
1
Electric Power (W)
Temperature: 18DB20
0 – 625 W
Tª / HR: DTH22
5 VDC
24 VDC
24 VDC
± 2 % HR
± 0.2 ºC
± 0.25 % full of
range
± 0.5 % full of
range
Digital
Analogical
(4 – 20 mA)
Analogical
(0 – 5 VDC)
Pressure: J&C p499
2
Experimental facility
Data Acquisition System
• Two LCD have been used to show temperature, pressure, power consumption and
temperature and relative humidity of air.
• The DAQ has two power supplies with 5 VDC, 24 VDC y 8 VDC to supply Arduino,
transducers and evaporator and condesator fans.
Experimental facility
Assembly Costs
• The assembly costs included the price of all elements used.
• The total amount includes IVA and the corresponding discount (~40%).
• 4 sections have been defined:




Structure:
Refrigerating cycle:
DAQ + Transducers:
Electrical installation:
30.58 €
291,38 €
287,06 €
90,59 €
Total:
287.06
291.38
2
90.59
30.58
Structure
Refrigerating cycle
DAQ + transducers
Electrical installation
699,61 €
Total weight: 18,73 kg
INDEX
1
Introduction
2
Experimental facility
3
Results
Results
3
Results
• A compact and portable educational equipment based on vapour compression cycle, has
been developed and implemented with a DAQ system.
• In order to show students all the equipment possibilities, an easy manual has been
developed:







Identification of main components.
Representation of the cycle in the log P-h diagram.
Representation of the air evolution in the psychometrical diagram.
Calculation of the power exchanged by evaporator and condenser
Calculation of the refrigeration facility COP.
Calculation of the refrigerant mass flow rate.
Study how affects variations of variables in the energetic behavior of the cycle.
• Since this project has been developed in the present academic year 2013/2014, the reactions
of the students and teachers working with this unit have not been registered.
Development and
Implementation of
Educational Portable
Equipment for Artificial Cold
Production Subjects
Thank you!!
Questions? Please do not hesitate to contact me if you require further
information: [email protected]
Barcelona 7th – 9th July, 2014