Barcelona 7th – 9th July , 2014

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 LlopisDoménech Carlos Sanz Kock David Conesa Sorolla Hugo Negre Gómez Carlos Rodríguez Rodrigo Josep San Mateo Sanahuja Barcelona 7th – 9th July, 2014

2. 1 Introduction 2 Experimentalfacility 3 Results INDEX

3. 1 Introduction EducationalContext • 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”.

4. 1 Introduction Thermal Machines and EngineArea • 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.

5. 1 Introduction PracticeSessions • Allsubjectshaveseveralpracticesessionsgiven in thesamelaboratory. • Someexamples: Heat transfer throughplanesurfaces and extended surfaces Energeticdemand in buildings (LIDER) and radiationheat transfer Air conditioning and Combustion Cogeneration Refrigeratingplantsbasedonvapourcompressiontechnology

6. 1 Introduction PracticeSessions • 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.

7. 1 Introduction MainObjectives • 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.

8. 1 Introduction 2 Experimentalfacility 3 Results INDEX

9. 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 Experimental facility 2

10. Refrigerating Diagram • Vapourcompression 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 Experimental facility 2

11. MainComponents • Transparent heat exchangers  glass and ground glass • Maximum operating pressure 12 bar with Nitrogen Experimental facility • 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

12. MainComponents • Two DC fans are installed in order to modify easily the condensing and evaporating temperature. Both have a voltage regulator to modify its flow. Experimental facility 2

13. 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. Experimental facility 2

14. Data Acquisition System • Transducers: Experimental facility 2 Tª / HR: DTH22 Temperature: 18DB20 Pressure: J&C p499

15. 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 2

16. AssemblyCosts • 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: 30.58 € • Refrigerating cycle: 291,38 € • DAQ + Transducers: 287,06 € • Electrical installation: 90,59 € • Total: 699,61 € • Total weight: 18,73 kg Experimental facility 2

17. 1 Introduction 2 Experimentalfacility 3 Results INDEX

18. 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. Results • 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. 3

19. 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: sanchezd@uji.es Barcelona 7th – 9th July, 2014