Computer Controlled Geothermal (low enthalpy) Energy Unit
INTRODUCTION
Geothermal energy is generated using the heat given off by the Earth to obtain energy. The use of this energy is spreading quickly because it is a clean, renewable and almost unlimited source. Besides, depending on the Earth’s layer and the temperature at which it is obtained, the geothermal energy can be employed for different purposes: High enthalpy geothermal energy is the energy that uses a geothermal resource found at specific high temperature (higher than 150ºC) and pressure conditions. Low enthalpy geothermal energy is based on the capacity of the subsoil to accumulate heat and keep a sensibly constant temperature, at a depth between 10 and 20 m, throughout the year. The objective of the Computer Controlled Geothermal (low enthalpy) Energy Unit, “EG5C”, designed by EDIBON, is to introduce the student into an increasingly leading renewable energy and, particularly, in the use of this energy for the climate control of buildings. Moreover, the unit allows the student to start learning about systems that include heat pumps and to study and calculate the characteristic operating parameters of the unit depending on the environmental requirements (heat, temperature, refrigeration, etc.).
GENERAL DESCRIPTION
The Computer Controlled Geothermal (low enthalpy) Energy Unit, "EG5C", designed by EDIBON, consists of a cooling circuit, a small tank with pipes covered with water (bath) and a chilling unit (heat pump). The inside of the earth is simulated with them. There is another tank where the sanitary hot water heated by the unit is stored. The cooling circuit consists of a compressor, an air condenser/evaporator, and two water condensers/evaporators. The reason is that the unit has a 4 ways valve that can detect if it is summer or winter by the environmental conditions. According to this, it sends the refrigerant gas to one or another exchanger. So they are able to work as evaporators or condensers of the refrigerant liquid. The ground is simulated by means of a small tank that covers some pipes and a heat pump. The water of the tank is at a constant temperature, the same temperature that the earth has at 20 m of depth (15ºC [59ºF] approximately). This water goes to a bath, heating or cooling the water that flows through the pipes immersed in the bath. Finally, there is a tank to store the water heated by the unit. It simulates the sanitary hot water of a house. The unit has a cycle inversion valve, which is able to simulate winter and summer conditions, as it was mentioned before. Since the temperature of the earth at 20 m of depth is always 15ºC, this temperature will be higher than the environmental temperature in winter; therefore, the ground is used to heat (heating mode use). However, the environmental temperature in summer will be higher than 15ºC, so the ground’s water will be used to cool (refrigerating mode). This Computer Controlled Unit is supplied with the EDIBON Computer Control System (SCADA), and includes: The unit itself + a Control Interface Box + a Data Acquisition Board + Computer Control, Data Acquisition and Data Management Software Packages, for controlling the process and all parameters involved in the process.
EXERCISES AND PRACTICAL POSSIBILITIES
1.- Study of geothermal energy using a geothermal heat pump system for heating and/or cooling.
2.- Study of the system with different ground temperatures.
3.- Determination of the inlet power, produced heat and coefficient of performance, working in heating mode. Water-water heat pump.
4.- Determination of the inlet power, produced heat and coefficient of performance, working in cooling mode. Water-water heat pump.
5.- Determination of the inlet power and valuation of the air temperatures, working in heating mode. Water-air heat pump.
6.- Determination of the inlet power and valuation of the air temperature, working in cooling mode. Water-air heat pump.
7.- Preparation of performance curves of the heat pump, working in heating mode, with different inlet and outlet temperatures. Waterwater heat pump.
8.- Preparation of performance curves of the heat pump, working in cooling mode, with different inlet and outlet temperatures. Waterwater heat pump.
9.- Lay out of the steam compression cycle in a P-H diagram and comparison with the ideal cycle. Water-water heat pump. Heating mode.
10.- Lay out of the steam compression cycle in a P-H diagram and comparison with the ideal cycle. Water-air heat pump. Heating mode.
11.-Preparation of the performance curves of the heat pump based on the properties of the refrigerant and at different condensation and evaporation temperatures. Water-water heat pump. Heating mode.
12.- Preparation of the performance curves of the heat pump based on the properties of the refrigerant and at different condensation and evaporation temperatures. Water-water heat pump. Cooling mode. Additional practical possibilities:
13.- Sensors calibration. Other possibilities to be done with this Unit:
14.- Many students view results simultaneously. To view all results in real time in the classroom by means of a projector or an electronic whiteboard.
15.- Open Control, Multicontrol and Real Time Control. This unit allows intrinsically and/or extrinsically to change the span, gains; proportional, integral, derivate parameters; etc, in real time.
16.- The Computer Control System with SCADA allows a real industrial simulation.
17.- This unit is totally safe as uses mechanical, electrical and electronic, and software safety devices.
18.- This unit can be used for doing applied research.
19.- This unit can be used for giving training courses to Industries even to other Technical Education Institutions.
20.- Control of the EG5C unit process through the control interface box without the computer.
21.- Visualization of all the sensors values used in the EG5C unit process. - By using PLC-PI additional 19 more exercises can be done. - Several other exercises can be done and designed by the user.
With this unit there are several options and possibilities:
- Main items: 1, 2, 3, 4, 5 and 6.
- Optional items: 7, 8, 9, 10 and 11.
Let us describe first the main items (1 to 6):
1. EG5C. Unit:
- Unit mounted in anodized aluminum frame and panels of painted steel.
- This unit includes wheels for its mobility.
- Main metallic elements in stainless steel.
- Diagram in the front panel with similar distribution to the elements in the real unit.
- Heat pump:
- Hermetic compressor:
- Power: 0.5 CV, 4 A.
- Coefficient of performance: 1111 W at 0ºC.
- Power measurement from the computer.
- Two water condensers/evaporators, depending on heating or cooling configuration (winter or summer conditions), by using the cycle inversion valve:
- Capacity: 1580 W. Consumption: 170 l/h.
- Computer controlled air condenser/evaporator, depending on heating or cooling configuration (winter or summer conditions), by the cycle inversion valve:
- Maximum air flow: 980 m³/h. Coefficient of performance: 1591 W at 5ºC.
- High pressure control: 8 - 32 bar.
- Coolant storage tank.
- Refrigerant filter.
- Refrigerant separation tank.
- Expansion valve.
- Four way-valve (cycle inversion valve) - solenoid valve.
- Four “J” type temperature sensors for the refrigerant circuit.
- Two “J” type temperature sensors for the air temperature measurement.
- Two pressure sensors for the refrigerant circuit:
- High pressure, range: 0 - 25 bar.
- Low pressure, range: 0 - 10 bar.
- Four manometers for the refrigerant circuit.
- Refrigerant flow sensor, range: 5 - 60 l/h.
- Sanitary water circuit:
- Water tank. Capacity: 130 l.
- Water pump.
- Water flow sensor to measure water flow, range: 0.25 - 6.5 l/min.
- Three “J” type temperature sensors for the water temperature.
- Geothermal exchanger simulator:
- Water heat exchanger:
- A pipe system inside a water bath (at constant temperature).
- Three “J” type temperature sensors for the water temperature.
- Water pump to Circulate from the pipe System located inside the bath (to simulate the ground loop).
- Work in opened and closed loop by valves selection.
- Chilling unit to maintain constant temperature in the water bath:
- Power: 2 HP, 1464 W. Optimum water flow: 3000 - 6000 l/h.
- Water pump, to send the water from the chilling unit to the water bath.
- Two “J” type temperature sensors for the water temperature.
- Water flow sensor to measure water flow, range: 0.25 - 6.5 l/min.
- Enthalpy diagram of the refrigerant R134a.
- The complete unit includes as well:
- Advanced Real-Time SCADA.
- Open Control + Multicontrol + Real-Time Control.
- Specialized EDIBON Control Software based on LabVIEW.
- National Instruments Data Acquisition board (250 KS/s, kilo samples per second).
- Calibration exercises, which are included, teach the user how to calibrate a sensor and the importance of checking the accuracy of the sensors before taking measurements.
- Projector and/or electronic whiteboard compatibility allows the unit to be explained and demonstrated to an entire class at one time.
- Capable of doing applied research, real industrial simulation, training courses, etc.
- Remote operation and control by the user and remote control for EDIBON technical support, are always included.
- Totally safe, utilizing 4 safety systems (Mechanical, Electrical, Electronic & Software).
- Designed and manufactured under several quality standards.
- Optional ICAI software to create, edit and carry out practical exercises, tests, exams, calculations, etc. Apart from monitoring user's knowledge and progress reached.
- This unit has been designed for future expansion and integration. A common expansion is the EDIBON Scada-Net (ESN) System which enables multiple students to simultaneously operate many units in a network.
2. EG5C/CIB. Control Interface Box:
- The Control Interface Box is part of the SCADA system.
- Control interface box with process diagram in the front panel and with the same distribution that the different elements located in the unit, for an easy understanding by the student.
- All sensors, with their respective signals, are properly manipulated from -10V. to +10V. computer output.
- Sensors connectors in the interface have different pines numbers (from 2 to 16), to avoid connection errors.
- Single cable between the control interface box and computer.
- The unit control elements are permanently computer controlled, without necessity of changes or connections during the whole process test procedure.
- Simultaneous visualization in the computer of all parameters involved in the process.
- Calibration of all sensors involved in the process.
- Real time curves representation about system responses.
- Storage of all the process data and results in a file.
- Graphic representation, in real time, of all the process/system responses.
- All the actuators’ values can be changed at any time from the keyboard allowing the analysis about curves and responses of the whole process.
- All the actuators and sensors values and their responses are displayed on only one screen in the computer.
- Shield and filtered signals to avoid external interferences.
- Real time computer control with flexibility of modifications from the computer keyboard of the parameters, at any moment during the process.
- Real time computer control for pumps, compressors, heating elements, control valves, etc.
- Real time computer control for parameters involved in the process simultaneously.
- Open control allowing modifications, at any moment and in real time, of parameters involved in the process simultaneously.
- Three safety levels, one mechanical in the unit, another electronic in the control interface and the third one in the control software.
3. DAB. Data Acquisition Board:
- The Data Acquisition board is part of the SCADA system.
- PCI Express Data acquisition board (National Instruments) to be placed in a computer slot. Bus PCI Express.
- Analog input:
- Number of channels= 16 single-ended or 8 differential. Resolution=16 bits, 1 in 65536.
- Sampling rate up to: 250 KS/s (kilo samples per second).
- Input range (V)=±10 V. Data transfers=DMA, interrupts, programmed I/0. DMA channels=6.
- Analog output:
- Number of channels=2. Resolution=16 bits, 1 in 65536.
- Maximum output rate up to: 900 KS/s.
- Output range (V)=±10 V. Data transfers=DMA, interrupts, programmed I/0.
- Digital Input/Output:
- Number of channels=24 inputs/outputs. D0 or DI Sample Clock frequency: 0 to 100 MHz.
- Timing: Number of Counter/timers=4. Resolution: Counter/timers: 32 bits.
4. EG5C/CCSOF. Computer Control + Data Acquisition + Data Management Software:
- The three softwares are part of the SCADA system.
- Compatible with actual Windows operating systems. Graphic and intuitive simulation of the process in screen. Compatible with the industry standards.
- Registration and visualization of all process variables in an automatic and simultaneous way.
- Flexible, open and multicontrol software, developed with actual windows graphic systems, acting simultaneously on all process parameters.
- Management, processing, comparison and storage of data.
- Sampling velocity up to 250 KS/s (kilo samples per second).
- Calibration system for the sensors involved in the process.
- It allows the registration of the alarms state and the graphic representation in real time.
- Comparative analysis of the obtained data, after the process and modification of the conditions during the process.
- Open software, allowing the teacher to modify texts, instructions. Teacher’s and student’s passwords to facilitate the teacher’s control on the student, and allowing the access to different work levels.
- This unit allows the 30 students of the classroom to visualize simultaneously all the results and the manipulation of the unit, during the process, by using a projector or an electronic whiteboard.
5. Cables and Accessories, for normal operation.
6. Manuals:
- This unit is supplied with 8 manuals: Required Services, Assembly and Installation, Interface and Control Software, Starting-up, Safety, Maintenance, Calibration & Practices Manuals.
- References 1 to 6 are the main items: EG5C + EG5C/CIB + DAB + EG5C/CCSOF + Cables and Accessories + Manuals are included in the minimum supply for enabling normal and full operation.TENDER SPECIFICATIONS (for optional items)
a) Industrial configuration
7 PLC. Industrial Control using PLC (it includes PLC-PI Module plus PLC-SOF Control Software):
PLC-PI. PLC Module:
- Metallic box.
- Circuit diagram in the module front panel.
- Digital inputs (X) and Digital outputs (Y) block: 16 Digital inputs. 14 Digital outputs.
- Analog inputs block: 16 Analog inputs.
- Analog outputs block: 4 Analog outputs.
- Touch screen.
- Panasonic PLC:
- High-speed scan of 0.32 µsec. Program capacity of 32 Ksteps. High-speed counter. Multi-point PID control.
- Digital inputs/outputs and analog inputs/outputs Panasonic modules.
- EG5C/PLC-SOF. PLC Control Software:
- For this particular unit, always included with PLC supply.
- Practices to be done with PLC-PI:
- Control of the particular unit process through the control interface box without the computer.
- Visualization of all the sensors values used in the particular unit process.
- Calibration of all sensors included in the particular unit process.
- Hand on of all the actuators involved in the particular unit process.
- Realization of different experiments, in automatic way, without having in front the particular unit. (These experiments can be decided previously).
- Simulation of outside actions, in the cases do not exist hardware elements. (Example: test of complementary tanks, complementary industrial environment to the process to be studied, etc).
- PLC hardware general use.
- PLC process application for the particular unit.
- PLC structure.
- PLC inputs and outputs configuration.
- PLC configuration possibilities.
- PLC program languages.
- PLC different programming standard languages (ladder diagram (LD), structured text (ST), instructions list (IL), sequential function chart (SFC), function block diagram (FBD)).
- New configuration and development of new process.
- Hand on an established process.
- To visualize and see the results and to make comparisons with the particular unit process.
- Possibility of creating new process in relation with the particular unit.
- PLC Programming Exercises.
- Own PLC applications in accordance with teacher and student requirements.
b) Technical and Vocational Education configuration
8 EG5C/ICAI. Interactive Computer Aided Instruction Software System.
- This complete software package consists of an Instructor Software (EDIBON Classroom Manager - ECM-SOF) totally integrated with the Student Software (EDIBON Student Labsoft - ESL-SOF). Both are interconnected so that the teacher knows at any moment what is the theoretical and practical knowledge of the students.
- - ECM-SOF. EDIBON Classroom Manager (Instructor Software).
- ECM-SOF is the application that allows the Instructor to register students, manage and assign tasks for workgroups, create own content to carry out Practical Exercises, choose one of the evaluation methods to check the Student knowledge and monitor the progression related to the planned tasks for individual students, workgroups, units, etc...so the teacher can know in real time the level of understanding of any student in the classroom.
- Innovative features:
- User Data Base Management.
- Administration and assignment of Workgroup, Task and Training sessions.
- Creation and Integration of Practical Exercises and Multimedia Resources.
- Custom Design of Evaluation Methods.
- Creation and assignment of Formulas & Equations.
- Equation System Solver Engine.
- Updatable Contents.
- Report generation, User Progression Monitoring and Statistics.
- ESL-SOF. EDIBON Student Labsoft (Student Software).
- ESL-SOF is the application addressed to the Students that helps them to understand theoretical concepts by means of practical exercises and to prove their knowledge and progression by performing tests and calculations in addition to Multimedia Resources. Default planned tasks and an Open workgroup are provided by EDIBON to allow the students start working from the first session. Reports and statistics are available to know their progression at any time, as well as explanations for every exercise to reinforce the theoretically acquired technical knowledge.
- Innovative features:
- Student Log-In & Self-Registration.
- Existing Tasks checking & Monitoring.
- Default contents & scheduled tasks available to be used from the first session.
- Practical Exercises accomplishment by following the Manual provided by EDIBON.
- Evaluation Methods to prove your knowledge and progression.
- Test self-correction.
- Calculations computing and plotting.
- Equation System Solver Engine.
- User Monitoring Learning & Printable Reports.
- Multimedia-Supported auxiliary resources.
9 EG5C/FSS. Faults Simulation System.
- Faults Simulation System (FSS) is a Software package that simulates several faults in any EDIBON Computer Controlled Unit.
- The "FAULTS" mode consists in causing several faults in the unit normal operation. The student must find them and solve them.
- There are several kinds of faults that can be grouped in the following sections:
- Faults affecting the sensors measurement:
- An incorrect calibration is applied to them.
- Non-linearity.
- Faults affecting the actuators:
- Actuators channels interchange at any time during the program execution.
- Response reduction of an actuator.
- Faults in the controls execution:
- Inversion of the performance in ON/OFF controls.
- Reduction or increase of the calculated total response.
- The action of some controls is annulled.
- On/off faults:
- Several on/off faults can be included.
c) Multipost Expansions options
10 MINI ESN. EDIBON Mini Scada-Net System for being used with EDIBON Teaching Units.
- MINI ESN. EDIBON Mini Scada-Net System allows up to 30 students to work with a Teaching Unit in any laboratory, simultaneously.
- The MINI ESN system consists of the adaptation of any EDIBON Computer Controlled Unit with SCADA integrated in a local network.
- This system allows to view/control the unit remotely, from any computer integrated in the local net (in the classroom), through the main computer connected to the unit.
- Main characteristics:
- It allows up to 30 students to work simultaneously with the EDIBON Computer Controlled Unit with SCADA, connected in a local net.
- Open Control + Multicontrol + Real Time Control + Multi Student Post.
- Instructor controls and explains to all students at the same time.
- Any user/student can work doing "real time" control/multicontrol and visualisation.
- Instructor can see in the computer what any user/student is doing in the unit.
- Continuous communication between the instructor and all the users/students connected.
- Main advantages:
- It allows an easier and quicker understanding.
- This system allows you can save time and cost.
- Future expansions with more EDIBON Units.
- The system basically will consist of:
- This system is used with a Computer Controlled Unit.
- Instructor’s computer.
- Students’ computers.
- Local Network.
- Unit-Control Interface adaptation.
- Unit Software adaptation.
- Webcam.
- MINI ESN Software to control the whole system.
- Cables and accessories required for a normal operation.
DIMENSIONS AND WEIGHT
EG5C: Unit: - Dimensions: 2000 x 800 x 1550 mm. approx. (78.74 x 31.49 x 61.02 inches approx.) - Weight: 200 Kg. approx. (440.92 pounds approx.) Control-Interface Box: - Dimensions: 490 x 330 x 310 mm. approx. (19.29 x 12.99 x 12.2 inches approx.) - Weight: 10 Kg. approx. (22 pounds approx.)