Solar, wind and fuel cell rigs teach relationships very well and absolute numbers very badly. What each one is actually good for, why the lamp bank is a feature rather than a compromise, and the three costs that appear after commissioning.
Renewable energy trainers photograph well, which is part of the problem. A department sees a wheeled blue frame with a solar panel and a bank of lamps, or a wind turbine in a stainless tunnel, and reads it as a small version of the real thing. It is not. It is an instrumented demonstration of a relationship, and it is excellent at that and poor at almost everything else. Knowing which is which before the purchase order goes out saves a laboratory a great deal of quiet disappointment.
Photovoltaic units are the strongest of the family, because the physics they demonstrate genuinely does hold at laboratory scale. The EDIBON EESFB carries its own solar simulator, so a class plots the current against voltage and power against voltage curves, reads open circuit voltage and short circuit current, and sees what happens to both as the cell warms. That last one is the lesson worth the money in this climate: students who have watched output fall as a panel heats stop being surprised by a Bangladeshi rooftop's summer yield. MINI-EESF extends the same work into battery charging, DC loads, AC loads through an inverter and injection into the grid, and AEL-SAPV does the stand-alone case with an orientable panel and a lamp set.
The grid connected units are a different subject wearing the same clothes. AEL-PHVG replaces the panel with a programmable power supply that emulates an array, feeding a user programmable three phase grid inverter, and AEL-PHVGC adds SCADA for dynamic control of injected active power, local voltage control at network nodes and battery storage through hybrid inverters. AEL-PHIP compares island operation with parallel operation on the national grid. None of these teach much about solar cells. All of them teach power electronics and grid interaction, which is what a graduate joining a Bangladeshi EPC or a utility will actually be doing.
Wind units teach one thing extremely well and one thing badly. The thing they teach well is the shape of the power coefficient curve: WETFC is a gearless unit with adjustable rotor blades and a variable speed generator, built specifically so students can plot the power coefficient against tip speed ratio, blade pitch angle and yaw angle. The relationship is real. The numbers are not transferable to a full size machine, and a student who leaves believing otherwise has learned something wrong. WEDTA takes a different and arguably more useful angle, instrumenting the drive train from rotor simulation through gearing to generator with torque and speed sensors on both sides.
The electrical wind trainers are again a separate subject. AEL-WPT drives a permanent magnet synchronous generator and follows the energy through rectifier, regulator, battery and load. AEL-WPPI uses squirrel cage induction generators injecting into the network through a frequency converter so sub-synchronous, synchronous and super-synchronous operation can be compared. AEL-WPP is a doubly fed induction generator with SCADA that will reproduce a user defined wind curve and inject voltage dips to see how the machine rides through. These sit naturally alongside the electrical machines and power systems laboratory rather than in a renewable energy corner.
Fuel cell units teach the polarisation curve, and that is a genuinely difficult concept to convey any other way. EC5B is the teaching scale proton exchange membrane unit for power density, polarisation and efficiency, EC6B is the higher power version with a load regulation system, and AEL-FCLL frames the same stack as an energy application with protection and electronic loading. What they do not teach is anything about hydrogen at industrial scale, and they carry an operating burden discussed below.
Solar thermal is the quietly underrated part of the range in a country with this much sunshine and this much demand for process hot water. EEST heats water by thermosiphon or pumped circulation with its own simulator, a flat collector and an accumulator tank, so collector efficiency comes out as a measured number. ECESC is a parabolic trough on a mobile base with interchangeable collectors for concentration ratio and optical and geometrical losses. HTVC closes the loop by running a bench top Rankine cycle with a refrigerant working fluid from a hot water source, which is how a class sees solar heat become shaft power.
The most common objection to these rigs is that they run on artificial light rather than sunshine. In a teaching laboratory that objection is backwards. An indoor light source makes the experiment repeatable, gives every group in the class the same conditions, and means the practical runs in the third week of the monsoon when it has rained for nine days. A rig that only works on a clear roof is a rig that misses half the semester.
What matters is being honest about what a lamp bank is for. It sets a light level and holds it. It does not reproduce the solar spectrum or the irradiance uniformity that a module efficiency measurement requires, and no efficiency figure obtained under a teaching lamp bank should ever leave the laboratory as a performance claim.
If the department's ambition is measurement rather than teaching, that is a different purchase entirely: a classified solar simulator, steady state LED or xenon flash, with the uniformity and spectral match that the international test standards demand, and a temperature controlled test plane if temperature coefficients are wanted. Vvon supplies the EternalSun range for exactly this, and the distinction is covered in the article on precision PV testing. Departments get into trouble when they buy a teaching trainer and then accept module testing work with it.
The same warning applies to the programmable supplies that emulate a PV array. They are a good way to make a repeatable array characteristic for inverter work, and they are covered in choosing a programmable DC power supply for battery and PV testing. They are not a panel, and any conclusion about panel behaviour drawn from one belongs to the emulator's model.
These are the ones that turn a working laboratory into a room of covered equipment, and all three are visible at quotation stage if somebody asks.
Hydrogen. A fuel cell rig needs a hydrogen supply. A cylinder brings storage, a regulator, ventilation, leak detection, a permission conversation with the university's safety office and a supplier relationship that has to survive staff changes. The alternative is an electrolyser: EDILAB-ELEC1 produces hydrogen at a small rate for exactly this reason, and EDILAB-ELEC2 at a higher rate with the gas collected, dried and delivered at a displayed pressure. Both run on deionised or distilled water only, which means the laboratory now needs a water purification arrangement as well. Whichever route is chosen, fixed hydrogen detection in the room is not optional, and where it should be mounted is not obvious: see designing a laboratory gas detection system. A department that cannot commit to all of this should not buy the fuel cell rig, and saying so at planning stage is cheaper than saying it afterwards.
Software and the computer. Computer controlled units come with SCADA, and SCADA needs a machine to run on. One PC per unit is the default and it does not scale. EDIBON SCADA-Net puts the units on a local network so any unit can be driven or watched from any workstation, which is the right architecture for a laboratory with several rigs and shortens the practical because groups are not queuing. Ask three questions before signing: what operating system the software is supported on, what happens when the university's IT policy updates that operating system, and whether the courseware and the fault simulation system are included or are separate items. The answer to the last one is usually separate.
Consumables and wear. Simulator lamps have a life. Membrane stacks degrade with use and with contamination. Batteries on a storage bench are consumables measured in cycles, and AEL-BESTA exists to characterise exactly that, which means its own test articles wear out by design. None of these are large sums. All of them require a recurring budget line, and a laboratory without one stops running the practicals that consume anything. That is the whole argument in who maintains a teaching laboratory after the project ends.
Most Bangladeshi departments equipping a renewable energy laboratory are doing it once. If that is the situation, this is the order we would argue for, and it is deliberately weighted towards what graduates here are actually hired to do.
One more point that is easy to miss in a tender. The AEL series units are built from components that are sold on the open market rather than from purpose made teaching parts. That matters twice: a student who has wired a real inverter and a real protection relay recognises them on site, and a technician who needs a replacement can source one locally. When comparing two quotations at similar prices, ask which one is made of parts that exist outside the catalogue.