Energy in Tropical Climates a practical approach CEE-Engineering, Korenstraat 10, 3010 Kessel-Lo, Leuven, Belgium.

Energy in Tropical Climates

a practical approach

CEE-Engineering, Korenstraat 10, 3010 Kessel-Lo, Leuven, Belgium

Overview1. Basic elements

• Energy• Types and sources• Generation – conversion – transport – storage – consommation

2. Tropical-specific situations• Micro-climate• Independency• People

3. The Field Hospital• Design• Maintenance• Tropical Toolkit

4. Questions


Basic Elements1. Energy

• Greek: ενεργός => “active, working”• Energy = the capacity to do work

• Mechanical interpretation


Energy[Joule]

Work[Joule]

Power[Watt]

Basic Elements1. Energy

• Greek: ενεργός => “active, working”• Energy = the capacity to do work

• Electrical interpretation


Energy[Joule]

Work[Joule]

Power[Watt]

Basic Elements2. Types and sources of Energy

• Mechanical energy– Movement off mass: waterstream, rotating axis,…– Loaded spring– Compressed air

• Thermal energy– Heat or cold– Boiler– Heat pump– Refridgerator

• Electrical energy– Movement of elektrons (ampère)– Battery/generator/dynamo/…

• Chemical energy– Endothermal/exothermal reactions– Reduction/oxidation reactions– Battery

• Nuclear EnergyCEE-Engineering, Korenstraat 10, 3010 Kessel-Lo, Leuven, Belgium

Energy[Joule]

Power[Watt]

Work[Joule]

Basic Elements3. Generation – conversion – transport – storage -

consommation

• Consommation - type– Heat / cold : refridgeration, air-conditioning– Electricity: laptops, microscopes, lights,…– …

• Generation - type– Mechanical: rotating axis (wind, water-stream)– Fysico-Chemical: Acid solution, Solar radiation– …

• Conversion Performance– From one type to another– Within the same type (for example high voltage => low voltage)– Always loss of energy => minimize amount of conversions


Basic Elements3. Generation – conversion – transport – storage -

consommation

• Transport of energy– Heat / cold : piping-systems– Electricity: wires and cables– …

• Storage of energy– Difficult– Not possible without losses– E.g.: battery systems (long term storage), fly wheel (short term storage)


Tropical-specific situations1. Micro-Climate

• Extreme temperatures: up to 40 °C is normal

» Cooling of computers/engines/generators more difficult» Cold chain for medicines is must

• Extreme humidity: up to 100% relative humidity

» Heavy corrosion problems» Short circuits because of condensate

• Extreme Lightening

» Tension peakes damages elektrical equipment

• Extreme Rain

» Damages ill-protected electrical circuits


Tropical-specific situations2. lndependancy

– No or old Local area energy-systems

– Very insulated areas => transport-cost

– Long-distance transport => spare-parts!

3. Local People– Very pore

– Understanding attitude is must

basic toolkit, spare-parts and back-up systems necessary


The Field Hospital


The Field Hospital1. Design

– Consommation detail– Generation possibilities– Back up systems– Protection of the complete system– Human protection

2. Maintenance

– Small maintenance– Big maintenance– Spare parts


The Field Hospital1. Design: Consommation detail

• Office: 2 normal rooms

– Light bulbs: 4 x 50 W = 200 W – TL-lights (give brighter light): 4 x 20 W = 80 W– Computers: 2 x 400 W = 800 W– Laptops: 3 x 75 W = 225 W– Air-conditioning: 1 x 1.8 kW = 1.8 kW– Ventilators: 2 x 60 W = 120 W– Printers: 1 x 100 Watt

=> TOTAL = 3.3 kW



• Lab (1 room)– Light bulbs: 2 x 50 W = 100 W – TL-lights (give brighter light): 2 x 20 W = 40 W– Computers: 1 x 400 W = 400 W– Air-conditioning: 1 x 1.8 kW = 1.8 kW– Microscopes: 2 x 50 W = 100 W– Sterilisator / autoclaves: 2 x 1.4 kW– Refridgerator (6°C): 1 x 200W– Fridge (- 20 °C): 1 x 350 W

=> TOTAL = 5.8 kW



• Surgery (1 room)– Light bulbs: 2 x 50 W = 100 W – TL-lights (give brighter light): 2 x 20 W = 40 W– Operating Lamp: 2 x 80 W = 160 W– Air-conditioning: 2 x 1.8 kW = 3.6 kW– Aspirator/Oxygen-equipment: 300W

=> TOTAL = 4.2 kW


The Field Hospital1. Design: Consommation detail - Overview


place item consommation urgency

[W] [W]Office light 280 0 computers 800 0 laptops 225 0 Air-conditioning 1800 0 Ventilators 120 0

Printers 100 0Lab light 140 140 computers 400 0 Air-conditioning 1800 0 microscopes 100 0 sterilisators/autoclaves 1400 700 refridgerator 200

fridge 350 Surgery light 140 140 operation lamp 160 80 Air-conditioning 3600 1800

aspirator/O²-equipment 300 300

SUM 11915 3160

The Field Hospital1. Design: Generation Possibilities

• Demands = Electrical energy for equipment– Tension = 230 V– 2 phazes– Alternating current (AC)– 50 Hz– Power determined according to previous information



• Solar Systems - characteristics– The panel: photovoltaic cells (silicium semi-conductant)– Solar energy is converted into electrical energy– The power-generation: Direct-current (DC)– Tension generation = 12 V– Sun-dependent– Orientation-dependent– Expensive– Generation: 125 Wp / m²



• Solar Systems

12V - Direct current Invertor (12V/230V) Consommation 125 W >125 W <125 W

REMINDER: EVERY Equipment in the conversion chain, must be able to transport the power.

PROBLEM: Sun does not shine when we would like to, even in tropical climates



• Solar Systems with integrated battery-system

12V - Direct current Charger/Invertor (12V/230V) Consommation 125 W >125 W <125 W

Battery: 12 V, 120 Ah


http://dfarrell.trustpass.alibaba.com/product/11383197/Solar_Inverter_Charger.html


• Generator systems

– Motor/EngineFrom chemical energy (diesel) into mechanical energy

– Rotating axis

– Generator/Alternator



• Generator systems: Types

– Mono-phaze (2 cables output)




– Tri-phaze (4 cables output)




– Monophaze Tri-phaze

=> Tri-phaze better for tropical climates because of lower rotationspeed of the axis. (lower wear and tear)


Poles RPM at 50Hz RPM at 60Hz

2 3000 3600

4 1500 1800


• Generator systems: characteristics

– Power-output in kVA e.g. 15 kVA

– Performance in cosinus-phi e.g. 0.8

– Mono-phaze or 3: Power calculation is different!


The Field Hospital1. Design: Generation Possibilities: CONCLUSIONS

• Combination of solar and generator systems

– Smaller power demand (lights, portable pc) with solar panels

=> +- 6 m² is necessary with 3 batteries of 120 Ah, 12V

– Higher powerdemands (cooling, sterilisation) with generator

=> Rest with 3-phaze generator of 10 kVA (3.5 L/h diesel)

– Emergency-power (in case of surgery)

=> 3-phaze generator of 5 kVA (2.5L/h diesel)CEE-Engineering, Korenstraat 10, 3010 Kessel-Lo, Leuven, Belgium


• Extras: depending on local opportunities

– Micro-hydro central (5 up to 100 kW)



• Extras: depending on local opportunities

– Vertical-axis wind mill (300W up to 20 kW)=> minimum wind-speed of 8 km/h necessary!


The Field Hospital1. Design: Back-up system

• UPS

– Uninterruptible Power Supply

– Based on batteries (loaded) and regulating electronics with detection system

– Characterized by maximal power (kW) and maximum stand-alone run time (usually 5 up to 10 minutes)



• UPS

– Most reliable type: double-conversion method

Protects at same time for powerdips, tensionspikes, frequency-modulation …

Double energy-conversion = losses (up to 10 %)CEE-Engineering, Korenstraat 10, 3010 Kessel-Lo, Leuven, Belgium

http://upload.wikimedia.org/wikipedia/commons/3/3a/Double_conversion_UPSII.png


• UPS

– Alternative types: off-line UPS

Start time 2 ms after feeding-disturbance Only reliable when current falls out


http://upload.wikimedia.org/wikipedia/commons/b/b7/Off_line_ups.png


• UPS

– Alternative types: line-interactive UPS

Incoming power is filtered Not as much certainty as double conversion UPS


http://upload.wikimedia.org/wikipedia/commons/c/c8/Line_interactive_UPSII.png

The Field Hospital1. Design: Protection of equipment and humans

• Tension-disturbance

– Lightening– Failure of alternator– After start of heavy electric equipment

UPS double conversion type AVR-technologie (Automatic Voltage Regulation)

DUST-FREECEE-Engineering, Korenstraat 10, 3010 Kessel-Lo, Leuven, Belgium


• Current-protection

– Lightening– Failure of alternator– During start of heavy electric equipment

On every line (phaze and zero-line) Don’t take it out! TT 250/62mA TT250/1.6A

DUST-FREECEE-Engineering, Korenstraat 10, 3010 Kessel-Lo, Leuven, Belgium


• Earthening of equipment

– To protect the steel casing/chassis to get loaded because of elektromagnetic coupling or leakage current

– Protects against possible elektroshocks. VERY IMPORTANT FOR WEAK PATIENTS



• Earthening of equipment

– Connection of casing with the earth

– Wires have to be big enough, otherwise no protection



• Differential current-switch

– Human elektro-shock– Loading of other tool with tension (static)

=> On every phaze !CEE-Engineering, Korenstraat 10, 3010 Kessel-Lo, Leuven, Belgium


• Lightening – Faraday’s cage

– Static tension in clouths above earth– Break through of the current in the atmosphere into earth– Looks for high peaks


The Field Hospital2. Maintenance: Strugle against DUST, HEAT and SUN

• Electric devices/networks

– Keep the performance of the equipment high– Keep clean from dust– Check protection switches by means of multimeter– Every 6 months, complete electric circuit has to be checked (connections

screwed, insulation of wiring, ..)– Keep the consommation in balance with the production– Check on regular basis battery-quality– Check the UPS-systems


The Field Hospital2. Maintenance: Strugle against DUST, HEAT and SUN

• Mechanics

– Keep clean (cooling fans of motors, electric connections)– Exhaust gases of motors must be able to quit the place– Steel moving parts: clean and grease– Rubber bands: check for deterioration and replace in time– Transparancy-Test the fuel in a glass before consuming it


The Field Hospital3. Tropical toolkit

– Multimeter

– Basic tools



– Spare-protection

– Spare wiring/contacts



– Oil/grease

– Rubber


Questions ?


Energy in Tropical Climates a practical approach CEE-Engineering, Korenstraat 10, 3010 Kessel-Lo, Leuven, Belgium.

Documents

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