1. Health Clinic – Las Mercedes, Honduras Janelle Barth, Stephanie Chang, Greer Mackebee, Walter Li

2. Structural Design

3. Current Footprint – 60’x80’

4. Notes - Footprint Cut and fill enough to fill hole without extra soil left over Strip footing Soil – mostly clay Minimum 5’ from boundaries Allow space for latrine

5. Current Floor Plan

6. Notes - Plan Use spaces on exterior – optimize sunlight Kitchen on right – minimize distance to latrine Sink near shower – minimize piping Delivery near kitchen for access to hot water (as opposed to being connected to Recovery) 8’ hallways for easy maneuverability (i.e. moving beds, etc.) 2 entrances – main (to waiting area) and kitchen (to load supplies/easy access to latrine)

7. Other Notes Roof – corrugated tin and corrugated translucent material (optimize sunlight) 10’ walls Materials: CMU (8”x8”x16”), rebar, poured concrete base, wood beams for roof support system Sketch-up Model

8. Next steps Convert to metric Determine optimal base depth for cut and fill Design roof structure Determine loads Find North for solar panel/roof design

9. Standard Solar Powered System Design

10. Our System 6 x Isofoton 75 Watt solar panel Xantrex 40 amp + 30 amp charge controller 12 V 115 amp hr Nautlius deep cycle battery WyckomarUV-250 UV water filters 3 x Low powered laptops 600 watt power inverter Sunfrost Vaccine Refrigerator Thin-Lite DC fluorescent lights

11. Location of Load componets Battery /Charge Controller/Inverter Storage 13 watt lights 30 watt lights Vaccine Fridge 13 watt lights 13 watt lights/Laptops

12. Calculations for Total Power Consumption Total power consumption = Σ Appliance Wattage rating * Hours used/day *Total number of Appliance ApplianceWattsHours /DayQuantityTotal Watts Sunfrost Vaccine Fridge 547.51 380 Thin-Lite 30 watts Fluorescent lights 3063540 Thin-Lite 13 watts Fluorescent lights 1368624 Laptops 84396 UV filter 3041120 Total 1760

13. Sizing the solar panel JanFebMarAprMayJunJulAugSeptOctNovDec 4.395.265.976.145.605.485.565.655.244.644.314.13 Solar panels are tested at 1000 W/m at 25 ⁰ C The solar panel should be able provide the required wattage at both the summer and winter hours For temperature ranges between 25⁰ and 40⁰ C, the power output is close to linear http://www.reuk.co.uk/Effect-of-Temperature-on-Solar-Panels.htm] http://www.reuk.co.uk/Effect-of-Temperature-on-Solar-Panels.htm 75 watt panels = 75/1000 = 0.075 % efficiency At lowest solar isolation of 4.13 kWh/m 2 /day produces 4.13 * 0.075 = 310 watts per panel Total number of panels needed = Total power consumption/watts per panel = 1760/310 = 5.6 panels ≈ 6 panels minimum To compensate for cloudy days and system losses, 7-8 solar panels may be necessary Monthly Averaged Insolation Incident On A Horizontal Surface (kWh/m 2 /day)

14. Sizing the battery system Nautilius Deep cycle are rated at 115 amp hrs and 12 volts for a total of 1380 watt hrs Although deep cycles can be discharged to 80 %, they have a much larger cycles is discharged at lower percentages This is a graph comparing cycles of discharge vs. discharge %

15. We want both a long lifespan for our system and also the power the solar fridge for several days if there are consecutive cloudy or rainy days/solar panel malfunctions Aiming for optimally 20 % discharge rate, each battery would be able to provide 0.2* 1380 = 276 Watt hours Number of batteries needed = Total wattage/ Watt hour per battery = 1760 /276 = 6.3 ≈ 7 batteries After 2 days, total watt hours available = (0.8) 2 * 7 * 1380 = 6048 watt hrs This can still provide 16 days of the vaccine fridge running by itself At 20% discharge rate, the batteries will last for 2500 cycles. Assuming 1 cycle per day for each battery = 2500/365 = 6.8 years before replacement. This will probably be 6 years, due to some over discharging.

16. Sizing the Charge controller The charge controller prevents the batteries from overcharging/discharging, maintains the rates of charging/discharging, keeps power from batteries from going back into solar panels, and also converts the variable voltage from the solar panels into a steady voltage For 75 watt solar panel, should be at 75 watts/12 volts = 6 amps, however this current can spike up to 8 amps. For our solar system, 7 * 8 amps = 56 amps. Thus we could use two charger controllers, a 40 amp and a 30 amp charge controller.

17. Sizing the Inverter A 600 watt system will have enough capacity to power 5 amp tools, fans, and also our needs for a water filter, and laptops. The water filter = 30 watts 3 laptops total = 24 watts The 600 watt system will exceed our daily needs but will allow greater expansion of AC appliances.

18. Choosing the laptop Netbooks are very power efficient The Dell mini 9 makes if easy to upgrade RAM and hard drive The solid-state hard drive is less likely to fail Linux drive Operating System can be re-installed and rebooted from a USB drive, and thus making system recovery very easy

19. Choosing the Vaccine Fridge Sunfrost energy specifications Energy Consumption (12 volt) making 2.2 kg ice/day.38 kWh/day @ 32° C (90° F) Running Current: 4.5 amps for 12 volt system, 2.3 amps for 24 volt system Starting Current: 15 amps for 12 volt system, 7.5 amps for 24 volt system Room Temperature 21° C (70° F)32° C (90° F)43° C (110° F) Refrigerator Temperature 3° C (38° F) Freezer Temperature -11° C (12° F)-9° C (15° F)-5° C (23° F)

20. The Sunfrost Fridge: – has been approved by the World Health Organization – is very power efficient – can maintain a fridge temperature of 3° C at a large range of temperatures