Health Clinic – Las Mercedes, Honduras

Janelle Barth, Stephanie Chang, Greer Mackebee, Walter Li

Structural Design

Current Footprint – 60’x80’

Notes – Footprint/Foundation

• 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

Current Floor Plan

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)

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

Next steps

• Determine optimal base depth for cut and fill• Design roof structure• Determine loads• Find North for solar panel/roof design• Convert to metric• Door/Window Design

Standard Solar Powered System Design

Our System6 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

Location of Load componets

Battery /Charge Controller/InverterStorage

13 watt lights

30 watt lights

Vaccine Fridge

13 watt lights

13 watt lights/Laptops

Calculations for Total Power Consumption• Total power consumption =

Σ Appliance Wattage rating * Hours used/day*Total number of Appliance

Appliance Watts Hours /Day Quantity Total WattsSunfrost Vaccine Fridge

54 7.5 1 380

Thin-Lite 30 watts Fluorescent lights

30 6 3 540

Thin-Lite 13 watts Fluorescent lights

13 6 8 624

Laptops 8 4 3 96UV filter 30 4 1 120Total 1760

Sizing the solar panel

Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec

4.39 5.26 5.97 6.14 5.60 5.48 5.56 5.65 5.24 4.64 4.31 4.13

• 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]• 75 watt panels = 75/1000 = 0.075 % efficiency• At lowest solar isolation of 4.13 kWh/m2/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 minimumTo compensate for cloudy days and system losses, 7-8 solar panels may be necessary

Monthly Averaged Insolation Incident On A Horizontal Surface (kWh/m2/day)

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 if discharged at lower percentages

• This is a graph comparing cycles of discharge vs. discharge %

• 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 hrsThis 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.

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.

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.

Choosing the laptop • Netbooks are very power efficient• The Dell mini 9 makes it 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

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) 3° C (38° F) 3° C (38° F)

Freezer Temperature -11° C (12° F) -9° C (15° F) -5° C (23° F)

• 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

Water/Sewage

Manning's Eqn for Sewage System:

• Determination of Pipe Angle• V=(k/n)*R^(2/3)*S^(1/2)

PVC R (in)= 2

V (ft/s) k n Rh (ft) S (ft/ft) S (degrees)2 1.486 0.009 1 0.02422611 1.388757919

2.5 1.486 0.009 1 0.037853297 2.1699342483 1.486 0.009 1 0.054508748 3.124705318

3.5 1.486 0.009 1 0.074192463 4.2530711274 1.486 0.009 1 0.096904441 5.555031676

4.5 1.486 0.009 1 0.122644684 7.0305869655 1.486 0.009 1 0.15141319 8.679736993

5.5 1.486 0.009 1 0.18320996 10.502481766 1.486 0.009 1 0.218034993 12.49882127

6.5 1.486 0.009 1 0.255888291 14.668755527 1.486 0.009 1 0.296769852 17.01228451

7.5 1.486 0.009 1 0.340679677 19.529408238 1.486 0.009 1 0.387617766 22.2201267

8.5 1.486 0.009 1 0.437584118 25.084439919 1.486 0.009 1 0.490578735 28.12234786

9.5 1.486 0.009 1 0.546601615 31.3338505510 1.486 0.009 1 0.605652759 34.71894797

Range of angles for construction:1.39 to 34.72

Soil Data

Infiltration Rates

Calculations

• Assumptions: – pan required 2 L/flush– latrine will serve an average of 15 people/year– 2 L/flush is used for anal cleansing– soil infiltration rate is 30 L/(m2*day) – corresponds to “sandy loam,

loams” soil type– 1 urination/(person*day)– deep water table– 2 flushes/(person*day)– bricks are 4 in by 4 in by 8 in (101.6 mm by 101.6 mm by 203.2 mm)

Calculations

• q = wastewater flow per person• q = Nf ( vw + vc ) + vf + ( a Nu vw ) + vu

• q = (2 flush/day)(2 L/flush + 2 L/flush) + (0.3 L/day + 1.2 L/day) + [(1)(1 flush/day)(2 L/flush)]

• q = 11.5 L/day

• Q = total wastewater flow• Q = p * q• Q = (15 people)(11.5 L/day) = 172.5 L/day

Calculations

• vs = solids storage volume

• vs = (25 L/(person*year))(10-3 m3/L)(2 year)(15 people) = 0.75 m3

• Infiltration area required = Q / soil infiltration rate = 172.5 L/day / 30 L/(m2*day) = 5.75 m2

• 0.75 m3 = (π)(d2/4)(h), where d is the internal pit diameter and h is the effective depth

• h = [(4)(0.75)] / [(π)(d2)]

Calculations

• Outside pit diameter = D = d + 2(block width) = d + 2(0.1016) = d + 0.2032

• Infiltration area = Ai = (D)(h)(π) = (d + 0.2032)*[(4*0.75)/(d2*π)]*(π) = (3d + 0.6096)/d2

• Setting Ai equal to 5.75 m2, d = 0.67 m.

• Therefore, effective depth (h) = 2.127 m

• Adding the 0.5 m free space necessary at the top of the cylinder, the actual height (H) ≈ 2.6 m

PRELIMINARY DIMENSIONS:

• d = 0.67 m• D = 0.875 m• H = 2.6 m

0.875 m

2.6 m

V = 1.56 m2

Brick lining

Pit

0.1016 m

0.1016 m

0.2032 m

Slab

20 mm 15°

SUPERSTRUCTURE

TRAP

1.2 m

1.2

m

2.5

m

PAN

PIT

VALVE