| System | 💰 Initial | 💸 Annualized | 🛠️ Labor (hours) | Other Resources Used | 🤑 Revenue | ✨ Benefits | | ------------------------------------------------- | ---------- | ------------- | ------------------- | -------------------- | ---------- | ---------------------------------- | | Passive Solar Heating with Water-Filled PVC Pipes | $1,520 | $76 | 133.33 per dwelling | - | - | Efficient, low-maintenance heating | ### Assumptions - **Room Dimensions**: 12 ft x 25 ft x 8 ft. - **Outdoor Temperature Range**: 0°F to 40°F. - **Heating Requirements**: 4,641 BTU/hour to maintain 65°F at 0°F outside. - **Number of Pipes per Dwelling**: 19 vertically mounted 8-ft pipes. - **Number of Dwellings**: 400. - **Insolation Efficiency**: 50% due to reflection and other losses. - **Thermal Mass Material**: Water with a specific heat capacity of 1 BTU/lb·°F. - **Solar Exposure**: Direct clerestory window exposure. - **Pipe Dimensions**: 6 inches in diameter, 8 ft in height. - **Thermal Efficiency**: No supplemental insulation required due to indoor placement and earthen walls. #### Labor .596 per -> 238 Hours | Task | Hours/Dwelling | amortized | Notes | | --------------- | -------------- | --------- | ---------------------------------------------------- | | Pipe Production | 3.17 | .064 | 10 min/pipe Includes cutting, capping, and painting. | | Installation | 1.58 | .032 | 5 min/pipe for 19 pipes | | maintenance | .5 | .5 | 15 min bi-annual inspection | | **Total** | **4.75** | .596 | Per dwelling installation and production. | #### Operating Costs $5 per -> $2k | Component | Annual Cost ($) | Justification | | --------------------- | --------------- | ------------------------------------------------ | | Maintenance Supplies | $5 | Includes periodic inspections and minor repairs. | | **Total Annual Cost** | **$5** | Per dwelling maintenance costs. | #### Initial Costs $1,520 per -> $30.4k | Component | Initial Cost/Dwelling ($) | Lifespan (years) | Amortized Cost/Year ($) | Justification | |--------------------|--------------------------|------------------|-------------------------|--------------------------------------| | PVC Pipes (19) | $760 | 50 | $15.20 | 6-inch diameter, 8-ft tall pipes. | | End Caps | $380 | 50 | $7.60 | Two per pipe. | | Mounting Brackets | $285 | 50 | $5.70 | Secures pipes to walls. | | Paint | $95 | 10 | $9.50 | UV-resistant black paint. | | **Total** | **$1,520** | - | **$38/year** | Per dwelling amortized cost. | #### Per Pipe - Water Amount: 11.72 gallons - Water Weight : 97.74 lb - Total Assembled Weight: 108 - Specific Heat Capacity of Water: 1 BTU/lb·°F - thermal efficiency: 50% - High-quality matte black paint: 90% absorption - ... - pipe surface area: 12.57 ft² = 1.168 m² - solar insolation on heavy overcast winter day: 1 kWh/m²/day = 3,412 BTU/m²/day - ~2K BTU/day #### System Output | Outside Temp (°F) | Insolation (kWh/m²/day) | Total Heat Gain (BTU/day) | Net Heat Gain (BTU/hour) | Estimated Room Temp (°F) | |--------------------|------------------------|--------------------------|--------------------------|--------------------------| | 0 | 0.5 | 18,924 | +644 | 65.14 | | 0 | 1.0 | 37,848 | +2,144 | 77.10 | | 0 | 2.0 | 75,696 | +6,187 | 106.23 | | 20 | 0.5 | 18,924 | +1,284 | 68.65 | | 20 | 1.0 | 37,848 | +2,784 | 80.61 | | 20 | 2.0 | 75,696 | +6,827 | 109.74 | | 40 | 0.5 | 18,924 | +2,084 | 74.92 | | 40 | 1.0 | 37,848 | +3,584 | 86.89 | | 40 | 2.0 | 75,696 | +7,627 | 115.02 | #### Benefits - **Cost-Effective**: Low initial investment and zero operational costs. - **Eco-Friendly**: Utilizes passive solar energy. - **Long Lifespan**: Minimal wear and tear with proper maintenance. - **Synergy with Earthen Walls**: Heat transfer complements thermal mass properties. - **Flexible Mitigation**: Overheating can be addressed through ventilation. #### Considerations - **Freeze Risk**: Mitigate in extreme climates with antifreeze. - **Overheating Potential**: Ventilation or shading adjustments as needed. - **UV Degradation**: Use quality paint for longevity.