| system | initial cost ($ + hrs) / unit | annualized cost ($ + hrs) / unit | sqft building | acre land | revenue | market cost | benefits | | ------------------------------------ | ----------------------------- | -------------------------------- | ------------- | --------- | ------- | ------------- | ------------------------------------------------------------------------------------------------- | | Cold Water Storage System (Salvaged) | $845 + 400 hrs | $348 + 102 hrs | 16 sqft | 0 | $0 | $5,000-10,499 | Health benefits from cold plunge therapy, energy efficiency, customized solution, waste reduction | - This system trades additional labor (both initial and ongoing) for significant cost savings. The amortized cost per cold plunge is approximately 41% lower than with [[cold bath reservoir - diy - new components]], but requires community members with technical skills in refrigeration, plumbing, and electronics. ```dv dv.paragraph(("https://jimr.fyi/" + dv.currentFilePath.replace(/\.md$/, "").replace(/ /g, "+"))) ``` #### Assumptions - System provides near-freezing water (35°F) to residential bathtub - Non-pressurized design with 120-150 gallon capacity - Insulated utility room (4' x 4' x 6') utilizing salvaged materials - Daily use scenario (one cold plunge per day) - Operating schedule: 24/7 with automated temperature maintenance - Internal resource utilization per year: - Electricity: ~150 kWh (slightly higher due to less efficient salvaged chiller) - Water: ~18,250 gallons (assuming 50 gallons per daily use) - Additional 100 hours labor compared to new components due to sourcing, testing and adapting salvaged parts #### Market Solutions $3,650-6,650/year - Commercial cold plunge tubs: $3,000-10,499 initial cost - High-end commercial products (The Plunge, Sun Home Cold Plunge Pro): $5,000-10,499 - Operating costs: $365/year for maintenance supplies - Budget options (stock tank with ice): $100-250 initial + $3,650-11,680/year for daily ice #### Labor 40 Hours/year | task | hours/year | notes | | ------------------------------ | ---------- | ------------------------------------------------------------- | | Weekly temperature check | 8.7 | 10 minutes per week | | Monthly leak inspection | 6 | 30 minutes per month (more frequent with salvaged components) | | Quarterly cleaning | 8 | 2 hours per quarter | | Annual maintenance | 12 | Additional time for maintenance of used components | | Periodic component replacement | 5.3 | Replacing worn salvaged parts as needed | | total labor (hours) | 40 | Higher maintenance needs for salvaged system | #### Operating Costs $200/year | component | external cost ($) | notes | | ------------------- | ----------------- | ----------------------------------------------------------- | | Electricity | $150 | ~$12.50/month (slightly higher with less efficient chiller) | | Water | $80 | Municipal water for filling/refilling | | Filter replacements | $30 | DIY filter media replacements | | Cleaning supplies | $40 | Basic sanitizers and cleaning agents | | Misc. maintenance | $0 | Using salvaged replacement parts | | total annual cost | $200 | | #### Initial Costs $845 + 400 hrs -> $148 + 62 hrs/year | Component | Initial Cost ($ + hrs) | Lifespan (Years) | Amortized Cost/Year ($ + hrs) | Justification | | ------------------------- | ---------------------- | ---------------- | ----------------------------- | -------------------------------------------------- | | Utility Room Construction | $120 + 100 | 15 | $8 + 6.7 | Salvaged insulation and lumber | | Water Storage Tank | $125 + 60 | 10 | $12.5 + 6 | Used food-grade container | | Plumbing Components | $100 + 80 | 7 | $14.3 + 11.4 | Mix of salvaged parts with new critical components | | Cooling System | $400 + 120 | 5 | $80 + 24 | Refurbished commercial refrigeration unit | | Monitoring & Safety | $100 + 40 | 3 | $33.3 + 13.3 | DIY sensor system with some new components | | total initial cost | $845 + 400 | - | $148 + 62 | | #### Salvaged/Used Components List ##### Utility Room Construction ($120) - Salvaged rigid insulation from commercial building demolition: $0 (100 sqft) - Reclaimed lumber from pallets/demolition: $0 - Used 6-mil poly vapor barrier (partial rolls from construction sites): $15 - Recycled denim insulation (from habitat for humanity ReStore): $75 - Spray foam from partial cans (community collection): $0 - Salvaged door from old refrigerator: $0 - Weather stripping and tape: $30 (new) ##### Water Storage Tank ($125) - Used food-grade IBC tote (sanitized): $100 - Salvaged bulkhead fittings from decommissioned aquaponics system: $0 - New gaskets and seals: $25 ##### Plumbing Components ($100) - Salvaged copper pipe and fittings: $0 - Repurposed PEX from renovation project: $0 - Toilet float valve (new): $15 - Backflow preventer (new): $40 - Salvaged diverter valve from bathroom remodel: $0 - Used pipe insulation: $0 - New compression fittings: $45 ##### Cooling System ($400) - Refurbished beverage cooler compressor: $300 - Salvaged heat exchanger coil from old refrigerator: $0 - Used aquarium pump from classified ads: $25 - Salvaged relay and electrical components: $0 - Copper tubing for refrigerant: $35 - Refrigerant recharge: $40 ##### Monitoring & Safety ($100) - Repurposed aquarium temperature controller: $0 - Arduino-based control system (partially new components): $25 - Salvaged float switches: $0 - Used leak detectors: $30 - DIY automatic shutoff system (mix of new/used parts): $45 #### Time Estimates For Assembling Components 1. **Sourcing time**: 40-50 hours - Visiting salvage yards, ReStores, and online marketplaces - Coordinating pickups from demolition sites - Networking with local businesses for food-grade containers - Attending auctions for refrigeration equipment 2. **Testing and evaluation**: 20-25 hours - Pressure testing salvaged plumbing components - Testing used pumps and refrigeration units - Evaluating insulation R-values - Checking for contamination in food-grade containers 3. **Modification and adaptation**: 25-30 hours - Customizing salvaged parts to work together - Modifying the refrigeration system - Building control systems from repurposed components - Creating compatible connections between dissimilar components 4. **Documentation**: 5-10 hours - Documenting component origins and specifications - Creating detailed system diagrams for future maintenance - Recording testing results for each salvaged component #### System Outputs | Output Type | Daily Units | Annual Units | Internal Cost ($/unit) | Internal Cost (hrs/unit) | Notes | | ---------------- | ----------- | ------------ | ---------------------- | ------------------------ | ---------------------- | | Cold Plunge Bath | 1 | 365 | $0.55 | 0.11 | 35°F water for bathtub | #### Revenue $0/year | service category | revenue ($) | notes | | --------------------- | ----------- | ------------------------------------------- | | Cold plunge therapies | $0 | For community use only, no external revenue | | total | $0 | | #### Reliability Enhancement Features for Salvaged System 1. Redundant Systems: Multiple salvaged temperature sensors with averaging logic 2. Component Testing Protocol: Extra 30 hours in setup dedicated to thorough testing of all salvaged components 3. Modular Design: Quick-disconnect fittings to allow fast replacement of any failing components 4. Visual Inspection Ports: Clear sections of tubing and viewports for easy monitoring 5. Manual Backup Controls: Simple mechanical systems that can bypass electronic components if needed 6. Comprehensive Documentation: Detailed system map showing source of each component and likely failure points #### Sourcing Strategy 1. Community Outreach: Post specific needs to community bulletin boards and online groups 2. Restaurant Equipment Auctions: Source commercial-grade refrigeration components 3. Construction Site Partnerships: Arrange to collect insulation offcuts and excess materials 4. ReStore and Salvage Yards: Regular visits to find suitable components 5. Local Manufacturing Contacts: Collect food-grade containers from local food producers 6. Appliance Repair Shops: Obtain working parts from otherwise non-functional units