Project Status: IN-PROGRESS 🛠️
Location: Northeast US (Basement Environment: 74°F / 23°C)
This project converts a decommissioned freezer unit (18"D×23"W) into a high-efficiency, active-chilled storage unit. It leverages the Latent Heat of Fusion of water to maintain a stable 34°F–38°F (1°C–3°C) environment, specifically optimized for high-humidity produce and beverage storage.
The unit is positioned horizontally (lying on its back/side) to maximize top-access and maintain thermal stratification.
- Thermal Sink (Bottom 6"):
- Contains ~60 lbs of ice/water mix.
- Acts as a 32°F (0°C) ballast for constant temperature reference.
- Air Gap (1"):
- Prevents direct conduction between the ice and stored goods.
- Reduces the risk of "freezer burn" on sensitive produce.
- Grid Shelf (Support):
- A stainless or high-grade plastic grid installed at the 7" height mark.
- Provides a level surface for crates and containers while allowing free air circulation.
- Active Air Handler:
- 12V DC Pump + 1/4" Copper Coil + 120mm PWM Computer Fan assembly.
- Mounted above the thermal sink to circulate chilled air.
- Insulation: 5–8 cm High-density Polyurethane (built into the freezer hull).
- Ice Requirement: ~3x 20 lb bags for the initial pull-down.
- Replenishment: ~14 lbs every 48–72 hours (dependent on fan duty cycle and ambient heat load).
- Internal RH: 85%–95% (Ideal for leafy greens and root vegetables).
To audit the insulation quality and monitor degradation, use the melt-water measurement method:
Q=tm⋅334
Where:
- m = mass of melted water (kg).
- 334 = Latent heat of fusion for water (kJ/kg).
- t = time interval (seconds).
- Result (Q) is in Watts.
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