ReChill Systems · residential / prosumer sketch · page 1 of 3
Cold Room On A Pack.
Multi-zone walk-in · butcher cooler + cheese cave + chocolatier + deep freeze · runs a week off one Tesla pack
DOC. RC-SKETCH-007
2026-05-28
T. ELLSWORTH
JUST WONDERING
Same drivetrain that runs Marinovich's blast tunnel runs a serious home cold room. Different scale, same parts. Hover the toggle — what exists today vs what a single Tesla pack + a small commercial compressor + a 12×12×8 chamber gets you. Spoiler: it's not a fridge. It's a butcher's walk-in, cheese cave, chocolatier room, and deep freeze in one box, off-grid for a week.
AS ISSub-Zero kitchen + DIY walk-in · 2 zones · no battery
TO BEReChill multi-zone home walk-in · 4 zones · pack-powered · week off-grid
What you can buy todayBest current home options: a $30-50K Sub-Zero / Wolf integrated kitchen (single-zone fridge + single-zone freezer, grid-tied 24/7) plus maybe a chest freezer in the garage. Or a $25-40K custom walk-in builder (1-2 zones, no battery, no smart controls, runs on commercial HFC). Neither does serious meat aging, cheese caving, charcuterie, or chocolatier work properly.
What ReChill home is4-zone walk-in (deep freeze · standard freeze · cooler · aging chamber) running off one salvaged Tesla M3 LR pack + a single 3-5 HP variable-speed compressor + R-454B (HFO blend, low-GWP, residential-permitted). Pack provides 6-7 days of off-grid runtime. Variable speed means silent operation. Charges off-peak only.
Chamber Volume
~120 cu ft~400 cu ft
Sub-Zero · 2 zoneswalk-in · 4 zones
Refrigerant
R-600a + R-449AR-454B
two systems, two chargeslow-GWP · serviceable
Daily Draw
~5 kWh11.5 kWh
grid 24/7100% off-peak shifted
Off-Grid Runtime
0 hr6.5 days
grid down = food lost75 kWh on the pack
Why this exists at all
Same drivetrain that runs Marinovich's blast tunnel runs your home cold room.
The salvage Tesla pack is the same part. The variable-speed inverter is the same part. The
Bitzer / Copeland compressor is just a smaller version of the same one.
ReChill at industrial scale is the proof. ReChill at home is the kitchen application.
ReChill Systems · the technical landscape · page 2 of 3
Why isn't CO₂ already in your fridge?
The honest answer · six interlocking constraints · all solvable, none solved yet
DOC. RC-SKETCH-007
2026-05-28
T. ELLSWORTH
JUST WONDERING
The honest answer to 'why doesn't every fridge already use CO₂ if it's so good?' is a stack of six interlocking constraints. None of them are unsolvable, but together they've kept residential CO₂ off the market while supermarket transcritical CO₂ has taken over Europe and is scaling fast in NA. Here's the stack.
1 · Pressure
CO₂ transcritical runs at 90-120 bar (1,300-1,750 psi) on the high side. R-600a isobutane (what's in your fridge today) runs at 10-25 bar. The 8-10× pressure delta means thicker copper or steel tubing, higher-quality brazed joints, and ASME-rated pressure relief valves. Adds $300-600 to a $700 fridge BOM. Consumers don't see the value because their utility bill barely moves.
2 · No small CO₂ compressors
Bitzer / Dorin / Mayekawa make industrial CO₂ compressors starting at 5+ HP. The smallest commercial transcritical CO₂ compressors are for supermarket display cases — still 1-2 kW. A standard fridge needs 100-200 W. Embraco / Tecumseh / Danfoss have shown 1/4 HP transcritical CO₂ prototypes; nothing in mass production. Classic chicken-and-egg: no fridge maker will spec a part that isn't mass-produced; no compressor maker will tool up for a part that has no fridge maker behind it.
3 · R-600a already solved the GWP problem at this scale
Isobutane has GWP = 3. Slightly flammable (charge capped at 57g residential), but for the small charges in a fridge that's plenty. EU fridges have used it since the early 2000s, US since ~2016. The regulatory pressure that drove supermarkets to CO₂ doesn't exist at residential scale because R-600a is already there.
4 · No 100-bar residential service workforce
Every HVAC tech in the country can recover and recharge R-134a or R-600a. Almost zero residential techs are trained on 100-bar transcritical CO₂. When the consumer's fridge breaks at 9 PM on a Saturday, who fixes it? Service network is a hard infrastructure build that nobody's funded.
5 · Capacity loss in hot kitchens
Transcritical CO₂ efficiency drops 15-30% above 25°C ambient. Your kitchen in Phoenix in August is exactly that case. You can engineer around it — parallel compression, ejector, oversized gas cooler — but every fix adds cost. R-454B + variable-speed handles high-ambient cleanly and cheaply by comparison.
6 · Industrial CO₂ doesn't scale down gracefully
There's a complexity floor on transcritical: gas cooler, internal heat exchanger, expansion valve, oil management, parallel compression for hot ambient. You cannot build a $500 transcritical mini-system. The minimum viable rack is at small commercial scale ~$5-8K BOM. Below that, the economics break.
So what's the ReChill home answer? Not transcritical CO₂. Not at this scale, not yet. The practical R1 refrigerant for the home cold room is R-454B (HFO blend, 466 GWP, residential-permitted). Compressors at 1-5 HP are off-the-shelf from Copeland, Bristol, Bitzer Octagon. Service techs already work on R-454B because it's replacing R-410A in residential HVAC. The Tesla pack + variable-speed control + multi-zone capability is the differentiator — not the refrigerant choice. CO₂ stays the industrial story (Marinovich, Del Mar, Hilmar). The home product wins the kitchen on battery + variable-speed + multi-zone.
ReChill Systems · the math + the chamber · page 3 of 3
The kitchen budget. The chamber spec.
Home Cold Room · 4-zone walk-in · 75 kWh Tesla pack · R-454B variable-speed
DOC. RC-SKETCH-007
2026-05-28
T. ELLSWORTH
JUST WONDERING
Zone-by-zone breakdown
Zone
Setpoint
kWh/day
Deep freeze
50 cu ft · fish, hunting, batch cooking, ice cream base
-20°F
3.0
Standard freeze
100 cu ft · everyday frozen storage, stock, prepped meals
0°F
4.0
Cooler
200 cu ft · produce, dairy, plated mise-en-place, sauces
38°F
3.0
Aging chamber
50 cu ft · dry-age beef, cheese cave, charcuterie, sourdough
55°F @ 80%RH
1.0
Lights + controls + pack idle
0 cu ft · smart controls, LED lighting, BMS overhead
—
0.5
TOTAL DAILY DRAW75 kWh pack ÷ 11.5 kWh/day = 6.5 days off-grid per charge
—
11.5
Cost stack vs current options
Path
Capex
$/yr electric
Sub-Zero + Wolf integrated kitchen
2 zones · grid 24/7 · single-circuit refrigeration
$30-50K
~$700
Custom walk-in (commercial vendor)
1-2 zones · R-449A · grid 24/7 · no smart controls
$25-40K
~$1,100
ReChill home cold room4 zones · variable-speed · 75 kWh pack · 100% off-peak shifted · ~7 days off-grid runtime
$26-38K
~$250
How the math reads
Chamber size: 12 × 12 × 8 ft walk-in split into 4 zones via insulated partitions.
Total interior ~400 cu ft, similar to a small one-car garage. Fits along a basement wall, in a pantry
extension, or as a detached garden shed (zoning permitting).
Refrigeration: Single 3-5 HP variable-speed compressor (Copeland H-series or Bitzer
Octagon) feeds a primary glycol loop. Glycol routes to 4 evaporators, one per zone, each with its
own electronic expansion valve and zone thermostat. R-454B HFO blend (GWP 466 · residential-permitted
under EPA SNAP) keeps the engineering accessible and the service workforce existing.
Pack integration: Tesla M3 LR pack at 350V DC feeds the motor inverter directly. Pack
cycles charge during off-peak hours (typical PG&E E-TOU-C: midnight to 3 PM at $0.06-0.09/kWh) and
discharges during peak. Grid demand at the meter drops to zero during peak hours.
The line worth saying out loud
The serious home cook has no good option today. Sub-Zero is great at being a fridge. Custom walk-ins are great at being one big cold room. Neither is the multi-zone aging + deep-freeze + chocolatier kitchen that real cooking actually needs. ReChill home is that product, with a Tesla pack of off-grid runtime baked in as a feature, not an option.
Be brutal · the engineering work that's actually left
Custom-built. No off-the-shelf product exists yet. R-454B is the practical refrigerant at this scale (not CO₂ — see page 2 for why). Pack handling at residential requires either DC bus into the compressor inverter or DC-DC down to 240V split-phase. UL listing for residential pack is a real engineering bridge. Permitting varies by jurisdiction. None of this is hypothetical, but all of it has to be solved on the way to a productized SKU.