u/Joe84mobil

Hey everyone, I’m looking for input from anyone with experience repurposing commercial walk-in freezers for cannabis cultivation.
We’re evaluating a retrofit of an existing insulated freezer space into a flower room rather than building a traditional HVAC system from scratch. The idea is to operate the room around 60–75°F with tight humidity control, using the existing refrigeration infrastructure where possible.
I’m especially interested in hearing from anyone who has:
Successfully converted a freezer into a flower room.
Retrofitted existing condensing units or evaporators instead of replacing everything.
Integrated dehumidifiers with the refrigeration system.
Learned any lessons about defrost cycles, airflow, coil sizing, controls, or maintaining stable VPD.
If you’ve done something similar, I’d appreciate hearing what worked, what didn’t, and anything you’d do differently. Photos, build threads, or engineering resources would also be greatly appreciated.
Thanks in advance!

Repurposing an insulated panel walk-in as a climate-controlled room with a big steady-state heat load. Deciding whether to convert the existing low-temp refrigeration up to med-temp or scrap it for purpose-built cooling. Want a gut-check from anyone who’s done LT→MT on old iron.
Load: ~1,900 sq ft, well-sealed. Setpoint 65–75°F. ~20 tons continuous, essentially all-sensible/high-SHR (latent handled by separate standalone dehumidification, which also dumps ~25–30k BTU/hr reheat back in). Not a pulldown app — near-constant max load.
Equipment (all LT, 0°F design, ’88–’92):
3× Krack KPO-14-7-L5 — orig R-502, ~32 RLA / 161 LRA, 230/3

1× Superior D52AL-600-3 — R-404A, 28.8 RLA, 208-230/3

Krack SSX unit coolers, electric defrost, wide-fin LT geometry

Proposed: TXV swap, reset superheat, new temp/pressure controls, kill defrost heaters (off-cycle at MT), hot-gas bypass. Tech pegged 5–7 tons/unit (~20–28 total).
Reality check:
Compressor envelope — MT suction fattens the gas and drives mass flow up. Do these LT-sized motors sit past RLA on continuous 100% duty? Is this really a compressor swap, and are these bodies worth it?

Condenser split — sized for LT rejection. Does head pressure climb and walk the 5–7 back? Is the condenser the real ceiling before the compressor?

HGB — I read it as an unloading/false-load device for part-load stability, not added capacity. On a load already pinned near max, do I even need it?

The 5–7 — MT delivered at box conditions (~45–50°F SST, 65–70°F room), or nominal?

R-502 — realistic retrofit path, and worth it on 35-yr bodies vs. new?

Redundancy — all four pinned = one down cooks the room. Anyone run staged old condensing units at continuous near-max long-term without accelerating failures?

Not married to saving these — if the answer is “won’t hold MT capacity continuously,” better to hear it now. Nameplate pics attached.

Has anyone converted a walk-in freezer into a commercial flower room?

Low-temp → med-temp conversion on 4 aging Krack/Superior condensing units to cover a ~20-ton continuous load — where does it fall apart, motor amps or condenser split?