What we do

Packaged units and split system options

we can accommodate any multitude of building configurations and can adapt to any existing conditions for retrofit applications or challenges relating to layout constraints. We have a robust list of standard options as well as
customized options.

Digital scroll compressors, used as lead compressor on both refrigeration circuits. All units have two independent refrigeration circuits with dual scrolls (three different capacities) on each circuit.

Different size scroll compressors provided smoother sequencing to match the dehumidification loads. Close temperature and RH control was achieved by changing temperature set points and increasing dehumidification loads as plants grow and flower. Highest efficiency was attained by matching compressor capacity (KW) to varying load conditions.

Minimal purge cycles (100% compressor operations) requiring less electric heat to maintain space temperature. Modulating hot gas reheat on both circuits – no electric reheat. Seamless transition of temperature and RH when lights are turned off and on every twelve hours. Digital scrolls are constant speed, therefore, no overspeed cycles required for low load oil return as required for VSD scrolls. Linear capacity modulation with high turndown – 100% down to 10% per digital scrolls.

Modulating parallel piped modulating hot gas reheat on both circuits

Only hot gas that is not needed for reheat is directed to the condenser which minimizes reduction of temperatures/pressures at low ambient below 35℉. Modulating Hot Gas Reheat (MHGR) on second circuit eliminates the need for electric reheat during high dehumidification loads during the second half of grow cycle.

Wind blowing through condensers with series piped hot gas reheat will depress refrigeration temperature/pressure causing trip outs. This configuration and design allows for unmatched humidity control to within 2% of setpoint.

Low ambient with modulating low ambient control valves

Modulating electronic low ambient control valves (LACS) were designed for both refrigeration circuits. This was critical for protecting the compressors. The LACS keep the compressors within their stable and safe operating envelope as recommended by Copeland under all conditions. Low ambient on both circuits assumes full dehumidification can be provided down to 0℉ ambient temperatures.

Simultaneous dehumidification and electric heating

The grow rooms cannot maintain temperature set points when plants are small (first four weeks) with the lights are off. Electric heat must be energized while unit in dehumidifying mode. During refrigerant purge cycles of 2-3 minutes every 2 hours…

(required for purging hot gas reheat coils), electric heat is energized to prevent downward spikes in space temperature and resulting increase in RH when compressors are full capacity. Variable Speed Drives (VSD) scrolls require more frequent scroll overspeed for purge cycles and during light load conditions for oil return.

Supply fan speed reset

Unit in constant volume until RH is above set point with compressors operating at 100% capacity. Supply Variable Frequency Drive (VFD) reduces airflow in 5% increments down to 29℉ suction low limit.

This lowers unit dew point temperature and maximizes the moisture removal capacity during the last two weeks of flower cycle. The growing cultivation phases: i. Mother/Veg ii. Flower iii. Dry iv. Each phase requires an HVACD unit which is designed and selected for the specific conditions and usage. URBAN FARMS will offer a full range of cultivation units designed, controlled and monitored to meet the grower requirements.

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