Parameter Generation & Control PGC develops new freezer/cooler dual-room stability chamber

12-11-2020

Innovative System Maintains ICH specs of Two Rooms with Single Conditioner

This innovative system controls two stability rooms — the first one set at -20°C and the second at 5°C — with a single energy-efficient conditioner which maintains International Conference on Harmonisation (ICH) specifications for both rooms, even during a defrost cycle. The new system represents a marked technological advancement over the industry standard in several ways.

First, maintaining two rooms at two different temperatures typically requires two separate conditioners, one set for each temperature. Parameter’s system maintains two rooms at two different temperatures with only one conditioner. Second, most of -20°C rooms are chilled by a refrigeration coil hanging from inside the ceiling, with an internal fan circulating air. It’s generally not possible for an internal-coil system to run a defrost cycle and still keep the room within ICH specification.

Parameter’s system isolates the coil outside the room, so that heat needed for a defrost cycle doesn’t affect the room’s internal temperature as much as it would with an internal coil and, thus, ICH specification is maintained uninterruptedly. The third unique feature of the new system is that the defrost cycle is generated by an evaporator temperature figure — so that defrost is performed when actually needed, rather than according to a specific timer.

Another feature is the optional use of a second system for redundancy. With this option, the “off-duty” unit controls the space when a defrost cycle is generated. If one system goes offline, the other system will work independently until the first unit is restored to full operation. This further reduces the amplitude of the defrost spike experienced with a single conditioner, wherein the room may warm up 4°C.  The dual-unit arrangement reduces this by half while also providing redundancy.

Benefits of this system include:

  1. One conditioner to control two rooms at different conditions.
  2. Total redundancy if utilizing two conditioners.
  3. Cooling coil is located outside of conditioned space for enhanced uniformity and minimal disruption during defrost cycle.
  4. A “need for defrost” scheme that significantly increases the time between defrost cycles.
  5. Very low energy consumption with extremely close control at both -20°C and 5°C conditions.