Schreiber Chillers 15MEDAC_GEN2 - Manual (Page 9)

Chiller Specifications:
Refrigeration:
The 15MEDGEN2 uses a unique modular refrigeration system. Each refrigeration circuit
is mounted on an independent refrigeration “skid” that can be removed from the chiller
while the other refrigeration system is still running. This allows for an entire
refrigeration system (except the condenser) to be replaced in one piece, while the
chiller is still servicing the MR equipment. The chiller includes two (2) independent
equal capacity refrigeration systems. Each system performs a nominal seven and a half
(7.5) ton of cooling, as the combination of two systems will provides a nominal 15-ton
capacity at rated condition. During idle condition the MR system will generate a small
amount of heat loading to the chiller that causes the water temperature to increase.
Because of the large reservoir and low flow rate in the system, the temperature in the
reservoir raise slowly to the set point. At this moment, compressor #1 will activate.
Compressor#2 will only activate under two conditions:
1. The return temperature is higher than the supply temperature by TEMP RISE
set point.
2. The supply temperature is higher than the sum of the set point and TEMP
RISE set point, regardless of the return temperature.
This will result in a more constant temperature to the MR system and quick reaction
cooling when MR is in used for scanning.
Each skid includes:
• Hermetically sealed scroll compressor with rota-lock service valves and access
ports.
• 316L stainless steel brazed plate evaporator
• Balanced port, externally equalized expansion valve
• Liquid line/suction line heat exchanger
• Liquid line filter drier, Sight Glass, Liquid line solenoid valve
• Liquid Receiver (permanently mounted to chiller)
• Manually Reset High pressure switch
• Automatic Reset Low Pressure switch
• Head Pressure - pressure transducer
• Quick connector for all signal connections.
• Discharge and Return temperatures for each loop
Condenser System
The 15MEDGEN2 chiller utilizes two equal independent circuit condensers; Each
condenser circuit performs 9-ton of heat rejection. They are mounted on a module that
is sits above the refrigeration system. This allows for cool incoming air to be brought
across the refrigeration system during operation. In addition, this provides cooling
effect to the internal components of the chiller while the system is running.