Low Temperature And Brine Solution Option (Option 6B) - United Technologies Carrier 30RQM 160 Installation, Operation And Maintenance Instructions

9 - MAIN COMPONENTS OF THE UNIT AND OPERATING CHARACTERISTICS
9.13 - Low temperature and brine solution
option (Option 6B)
Brine solution production from 0°C to -8°C is only possible with
the low-temperature brine solution option (6B).
The unit is equipped with insulation on the suction tubes. The
insulation is reinforced on the low-temperature brine solution
option.
The operating range depends on:
- the unit size,
- the glycol type,
- its concentration,
- the flow rate,
- the temperature of the glycol solution,
- the condensing pressure (ambient temperature).
9.13.1 - Frost protection
The low-pressure and frost protection thresholds of the evaporator
depend on the antifreeze level in the water loop.
The evaporator pinch (LWT – SST) and the antifreeze protection
threshold depend on this level.
It is therefore essential, when first activating the unit, to check the
antifreeze level in the loop (circulate for 30 minutes to ensure good
mixing homogeneity before sampling).
Refer to the manufacturer or supplier data to define the freezing
temperature according to the measured concentration level.
The minimum frost protection temperature must be entered in the
unit controller's parameters.
This value will be used to configure the following protection:
1. Evaporator antifreeze protection.
2. Low-pressure protection.
For information, for the different antifreezes used in our laboratory,
the protection values given by our supplier are as follows (these
values may change depending on the suppliers).
It is therefore recommended that a medium or low temperature
installation be commissioned by the manufacturer.
9.13.2 - Required glycol concentration
Ethylene and Propylene glycol freezing curve
Minimum frost protection temperature (°C)
Ethylene glycol (%)
Propylene glycol (%)
Minimum frost protection temperature based on the
leaving water temperature (example)
Leaving water temperature (°C)
For example, based on the above curves, if the ethylene glycol
mass concentration measured in the loop is 30%, the frost
protection temperature value of -14.8°C must be entered in the
software. This corresponds to a minimum leaving water
temperature of -6.7°C. The control point must be adjusted as a
result.
IMPORTANT:
- It is vital to perform a (minimum) annual inspection of
the glycol level and adjust the software's frost protection
based on the measured level.
- This procedure must be systematic when topping up
with water or antifreeze solution.
- Observe the minimum frost protection temperature
based on the leaving water temperature.
NOTE:
- In the case of frost protection of the unit by low air
temperature, the percentage of glycol must be evaluated
accordingly.
- The maximum glycol level in the case of units equipped
with a hydraulic module is 45%.
- In order to facilitate maintenance operations, it is
recommended to install isolation valves upstream and
downstream of the machine
43