Partial Heat Recovery - Trane CGAM Installation & Operation Manual

Installation - Mechanical

Partial Heat Recovery

The partial heat recovery is comprised of an auxiliary heat
exchanger installed in the discharge line between the
compressor and the air -cooled condenser.The heat
exchanger cools compressor discharge gas and rejects the
energy to a separate water loop for hot water applications.
The chiller can simultaneously produce chilled and hot
water.
The heating capacity is driven by the cooling demand on
the chiller, the condensing temperature and the flow rate
through the heat exchanger.
The partial heat recovery includes:
• Brazed plate heat exchanger
• Units 20-35Tons have a single braze plate heat
exchanger. Units 40-130Tons have two braze plate
heat exchangers in parallel arrangement.
• Piping between the heat exchanger(s)
• Insulation of the heat exchanger(s) and water pipe
• Two temperature sensors to read the inlet/outlet hot
water temperature information on the unit control
display
• Heater on partial heat recovery heat exchanger(s) and
water pipe
• Manual air vent
• Drain pipe
Water circulating inside the heat recovery heat exchanger
should never be used for drinking water, it must be used
through an indirect loop to heat or preheat hot water.
Important: The installation must comply with the rules
and legislation applicable at the jobsite
location regarding the use of drinkable
water.The use of the water circulating in the
heat recovery exchanger as drinkable water
is not recommended. An intermediate heat
exchanger should be used.
The partial heat recovery pump must run at least three
minutes after the partial heat recovery fan control is
disabled. During the three minutes, water flow through the
brazed plate heat exchanger will gradually be reduced and
the unit can be switched to conventional cooling mode
without partial heat recovery fan control.
NOTICE:
Equipment Damage!
If the partial heat recovery heat exchanger is drained
the heater must be turned off to avoid damaging the
partial heater recovery heat exchanger. The heater
should only be on when the heat recovery heat
exchanger has water in it.
54
Partial Heat Recovery Piping
A field installed safety or relief valve on the water side is
required with the partial heat recovery to prevent risks
resulting from a failure of the thermostat.
A 16 mesh strainer must be installed close to the partial
heat recovery heat exchanger entering water line to
protect the heat exchanger.
The partial heat recovery water temperature should be
controlled via an external devise such as a 3-way valve or
variable speed pump. In addition, a water tank and
additional heater is suggested in the partial heat recovery
loop.
Insulate water lines and other portions of the heat recovery
water loop to prevent heat loss and potential injury due
exposure to a hot surface.
For recommended partial heat recovery piping see
Figure 56, p. 55.
NOTICE:
Proper Water Treatment!
The use of untreated or improperly treated water could
result in scaling, erosion, corrosion, algae or slime. It is
recommended that the services of a qualified water
treatment specialist be engaged to determine what
water treatment, if any, is required. Trane assumes no
responsibility for equipment failures which result from
untreated or improperly treated water, or saline or
brackish water.
NOTICE:
Equipment Damage!
Do not use untreated or improperly treated water in the
heat recovery water loop since it will cause inefficient
operation and potential damage to the unit such as:
reduced heat transfer between water and refrigerant,
increased water pressure drop and reduced water flow.
CG-SVX17E-EN