Partial Heat Recovery; Partial Heat Recovery Piping - 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:
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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
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.

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 below.
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Brazed plate heat exchanger
• Units 20-35 Tons have a single braze plate heat exchanger. Units 40-130 Tons 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
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.
CG-SVX17D-EN