Total Heat Recovery - Lennox NEOSYS NAC 200 Application Manual

TOTAL HEAT RECOVERY

Heat recovery is one of our solutions to decrease and offset energy
bills continually on the rise.
NEOSYS with Heat Recovery option operate as a standard chiller
as long as heat is not required or simultaneously produce chilled
and hot water which can be used for applications like preheating
of a boiler, heating or domestic hot water.
Heating or preheating in series with a boiler, the heat recovery
option enables to reduce :
- Purchase and installation cost : boiler is undersized.
- Operating cost : free hot water when unit produce chilled
water.
In series with an auxiliary heater , this option can also replace the
heater in low temperature heating systems.
A heat recovery chiller is suitable for all industrial process requiring
both chilled and hot water.
The LENNOX total heat recovery system on NEOSYS :
- Parallel assembly, stainless steel brazed plate heat exchanger
mounted in parallel to the air condensers maintain maximum
performance and effi ciency whatever the conditions : 100%
heat recovery in opposite of series assembly.
- Free hot water from 25 to 55°C
- Very Low refrigerant charge, no additional refrigerant charge
thanks to braze plate heat exchanger.
- High Total Energy Ratio values : TER (*)
- Standard Features factory mounted and tested:
• Stainless steel heat exchanger with control
• Paddle water fl ow switch
• Temperature hydraulic sensors
• Victaulic coupling
• 3 way valve ( 0-10V) for cold start
• On/Off pump control
• Antifreeze protection + insulation (in option)
(*) TER: Total Effi ciency Ratio is the total energy effi ciency of the units
when there is a production of chilled water and hot water simultaneously.
Cold water and hot water are valuated to the total power consumption
of the unit: TER = (cooling capacity + recovered heating capacity) / total
power consumption.
Total heat recovery : 100%
Free hot water up to 55°C
• 28 •
Air cooled condenser
Recovery condenser
Control principle:
The unit switches to recovery mode using a dry contact supplied
by the user and connected to the CLIMATIC. CLIMATIC controller
regulates the water leaving temperature of the recovery exchanger
using temperature probes included at inlet and outlet of the
exchanger. It offers the possibility of programming schedule one
or more setpoints.
Recovery capacity is entirely dependent of the cooling needs.
The capacity step is important due to two independent refrigerant
circuits and varies depending on the number of compressor ;
Unit with 4 compressors
Cooling capacity step
27%
53%
73%
100%
Unit with 6 compressors
Cooling capacity step
17%
33%
50%
67%
83%
100%
CLIMATIC provides a dry contact to control the on/off of the
pump(s). It also delivers a 0 -10V signal to control a 3-way valve
to avoid cold start if the inlet water temperature is too low ensuring
the correct operation of the unit. The use of a 3-way valve can
be avoided by using a variable speed pump. This solution allows
for greater control of the output temperature of water and thus to
reduce the power consumption of the pump.
Protection against lack of water fl ow is provided by a paddle fl ow
switch included in the option.
Electronic expansion valve
Application Guide / NEOSYS-AGU-1801-E
Heat recovery step
27%
27% or 53%
53% or 73%
53% or 100%
Heat recovery step
17%
17% or 33%
33% or 50%
33% or 67%
67% or 83%
50% or 100%
Scroll compressor
Evaporator