Maintenance Resources

Tuesday, December 8, 2009

Hot Water from Heat recovered from Air conditioner and chiller

Saving energy is on air. Awareness is increasing on global warming. Every body, as individual or as corporate are trying to contribute to save energy to stop global warming.

Saves 1 KWH in consumer end is equal to saves 2 KWH in generating end. So, if you save 1 KWH at your home or industry, you are contributing to save natural resource depletion and stopping generating of green house gases by saving Coal or gas which require to produce 2 KWH (Including line loss).

Here is an idea to recover heat from split unit ACs compressor , compressors of chillers. By which

1.      @ 4 Liter per minute flow, water can be heat up to 65 to 90 degree .
2.      Electricity consumed by compressor is reduced by around 15% due to better cooling.
3.      Compressor load reduced and so life increase.
4.      Saving in LPG require for water heating
5.      Savings in KWH require for water heating and AC consumption also got reduced
6.      Maximum payback period is 6 month to 1 year according to size.
Bellow is the normal operation of a Air conditioner system.

The compressor “sucks” the refrigerant from point 4 through tubing in the evaporator
Coil. This action causes the liquid refrigerant to “evaporate” and become cold (≈45ºF).
The evaporating refrigerant inside the tubes cools the air being circulated over the outside
Of the tubes and fins by the indoor fan.
• In order to move the refrigerant from point 1 to point 2, it must be raised to a higher
Pressure by the “compressor”. The compressing causes the refrigerant to become hot (a
similar effect occurs with an air compressor and this can be verified by quickly and
carefully touching the discharge line).
• The hot refrigerant is sent through the tubing inside the condenser. Outdoor air circulated
by the fan cools the refrigerant and causes it to return to a liquid (condense). Even
though the air may be warm (80-100ºF) it is cooler than the hot refrigerant (100-160ºF).
In some cases, water can be used to cool the hot refrigerant if higher efficiency is needed.
• The warm liquid leaving the condenser (point 3) passes through an expansion device
which lowers the refrigerant pressure before it returns to point 4 to repeat the cycle.
Now The modification:

The potential source of heat to be reclaimed comes from the refrigerant leaving the compressor [3]. In the original design of a conventional air conditioning system, the copper tube containing the superheated refrigerant from the compressor is diverted directly into the condenser coil for heat removal. In order to reclaim the potential heat source from the superheated refrigerant, modification need to be done on the rotary compressor of the air condition unit.

This circuit is replaced by plate type heat exchanger in place of condenser.