Can variable refrigerant flow outdoor units be combined

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Discussion Overview

The discussion revolves around the feasibility of combining variable refrigerant flow (VRF) outdoor units to achieve larger cooling loads than those specified by manufacturers. Participants explore the implications of combining modules, energy efficiency considerations, and the control of refrigerant flow to indoor units.

Discussion Character

  • Debate/contested, Technical explanation

Main Points Raised

  • Some participants inquire whether designers can combine outdoor units beyond the pre-combined configurations provided by manufacturers to achieve greater loads.
  • One participant discusses the energy savings associated with modulating compressor units in response to varying air conditioning loads, suggesting that operating fewer units at lower capacity can be more efficient.
  • Another participant expresses confusion about the proposed combination of single module units and seeks clarification on how this would affect maximum load and refrigerant flow control.
  • A participant asserts that combining outdoor units is not feasible due to each unit having its own compressor and condenser, questioning the practicality of such an approach.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the possibility of freely combining outdoor units, with some arguing against it while others seek clarification on the concept.

Contextual Notes

Limitations include the lack of clarity on the technical specifications and operational constraints of combining different outdoor units, as well as the dependence on manufacturer guidelines.

tj00343
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Hey,
I noticed that some manufacturers have provided data for pre-combined (2 or 3 modules) to achieve higher loads (limited to about 60 refrigeration tons).I was wondering if a designer could combine modules to achieve a greater even larger(different) loads or am i limited to the combinations provided by the manufacturer.
Thank You
 
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The modulation of compressor units outdoors you mentioned is for the purpose of energy savings. This is typical to establishment which air conditioning loads frequently varies in a day period.
Imagine if there is a central air conditioning system which is designed to cater maximum load say 100%, then the actual demand due to the deviation of use is just 10%? It is a waste of energy to let the unit operates in such condition. Compare it to, let say, 3 units, each capable only of delivering 33% only of the total maximum load. It would be a saving only running (1) 33% unit, and the (2) others are turned off,do you agree?
 
Last edited:
Legolaz said:
The modulation of compressor units outdoors you mentioned is for the purpose of energy savings. This is typical to establishment which air conditioning loads frequently varies in a day period.
Imagine if there is a central air conditioning system which is designed to cater maximum load say 100%, then the actual demand due to the deviation of use is just 10%? It is a waste of energy to let the unit operates in such condition. Compare it to, let say, 3 units, each capable only of delivering 33% only of the total maximum load. It would be a saving only running (1) 33% unit, and the (2) others are turned off,do you agree?

Yes I understand ,however I was wondering if I could combine and modulate single module units as i see fit , and if i can ,what would limit the maximum load and how refrigerant flow to indoor units would be controlled.
 
tj00343 said:
Yes I understand ,however I was wondering if I could combine and modulate single module units as i see fit , and if i can ,what would limit the maximum load and how refrigerant flow to indoor units would be controlled.
I'm sorry, I can not digest what you intend to do, could you please, elaborate further.
 
Legolaz said:
I'm sorry, I can not digest what you intend to do, could you please, elaborate further.
I'm just wondering if outdoor units can be freely combined.
 
Nope you can't freely combine, there is no sense because each has its own compressor and condenser set and why even bother to. It's an additional work, you know.
 
Last edited:

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