What design factors decides power comsumption

Hi,
What are the factors from the design of a refrigerator that determine its power consumption. I have 2 fridges of 280L capacity (both are frost free, top-freezer models). They are very similar to each other in terms of construction like their volumes, circuitry for run cycle and defrost etc. I also think their compressors are built by the same outsourcing vendor. But I do find that the energy consumption is different between the two of them (I can say that as they are plugged them to different energy meters) even when we I have let them closed for a long period of time (i.e no loss of coldness when opening the doors).

Some of the factors that I can think of are
1. Build quality (to ensure least heat leakage)
2. Quality of parts (but this doesnt affect when the critical ones are sourced from the same OEM parts vendor. May be it does, as the same vendor may follow different quality norms for different batches of supplies. To a large extent I think not.)
3. Type of evaporator coil (are there such things as type where the area, the number of fins etc play a role) (design time consideration)
4. Path of air circulation within fridge (design time consideration).
5. Thermostat sensitivity.
6. Amount of refrigerant in the system (design time consideration).

What else? Is my thinking right?
What are the factors beyond (post) design that can improve the efficiency of fridges?

Any thoughts are welcome.
-KLN

Quote:

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Originally Posted by kln

Hi,
What are the factors from the design of a refrigerator that determine its power consumption. I have 2 fridges of 280L capacity (both are frost free, top-freezer models). They are very similar to each other in terms of construction like their volumes, circuitry for run cycle and defrost etc. I also think their compressors are built by the same outsourcing vendor. But I do find that the energy consumption is different between the two of them (I can say that as they are plugged them to different energy meters) even when we I have let them closed for a long period of time (i.e no loss of coldness when opening the doors).

Some of the factors that I can think of are
1. Build quality (to ensure least heat leakage)
2. Quality of parts (but this doesnt affect when the critical ones are sourced from the same OEM parts vendor. May be it does, as the same vendor may follow different quality norms for different batches of supplies. To a large extent I think not.)
3. Type of evaporator coil (are there such things as type where the area, the number of fins etc play a role) (design time consideration)
4. Path of air circulation within fridge (design time consideration).
5. Thermostat sensitivity.
6. Amount of refrigerant in the system (design time consideration).

What else? Is my thinking right?
What are the factors beyond (post) design that can improve the efficiency of fridges?

Any thoughts are welcome.
-KLN

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Everything above and more:
Energy efficiency ratio of fridge.
Isolation quality.
Conditions in surrounding.
Quality and condition of door seals.
Amount and state of introduced goods.
Packing of goods.
Number and duration of door openings.
State of heat exchangers (considering cleaning and defrosting).
Etc.........

Any difference in the compressor may make a difference.

The actual construction of the machine even with identical components may be different. Same insulation but not fitted correctly perhaps?

Slight difference in piping causing different run times etc.

Type of refrigerant. Some refrigerants transport the heat/cold better than others.